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SELENIUM

1. CHEMICAL IDENTITY

Common name: Selenium

CAS no: 7782-49-2

Mol. formula: 34Se

Atomic Weight: 78.971 (average mass of the atom)

Chemical class: Non-metal trace element

2. EXISTING EVALUATIONS AND REGULATORY INFORMATION

- Selenium is pre-registered under REACH

(http://echa.europa.eu/substance-information/-/substanceinfo/100.029.052)

- Due to uncertainties inherent in the scientific database, the World Health Organization suggests a

provisional guideline value of 40 µg/L for selenium in drinking water (WHO, 2011).

- The European Union (EU) and a few other countries, including several member states, recommend a

drinking water limit of 10 µg/L for selenium (Ireland Environmental Protection Agency, 2011; Northern

Ireland Environment Agency, 2011; Gdańsk University of Technology, 2006; The European Council,

1998; Union of India, 1993; Australian Government, 2011).

- The U.S. EPA set a drinking water limit of 50 μg/L (United States Environmental Protection Agency,

2012).

- Under the EU Cosmetics Regulations, all selenium compounds with the exception of selenium sulfide

are banned from all cosmetic products. Selenium sulfide can be used in anti-dandruff shampoos in

concentrations of less than 1% by weight, and must be labelled (The European Parliament and the

Council, 2009).

- Selenium can be found on the list of vitamins and minerals that can be added to foods, including food

supplements (COMMISSION REGULATION (EC) No 1170/2009 amending Directive 2002/46/EC of the

European Parliament and of Council and Regulation (EC) No 1925/2006 of the European Parliament)

- The selenomethionine has been approved as an effective source of selenium for all animal species

(COMMISSION IMPLEMENTING REGULATION (EU) No 427/2013)

- The United Kingdom set a daily upper intake level of 450 µg, with 350 µg allowed from dietary

supplements (Expert Group on Vitamins and Minerals, 2003)

- In 2013, the U.S. FDA announced a proposed rule to add selenium to the list of required nutrients for

infant formulas, and to establish both minimum and maximum levels of selenium in infant formulas

(United States Food and Drug Administration, 2013)

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- The U.S. FDA permits the use of selenium yeast in chicken, turkey, swine, beef cattle, and dairy cattle

feed at levels not exceeding 0.3 ppm of added selenium (United States Food and Drug Administration,

2013)

- The U.S. EPA has fish consumption screening values for selenium of 20 µg Se/g (w/w) for recreational

fishers and 2.5 µg Se/g (w/w) for subsistence fishers (United States Environmental Protection Agency,

2000).

- Australia and New Zealand have developed a joint guideline for fresh and marine water quality with a

trigger value of 11 µg/L (total selenium) for the protection of 95% of freshwater species. These

guidelines are currently under review (Agriculture and Resource Management Council of Australia and

New Zealand and the Australian and New Zealand Environment and Conservation Council, 2000).

- South Africa established a chronic effect value of 5 µg/L for the toxic effects of selenium on aquatic

organisms (Department of Water Affairs and Forestry, 1996).

- India's standard for the maximum selenium concentration in all industrial effluents to surface waters,

marine and coastal areas, and to public sewers is 50 µg/L (Union of India, 1993).

- In Canada, most provincial and territorial guidelines on selenium refer to the CCME water quality

guidelines, which recommend 1μg/L for freshwater, 20μg/L for continuous irrigation, 50μg/L for

intermittent irrigation, and 50μg/L for livestock feed water (Canadian Council of Ministers of the

Environment, 2009). British Columbia is a notable exception. In 2014, the British Columbia Ministry of

the Environment published its updated water quality guidelines for selenium. The updated guidelines

provide fresh and marine water quality guidelines (2 µg/L), whole-body fish tissue guidelines (4µg/g,

dry weight), fish egg/ovary guidelines (11 µg/g, dw), and muscle tissue guidelines (4 µg/g, dry weight)

(British Columbia Ministry of Environment, 2014).

- The U.S. EPA published, for public consultation, a draft updated national recommended chronic

aquatic life criterion for selenium. The proposed limits for chronic exposure are: 15.2 mg/kg dry

weight in fish eggs or ovaries, 8.1 mg/kg dry weight in fish whole-body, 11.8 mg/kg dry weight in fish

muscle, 1.3 μg/L in lentic aquatic systems, and 4.8 μg/L in lotic aquatic systems (United States

Environmental Protection Agency, 2014). It should be noted that the U.S. EPA considers selenium to

be a bioaccumulative substance.

- The Government of Canada is considering measures to reduce anthropogenic releases of selenium to

water (all forms of selenium found in the environment: 29 selenium-containing substances identified

in the Selenium-containing Substance Grouping), from the following sectors to address ecological

concerns: Metal mining and coal mining, Base metals smelting and refining, Power generation and

Agriculture (Risk Management Scope for Selenium and its Compounds under the Selenium-containing

Substance Grouping. Environment Canada, Health Canada)

(http://www.ec.gc.ca/ese-ees/default.asp?lang=En&n=12443637-1)

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3. PROPOSED QUALITY STANDARDS (QS)

CAS number

Substance name Type MS Value (μg/L) Reference

7440-61-1 Selenium AA-EQS NL 0.05 RBSP (NL)

EQS RO 0.07 RBSP-ECOSTAT, UBA (2014)

EQS ES 1 RBSP-ECOSTAT, UBA (2014)

EQS BE 2 RBSP-ECOSTAT, UBA (2014)

EQS CZ 2 RBSP-ECOSTAT, UBA (2014)

EQS DE 2.5 RBSP-ECOSTAT, UBA (2014)

EQS LU 2.9 RBSP-ECOSTAT, UBA (2014)

EQS AT 5.3 RBSP-ECOSTAT, UBA (2014)

EQS SI 6 RBSP-ECOSTAT, UBA (2014)

EQS PL 20 RBSP-ECOSTAT, UBA (2014)

PNEC ECHA 2.67 ECHA DOSSIER

PNEC INERIS 0.88 SSD with all available valid

data, mainly from the ECOTOX US EPA

The PNEC we selected for the STE run was a value of 0.05 µg/L, proposed as an AA-QSfreshwater for the

Netherlands.

We received several comments concerning the appropriateness of the PNEC value for STE run.

Eurometaux considers a PNEC value reported in ECHA dossier (2.67 µg/L) more reasonable due to the most

comprehensive and robust data set used in the analysis, to the reliability of the derivation process, and the

typical natural background concentration of Se in fresh surface water (0.32 µg Se/L)

REACH Selenium & Tellurium Consortium commented the STE SCORES for selenium (22 March 2016): The

combination of the selected PNEC value with the monitoring data (95th percentile) leads to the “very high”

score for selenium in the 2nd review. This is not surprising, since the PNEC of 0.05 μg/L is factor 6 below

median baseline concentration of 0.32 μg Se/l and thus even samples from non-industrial and unaffected

areas contribute to the ranking. It is, however, questionable, if this approach provides a realistic scoring of

suspected risks as a basis for adequate and successful risk management.

The experts from Germany commented that the PNEC 0.05 µg/L is too low compared with background concentration of selenium in water for the Netherlands (= 0.2 µg/L; Osté, 2013).

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JRC notes:

NL RIVM already presented risk limits for selenium in 2005 (Van Vlaardingen et al. 2005).

Since chronic toxicity data were available for 8 taxonomic groups and for 36 species, the QS was derived using

statistical extrapolation (Species sensitivity distribution of chronic selenium toxicity to aquatic organisms;

QS=2.1 µg/L with AF=2).

The same SSD approach was used to calculate the PNEC value as proposed by INERIS, however with higher AF

(AF=5 and therefore PNECwater = 0.88 µg/L) (INERIS 2011).

The SSD approach was also used to derive the QS proposed by Germany (2.5 µg Se/L; AF=2) (Nendza 2003).

In 2007, a new European guidance for the derivation of environmental risk limits was implemented in the Netherlands, following the Water Framework Directive. This new methodology was used in the derivation of the most recently proposed NL EQS value of 0.05 µg/L, which is not based on the direct ecotoxicity but on secondary poisoning (QSwater, secpois). Therefore, the added risk approach does not apply here (the natural background concentration (Cb) is not added to the standard. As consequence, the QS value may be lower than Cb).

Detailed information about how this value was derived can be found in RIVM Report (van Vlaardingen and

Verbruggen, 2009: http://www.rivm.nl/bibliotheek/rapporten/601714011.pdf).

It should be noted, that there are strong indications that poisoning (via secondary poisoning and human fish consumption) is considered to be very relevant for selenium (Hilton 1980; Hamilton 2004; Lemly 2004; Lenz and Lens 2009; Luoma 2009; Sappington 2002). Consequently, the United States Environmental Protection Agency has proposed tissue concentration based chronic criterion values as a more appropriate measure for ecotoxicological risk compared to waterborne concentration based values (US EPA, 2008). This effort has however been put on hold due to differences of opinion on the appropriate selenium concentration for a national tissue-based criterion.

JRC recognizes the need to refine the PNEC/EQS values for all the substances which scored high in the STE

exercise; therefore, for the sake of comparison, we performed additional STE runs considering the EQS from

DE (2.5 µg/L) and INERIS (0.88 µg/L). The results are presented in this document, under section 6 (MEASURED

ENVIRONMENTAL CONCENTRATIONS).

