10/24/2016. Environmental Exposure Modeling of Microplastic Cosmetic Ingredients. Outline. Study Purpose

Transcription

1 Environmental Exposure Modeling of Microplastic Cosmetic Ingredients Christopher Holmes, Nikki Maples-Reynolds, Raghu Vamshi Waterborne Environmental, Inc. Iain Davies, Beth Jonas - Personal Care Products Council Scott Dyer - The Procter & Gamble Company Paul DeLeo American Cleaning institute 2016 Science Symposium and Expo Environmental Safety Workshop Alexandria, VA October 25, 2016 Outline Purpose of study Underlying model & data Application to microbeads & microplastics PCPC online exploration tool Application to published numbers Feedback 2 Study Purpose Help understand potential aquatic environmental concentrations of microplastics in freshwater Initially focused on microbeads Put reported numbers from literature, media into context Use refined exposure modeling approaches Challenges Incorporate minimal, but growing, knowledge around environmental fate and exposure of microplastics Still provide useful information, now and in the future Build a tool, not just provide a report Benefit PCPC Global Plastic Task Force's three-pronged approach to plastic and polymer environmental stewardship efforts (scientific, legislative and communications) 3 1

2 Timeline Conceptualization Q Initiation Q Design and parameterization Q Pilot model runs Q Full model runs Q Tool construction & testing Q Availability Q Presentations Q Publication Q Based on istreem model istreem is a web-based tool that models the concentrations of a chemical that goes down the drain May relate to use and disposal of home and personal care products, cosmetics, pharmaceuticals and pesticides Resulting concentrations are estimated at the discharge points of over 10,000 wastewater treatment plants and downstream receiving waters covering over 200,000 river miles across the continental United States and part of Canada (Ontario) Based on best available public data sets Model is sponsored and made available to the public by the American Cleaning Institute ( Web Web Server User Info GIS-ROUT Model Model Input Databases 5 Overview of istreem Influent to WWTP (per capita use x population served) Removal in WWTP (e.g., to biosolids) Inputs to segment WWTP Effluent Upstream Input Tributary Input WWTP Effluent Calculates effluent concentration Loss within segment i.e., decay Biodegradation Adsorption Downstream Transport Burial Calculates concentration for all effluent-impacted streams 6 2

3 Predicted Environmental Concentration (PEC) PEC = Q x (1 R) 365 x WW x POP x DF Q = annual quantity of substance used R = fraction of chemical removed by WWTP Variable efficiency for different WWT technologies WW = per capita wastewater generation POP = population served Specific to each facility DF = dilution factor of the receiving water Site specific dilution, mean & low stream flow 7 How does this relate to microbeads / microplastics? Helps understand potential aquatic environmental concentrations, or put published data into context But what modeling parameters to use for microplastics? We know that A portion of microbeads are disposed of down the drain Varying or uncertain amount of removal in treatment process Remainder enters the aquatic environment Currently there is a large amount of uncertainty in the science around exposure and effects for these compounds, as well as their physical / chemical properties and env. fate How to proactively evaluate potential for risk? Objectively evaluate reported environmental concentrations? Need something flexible, accessible, viable, financially feasible. 8 PCPC Microplastics Environmental Explorer Develop a web-based tool Use a defined set of istreem runs to bound possible environmental concentrations Make use of available information from US & Canada Incorporate minimal, but growing, knowledge around environmental fate and exposure of microplastics Provide ability for visualization and manipulation of results based on user input 9 3

