NEW ADVANCES IN PASSIVE SAMPLING FOR SEDIMENT RISK ASSESSMENT Upal Ghosh Department of Chemical, Biochemical, & Environmental Engineering UMBC SETAC HDC Oct 7, 2015

Legacy contaminants in exposed sediment contaminates the food chain through: 1)bioaccumulation in benthic organisms 2)flux into the water column, and uptake in the pelagic food web. Contaminated sediment 1 Bioaccumulation of Hydrophobic Compounds Predictions work reasonably well for natural systems Predictions become more challenging for industrially impacted sediments

3 2 L water 100g fish mg DDD 1.7 mg DDD Sediment 1 ppm K oc = 151,000 Large fish 1.7 ppm Small fish 0.5 ppm Plankton ppm Water ppm Bioaccumulation And Exposure of DDD

Ehlers and Luthy, ES&T 2003

Measurement of HOCs in Water is Challenging Need to measure <ng/L concentrations in sediment porewater Two approaches to get to this concentration: 1)Modeling based on partitioning calculations: A)Sediment concentration and fraction OC B)Model presumes a certain partitioning behavior for the OC C)Complication from the presence of BC D)Difficult to characterize BC partitioning 2)Direct measurement: A)Detection limits associated with manageable grab sampling B)Separation of colloids challenging C)Passive sampling

Carbon Type Influences PAH Partitioning in MGP Sediments Red line shows predicted K oc based on NOM partitioning Measured K oc higher by two orders of magnitude PAH association with coal, coke, pitch, or soot increases observed K oc

7 Organic Carbon Types in Soil/Sediment Sediment contains sand, silt, clays, charcoal, wood, char, coal, & shells PCBs/PAHs bound to carbonaceous particles less bioavailable charcoal coal sand wood shell char Petrography images coalcharcoalcoke Phenanthrene partitioning for various organic materials From: Ghosh et al. Environ. Sci. Technol. 2003

1)Hydrophobic chemicals partition among the aqueous and different solid phases 2)Equilibrium distribution can be described by: Freely dissolved Passive sampler DOC POC Two approaches to measure total and freely dissolved concentrations: 1)Remove POC by centrifugation, measure total dissolved concentration and DOC, estimate freely dissolved concentration. 2)Use calibrated passive sampler to measure freely dissolved concentration, measure DOC/POC, and estimate total dissolved concentration. Conceptual Understanding of Passive Sampling: C total = C free + DOC*K DOC *C free + POC*K POC *C free

PAH & PCB Uptake Kinetics in Well Mixed Batch Hawthorne et al. Analytical Chem & 2011 Under well-mixed conditions POM, PE, or PDMS reaches close to equilibrium in <30 days Used to measure site-specific partition constants

10 Polymer Partition Constants PDMS PAH: logK PDMS-w = 0.725logK ow (R 2 = 0.99) PCB:logK PDMS-w = 0.947logK ow – (R 2 = 0.89) POLYETHYLENE PAH: logK PE-w = 1.22logK ow – 1.36 (R 2 = 0.99) PCB:logK PE-w = 1.18logK ow – 1.26 (R 2 = 0.95) POLYOXYMETHYLENE PAH: logK POM-w = 0.839logK ow (R 2 = 0.97) PCB:logK POM-w = 0.791logK ow (R 2 = 0.95) The most important parameter necessary for calibration is Kpw Accurate measurement of Kpw for high Kow compounds is challenging A list of provisional Kpw values are available in Ghosh et al Common polymers : Polyethylene (PE), Polyoxymethylene (POM) and Polydimethylsiloxane (PDMS)

11 Practical guidance on the use of passive sampling methods (PSMs) for C free for improved exposure assessment of hydrophobic organic chemicals in sediments. Based on SETAC Technical Workshop “Guidance on Passive Sampling Methods to Improve Management of Contaminated Sediments,” 2012 Practical Guidance for Passive Sampling

Passive sampler uptake slow in static field deployments 12 Polymer-water partitioning coefficient United States Environmental Protection Agency. (2012, Dec). Guidelines for using passive samplers to monitor organic contaminants at superfund sediment sites

Diffusive Process of HOCs Into Polymers 13 Cp Ku Ke Cw A function of overall mass transfer coefficient Dissipation of Performance Reference Compounds X Cw Cp D p =Diffusion coefficient in polymer, ε = porosity, ρ = particle bulk density D = effective diffusion coefficient, K d = sediment-water partitioning coefficient

Tracking pyrene diffusion with Fluorescence 14 PE/POM rod in Saturated Pyrene solution Aluminum foil Fluorescence intensity Distance (mm) Fluorescence image of polymer slice Cut

15 Pyrene diffusion into PE (static) Sediment side polymer

Performance Reference Compounds Equilibrium slow for: 1) high K ow ; 2) static porewater Mass transfer in sediment side difficult to predict Performance Reference Compounds (PRCs) are used to correct for non-equilibrium PRCs have similar diffusion properties as analytes 16 Passive sampler Time (days) Polymer fractional uptake