We would like to invite the experts to share their recommendations for the most appropriate PNEC value.

At the 6th meeting of the SG-R, it has been concluded that QS for biota should be derived. JRC agreed to

draft a dossier for selenium.

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4. MAJOR USES

This substance is manufactured and/or imported in the European Economic Area in 1 000 - 10 000 tonnes per

year.

This substance is used in the following products: coating products and laboratory chemicals.

This substance is used for the manufacture of: chemicals.

Release to the environment of this substance is likely to occur from industrial use: as processing aid, industrial

abrasion processing with low release rate (e.g. cutting of textile, cutting, machining or grinding of metal), in

the production of articles, manufacturing of the substance, formulation in materials and as an intermediate

step in further manufacturing of another substance (use of intermediates). Other release to the environment

of this substance is likely to occur from: outdoor use in long-life materials with low release rate (e.g. metal,

wooden and plastic construction and building materials) and indoor use in long-life materials with low release

rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and

cardboard products, electronic equipment).

This substance can be found in complex articles, with no release intended: machinery, mechanical appliances

and electrical/electronic products (e.g. computers, cameras, lamps, refrigerators, washing machines) and

electrical batteries and accumulators. This substance can be found in products with material based on: metal

(e.g. cutlery, pots, toys, jewellery).

(http://echa.europa.eu/substance-information/-/substanceinfo/100.029.052)

Selenium is a naturally occurring, solid substance that is widely but unevenly distributed in the earth's crust;

commonly found in rocks and soil. Selenium is found in metal sulfide ores, where it partially replaces the

sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during

production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial

uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.

Applications in electronics, once important, have been mostly supplanted by silicon semiconductor devices.

Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot.

(https://en.wikipedia.org/wiki/Selenium)

Coal combustion and crude oil processing are human activities causing environmental input of Se. Other input

sources of Se input are sulphide ore mining and erosion of seliniferous rocks or soils. The copper refining

industry is a source of selenium, which is further processed a.o. in pigments (used in plastics, paints, enamels,

inks, rubber), glass, anti-dandruff shampoos and fungicides (Van Vlaardingen et al. 2005).

About 2,000 tonnes of selenium were produced in 2011 worldwide, mostly in Germany (650 t), Japan (630 t),

Belgium (200 t), and Russia (140 t), and the total reserves were estimated at 93,000 tonnes. These data

exclude two major producers, the United States and China (Selenium and Tellurium: Statistics and

Information. United States Geological Survey).

There is a likelihood that Se issues will grow in the years ahead with the exploitation of coal and similar fossil fuels, irrigation in semiarid regions, and mining of phosphate ore (Presser et al., 2004).

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5. ENVIRONMENTAL BEHAVIOUR AND EFFECTS

Selenium is a natural element and therefore naturally present in all environmental compartments. According

to FOREGS, median background concentrations in waters is 0.34 μg Se/L.

General occurrence of selenium appears ubiquitous, but is unevenly distributed: regions with very low or very

high natural levels (seliniferous areas) can be identified.

Selenium salts are toxic in large amounts, but trace amounts are necessary for cellular function in many

organisms, including all animals. Selenium is an ingredient in many multivitamins and other dietary

supplements, including infant formula. It is a component of the antioxidant enzymes glutathione

peroxidase and thioredoxin reductase (which indirectly reduce certain oxidized molecules in animals and some

plants). It is also found in three deiodinase enzymes, which convert one thyroid hormone to another. Selenium

requirements in plants differ by species. (https://en.wikipedia.org/wiki/Selenium)

The primary manifestations of selenium toxicity are due to a simple but important flaw in the process of

protein synthesis. Sulfur is a key component of proteins, and sulfur-to-sulfur linkages (ionic disulfide bonds)

between strands of amino acids are necessary for protein molecules to coil into their tertiary (helix) structure

which, in turn, is necessary for proper functioning of proteins, either as components of cellular structure

(tissue synthesis) or as enzymes in cellular metabolism.

Selenium is similar to sulfur with regard to its basic chemical and physical properties (has same valence states

and forms analogs of hydrogen sulfide, thiosulfate, sulfite, and sulfate), and mammalian studies show that

cells do not discriminate well between the two as proteins are being synthesized (it is assumed that the

mechanistic features underlying toxicity are essentially the same for fish, since the resulting pathology and

teratogenic features are the same). When present in excessive amounts, selenium is erroneously substituted

for sulfur, resulting in the formation of a triselenium linkage or a selenotrisulfide linkage, either of which

prevent the formation of the necessary disulfide chemical bonds. The end result is distorted, dysfunctional

enzymes and protein molecules, which impairs normal cellular biochemistry (Lemly, 2002).

Luoma 2009: Uncertainties in protective criteria for Se derive from a failure to systematically link

biogeochemistry to trophic transfer and toxicity (Figure 1). In nature, adverse effects from Se are determined

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by a sequence of processes. Dilution and redistribution in a water body determine the concentrations that

result from mass inputs. Speciation affects transformation from dissolved forms to living organisms (e.g.,

algae, microbes) and nonliving particulate material at the base of the food webs. The concentration at the

base of the food web determines how much of the contaminant is taken up by animals at the lower trophic

levels. Transfer through food webs determines exposure of higher trophic level animals such as fish and birds.

The degree of internal exposure in these organisms determines whether toxicity is manifested in individuals.

Se is first and foremost a reproductive toxicant (both a gonadotoxicant and a teratogen): the degree of

reproductive damage determines whether populations are adversely affected. Adverse effects on

reproduction usually occur at lower levels of exposure than acute mortality, but such effects can extirpate a

population just as effectively as mortality in adults.

FIGURE 1. Conceptual model of Se fate and effects emphasizing the roles of speciation, biogeochemical transformation, and trophic transfer factors in modeling two aquatic food webs: a water column food web and a benthic food web. TTF) trophic transfer factor. Subscript ‘d’ means dissolved, subscript ‘p’ means particulate (Luoma, 2009).

According to the harmonised classification and labelling approved by the European Union, this substance is

toxic if swallowed, is toxic if inhaled, may cause damage to organs through prolonged or repeated exposure

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and may cause long lasting harmful effects to aquatic life. http://echa.europa.eu/brief-profile/-

/briefprofile/100.029.052

Chronic toxicity data for selenium were found for bacteria, cyanobacteria, protozoa, algae, macrophytes,

crustaceans, insects and fish.

Once in the aquatic environment, selenium it can rapidly attain levels that are toxic to fish and wildlife

because of bioaccumulation in food chains and resultant dietary exposure. This rapid bioaccumulation causes

the response curve for selenium poisoning to be very steep. For example, a transition from no effect to

complete reproductive failure in fish can occur within a range of only a few µg/L waterborne selenium. Thus,

activities that cause even slight increases in the water concentration of selenium pose a major ecological risk

(Lemly, 2004).

Accordingly, selenium concentrations in the tissues of lower invertebrates or fish can reach concentrations up

to 2000 times the selenium water concentration. It has been shown that adverse effects on fish can arise at a

waterborne selenium concentration of 5 μg/L, but do not necessarily occur at higher concentrations. The

review of selenium toxicity in the aquatic food chain by Hamilton (2004) covers aspects of selenium toxicity in

the aquatic food chain such as the emerging selenium contamination, selenium interactions with other

elements linked with delayed mortality in fish, inconsistent effects of selenium on survival and growth of fish,

differences in depuration rates and sensitivity among species, ecosystem recovery from selenium

contamination, and controversy among proposed selenium thresholds (Hamilton, 2004).

Selenium (Se) is a non-metal chemical element, a naturally occurring trace element, present in nature in five

oxidation states: −2, −1, 0, +4 and +6, under the forms of elemental selenium (Se0), selenide (Se2−), selenite

(Se(IV)), selenate (Se(VI)) and organic selenium. These different oxidation states have very different chemical

and toxicological properties. Total (or pseudo-total) concentration of an element is well recognized today as

insufficient for evaluation of toxicity, distribution, mobility and bioavailability. Speciation of selenium in water

medium is ruled by redox conditions, pH, availability of sorbing surfaces and biological processes occurring. In

water and wastewater treatment, the speciation is an important factor, since the treatment efficiency usually

depends on the oxidation state. (Santos et al., 2015).

Selenate, Se(VI), is the fully oxidized Se form and can be present in solution as biselenate (HSeO4−) or selenate

(SeO42−), with a pKa value estimated of 1.8 ± 0.1. Selenate predominates in oxidizing conditions, is very soluble

and with low adsorption and precipitation capacities. Selenite is present in moderate redox potential range

and neutral pH environments. In aqueous solution, Se(IV) exists as a weak acid under the forms of selenious

acid (H2SeO3), biselenite (HSeO3−), or selenite (SeO3

2−), with corresponding pKa values of 2.70 ± 0.06 (H2SeO3/

HSeO3−) and 8.54 ± 0.04 (HSeO3 −/SeO3

2−). In the pH conditions typically found in natural waters, selenium

species will be predominantly HSeO3− or SeO4

2−, under reducing or oxidizing environment, respectively. In

water and wastewater treatment, selenium speciation can however be markedly affected, since other metal

ions present in the solution affect Se speciation (Santos et al., 2015).

