RP3 Design, Sampling, Measurement and Design
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(CRA-1117-825974) Uae of Semipermeable Membrane Devices (SPMDs) in a Probabilistic Assessment of Virginia Rivers.

Cranor, W¹, Alvarez, D¹, Huckins, J¹, Perkins, S¹, Clark, R¹, Stewart, R², ¹ USGS, Columbia, MO, USA² Virginia Department of Environmental Quality, Richmond, VA, USA

ABSTRACT- The Virginia Department of Environmental Quality (VDEQ) has been charged with monitoring factors which may be indicators of water quality in free flowing freshwater streams and in estuarine waters. The VDEQ has adopted a strategy which incorporates a probabilistic monitoring program for free flowing freshwater streams, consisting of all non-tidal perennial streams and rivers within the Commonwealth of Virginia. As an integral part of this much larger study, lipid-containing semipermeable membrane devices (SPMDs) were used to sample ultra-trace (i.e., < ng/L) and trace (ng/L to mg/L) levels of hydrophobic organic contaminants in the water column of selected streams. The SPMDs were prepared by US Geological Survey (USGS) scientists and replicate samplers were deployed at 50 study sites by VDEQ personnel and recovered from 46 of the 50 sites. The SPMDs were processed and analyzed by USGS to determine concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and selected current-use pesticides including trifluralin, diazinon, dacthal, chlorpyrifos, endosulfans, and permethrins in stream waters. A number of OCPs, PAHs, and current use pesticides were detected in SPMDs at most sites. However, only pentachloroanisole (PCA; a microbial methylation product of the wood-preservative pentachlorophenol) was found at quantifiable levels at every site analyzed. Elevated levels of PCBs were found only at two sites. The highest concentrations of individual PAHs at sample sites were phenanthrene, fluoranthene and pyrene. This observation is typical of PAH concentrations in environmental waters where these chemicals originate from pyrogenic sources. Previously developed models were employed to estimate aqueous concentrations of contaminants of concern in the water columns of the rivers studied.

Key words: SPMDs, Water Concentrations, OCPs, PAHs