4 Range of WWTP removal rates Select set of 10 representative wastewater removal rates Activated sludge (AS) 99.9% 99% 95% 90% 85% 80% 75% 50% 25% 0% Oxidation ditch (OD) 99.9% 99% 97% 92% 87% 82% 77% 51% 26% 0% Trickling filter (TF) 99.9% 99% 95% 90% 85% 80% 75% 50% 25% 0% Lagoon (L) istreem category 94.9% 94% 90% 85% 81% 76% 71% 47% 24% 0% Rotating bio. con. (RBC) istreem 93.9% 94% 90% 85% 81% 76% 71% 47% 24% 0% Primary 66% 66% 66% 66% 66% 66% 33% 33% 25% 0% Determined relative fraction of removal compared to activated sludge using TSS data TSS removal Fraction of AS Activated sludge (AS) 96% 1.00 Oxidation ditch (OD) 98% 1.00 Trickling filter (TF) 96% 1.00 Lagoon (L) istreem category 91% 0.95 Stabilization Pond (SP) 89% 0.93 Aerated Lagoon (AL) 93% 0.97 Rotating bio. con. (RBC) istreem 91% Range of in-river removal rates Decay accounts for all processes for removal from water column E.g., dissipation, degradation, deposition, sorption to sediment Provide range of all likely values for exploration Spread across 10 values 5 orders of magnitude Values: to 100 Half-life = ln(2)/decay Decay Half-life (days) no decay 11 Scope of model inputs 100 total runs WWTP Removal River Loss-> Activated sludge (AS) 99.9 Oxidation ditch (OD) 99.9 Rotating bio. con. (RBC) 93.9 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Trickling filter (TF) 99.9 Lagoon (L) 94.9 Activated sludge (AS) 99 Oxidation ditch (OD) 99 Rotating bio. con. (RBC) 93.1 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 Trickling filter (TF) 99.0 Lagoon (L) 94.1 Activated sludge (AS) 95 Oxidation ditch (OD) 96.9 Rotating bio. con. (RBC) 89.3 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 Trickling filter (TF) 95.0 Lagoon (L) 90.3 Activated sludge (AS) 90 Oxidation ditch (OD) 91.8 Rotating bio. con. (RBC) 84.6 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 Trickling filter (TF) 90.0 Lagoon (L) 85.5 Activated sludge (AS) 85 Oxidation ditch (OD) 86.7 Rotating bio. con. (RBC) 79.9 E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 Trickling filter (TF) 85.0 Lagoon (L) 80.8 Activated sludge (AS) 80 Oxidation ditch (OD) 81.6 Rotating bio. con. (RBC) 75.2 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 Trickling filter (TF) 80.0 Lagoon (L) 76.0 Activated sludge (AS) 75 Oxidation ditch (OD) 76.5 Rotating bio. con. (RBC) 70.5 G1 G2 G3 G4 G5 G6 G7 G8 G9 G10 Trickling filter (TF) 75.0 Lagoon (L) 71.3 Primary (P) 33.0 Activated sludge (AS) 50 Oxidation ditch (OD) 51.0 Rotating bio. con. (RBC) 47.0 H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 Trickling filter (TF) 50.0 Lagoon (L) 47.5 Primary (P) 33.0 Activated sludge (AS) 25 Oxidation ditch (OD) 25.5 Rotating bio. con. (RBC) 23.5 I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 Trickling filter (TF) 25.0 Lagoon (L) 23.8 Primary (P) 25.0 Activated sludge (AS) 0 Oxidation ditch (OD) 0.0 Rotating bio. con. (RBC) 0.0 J1 J2 J3 J4 J5 J6 J7 J8 J9 J10 Trickling filter (TF) 0.0 Lagoon (L) 0.0 Primary (P)

5 Baseline model runs Baseline model run used for scaling as per user inputs Baseline usage rate of 0.01 g/cap/day Equates to about 500 t annual load Population with WWTP discharge to surface water 22 MGD effluent volume 140 million people Compare to 1 particle / L of WWTP influent (Carr et al, 2016) Particle (bead) width = 420 um PE density = 0.91 g/cm 3 Results in g/cap/day Mean annual flow used for environmental concentrations 13 Model run results Selected percentiles of output distributions >25,000 concentrations for each run (tool contains 100 runs) 95 th percentile 50 th percentile 14 Model Results (example: 95 th %ile, µg/l) River Loss no decay WWTP Removal Based on baseline usage rate of 0.01 g/cap/day (~500 t annual load through WWTP to river) 15 5

