arsenic in water

8/12/2019 Arsenic in Water

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Arsenic in Drinking Water

Huei-An Chu (Ann)

ET450 Environmental Regulation

11/09/2006


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Sinister Uses for Arsenic King of poisons

Victorian ladies of fashionused arsenic for cosmeticpurposes, as well as forkilling husbands.

In the 15th and 16th

century, the Borgias usedarsenic as their favoritepoison for politicalassassinations.

In WWII, arsenic used as awar gas Contact with the skin

produced huge blistersSource for this slide and the following some:

www.epa.gov/safewater/arsenic/pdfs/arsenic_training_2002/train1-background.pdf


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Arsenic poisoning isthought to beresponsible for thedeaths of some wellknown historicalfigures such as:

Claudius Pope Pius III and

Clemente XIV

Charles FrancisHall

Napoleon


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Was Napoleon Poisoned?

A toxicological study ofNapoleon's hair showedmajor exposure, and Istress 'major', to

arsenic." Natural upper limit of

arsenic concentration inhair is one nanogram

per milligram of hair. In one of the samples

tested, the concentrationwas 38 nanograms.June 1, 2001

CNN.com/world


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Arsenic (As)

Semi-metallic element

The metallic form (0 valence): no adversehealth effects

Toxic level: inorganic (As3+ > As5+) > organicform

Focus: inorganic arsenic

Mobile in the environment

The primary medium: water

Pharmaceutical usage for acute promyelocyticleukemia (APL): arsenic trioxide (As

2

O3

)


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Acute Health Effects

typically > 1,200 microgram per liter in water

abdominal pain

vomiting

diarrhea

muscular weakness and cramping

pain to the extremities

erythematous skin eruptions

swelling of the eyelids, feet, and hands

shock

death


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Chronic Health Effects (Arsenicosis)

Non-Cancer

Vascular effects, such as Blackfoot

Disease

Skin lesions, such as skin pigment,hyperkeratosis, and ulcreations

Others: cardiovascular, pulmonary,

immunological, and neurological and

endocrine (i.e. diabetes) effects

Cancer Skin cancer

Internal Cancers (bladder, liver, lung, kidney, colon, uterus,prostate, stomach, nasal passages, )

Mechanism: Arsenic may be a potent endocrine disruptor,

altering hormone-mediated cell signaling at extremely lowconcentration.


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Arsenic Occurrence

Natural source: erosion, dissolution or weathering from rocks or

soils volcanic eruption and forest fires

the dissolved arsenic enters groundwater orsurface water

primarily found in ground waters

Anthropogenic sources: industrial processes, such as mining, smelting,

wood preserving, pesticide spraying, agriculture,

pulp and paper production, coal burning


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Exposure Routes

Ingestion through DrinkingWater

higher in groundwater thanin surface water

from wells drilled througharsenic-bearing sediments

Primarily inorganic form

Inhalation of Air

mostly from occupational exposure

Food Intake

seafood, meat and poultry, grain and grain products,fruits and vegetables

primarily organic form

Primarily inorganic form


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Global Arsenic Concentration in Ground Water

Country Potential ExposedPopulation

Concentration (ppb)

Bangladesh 30,000,000 5,000

Taiwan 100,000 to 200,000 10 to 1,820

Inner Mongolia 100,000 to 600,000 1 to 9,900

Chile 400,000 100 to 1,000

USA and Canada - 100,000


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Arsenic Mass Poisoning in

Bangladesh and West Bengal Epidemics of cholera,

dysentery, and other

waterborne infectious diseasesb/c of bacteria.

Too many children were dying.

In the 1970s, the UnitedNations Childrens Fund(UNICEF), spearheaded aneffort to switch the regionspopulation from drinkingsurface waters to groundwater.

10 Millions tubewells weredrilled into arsenic-rich

sediments


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Arsenic Mass Poisoning in

Bangladesh and West Bengal (Cont.)

As a result, in many of these

wells arsenic levels reach5001,000 g/L and evenhigher.

More than 500 million people

(80% of Bangladeshis) at riskof chronic arsenic poisoning

The World HealthOrganization (WHO) has

labeled this the worst masspoisoning in history.

The need for alternative watersource.

Film trailer: http://www.ifilm.com/ifilmdetail/2745238


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Table Sources: Allan H. Smith et al (2002), Arsenic Epidemiology andDrinking Water Standards, Science, Vol. 296, pp 2145-2146.


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Arsenic Rulemaking

The US EPA made the new arsenic rule in 2001.

Lowers maximum contaminant level(MCL) from 50 to 10 g/L

Establishes maximum contaminant level goal(MCLG) at 0

Applies to Community water systems (CWSs)

Non-transient non-community water systems (NTNCWSs)

Not applied to Transient Non-Community Water System (TNCWS) Becomes enforceable on January 23, 2006

Base on arsenic cancer risk assessment,

considering technological feasibility (economicanalysis)

1


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USEP

A2001

USEP

A2001


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Regulating with Sound Science

EPA promotes sound science research and itsappropriate integration into regulatory policymaking.

Internal Science Advisory Board

Science Policy Council

peer review policy

specially trained staff

External oversight from committees in both congressional chambers

scrutiny from a multitude of scientific and technical

organizations Arsenic case: more scientific review

new evidence and data

expert panels review


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Arsenic Cancer Risk Assessment

Animal evidences and models are absent.

Based on epidemiological data from Taiwan

Skin cancer Internal cancers (bladder, lung, kidney, and lever)

Incidence per 10,000 People

Controversial because of uncertainty and variability

issues


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Uncertainty Issues in Arsenic

Case Limitations of Data from Taiwan

Study design Differences between Taiwan and U.S.

populations, e.g. genetics, lifestyles,

nutrition, diets

Dose-response models

Inconsistent epidemiological data

Low-dose extrapolation incomplete knowledge of the uptake,

bio-transformation, and distribution of

arsenic in the body


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Variability Issues

The risks to sensitive and susceptible

subpopulations may not be fully quantified

people with poor nutritional status

infants or children

pregnant and lactating women

Considering variability and uncertaintyissues in risk assessment, policy has to

apply a Margin of Safety.


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Arsenic Cost-Benefic Analysis

Economic analysis does not support EPAs new arsenicrule.

Table source: Burnett and Hahn (2001), A Costly Benefit, Regulation,

Fall, pp.44-49.


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What are the benefits of this rule?

protect approximately 13 million Americans served byCWSs and NTNCWSs

Prevent

~ 19-31 cases of bladder cancer ~ 5-8 deaths due to bladder cancer per year

~ 19-25 cases of lung cancer

~ 16-22 deaths due to lung cancer per year

substantial non-quantified

benefits of this rule, including

reducing the incidences ofnon-cancerous effects.


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How many people and how many systems

will be affected by this rule?

Table source: http://www.epa.gov/safewater/arsenic/regulations_techfactsheet.html


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How much will this rule cost?


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A Case for Decentralized Standard Setting?

The dilemma in setting anational standard whenthere are striking variations

in costs across waterdistricts.

exemptions provisionunder the Safe Drinking

Water Act Because the differences in

costs and preferencesacross various

communities, the best wayto accommodate suchvariation is to allow districtsto determine their ownstandards. Do you agree?

arsenic in water

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