Research Areas > Contaminants > Estimating Pollutant Loadings and Fluxes in Impaired Coastal Waterways Using Passive Samplers
Project: Estimating Pollutant Loadings and Fluxes in Impaired Coastal Waterways Using Passive Samplers
Background and Objective
Due to the lack of information on major contaminant sources and transport pathways for trace organic contaminants within aquatic systems, total maximum daily load (TMDL) regulations remain a challenge to justify and promulgate. This management technique sets a standard for total contaminant loading in one day, but in order to meet this goal, managers must be able to identify and mitigate the sources of contamination. For example, trace organic contaminants in estuaries may be contributed by both upstream runoff and instream release of contaminants from bottom sediments (Figure 1).
The goals of this project were to (1) test and compare several passive, in-situ water column samplers for measuring ultra-low levels of trace organics; (2) determine water column contaminant concentrations in-situ during low flow conditions; and (3) quantify contaminant source loading from an urban creek.
Figure 1. Simplified representation of contaminant sources, transport (arrows), and fate (stars) for a coastal estuary.
Status
This project was completed in 2009.
Methods
SPME (solid-phase microextraction) samplers and PEDs (polyethylene devices) were calibrated, and their performance was compared in lab experiments. Pre-calibrated samplers were then co-deployed along a spatial gradient in the Ballona estuary. Measurements from the samplers were validated using independent samples from a large volume in situ pump system.
Findings
Findings show that a combination of SPME and PED passive samplers measured regulated HOCs at less than 0.01 ng/L (nanograms per liter) in the water column. In-situ measurements of PAHs, DDTs, and chlordanes (CHL) using SPME samplers agreed well with the validation techniques (Figure 2). In situ measurements of PAH, PCBs and DDT by SPME and PED agreed well with validation techniques, including large volume water samples collected using an in situ pumping system (Figure 3).Coupled with data on bed sediment and porewater contaminant levels, these devices offer a new, more cost-efficient means for characterizing contaminant sources and transport pathways, while evaluating the effectiveness of management actions to reduce contaminant loading into impaired coastal waterbodies.
Figure 2. Dissolved water column levels of chlordanes (CHL), DDTs and PAHs measured by SPME samplers in Ballona estuary were in excellent agreement with data from a water sample collected using an in-situ pump system.
Figure 3. Aqueous concentrations of TMDL-regulated pollutants (e.g., PAH, PCB congeners and DDT compounds) determined by polyethylene and solid phase microextraction (SPME) passive samplers agreed well with validation methods in spiked laboratory experiments (top) and under field conditions (bottom). (LLE = liquid-liquid extraction; In-situ pump = high volume sample processed through XAD sorbent.)
Partners
Loyola Marymount University
University of Southern California
City of Los Angeles
Presentation
J Sayre, W Lao, R Adams, and K Maruya. August 2008. Comparing polyethylene devices (PEDs) and solid phase microextraction (SPME) for measuring ultra-low aqueous concentrations of regulated organic pollutants. Presented at 5th SETAC World Congress, Sydney, Australia.
Poster
JM Sayre, RG Adams, KA Maruya, J Peng, and W Lao. April 2007. Calibrating polyethylene devices (PEDs) to quantify organic pollutant concentrations and loadings in impaired urban waterways. Presented at the Society of Environmental Toxicology and Chemistry (SETAC) Southern California Regional Chapter 2007 Annual Meeting, Lake Arrowhead, CA.
This page was last updated on: 7/1/2014