There are also recent concerns about selenium toxicity in humans. The epidemiological study of Vinceti et al.

(2016) suggest that long-term exposure to high levels of inorganic hexavalent Se through drinking water may

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increase the risk of some cancer types and two neurodegenerative diseases. Finding raise the possibility that

adverse effects could be occurring near the current European standard of 10 µg/L (Vinceti et al., 2016).

The trace element selenium (Se) in its various chemical species continues to attract strong interest in

environmental health, due to the broad and varying effects suggested by laboratory studies, ranging from

toxic to beneficial, and to the intriguing effects on several human diseases suggested by epidemiologic

investigations. Mainly based on observational studies, Se has been hypothesized to have some beneficial

effects in the prevention of cancer and cardiovascular disease. However, recent randomized controlled trials

(RCTs) did not show decreases in cancer and cardiovascular rates in subjects taking organic Se supplements,

but instead showed some evidence of increased risk of advanced prostate cancer, diabetes and skin cancer.

These observations have raised concern about the safe range of Se intake. On the converse, very little is

known about inorganic Se effects on human health, although the results of most, but not all, laboratory

studies suggest it is more toxic than organic Se compounds found in foods, and it also appears to have peculiar

metabolic pathways (Jager et al.,2016). Inorganic Se forms tend to occur in occupational environments,

outdoor air in polluted areas, and drinking water. In drinking water, Se is generally present as inorganic

hexavalent, selenate, and sometimes approaches the European Union (EU) standard of 10 μg/l even outside

known seleniferous areas (Vinceti et al., 2016).

6. MEASURED ENVIRONMENTAL CONCENTRATIONS (2006-2014)

Inland dissolved fraction - Sc2-PNECQC (PNEC = 0.05 µg/L)

Data statistics: Number of countries with measurements, number of sites with measurements, total number of

samples, number of samples with concentration below LOD, number of samples with concentration below

LOQ, and aggregate percentage of non-quantified records (< LOD/Q).

countries sites samples samples < LOD samples < LOQ % non-quantified

7 913 4509 30 998 22.8

Statistics for concentrations of all measurements: min, average (mean), standard deviation (SD), median,

percentiles (25, 75, 90, 95, 99) and max (µg/L).

min mean SD median P25 P75 P90 P95 P99 max

0.0005 1.624 3.865 1.05 0.025 1.927 3.5 5.112 10 154.6

Range of LODs / LOQs and number of records reported as quantified samples.

LOD (µg/L) Missing 0.005 0.05 0.058

# samples 3456 1 7 17

LOQ (µg/L) Missing 0.001 0.1 0.5

# samples 1545 1 25 22

10

Range of LODs / LOQs and number of records reported as non-quantified samples.

LOD (µg/L) 0.05

# samples 30

LOQ (µg/L) 0.001 0.002 0.005 0.01 0.013

# samples 666 2 1 127 202

Note: All reported LODs (only a few exceptions) are below the PNEC value (0.05 µg/L) for quantified samples

(but this is not valid for LOQs). Seven MS reported many quantified exceedances. The quantified records

without information on LOD/Q seem to be real quantified measurements, and not false positive non-

quantified records.

Boxplot of concentrations of all measurements per year (the table below indicates the number of samples per

year).

Year 2006 2007 2008 2009 2010 2011 2012 2013

# samples 686 786 446 432 478 533 725 423

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Annual mean concentrations of all measurements per year (the time-trend is indicated by a dotted line). After

the increase (jump) in 2007-2008, there are symptoms of deceasing time-trend but the concentrations

(median and mean) remain higher than PNEC value.

Boxplot of concentrations of all measurements per country (the table below indicates the number of samples

per country).

Country #01 #05 #06 #10 #11 #24 #28

# samples 23 27 72 4115 36 181 55

0

0.5

1

1.5

2

2.5

3

3.5

4

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Selenium: annual mean concentrations (µg/L)

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Quantified concentrations of Selenium in Sc2 PNECQC (0.05) dissolved

Non-quantified concentrations of Selenium in Sc2 PNECQC (0.05) dissolved

0.0001

0.001

0.01

0.1

1

10

100

1000

0 500 1000 1500 2000 2500 3000 3500

Co

nce

ntr

atio

n (

µg/

L)

Number of samples

Selenium: quantified samples in Sc2 PNECQC (0.05) dissolved

quantified(N = 3481)

PNEC = 0.05

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Range of LOD/LOQ per country in monitoring data of Selenium in Sc2 PNECQC (0.05) dissolved

Range of LOD (µg/L)

Country from to

#01 n/a n/a

#05 n/a n/a

#06 n/a n/a

#10 n/a n/a

#11 n/a n/a

#24 n/a n/a

#28 0.005 0.058

Range of LOQ (µg/L)

Country from to

#01 n/a n/a

#05 n/a n/a

#06 0.001 0.001

#10 0.001 5

#11 n/a n/a

#24 n/a n/a

#28 0.1 0.1

STE assessment results: Spatial, temporal and extent factors, STE score, risk rank, and PNEC value (µg/L).

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.652 0.994 0.560 2.206 2 Selenium 0.05

STE assessment results: additional information for Fspat (site and country frequency of exceedances - as a part

from the total), Fext (extent of exceedance by Risk Quotient_P95) and samples frequency of exceedances (as a

part from the total).

site_freq country_freq EXCextent sample_freq

6.517E-01 1.000E+00 1.466E+02 0.749

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STE assessment results: additional information on exceedances

Country Site Sample Exceedance extent

Frequency of exceedances

1.00E+00 6.52E-01 7.49E-01 1.52E+02

Number of exceedances

7 595 3379 n/a

Total number (where measured)

7 913 4509 n/a

Note: the STE score is calculated by the refined STE tool after the 6th SG-R meeting.

Inland dissolved fraction - Sc2-PNECQC (PNEC = 0.73 µg/L)

Data statistics: Number of countries with measurements, number of sites with measurements, total number of

samples, number of samples with concentration below LOD, number of samples with concentration below

LOQ, and aggregate percentage of non-quantified records (< LOD/Q).

countries sites samples samples < LOD samples < LOQ % non-quantified

7 2885 18745 51 15213 81.4

Statistics for concentrations of all measurements: min, average (mean), standard deviation (SD), median,

percentiles (25, 75, 90, 95, 99) and max (µg/L).

min mean SD median P25 P75 P90 P95 P99 max

5.00E-04 0.749 1.960 0.5 0.5 0.5 1.240 2.200 5.736 154.6

Range of LODs / LOQs and number of records reported as quantified samples.

LOD (µg/L) Missing 0.005 0.05 0.058

# samples 3456 1 7 17

LOQ (µg/L) Missing 0.001 0.1 0.5

# samples 1545 1 25 22

Range of LODs / LOQs (µg/L) of records reported as non-quantified samples.

LODs: from 0.05 to 1

LOQs: from 0.001 to 2.

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Number of samples per year

Year 2006 2007 2008 2009 2010 2011 2012 2013 2014

# samples 707 2922 3312 3759 2660 1852 1555 1971 7

Number of samples per country

Country #01 #05 #06 #10 #11 #24 #28

# samples 953 27 72 17340 96 181 76

Quantified concentration of Selenium in Sc2 PNECQC (0.73) dissolved

0.0001

0.001

0.01

0.1

1

10

100

1000

0 500 1000 1500 2000 2500 3000 3500

Co

nce

ntr

atio

n (

µg/

L)

Number of samples

Selenium: quantified samples in Sc2 PNECQC (0.73) dissolved

quantified(N = 3481)

PNEC = 0.73

16

Non-quantified concentration of Selenium in Sc2 PNECQC (0.73) dissolved

Range of LOD/LOQ per country in monitoring data of Selenium in Sc2 PNECQC (0.73) dissolved

Range of LOD (µg/L)

Country from to

#01 n/a n/a

#05 n/a n/a

#06 n/a n/a

#10 n/a n/a

#11 n/a n/a

#24 n/a n/a

#28 0.005 1

Range of LOQ (µg/L)

Country from to

#01 1 1

#05 n/a n/a

#06 0.001 0.001

#10 0.001 5

#11 0.2 0.2

#24 n/a n/a

#28 0.1 2

0.0001

0.001

0.01

0.1

1

10

0 2000 4000 6000 8000 10000 12000 14000 16000

Co

nce

ntr

atio

n (

µg/

L)

Number of samples

Selenium: non-quantified samples in Sc2 PNECQC (0.73) dissolved

non- quantified(N = 15264)

PNEC = 0.73

17

STE assessment results: Spatial, temporal and extent factors, STE score, risk rank, and PNEC value (µg/L).

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.080 0.500 0.07 0.651 4 Selenium 0.73

STE assessment results: additional information for Fspat (site and country frequency of exceedances - as a part

from the total), Fext (extent of exceedance by Risk Quotient_P95) and samples frequency of exceedances (as a

part from the total).

site_freq country_freq EXCextent Sample_freq

0.141 0.571 3.455 0.132

STE assessment results: additional information on exceedances

Country Site Sample Exceedance extent

Frequency of exceedances

5.71E-01 1.41E-01 1.32E-01 3.45E+00

Number of exceedances

4 406 2476 n/a

Total number (where measured)

7 2885 18745 n/a

Note: the STE score is calculated by the refined STE tool after the 6th SG-R meeting. With the lower PNEC of

0.73 µg/L there is a considerable reduction of STE score.