6 Development of an istreem meta model Create meta-model to approximate selected PEC based on any input Using 100 runs from full set, determine regression that can be used for prediction based on any removal inputs Log transformed fit, resulting in r 2 = 84.9 Evaluation on hold at this time log(conc) ~ Removal * Decay * Visualization Assumptions High uncertainty around both WWTP and in-stream removal rates High uncertainty around environmental concentrations of concern Large potential user base (with diverse needs) Needs flexibility to apply to a range of substances Need to put output into meaningful context for user Purpose of the visualization is to provide a way for members to explore the possible environmental concentration space for a substance, without having to specify/define singular parameters of high uncertainty 17 Demonstration Input Parameters 18 6

7 Demonstration Output Table 19 Demonstration Output Chart 20 Applied to published numbers Use of Micro-Plastic Beads in Cosmetic Products in Europe and Their Estimated Emissions Gouin, T., Avalos, J., Brunning, I., Brzuska, K., de Graaf, J., and Kaumanns, J. (2015). International Journal for Applied Science. 263 tons/yr, or 2.4 mg/cap/day (entire population) ~47% of population discharge to surface water (freshwater) Resulting in 123 tons/yr in tool (equivalent to 2.4 mg/cap/day) Average WWTP influent concentration = 4.11 ug/l What kind of environmental concentrations might we estimate using these emissions? 21 7

8 Applied to published numbers Average influent concentration = 4.11 ug/l 95 th percentile distribution for all 100 combinations Distribution is >20,000 river segments Incorporates variable per capita water use environmental dilution factors in mixing zone other dilution from unimpacted streams upstream MP contributions 22 Applied to published numbers Average influent concentration = 4.11 ug/l Assume 90% WWTP removal In-river removal of 0.01 (70 day half-life) Full distribution plot 95 th = ug/l 50 th = ug/l 23 Features of PCPC Microplastics Visualization Tool Allows for variable usage, based on mass or particles Process by mass, beads, particles or fibers Presents 100 values across the entire range of possible environmental results 0 to 99.9% wastewater removal No in-river removal to ~10-minute half-life Nine points in each output concentration distribution (e.g., 95 th, 90 th, 50 th percentile) Puts published or media findings into context of what it would take to generate similar environmental numbers In terms of total mass in formulated products and removal in treatment and environment Web-based for member access 24 8

9 Some published uses of istreem Aronson D, Weeks J, Meylan B, Guiney PD, Howard PH Environmental release, environmental concentrations, and ecological risk of N,N-Diethyl-m-toluamide (DEET). Integr Enviro Assess Manage 8: Federle T, Sun P, Dyer S, and Kiel B Probabilistic assessment of environmental exposure to the polycyclicmusk, HHCB and associated risks in wastewater treatment plant mixing zones and sludge amended soils in the United States. Sci Total Environ, Kapo, DeLeo, Vamshi, Holmes, Ferrer, Dyer, Wang and White-Hull istreem : An approach for broad-scale in-stream exposure assessment of "down-the-drain" chemicals. Integr Enviro Assess Manage 12(4): Kapo, McDonough, Federle, Dyer, Vamshi Mixing Zone and Drinking Water Intake Dilution Factor and Wastewater Generation Distributions to Enable Probabilistic Assessment of Down-The- Drain Consumer Product Chemicals in the U.S. Science of the Total Environment, Volumes , pp DOI: /j.scitotenv Sanderson, H et al., Occurrence and Risk Screening of Alcohol Ethoxylate Surfactants in Three U.S. River Sediments Associated with Wastewater Treatment Plants. Science of The Total Environment : doi: /j.scitotenv Simonich S, Sun P, Casteel K, Dyer S, Wernery D, Garber K, Carr G, and Federle T Probabilistic Analysis of Risks to US Drinking Water Intakes from 1,4-Dioxane in Domestic Wastewater Treatment Plant Effluents. Integrated Environmental Assessment and Management 9(4): Next Steps Presentation PCPC Fall Science Symposium SETAC North America Feedback from you Peer-reviewed publication Future enhancements 26 Questions? 9

10 Thank you! For more information: Waterborne Environmental, Inc. 897b Harrison St., SE Leesburg VA (703) Chris Holmes Raghu Vamshi Nikki Maples-Reynolds 10