ACS Boston seminar presentation 2015

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  • Samuel D. Supowit, Akash M. Sadaria, Edward J. Reyes, Rolf U. Halden

    Mass balance of fipronil in a wastewater treatment train and engineered wetland

    GLOBAL SECURITY INITIATIVE

  • Fiproles

    2

    Fipronil Sulfide Sulfone Amide Desulfinyl

  • Rationale Fipronil is a high production chemical

    Banned for use on rice in China, 2009

    It has been banned for most agricultural uses in the E.U., 2013

    3

  • 4

    Implicated in colony collapse disorder

    Highly toxic to bees

    LD50 = 1-6 ng/bee

    Rationale

    Compound

    Procambarusa Hyalella aztecab Diphetor hagenib 33 OC urban

    water conc.

    (g/L)

    Half-life

    31 LC50 (g/L) 30 LC50 (g/L)

    30 EC50 (g/L)

    30 LC50 (g/L)

    30 EC50 (g/L)

    34 Silt loam (d)

    35 Facultative conditions (d)

    Fipronil 14.3-19.5 1.3-2.0 0.65-0.83 0.20-0.57 0.11-0.21 0.05-0.39 210.15 -

    -desulfinyl 68.6 - - - - 0.05-0.13 - 217-497

    -sulfide 15.5 1.1-1.7 0.007-0.003 - - ND >200 195-352

    -sulfone 11.2 0.35-0.92 0.12-0.31 0.19-0.54 0.055-0.13 0.05-0.19 >200 502-589

    aProcambarus species were clarkii and zonangulus. bValues for H. azteca and D. hageni are the 95% confidence interval. OC Orange County, California

    ND non detect

    1

  • Rationale

    5 http://www.actbeyondtrust.org/wp-content/uploads/2013/07/IUCN2013sympo03_sluijs.pdf

  • Rationale

    6

    Plants uptake and translocate pesticides through their xylem, providing an indirect route of exposure to non-target foragers and pollinators

  • Rationale

    7

    Plants uptake and translocate pesticides through their xylem, providing an indirect route of exposure to non-target foragers and pollinators

  • Rationale Fiprole

    degradate fate in WWTPs not assessed in literature.

    Only one study assessed fipronil in influent, effluent, biosolids.

    8

  • Background

    In a prior study, Heidler & Halden (2009) determined 18 22 % aqueous removal of fipronil in a conventional WWTP.

    Are similarly toxic degradates formed?

    9

  • Objective

    Perform a mass balance for fiproles over a wastewater treatment train and engineered wetland, screening for heretofore unexamined metabolites.

    Use isotope dilution and standard addition for quality control to produce high prec. data.

    10

  • Specific Aims 1. Develop analytical methods for assessing

    fiproles in WWTP matrices (influent, effluent, sludge).

    2. Design a sampling campaign in order to determine the fate of fiproles across primary, secondary, and tertiary treatment.

    3. Perform a mass balance for fiproles over a WW treatment train and engineered wetland.

    11

  • Fiproles are largely resistant to degradation in treatment.

    Hypothesis

    12

  • Fiproles are largely resistant to degradation in treatment.

    If parent compound disappears, degradates form in treatment.

    Biosolids have more sulfide.

    WAS has more sulfone.

    Wetland has more amide.

    Hypothesis

    13

    WWTP

  • Sampling plan Locations

    14

    PP

    Wetland

    River

    = =

    Primary sedimentation

    basins

    Secondary sedimentation

    basins

    Headworks Aeration

    basins

    PS Thickening Centrifuge

    WAS Thickening Centrifuge

    Acid Phase

    Methane Phase

    DS Thickening Centrifuge

    Centrate Treatment

    Disinfection

  • ISCO 6700 and 6712 Incremental sampling

    program to approximate flow pattern

    20 mL increments at designated times

    2.5 L composites

    15

  • Experimental design Extraction (water)

    16

    1000 mL

    WAS & PS

    500 mg/3 mL Strata XL 4 mL eluate x 2

    LC-MS/MS

    Concentrations calculated by both standard addition and isotope dilution

  • Experimental design

    Extraction (solids)

    17

    Surrogate addition

    Acetone extraction

    Shake Centrifuge Solvent

    switch to hexane

    Cleanup on Florisil

    Analyze by

    LC-MS/MS

  • Method performance

    18

    Chemical

    Wastewater Solids

    Spiking

    level

    (pg/L)

    MDL

    (pg/L)

    Relative

    recovery

    (%)

    Absolute

    recovery

    (%)

    Spiking

    level

    (pg/g)

    MDL

    (pg/g)

    Relative

    recovery

    (%)

    Absolute

    recovery

    (%)

    Fipronil 100 46 116 14 60 14 50 19 120 13 55 18

    -Sulfide 300 159 N/A 67 13 150 144 N/A 48 18

    -Sulfone 200 72 N/A 101 19 100 98 N/A 89 32

    -Amide 500 304 N/A 87 22 250 88 N/A 90 21

    -Desulfinyl 1000 773 N/A 78 15 500 242 N/A 85 15

    N/A Not applicable

    1

    Table 1. Spike levels, detection limits, and recoveries of fiproles extracted from surrogate wastewater and sludge matrices (n = 7).