Inland dissolved fraction - Sc2

Note: Scenario Sc2 is provided in the factsheet only for information and this scenario is not used in the final

judgment of substances. However, since the STE scores of Sc2 and Sc2-PNECQC do not differ so much and Sc2

is completely independent from the chosen PNECs, the Sc2 was used in quick checks of the impact of PNEC

changes when such request has been received from the SG-R. If the substance is selected for a finalisation of

the PNEC, the STE score for sc2 PNECQC will be recalculated once the PNEC is agreed upon.

Data statistics: Number of countries with measurements, number of sites with measurements, total number of

samples, number of samples with concentration below LOD, number of samples with concentration below

LOQ, and aggregate percentage of non-quantified records (< LOD/Q).

countries sites samples samples < LOD samples < LOQ % non-quantified

7 3286 25422 51 21890 86.3

18

Statistics for concentrations of all measurements: min, average (mean), standard deviation (SD), median,

percentiles (25, 75, 90, 95, 99) and max (µg/L).

min mean SD median P25 P75 P90 P95 P99 max

0.0005 8.213 39.03 0.5 0.5 1.5 5.4 12.5 250 250

Statistics for number of samples per year by country

Statistics for mean concentration per year (µg/L) by country

Statistics for median concentration per year (µg/L) by country

Country

2006 2007 2008 2009 2010 2011 2012 2013 2014

#01 946 7

#05 13 13 1

#06 21 26 14 11

#10 1125 3646 3901 4891 3958 2184 2251 2061

#11 96

#24 181

#28 76

Number of samples per year

Country

2006 2007 2008 2009 2010 2011 2012 2013 2014

#01 0.566 0.500

#05 1.804 1.299 0.500

#06 3.457 5.112 5.450 2.355

#10 0.692 8.984 0.866 9.466 19.813 5.144 12.350 3.464

#11 0.151

#24 0.228

#28 0.755

Mean concentration per year (µg/L)

Country

2006 2007 2008 2009 2010 2011 2012 2013 2014

#01 0.500 0.500

#05 1.550 1.240 0.500

#06 0.700 0.600 0.500 0.600

#10 0.007 0.500 0.500 0.500 0.500 0.500 1.059 1.576

#11 0.100

#24 0.194

#28 0.485

Median concentration per year (µg/L)

19

Statistics for P_95 of concentration per year (µg/L) by country

STE assessment results: Spatial, temporal and extent factors, STE score, risk rank, and PNEC value (0.05 µg/L).

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.913 0.995 1.000 2.908 1 Selenium 0.05

STE assessment results: additional information for Fspat (site and country frequency of exceedances), Fext

(extent of exceedance by Risk Quotient_P95) factors and samples frequency of exceedances.

site_freq country_freq EXCextent Sample_freq

9.127E-01 1.000E+00 4.808E+03 0.955

Recently the discussion group on Selenium has proposed a new PNEC value of 0.73 µg/L.

STE assessment results: Spatial, temporal and extent factors, STE score, risk rank, and PNEC value (0.73 µg/L).

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.257 0.566 0.560 1.383 3 Selenium 0.73

STE assessment results: additional information for Fspat (site and country frequency of exceedances - as a part

from the total), Fext (extent of exceedance by Risk Quotient_P95) and samples frequency of exceedances (as a

part from the total).

site_freq country_freq EXCextent Sample_freq

0.449 0.571 342.466 0.36

Note: the STE scores are calculated by the refined STE tool after the 6th SG-R meeting.

Country

2006 2007 2008 2009 2010 2011 2012 2013 2014

#01 0.500 0.500

#05 2.808 1.824 0.500

#06 20.000 30.000 33.500 10.350

#10 1.500 3.000 2.400 12.500 250.000 12.500 150.000 10.000

#11 0.300

#24 0.503

#28 1.000

P_95 of concentration per year (µg/L)

20

Two requests for a change of PNEC ware made. Below the STE scores the EQS from DE (2.5 µg/L) and INERIS

(0.88 µg/L) are reported

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.254 0.563 0.560 1.377 3 Selenium 0.88

site_freq country_freq EXCextent

4.437E-01 5.714E-01 2.841E+02

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.110 0.393 0.410 0.913 4 Selenium 2.5

site_freq country_freq EXCextent

2.830E-01 4.286E-01 1.000E+02

Note: With the lower PNECs, the STE score (calculated by the refined STE tool after the 6th SG-R meeting)

tends to decrease considerably. However, we should clarify that the PNEC value derived from the NL is taking

into account the secondary poisoning which is relevant for selenium bioaccumulation.

Inland dissolved fraction – Sc1

Data statistics: Number of countries with measurements, number of sites with measurements, total number of

samples, number of samples with concentration below LOD, number of samples with concentration below

LOQ, and aggregate percentage of non-quantified records (< LOD/Q).

countries sites samples samples < LOD samples < LOQ % non-quantified

7 654 3481

0.00

Statistics for concentrations of all measurements: min, average (mean), standard deviation (SD), median,

percentiles (25, 75, 90, 95, 99) and max (µg/L).

min mean SD median P25 P75 P90 P95 P99 max

0.001 2.1039491 4.2840841 1.326 0.58 2.32 4 5.97 12.46 154.6

21

STE assessment results: Spatial, temporal and extent factors, STE score, risk rank, and PNEC value (0.73 µg/L).

CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.463084 0.90452 0.18 1.5476047 3 Selenium 0.73

STE assessment results: additional information for Fspat (site and country frequency of exceedances - as a part

from the total), and Fext (extent of exceedance by Risk Quotient_P95).

site_freq country_freq EXCextent

6.483E-01 7.143E-01 1.256E+01

Note: the STE score is calculated by the refined STE tool after the 6th SG-R meeting.

At the 6th meeting of the SG-R it has been concluded that QS for biota should be derived. JRC agreed to draft

a dossier for selenium.

7. MONITORING STUDIES FROM LITERATURE

Selenium was monitored in the effluents of Austrian waste water treatment plants. The mean concentration

was 2.8 µg/L (median: 0.3 µg/L; maximum: 32 µg/L) (Clara et al., 2012).

In California (US), the Salton Sea, the largest inland surface water body in California and its two main

tributaries, the New River and Alamo River are impacted by urban and agriculture land use wastes. The

purpose of this study was to temporally and spatially evaluate the ecological risks of contaminants of concern

in water, sediments and fish tissues. A total of 229 semivolatile organic compounds and 12 trace metals were

examined. Among them Selenium, DDTs, PAHs, PCBs, chlorpyrifos and some current-use pesticides such as

pyrethroids exceeded risk thresholds and were associated with the toxicity of sediments and water collected

from the rivers. Selenium showed reductions in concentrations from 2002 to 2007, but then gradual increases

to 2012. The selenium PNEC in this study was 5 µg/L for water, 2000 µg/kg in sediment, and 1000 µg/kg in

biota (Xu et al. 2016).

8. ANALYTICAL METHODS

Pettine et al. (2015) and Santos et al. (2015) have reviewed the analytical methods for the determination of

selenium in natural water samples.

22

Total selenium determination in the low detection limits required in legislation (μg/L levels), is no longer a

problem nowadays. Speciation, however, has two common problems: the low concentration of the species

(often below the limits of quantification) and the matrix interferences. Speciation of an element is generally

achieved using hyphenated methods combining an efficient separation with a sensitive and selective

detection. Speciation into different inorganic and organic species is needed for some biological samples and

can be a complex task (Gomes da Silva et al., 2013; Peng et al., 2015; Santos et al., 2015).

If total inorganic dissolved selenium is to be analyzed, then the sample should be filtered through a

preconditioned or prewashed membrane filter (rinsed in deionized water or soaked in acid), typically 0.45 μm

pore diameter, of polycarbonate or cellulose esters (Santos et al., 2015).

The most popular analytical techniques applied for inorganic Se determination are hydride generation coupled

with the atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectroscopy

(ICP-OES), and atomic fluorescence spectroscopy (AFS). Nevertheless, the direct determination of Se species in

food, biological or environmental samples is usually hampered by its low concentration. Therefore,

preconcentration step is usually required prior to quantitative analysis in order to improve sensitivity and

precision of applied techniques. This approach is also very useful when the influence of complicated matrix

should be reduced. Different preconcentration procedures, i.e.co-precipitation with hydroxides, extraction,

microextraction, anion exchange chromatography and isotachophoresis have been recently proposed for Se

determination (Kocot et al., 2015).

Colorimetric/spectrophotometric methods, such as the methylene blue and the 2,3-diaminonaphthalene are

classical approaches to access selenium and its speciation. These methods are time-consuming, difficult to

apply to a high number of samples, and were known by the low detection capacities. Furthermore, some

reagents used are toxic and relatively unstable. Several works on spectrophotometric methods have shown

detection limits (LOD) in the range of 0.3–15 μg/L (Santos et al., 2015).