Limitations of PRC-correction methods Low fractional loss of high molecular weight PRCs Extrapolation from low molecular weight PRCs difficult: 17 Loss of low molecular weight PRCs C free High molecular weight analytes Adjustment methods Inaccurate for high molecular weights Diffusion model & K d -K ow correlation 2 1 st order model & molar volume correlation 1 1- Booij, K.; Hoedemaker, J. R.; Bakker, J. F. Environ. Sci. Technol. 2003, 37 (18), 4213– Fernandez, L. A., C. F. Harvey, and P. M. Gschwend, 2009a. Environmental Science & Technology, v. 43, p

How Do You Use Freely Dissolved Concentrations in Porewater (C free ) ? DO NOT: Call it : Bioavailable concentration or Bioavailable fraction Need a robust toxicity or biouptake model to plug in C free For PAHs: Can plug directly into toxic units calculation based on the narcosis model For other bioaccumulative compounds need to plug into a bioaccumulation model Examples in last talk by Huan Xia

1)Ex-situ equilibrium measurements of sediment porewater 2)In-situ probing to assess ambient contaminant concentrations or to assess changes with time or with treatment Pictures of typical applications: sediment water Applications of Passive Sampling Laboratory batch equilibrium Field evaluation of treatment performance Depth profiling of porewater conc. in sediment Passive sampling of porewater and in-situ bioaccumulation

Tool for inserting passive sampler frame in sediment. The 8’ pole allows deployment from a boat in shallow water sediments Passive sampler encased in stainless steel mesh and framed for sediment deployment Underwater video camera for confirming placement depth Rope and buoy for retrieval after deployment Deployment Device For Inserting Passive Sampler Frame Into Surface Sediments Image from underwater camera showing the passive sampler being inserted into sediment

Figure 1. Chronic toxicity to H. azteca (28- day) can not be predicted from total PAH concentration in MGP sediment Figure 2. Chronic toxicity to H. azteca (28- day) can be predicted by estimating PAHs in sediment pore water. Prediction of Toxicity: Sediment vs. Freely Dissolved Conc. Kreitinger et al, ETC 2007

Prediction of Biouptake in benthic organisms: Sediment vs. Freely Dissolved Conc. 7 freshwater and marine sediments Freely dissolved conc. measured by passive sampling and also directly Lipid concentrations better predicted from freely dissolved porewater Werner et al. ES&T 2010 Predicted from sediment Predicted from porewater

Sediment Passive samplers Water flow in aquaria tanks Components in each aquaria Treatments: Clean sediment (Rhode River) PCB impacted sediment (Near-shore Grasse River) PCB impacted sediment-AC treated in the lab Replicate aquaria with passive samplers in water column and sediment Fish species: Zebrafish PCB-free diet Sampling after 45 and 90 days 23 Prediction of PCB Uptake in Fish Fadaei et al. ES&T 2015

24 Sediment Partitioning Coefficient Predictions

The total PCB concentration in fish was decreased by 87% after treatment with AC 25 PCB Residue in Zebrafish after 90 Days

26 k1k1 k2k2 keke Predicting PCB Uptake in Fish (Arnot and Gobas 2004)

Observed and predicted PCB concentrations in fish Equilibrium model Kinetic model with ingestion

ACKNOWLEDGMENTS Funding support from SERDP/ESTCP programs, NIEHS, USEPA GLNPO, and Alcoa Several students and post docs KEY MESSAGES Freely dissolved concentrations of HOCs good predictor of biouptake and toxicity Passive samplers can accurately measure freely dissolved concentrations at equilibrium Corrections needed for non-equilibrium for in-situ measurements

30 Extraction Device also containing a lipid source (sunflower oil) to mimic the lipophilic environment  Phase one: acidic gastric condition  Phase two: near-neutral intestinal condition Simulated gastrointestinal fluid CARBON TYPE ALSO INFLUENCES PAH BIOAVAILABILITY IN ANIMAL GUT SERDP FUNDED STUDY

31 COMPARISON BETWEEN SOIL K D & BIOACCESSIBILITY

BACKGROUND ON ESB GUIDANCE (2003, 2008) ESBs are based on a target lipid model (Di Toro et al. 2000) Developed critical lipid concentrations for 49 aquatic species 5 th percentile expected to be protective of 95 percent of species tested Genus Mean Acute Value (  mol/g octanol) Percentage Rank of Genera

TIERED ASSESSMENT

PAH AND PCB ABSORPTION EFFICIENCY IN CLAMS From: McLeod et al. Environ. Sci. Technol Tracking 3 H-BaP and 14 C-2,2’,5,5’ PCB through a clam

ESB GUIDANCES (2008, 2005)