    Figure 1. (Right) Chromatograms of five fiproles extracted from spiked (20 ng/g nominal) and unspiked dewatered sludge, after cleanup on Florisil and elution with 4 mL DCM. Primary ion transitions are shown at top, and secondary (qualitative) transitions at bottom. *Fipronil-desulfinyl was analyzed by GC-MS/MS.

    ESI negative mode C8 column

  • Sampling

    19

  • Sampling

    20

  • Sampling

    21

  • Results

    22

    Figure 2. Concentrations of fiproles in (A) WWTP influent, (B) WWTP effluent (wetland influent), (C) wetland effluent, and (D) biosolids. Biosolids concentrations are normalized to 1 g dry weight. Error bars represent max and min values for water streams (n = 2), and standard deviation for biosolids (n = 3).

    Co

    nce

    ntr

    atio

    n (

    ng/

    L)

    WWTP influent

    WWTP effluent

    Wetland effluent

    Biosolids

  • Results

    23

    Figure 3. Fiprole mass distribution in three WW streams. The most abundant congener in all three streams is fipronil. The amide and desulfinyl degradates were not detected in these streams.

  • Results parent compound mass balance

    24

    1.1 0.1% adsorbed to WAS

    25 3% transformed 74 3% passed

    through to disinfection

    basin effluent

    Fipronil mass balance over treatment train Fipronil mass balance over wetland

    44 4% transformed or

    accumulated

    56 4% passed through

    Figure 4. Fipronil mass balance over treatment train from primary treatment to disinfection (left) and engineered wetland (right).

    Accounted for by degradates

    Not accounted for by degradates

  • Results total fiproles over treatment train

    77 11 73 11 83 24

    0.09 68 6 1.4 0.003

    Qx Combined flow from other treatment trains

    Figure 5. Treatment train total 5-day fiprole load in mmol.

  • Results individual fiproles

    26

    Figure 6. Fiprole mass loads (in mmol) in wastewater streams over the course of five days. Direction of water flow is from left to right, (primary influent to disinfection basin effluent). Error bars represent high and low values from two experimental replicates. The bars on top are enlarged portions of the histogram on the bottom, in order to make fipronil-desulfinyl masses visible. Fipronil-desulfinyl concentrations are estimated, near the detection limit. Sludge streams are omitted, as their mass contributions are negligible (n = 2 ). m

    mo

    l

  • Results

    27

    Figure 7. (A) Average daily mass loads of fiproles over five days, where error bars represent standard deviations (n = 10). (B) Daily mass loads of wetland (WL) influent and effluent streams on days 1 and 5, respectively, where error bars represent max/min values (n = 2); the hydraulic retention time of the wetland was 4.7 days. The right-hand y-axis is expressed as grams of fipronil per day.

    47 13% total fiprole reduction

    No discernable change

  • Discussion Total fiprole mass discharge = 7.9 f g/day (into wetland)

    = 6.3 lb/yr

  • Calculating annual mass discharge

    20

    3.785

    106

    75

    365

    1012

    2.2

    = .

  • Discussion

    30

    The entire volume of AG fipronil in the U.K. during peak use was about 124 kg/yr (273 lb/yr)

    The estimated, extrapolated discharge by US WWTPs is 520 kg/yr (1140 lb/yr)

  • Discussion

    31

    While the amount of fipronil inadvertently discharged into the environment in the form of treated wastewater is alarmingly high, it is unclear how wastewater contributes to the fiprole pollen loads in angiosperms, the body burdens of aquatic organisms, or the toxicological effects for other non-target organisms. Further research is needed to link the fiprole load in wastewater effluents to plant uptake and non-target organism exposure and effects.

  • Conclusions

    Conventional wastewater treatment is not efficient at removing fiproles.

    Reduction in parent compound mass may coincide with degradate formation (sulfone, in particular).

    Total fiprole levels re-entering the environment from wastewater treatment are toxicologically relevant and may impact biota.

    32

  • Future research needed

    Modeling uptake of fiproles in plants and food chain

    Risk assessment needed in order to determine ecotoxicological effects

    33

  • Acknowledgements

    Dr. Rolf Halden, PI

    Dr. Arjun Venkatesan

    Akash Sadaria

    Edward Reyes

    Top secret collaborators

    34

  • Questions

    35