Instrumental methods, on the other hand, ensure shorter analysis time and higher detection capacities. For

applications where selenium is present at mg/L levels (as in several wastewater samples), nitrous

oxide/acetylene flame Atomic Absorbance Spectrometry can be employed. Electrothermal Atomic Absorption

Spectrometry (ETAAS), also known as graphite furnace, is able to quantify selenium, using appropriate matrix

modifiers (commonly Pd/Mg or Ni), with limits of detection of 1–2 μg/L (Pettine et al., 2015). It is highly

sensitive, with low spectral interferences and a low amount of sample is required. Plasmic spectrometric

methods have also been extensively reported for elemental Se analysis (B'Hymer and Caruso, 2006; Xiong et

al., 2008). Inductively Coupled Plasma with Atomic Emission (ICP-AES) usually presents lower detection

capacity than ETAAS. Inductively Coupled Plasma Mass Spectrometry (ICP-MS), on the other hand, presents an

excellent detection ability, with typical instrumental detection limit for Se of 0.1 μg/L (Pettine et al., 2015). The

method requires preferably experienced analysts in ICP-MS, in the interpretation of spectral and matrix

interference, and procedures for their correction. Hydride generation (HG) is a well-known separation

technique, providing selenium separation as gas from the original matrix. It is commonly used in combination

with atomization of the hydride in AAS, Atomic Fluorescence Spectrometry (AFS) or Inductively Coupled

Plasma (ICP). HG-AAS and HG-AFS present typical instrument detection limits of 0.1 μg/L (Pettine et al., 2015).

Catalytic kinetic spectrophotometric method for the determination of Se(IV), Se(VI) and total inorganic

selenium in water; LOD: 1.3 µg/L (Chand and Prasad, 2009).

23

The waste water samples were acidified with nitric acid to pH<2 (65%, sub-boiled; 1 ml per 100 ml water

sample) for Cd, Pb, Ni, Ag, As, Cr, Se, Cu, Zn; for Hg addition of K2Cr2O7/HNO3 to pH<2 took place. After

addition of an internal standard mixture (In, Rh, Re, Li) analysis of cadmium, lead, nickel, silver, arsenic,

chromium, selenium, copper and zinc of water samples was performed by Quadrupole-ICP-MS (Inductively

Coupled Plasma – mass spectrometry) according to standard ÖNORM EN ISO 17294-2.

LOD for selenium: 0.06-0.4 µg/L (Clara et al., 2012).

Speciation analysis of Se (IV) and Se (VI) in environmental water samples using nano-sized TiO2 colloid as

adsorbent and hydride generation atomic fluorescence spectrometry (HG-AFS) as determination; LOD: 0.024

µg/L and 0.042 µg/L for Se (IV) and Se (VI), respectively (Fu et al., 2012).

Determination and speciation of trace and ultratrace selenium ions by energy-dispersive X-ray fluorescence

spectrometry using graphene as solid adsorbent in dispersive micro-solid phase extraction; LOD: 0.032 μg/L

(Kocot et al., 2015).

ICP-MS; LOD: 0.05 μg/L (Økelsrud et al., 2016).

In-tube solid phase microextraction followed by AAS; LOD: 0.004 µg/L (Asiabi et al., 2016).

9. CONCLUSIONS

Summary of the findings of the factsheet:

1) Selenium, with a secondary poisoning PNEC of 0.05 µg/L, has been analysed in seven countries, at 3286

monitoring stations (sites) with 25422 measurements (scenario 2), and 13.7 % of them quantified

(> LOD/Q). In sc2-PNECQC, 913 sites and 4509 samples are available in seven countries, 77.2 % of them

quantified. The available monitoring data are for the “dissolved” fraction.

2) A detailed check of the monitoring data showed that the quality of data for selenium is good, because

the quantified records without information on LOD/Q seem to be real quantified measurements, and

not false positive non-quantified records. Seven MS reported many quantified exceedances.

3) LODs and LOQs below the PNEC are reported by the MS laboratories and in the literature.

4) The STE score of sc2-PNECQC is high (2.206 with PNEC=0.05 µg/L), indicating a high risk to the aquatic

environment.

5) According to the harmonised classification and labelling approved by the European Union, this

substance may cause long lasting harmful effects to aquatic life.

6) Selenium is a bioaccumulative pollutant of substantial toxicity, if toxicity is determined from diet, not

dissolved exposure.

7) Selenium pollution seems to be a worldwide phenomenon, with wide differences in regulations

among jurisdictions and environments. Once selenium contamination begins, a cascade of

bioaccumulation events is set into motion. According to the available scientific evidence, integrating

the chemistry of selenium with its biology and ecotoxicology may give indications on how to regulate

its environmental levels.

24

8) In Austria, selenium was identified as one of the relevant substances with impact on good chemical

status of surface water quality via the discharge of treated wastewater (Clara et al., 2012).

Conclusion of the JRC:

According to JRC, selenium could be a good candidate for EQS derivation. Natural background levels and

bioavailability issues should be considered.

Conclusion of the SG-R:

SG-R agreed that Selenium is a good candidate substance for EQS derivation and consideration as potential

PS (four experts ) while others support the need to gather existing monitoring data on biota and derive

QS for biota, before deciding on eventually shortlisting of Se.

Therefore it was concluded that the existing monitoring data on biota should be collected as well as all the

available literature data.

JRC agreed to draft a dossier with aim to collecting the literature data and monitoring data on biota with

the possibility to derive a QS for biota.

10. REFERENCES

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Chand, V., Prasad, S., 2009. Trace determination and chemical speciation of selenium in environmental water

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FOREGS (2005). Geochemical Atlas of Europe - STATISTICAL DATA OF ANALYTICAL RESULTS. http://weppi.gtk.fi/publ/foregsatlas/ForegsData.php http://weppi.gtk.fi/publ/foregsatlas/articles/Statistics.pdf Fu, J.Q., Zhang, X., Qian, S.H., Zhang, L., 2012. Preconcentration and speciation of ultratrace Se (IV) and Se (VI)

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Gdańsk University of Technology. (2006). Polish and International regulations. Gdańsk University of Technology: http://www.pg.gda.pl/chem/Dydaktyka/Analityczna/WQC/WATER_REG.pdf Gomes da Silva, E., Verola Mataveli, L.R., Zezzi Arruda, M. A. Speciation analysis of selenium in plankton, Brazil

nut and human urine samples by HPLC–ICP-MS. Talanta 110 (2013) 53–57.

Hamilton SJ. (2004). Review of selenium toxicity in the aquatic food chain Review. Science of the Total Environment 326, 1–31. Hilton, JW, Hodson PV, Slinger SJ. (1980). The requirement and toxicity of selenium in rainbow trout (Salmo gairdneri). J. Nutr, 110 (12), 2527-2535. INERIS (2011). SÉLÉNIUM ET SES COMPOSÉS. Fiche de données tox icologiques et env i ronnementales des subs tances chimiques. DRC-08-83451-01269B. Version N°2.2 septembre 2011. http://www.ineris.fr/substances/fr/substance/1649 Ireland Environmental Protection Agency. (2011). The Provision and Quality of Drinking. Retrieved from EPA: http://www.epa.ie/pubs/reports/water/drinking/DrinkingWater_web.pdf

Kocot, K., Leardi, R., Walczaka, B., Sitko, R., 2015. Determination and speciation of trace and ultratrace

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Lenz M, Lens PNL. (2009). The essential toxin: The changing perception of selenium in environmental sciences.

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Lemly A.D. (2004). Aquatic selenium pollution is a global environmental safety issue. Ecotoxicology and Environmental Safety 59 (2004) 44–56. Luoma SN. (2009). Emerging Opportunities in Management of Selenium Contamination. Environ. Sci. Technol, 43, 8483–8487. Nendza M. (2003). Entwicklung von Umweltqualitätsnormen zum Schutz aquatischer Biota in Oberflächengewässern. Im auftrag des UBA. Umweltforschungsplan des Bundesumweltministeriums für Umwelt, Naturschutz und Reaktorsicherheit, Förderkennzeichen (UFOPLAN) 202 24 276. Northern Ireland Environment Agency. (2011, October). European and National Drinking Water Standards. Department of Environment: http://www.doeni.gov.uk/niea/european_and_national_drinking_water_quality_standards_-_october_2011.pdf Økelsrud, A., Lydersen, E., Fjeld, E. Biomagnification of mercury and selenium in two lakes in southern Norway.

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Presser, TS, Piper DZ, Bird KJ, Skorupa JP, Hamilton SJ, Detwiler SJ, Huebner MA. (2004). The Phosphoria Formation: A model for forecasting global selenium sources to the environment. In Life Cycle of the Phosphoria Formation: From Deposition to Post-Mining Environment; Hein, J. R., Ed.; Elsevier: New York, 2004; pp. 299-319. Sappington, K. G. (2002). Development of aquatic life criteria for selenium: a regulatory perspective on critical issues and research needs. Aquat. Toxicol., 57 (1-2), 101–113. Santos, S., Ungureanu, G., Boaventura, R., Botelho, C. Selenium contaminated waters: An overview of

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United States Food and Drug Administration. (2013). http://www.regulations.gov/#!docketDetail;D=FDA-2013-N-0067 www.fda.gov/animalveterinary/newsevents/cvmupdates/ucm048424.htm United States Environmental Protection Agency. (2000). Guidance for assessing chemical contaminant data for use in fish advisories. Volume 1. Fish Sampling and Analysis. Third Edition. EPA 823-B-00-008. November 2000. Washington, DC (US): U.S. Environmental Protection Agency, Office of Water. United States Environmental Protection Agency. Draft Selenium Aquatic Life Criterion Fact Sheet; 2008. United States Environmental Protection Agency. (2012). Basic Information about Selenium in Drinking Water. http://water.epa.gov/drink/contaminants/basicinformation/selenium.cfm United States Environmental Protection Agency. (2014). Aquatic Life Criterion - Selenium. http://water.epa.gov/scitech/swguidance/standards/criteria/aqlife/selenium/index.cfm Union of India. (1993). General Standards for Discharge of Environmental Pollutants. Himachal Pradesh State Pollution Control Board: http://hppcb.gov.in/eiasorang/spec.pdf Van Vlaardingen P.L.A., Posthumus R. and Posthuma-Doodeman C.J.A.M. (2005). Environmental Risk Limits For Nine Trace Elements. National Institute of Public Health and the Environment (RIVM). RIVM report 601501029/2005. Bilthoven, The Netherlands.247. van Vlaardingen P.L.A. and E.M.J. Verbruggen. (2009). Aanvulling milieurisicogrenzen voor negen sporenelementen. Afleiding volgens Kaderrichtlijn Water-methodiek. RIVM Briefrapport 601714011/2009. http://www.rivm.nl/bibliotheek/rapporten/601714011.pdf Vinceti M, P Ballotari, C Steinmaus, C Malagoli, F Luberto, M Malavolti, PG Rossi. (2016). Environmental

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Xiong, C., He,M., Hu, B., 2008. On-line separation and preconcentration of inorganic arsenic and selenium

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COMMENTS on the factsheet

29

REACH Selenium & Tellurium Consortium

Comments on Selenium draft factsheet_v3_29July2016 1 September 2016

General remarks The PNEC selected for the STE was a value of 0.05 μg/L, proposed as an AA‐QSfreshwater developed by the Netherlands based on secondary poisoning (QSwater, secpois). This value was the lowest of 12 values obtained from the literature or government documents. The values ranged from 0.05 – 5.3 μg/L. Selection of a very low value for the QS or STE evaluation, while conservative, does not reflect the state of the science for selenium assessment. Additionally, water derived PNEC values, as traditionally developed for cationic metals and organic substances, are not applicative to selenium. Rather than critique the draft document section by section, it is best to summarize the key literature and lay out the decades of work that have been done on selenium assessment for the aquatic environment including aquatic dependent birds. We encourage the JRC to review this body of literature before proceeding with the STE assessment. Details are provided in the following pages.

1 http://ww2.setac.org/globe/2012/december/commemoration‐accomplishments.html Summary 1. Selenium is an essential element for all invertebrate and vertebrate species and involved in a series of vital metabolic functions. BAF/BCFs for selenium are not larger than those for other essential metals and are inversely related to exposure concentration; 2. A selenium QS at 0.05 μg/L would be well below background for freshwater European surface waters and could be in the range of deficiency for some species; 3. Analytical measurement of selenium in water below 1 μg/L remains an issue to be addressed when comparisons between laboratories are made; 4. Observation of toxicity in natural (field) environments indicates effects occur at concentrations greater than 5 μg/L;

30

5. Selenium in aquatic environments affects both fish and avian wildlife via dietary exposure. Concentrations in water that are thought to be protective for aquatic life and birds are in the 2‐10 μg/L range; and 6. The approach taken by the USEPA in its draft water quality criteria document has the most up to date database on aquatic effects, is built upon water and dietary exposures and reflects the importance of recognizing selenium effects occur at different concentration depending upon whether or not the receiving water is a lotic or lentic environment. 1. Essentiality of selenium and bioaccumulation Selenium is an essential element for all invertebrate and vertebrate species and involved in a series of vital metabolic functions. Selenium is found in the amino acids selenomethionine and selenocysteine which are essential for life. Both compounds play a role together with vitamin E in protecting cells from reactive oxygen species. There is also scientific opinion on the safety and efficacy of selenium compounds as feed additives for all animal species (EFSA, 2015). Trophic transfer is used to define the extent to which chemical substances are transferred through the food chain. Researchers look to determine whether or not the levels are increasing in higher trophic levels. If the increase in the food chain increases across three or more trophic levels the substance is said to biomagnify. Selenium only biomagnifies to a very small extent (factors of 1‐3) (Presser and Luoma 2010) unlike DDT or mercury (10‐1000). In many food webs selenium does not biomagnify. a. The draft JRC document cites the USEPA indicating selenium is a bioaccumulative substance. On the basis of

the trophic transfer factors (TTF) one would not consider selenium to be a bioaccumulative substance. Further evidence is provided in that regard from the data on bioaccumulation factors (BAF) for selenium which are typically in the range of 500‐3000 (Presser and Luoma 2010, DeForest and Adams 2003). These BAFs are very consistent with values for other essential metals such as copper, iron and zinc (McGeer et al 2003). There is nothing unusual for selenium that would necessitate calling the substance bioaccumulative. This nomenclature for selenium comes from the fact that toxicity is the result of dietary exposure; however, there is nothing unique about the size of the bioaccumulation factors for selenium.

b. Trophic transfer and bioaccumulation factors (BAFs) for some substances provide a means to assessing toxicity potential, especially non‐polar organic chemicals. However, for metals and metalloid this is not the case. BAFS and TTFs are inversely related to exposure concentration and are not linear in relation to exposure. The science behind the development of bioconcentration factors (BCFs) was developed for non‐polar organic substances where the BCFs/BAFs are independent of the water exposure factor. This allows for a comparison of bioaccumulation potential across specific sites and chemicals. This is not the case for metals/metalloids where very low exposures values, in the range of barely meeting essential requirements, have the largest BAFs and BCFs. Exposures at elevated concentrations approaching toxicity have very low BCFs/BAFs. The use of these factors are not useful for hazard assessment (USEPA 2004).

The non‐applicability of BCFs for essential metals was already recognized in the regulatory framework of aquatic hazard classification (OECD, 2001 and CLP guidance (Annex IV)): “For most metals and inorganic metal compounds the relationship between water concentration and BCF in aquatic organisms is inverse, and bioconcentration data should therefore be used with care. This is particularly relevant for metals that are biologically essential. Metals that are biologically essential are actively regulated in organisms in which the metal is essential (homeostasis). Removal and sequestration processes that minimize toxicity are complemented by an ability to up‐regulate concentrations for essentiality. Since nutritional requirement of the organisms can be higher than the environmental concentration, this active regulation can result in high BCFs and an inverse relationship between BCFs and the concentration of the metal in water. When environmental concentrations are low, high BCFs may be expected as a natural consequence of metal uptake to meet nutritional requirements and can in these instances be viewed as a normal phenomenon”.

BAF/BCFs for selenium are not larger than those for other essential metals

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BAF/BCF are inversely related to exposure concentration and are thus not useful for hazard assessment. 2. Natural background concentration of selenium Selenium is a natural element and therefore naturally present in all environmental compartments. Background concentrations of selenium as reported in the FOREGS Database averaged 0.57 μg/L with a median and range of 0.34 and 0.01‐15 μg/L, respectively for 807 samples (Salminen et al. 2005). The data in FOREGS is noteworthy in that the samples were collected to avoid direct anthropogenic inputs. Hence, the values are intended to reflect natural background. These data indicate that an EQS of 0.05 μg/L would be well below natural background (by up to a factor of 10) and could be in the range of deficiency for some species. For example, in the past, the American society of Testing and Materials has recommended 1.0 μg/L in laboratory water for the culture of Daphnia magna.

A selenium QS at 0.05 μg/L would be below background for freshwater European surface waters and could be in the range of deficiency for some species. 3. Analytical measurement of selenium The routine analytical measurement of selenium in water at concentrations below 1.0 μg/L remains a problem at many laboratories. While the JRC draft selenium document states “total selenium determination in the low detection limits required in legislation (μg/L levels) is no longer a problem” our experience indicates otherwise. Ring tests over the past decades show inconsistency between laboratories when concentrations are below 5 μg/L. Reporting at 0.05 μg/L is possible at a few specialized laboratories. However, there has been no demonstration that the measurements can be reliably repeated and can be achieved between laboratories. To achieve a reliable value of 0.05 μg/L the method has to be able to detect ~ 0.01 μg/L + three standard deviations. This is very difficult to achieve. Selenium analysis is hampered by interferences from other elements and in particular is unreliable in waters high in total dissolved solids.

Analytical measurement of selenium in water below 1 μg/L remains an issue to be addressed when comparisons between laboratories are made. 4. Field and Laboratory toxicity data Selenium is one of the few substances for which there are extensive chronic field and laboratory toxicity data for comparison. These data confirm that invertebrate and plant/algal species are relatively insensitive to selenium and that fish and birds can be effected at elevated levels of selenium via the diet resulting in chronic effects including embryo teratogenesis and or failure of eggs to hatch. a. Aquatic effects: Belews Lake: In the early 1980s, selenium had been identified as a principal cause of toxicity

to several species of fish in Belews Lake, North Carolina, USA (Cumbie and Van Horn 1978). Centrarchid populations (especially bluegills and green sunfish) were identified as having been severely impacted in the lake at waterborne concentrations >10 μg Se/L. No effects were observed in portions of the lake where the selenium concentrations were less than 5 μg/L. These observations were used to derive a water quality standard of 5 μg/L for the United States (USEPA, 1987). This is the current national standard. Laboratory studies with bluegills have substantiated their sensitivity to selenium.

b. Avian Wildlife: aquatic invertebrates and plants bioaccumulate selenium via the water and diet, and aquatic birds which feed upon these invertebrates and plants during the breeding season transfer a significant fraction of their dietary intake to the eggs [Hothem and Ohlendorf, 1989 and Ohlendorf et al, 1993]. At sufficiently high egg selenium concentrations, teratogenic effects on developing embryos can result [Hoffman et al., 1988 and Hoffman and Heinz 1988]. Selenium interferes with embryo development and, at sufficiently high concentrations, can result in gross abnormalities such as anophthalmia, incomplete beak development, brain defects (hydrocephaly and exancephaly), foot defects and other terata. Subtle teratogenic effects such as enlarged hearts, edema, liver hypoplasia, and gastroschisis also occur. These

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effects are what lead to reduced embryo and chick survival. Adams et al, 2003 reviewed the thresholds for birds. The primary avian exposure pathway for selenium is the diet [Adams et al, 1998, and Lemly and Smith, 1987)]. Selenium concentrations in irrigation ponds at Kesterson, California resulted in significant effects on several species of birds, especially black‐necked stilts. Concentrations of selenium in the water ranged from 10‐>100 μg/L. Dietary thresholds for black‐necked stilts were developed from field exposures (Skorupa, 1996) and further refined by Adams et al., 2003.

Observation of toxicity in natural (field) environments indicates effects occur at concentrations greater than 5 μg/L.

5. PNEC derivation The draft factsheet cites literature that supports the transfer of selenium via the diet (Lemly, Luoma and Sappington references). Other references that go into the details of selenium toxicity via dietary exposure include the following: a. Adams et al. 2003 and 2004, Chapman et 2009, DeForest et al 2007, DeForest et al 2008, and DeForest and

Adams 2012. Chapman et 2009 is a summary (book) from a SETAC Pellston workshop with its entire focus on selenium assessment and emphasizes the importance of diet. Keeping in mind the importance of diet, PNEC values derived from water only exposures for aquatic life do not provide a reliable approach to deriving chronic thresholds for effects.

b. Meyer et al. 2004 recommend for metal substances where the dietary route of exposure is important that toxicity studies include tests where the exposure routes are combined, i.e., aqueous and dietary exposures in the same study. Such studies have been performed for selenium and are part of the database contained in the EPA selenium criteria document (June 2016).

The draft fact sheet refers to US EPA of 2008 which proposed tissue concentration based chronic criterion values as a more appropriate measure for ecotoxicological risk compared to waterborne concentration. We recommend consulting the up‐to‐date version of this document, which provides Selenium Ambient Chronic Water Quality Criterion values derived via a calculation method starting from Se concentrations in fish eggs and ovaries and which are in the range of the higher PNEC values. The primary focus of past selenium assessments has been on maternal transfer of selenium to embryos of aquatic organisms and avian wildlife with some limited evidence of the same effects for amphibians. Publications cited above discuss and substantiate the importance of maternal transfer. Publications by Fairbrother et al. 1999 and Adams et al 2003 discuss threshold for effects for birds via the diet and relate the effects back to water concentrations that may be protective. In general, concentrations in water that are thought to be protective for aquatic life and birds are in the 2‐10 μg/L range. A review of the selenium literature by DeForest and Adams 2012 is recommended.

Direct toxicity from water is not the primary exposure route for toxicity expression or obtaining selenium for nutritional needs;

Selenium in aquatic environments affects both fish and avian wildlife via dietary exposure;

Concentrations in water that are thought to be protective for aquatic life and birds are in the 2‐10 μg/L range. 6. Toxic effects of selenium in lotic and lentic environments The concentrations at which effects to aquatic life occur changes depending upon the receiving water. It has been shown (Adams et al., 2000 and Presser and Luoma, 2010) that BAFs and TTFs are smaller in flowing (lotic) environments and can be considerably larger in standing water (lentic, i.e., lakes and reservoirs). This is attributed to the conversion of inorganic selenium to organic forms in lentic environments. The USEPA water quality criterion for selenium (June 2016) reflects these difference by using BAFs derived from lotic and lentic

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environments to back calculate water concentrations that are protective for these two environmental types. These data argue that a single number for all aqueous environments is not necessary and not reflective of the published selenium literature.

The approach taken by the US EPA in its draft water quality criteria document has the most up to date database on aquatic effects, is built upon water and dietary exposures and reflects the importance of recognizing selenium effects occur at different concentration depending upon whether or not the receiving water is a lotic or lentic environment. References Adams WJ, Brix KV, Cothern KA, Tear LM, Cardwell RD, Fairbrother A, and Toll JE. 1998. Assessment of selenium food chain transfer and critical exposure factors for avian wildlife species: need for sitespecific data, in Environmental Toxicology and Risk Assessment: Seventh Volume, E.E. Little, A.J. Delonay, and B.M. Greenberg, Editors. American Society for Testing and Materials: Philadelphia, Pennsylvania. 312‐342. Adams, W.J., J.E. Toll, K.V. Brix, L.M. Tear and D.K. DeForest. 2000. Site‐specific approach for setting water quality criteria for selenium: differences between lotic and lentic sites. Ministry of Energy and Mines, Williams Lake, British Columbia, Canada, June 21‐22, 2000. Adams, W. J., K. V. Brix, M. Edwards, L. M. Tear, D.K. DeForest, and A. Fairbrother. 2003. Analysis of field and laboratory data to derive selenium toxicity, thresholds for birds. Environ. Tox. And Chem. Vol. 22, No. 9, 2020‐2029. Adams, W.J., R. Stewart, K. Kidd, K.V. Brix, and D. K. DeForest. 2004. Selenium and Mercury: Importance of Dietary Exposure As Related To Bioaccumulation And Toxicity In Aquatic Ecosystems, In, Meyer et al. 2004, the Role of Dietary Exposures in the Evaluation of Risk to Aquatic Organisms, SETAC Pellston Workshop, SETAC Press, Pensacola, FL. Adams, W.J., R. Blust, U. Borgmann, K.V. Brix, D.K. DeForest, A.S. Green, J. Meyer, J.C. McGeer, P. Paquin, P. Rainbow, and C. Wood. 2011. Utility of tissue residues for predicting effects of metals on aquatic organisms. Integ. Environ. Assess. Manag. 7(1): 75‐98. Brix. K. V., J. Toll, L. M. Tear, D. K. DeForest and W. J. Adams. 2005. Setting site‐specific water quality standards using tissue residue criteria and bioaccumulation data. Part 2. Calculating site‐specific selenium water quality criteria standards for protecting fish and birds. Environ. Tox. and Chem., Vol. 24, No. 1, pp. 231‐237. Chapman P., W. Adams, M. Brooks, C. Delos, S. Luoma, W. Maher, H. Ohlendorf, T. Presser, D. Shaw. 2009. Ecological assessment of selenium in the aquatic environment: summary of a SETAC Pellston Workshop. SETAC Press, Pensacola, Florida. Cumbie P.M. and Van Horn S.L. 1978. Selenium accumulation associated with fish mortality and reproductive failure. Proc Annual Conference Southeastern Association Fish Wildlife Agencies 32:612‐624. DeForest, D., K. V. Brix, W. J. Adams. 2007. Assessing metal bioaccumulation in aquatic environments: the inverse relationship between bioaccumulation factors, trophic transfer factors and exposure concentrations. Aquatic Toxicology 84:236‐246. DeForest D K., P. M. Chapman, W. J. Adams. 2008. What is an appropriate level of protection? An example considering selenium exposures by aquatic birds. A learned Discourse in: Integrated Environmental Assessment and Management, SETAC Press. DeForest DK, Adams WJ. 2012 Selenium accumulation and toxicity in freshwater fishes. In: Beyer WN, Meador JP, editors. Environmental contaminants in biota: interpreting tissue concentrations. 2nd edition. Boca Raton (FL, USA): Taylor and Francis. Cardwell R., D. DeForest, K. Brix and W. Adams. 2013. Critical Evaluation of Cd, Cu, Ni, Pb and Zn Biomagnification in Aquatic Ecosystems. Reviews of Environmental Contamination and Toxicology Volume 226. Pp101‐121. EFSA 2014: Scientific Opinion on Dietary Reference Values for selenium, EFSA Journal 2014;12(10):3846 [67 pp.]. http://www.efsa.europa.eu/en/efsajournal/pub/3846

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Hothem RL and Ohlendorf HM. 1989. Contaminants in foods of aquatic birds at Kesterson Reservoir, California, 1985. Arch. Environ. Contam. Toxicol. 18:773‐786. Hoffman DJ, Ohlendorf HM, and Aldrich TW. 1988. Selenium teratogenesis in natural populations of aquatic birds in Central California. Arch. Environ. Contam. Toxicol. 17:519‐525. Hoffman DJ and Heinz GH. 1988. Embryotoxic and teratogenic effects of selenium in the diet of mallards. J. Toxicol. Environ. Hlth. 24:477‐490. Lemly AD and Smith GJ. 1987. Aquatic cycling of selenium: implications for fish and wildlife. U.S. Fish and Wildlife Service. Lemly A.D. (2004). Aquatic selenium pollution is a global environmental safety issue. Ecotoxicology and Environmental Safety 59 (2004) 44–56. Luoma S. (2009). Emerging Opportunities in Management of Selenium Contamination. Environ. Sci. Technol, 43, 8483–8487. McGeer, J.C., K.V. Brix, D.K. DeForest, S.I. Brigham, J.M. Skeaff, W.J. Adams and A. Green. 2003. Bioconcentration Factor for the Hazard Identification of Metals in the Aquatic Environment: A Flawed Criterion? Environ. Tox. and Chem. Vol. 22, No. 5, pp. 1017‐1037. Meyer et al. 2004. the Role of Dietary Exposures in the Evaluation of Risk to Aquatic Organisms, SETAC Pellston Workshop, SETAC Press, Pensacola, FL. Ohlendorf HM, Kilness AW, Simmons JL, Stroud RK, Hoffman DJ, and Moore JF. 1993. Food‐chain transfer of trace elements in wildlife. in Management of irrigation and drainage systems: integrated perspectives. Park City, Utah: American Society of Civil Engineers. Presser T. and S. Luoma 2010. A methodology for ecosystem‐scale modeling for selenium. IEAM 6:(4) 685‐710. Salminen R. et al. 2005. Geochemical atlas of Europe – Background information and maps. Geological Survey of Finland, Espoo, Finland. Sappington, K. G. (2002). Development of aquatic life criteria for selenium: a regulatory perspective on critical issues and research needs. Aquat. Toxicol., 57 (1‐2), 101–113. Skorupa JP, Morman SP, and Sefchick‐Edwards JS. 1996. Guidelines for interpreting selenium exposure of biota associated with non‐marine aquatic habitats. U.S. Fish and Wildlife Service, National Irrigation Water Quality Program. Toll, J., L. M. tear, D. K. DeForest, K. V. Brix and W. J. Adams. 2005. Setting site‐specific water quality standards using tissue residue criteria and bioaccumulation data. Part 1. Methodology. Environ. Tox. and Chem., Vol. 24, No. 1, pp. 224–230. U.S. Environmental Protection Agency. 1987. Ambient water quality criteria for selenium ‐ 1987. Washington, DC, USA: USEPA. EPA 440/5‐87‐006. 121 p. U.S. Environmental protection Agency 2004. Framework for Metals Risk Assessment. EPA/630/P‐ 04/068a. Risk Assessment Forum, USEPA, Washington, DC. U.S. Environmental Protection Agency. Aquatic Life Ambient Water Quality Criterion for Selenium – Freshwater 2016, EPA 822‐R‐16‐006, June 2016. https://www.epa.gov/wqc/aquatic‐life‐criterionselenium‐ documents.

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Comments from NL, UK and DE

Text has been slightly revised as follows:

1. Section 3: Added: (via secondary poisoning and human fish consumption)

Other comments are reported below:

Comments from NL

Text:

NL RIVM already presented risk limits for selenium in 2005 (Van Vlaardingen et al. 2005).

Comment from NL, 23 August 2016:

This is not the most recent derivation, also not for the direct ecotoxicity. In the report mentioned below

(http://www.rivm.nl/bibliotheek/rapporten/601714011.pdf), the QSeco=1.3 ug/L. This value is based on a

reviewed and revised dataset and is thus more reliable than the value of 2.1 ug/L from

http://www.rivm.nl/bibliotheek/rapporten/601501029.pdf.

The QS hh, food, fw is 0.72 ug/L, calculated with a not very conservative BAF of 421.

The QS sp, water is 0.05 ug/L. The NOAEC for reproduction of mice is without an assessment factor of similar

magnitude as the QS hh, food.

Text:

We would like to invite the experts to share their recommendations for the most appropriate PNEC value.

Comment from NL, 23 August 2016:

It could be argued that the value for secondary poisoning is too stringent in view of the essentiality and the

application of an assessment factor (though rather low). However, the US EPA TDI that has been used is

agreed upon by several human toxicological experts (taking both toxicity and essentiality into account) and

this value should not be exceeded (http://www.rivm.nl/bibliotheek/rapporten/711701004.pdf). For this

reason I think that the value of 0.73 ug/L should be the highest value to be used in the assessment, especially

because the BAF that was used in this calculation is not even particularly high.

Moreover, because relevant NOAELs for birds and mammals are already equal or lower than the QShh, food

the QS for sec pois will not be higher than this value.

Text:

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CAS Fspat Ftemp Fext STE score Risk Substance PNEC

#7782-49-2 0.254 0.563 0.560 1.377 3 Selenium 0.88

Comment from NL on “Fspat”, 15 August 2016:

I think this number shows the implications of multiplying Fsite with Fcountry. Looking at the figure above for

countries and taking a PNEC of 0.88 into account, a Fspat value of 0.5 (i.e. the average and not the product),

seems to be more appropriate.

Text:

According to JRC, selenium could be a good candidate for EQS derivation. Natural background levels and

bioavailability issues should be considered.

Comment from NL, 15 August 2016:

I agree. For a final QS, BAF values and mammalian and avian toxicity should be reviewed carefully.

Comment from DE, 29 August 2016:

Remarks: The route of secondary poisoning appears to be the critical one (without AF). But the PNEC of 0.05

µg/l is to low compared with the natural background in water (Median 0,34 µg/L (FOREGS cited in the

factsheet). Also the route for human fish consumption leads to a lower QS than direct ecotoxicity.

A good refined assessment of secondary poisoning and human health including the bioaccumulation potential

of selenium is needed to complete the picture of the QS exceedance and STE score.

Data for fish and mussel are available in the German Umweltprobenbank.

Fresh water

mussel (Dreissena polymorpha):

https://www.umweltprobenbank.de/de/documents/investigations/results/analytes?analytes=10008&samplin

g_areas=10092+10048+10023+10008+10006+10003&sampling_years=&specimen_types=10029

fish Bream (Abramis brama)

https://www.umweltprobenbank.de/de/documents/investigations/results/analytes?analytes=10008&samplin

g_areas=&sampling_years=&specimen_types=10007

The lowest values for freshwater fish Abramis brama were recorded for the reference site Lake Belau (arth.

mean Range (1997 - 2013) = 95 - 259 µg/kg ww).

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For the marine environment data for fish, shellfish and seabird eggs are available:

https://www.umweltprobenbank.de/de/documents/investigations/results/analytes?analytes=10008&samplin

g_areas=&sampling_years=&specimen_types=10022+10024+10027

Text

According to JRC, selenium could be a good candidate for EQS derivation. Natural background levels and

bioavailability issues should be considered.

Comment from DE, 29 August 2016:

Agree with JRC: derive a QS for secondary poisoning and human health based on the revised TGD method.

A decision on shortlisting should be made afterwards.

Comment from SEPA, UK, August 2016:

Regarding the EQS and background levels of selenium for water column EQS, similar comment to that made

for silver – for the added risk approach it is better to adjust monitoring data rather than adjust an EQS. This

way, different background levels in different geographical locations can be taken into account with a “one size

fits all” EQS, and if a bioavailability correction is needed on the anthropogenic measured fraction it still works

(as is the case for zinc). It is simpler to deal with background concentrations in the same way for all

substances.

From the information presented in the factsheet it sounds as if higher dietary doses of selenium in prey that

has appreciably bioaccumulated selenium is the major form of exposure and source of toxicity in sensitive

species. If this is the case, then an EQS representative of secondary poisoning should definitely be derived,

should this substance be taken forward.

Regarding the use of a biota standard to reflect the RIVM secondary poisoning derivation, there may be

problems with this as selenium is an essential element and so will be regulated at different levels in different

species. Also, some species are more suitable than others for monitoring. If molluscs or invertebrates would

be the most suitable species to monitor in terms of trophic level and peak concentrations for this substance

(and as is the case for PAHs and as the citation from the paper by Hamilton (2004) seems to suggest), there

are some countries, including Scotland, where no suitable species in rivers are available for such monitoring.

Therefore a water column EQS, “back-calculated” to represent secondary poisoning, might be preferable.

JRC reply: JRC could test in the STE runs additionally other PNEC values for these substances.

Comment from EA, UK, August 2016:

JRC note that selenium could be a good candidate for EQS development but that natural background levels

and bioavailability issues should be considered.

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Based on the data presented in the datasheet agree that further consideration is needed before it can be

considered for EQS development. Although JRC noted that natural background levels and bioavailability need

consideration we would highlight that the PNEC used in the STE assessment also needs consideration for the

reasons highlighted below.

- A range of PNEC values are noted in the datasheet and in addition comments received to date and

documented in the datasheet have commented on the PNEC that was used in the STE calculation. Some of

the values have been derived based on consideration of secondary poisoning – this includes the Dutch value

which has been used in the STE derivation. The USEPA published a water quality threshold for

https://www.epa.gov/wqc/aquatic-life-criterion-selenium in April 2016 – this also took into account impact of

selenium via secondary poisoning. The USEPA report notes that selenium toxicity to aquatic life is primarily

based on organisms consuming selenium contaminated food rather than being exposed only to selenium

dissolved in water.

The PNECs vary considerably and this can therefore have an influence on the STE. Further consideration needs

to be given to the PNEC to be used before selenium can be considered further.

JRC reply: JRC could test in the STE runs additionally other PNEC values for these substances