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

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USEPA Assistance Agreement No CR-830796-01-3
Use of Semipermeable Membrane Devices (SPMDs) in
a Probabilistic Assessment of Virginia Rivers
Poster RP016 SETAC 26th Annual Meeting,
Baltimore, MD, Nov. 13-17, 2005
W.L. Cranor1, D.A. Alvarez1, J.N. Huckins1, S.D.
Perkins1, R.C. Clark1, and R.E. Stewart2
1 U.S. Geological Survey, Columbia Environmental
Research Center, Columbia, MO, USA 2 Virginia
Department of Environmental Quality, Richmond VA,
USA.
ABSTRACT
ENRICHMENT ANALYSIS
CALCULATION OF WATER CONCENTRATIONS FROM SPMD DATA
SPMD DEPLOYMENT SITES
SPMD ANALYSIS RESULTS (Continued)
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,
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., lt
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
and recovered from 46 of the 50 sites by VDEQ
personnel (Figure 1). The SPMDs were processed
and analyzed by USGS (Figure 2) 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.
Figure 1. Site Locations for SPMD Deployments
Figure 3. Sample Processing and Analysis Flow
Chart
Many of the sites had measurable levels of some
of the historic use OCPs, which included the
chlordanes, the nonachlors, hexachlorobenzene,
dieldrin and endrin. Methoxychlor was
quantifiable at six sites, but the observed level
at site 9-SNK019.59 was eight times higher (37
ng/SPMD) than at any of the other five sites.
Every one of the six targeted current-use
pesticides was detected in SPMDs at one or more
of the 46 exposure sites. Diazinon was detected
in SPMDs more frequently (26 of the 46 sites)
than any other current-use pesticide. All
Diazinon levels were below the MQL (18 ng/SPMD).
The amounts of Endosulfan, Endosulfan-II, and
Endosulfan Sulfate in SPMDs were above their MQLs
(2.6, 1.8, 3.3 ng/SPMD respectively) at over
half of the sites. PCBs were detected in SPMDs
at only two sites. Total PCBs, as the sum of
individual congeners, was greater than the MQL
(65 ng/SPMD) at only one site, 3-MTN003.31. PAHs
were detected at all sites. The highest levels
of individual PAHs measured in SPMDs were
phenanthrene, fluoranthene and pyrene. In
several cases, methylated PAHs were also
observed.
To estimate water concentrations from SPMD
amounts with a reasonable degree of certainty,
the amounts of targeted contaminants and one or
more performance reference compound (PRC) must be
accurately measured in exposed SPMDs. Also,
appropriate calibration data for both target
compounds and PRCs must be available (1). The
overall accumulation of contaminant residues by
SPMDs is related to that specific contaminants
water concentration by Cw N/(VsKsw1?exp(?Rst/
VsKsw)) where Cw is the concentration of
the chemical in ambient water, N is the amount of
the chemical sampled by an SPMD (typically ng),
Vs is the volume of an SPMD (L), Ksw is the
equilibrium SPMD-water partition coefficient, Rs
is the SPMD sampling rate (L/d) and t is the
exposure time (d). Site specific in situ
sampling rates were derived for target compounds
using exposure adjustment factors (EAFs) to
correct laboratory derived Rs values. The EAF is
a ratio that is approximately equivalent to the
in situ sampling rate of a selected PRC divided
by the sampling rate of the same PRC from
calibration data (2). Then, the in situ or site
specific sampling rate (Rsi) of an analyte is the
EAF times its laboratory calibration Rs.
Perdeuterated PAHs, phenanthrene-d10 and
pyrene-d10, were used as PRCs in this study.
3-MTN003.31
9-SNK019.59
CONCLUSIONS
Table I. Frequency of Detection and Quantitation
of Targeted Analytes (number observed out of 46
sites)
Water concentration of total PCBs (2.1 ng/L) at
site 3-MTN003.31 was elevated compared to the
background levels observed at all other sites.
This aqueous concentration was the only
contaminant level observed in the study at a
sufficiently high level to classify the stream as
Impaired. Interestingly, this stream had
previously been classified, by the Virginia
Department of Environmental Quality, as
Impaired based on PCB levels in fish tissue.
Water concentrations of all targeted contaminants
(Table I) were well below (orders of magnitude)
levels which would trigger classification of the
stream as Impaired based on organic contaminant
concentrations. Because of the toxicity and
ubiquitous distribution of phenanthrene,
fluoranthene and pyrene, they are listed by the
US Environmental Protection Agency as priority
pollutants (PP). Water concentration estimates
of these PP PAHs are typical of published data on
PAH concentrations in environmental waters.
These chemicals often originate from pyrogenic
sources. Methylated PAHs, also observed, are
characteristic of petrogenic sources. The
dissolved phase concentrations of these PP PAHs
approach ng/L (i.e. ppt) concentrations (e.g.
site 3-MTN003.31 ). Of particular concern is
that phototoxic fluoranthrene and pyrene
represent two of the three highest PAHs found in
study waters. Fluoranthrene has been shown to be
toxic to fish fry during solar radiation cycles,
when water concentrations approach 5-ng/L. This
level of fluoranthene was approached only at site
3-MTN003.31 (4.3 ng/L). The concentration of
methoxychlor (0.33 ng/L) at site 9-SNK019.59
is also well below a level which would classify a
stream as Impaired. However, specific note is
taken in that methoxychlor is only rarely seen in
environmental waters.
EXPERIMENTAL DESIGN
This work was conducted as part of a
collaborative effort between the U.S. Geological
Surveys (USGS) Columbia Environmental Research
Center (CERC) and the Virginia Department of
Environmental Quality (VDEQ). The study was
designed to satisfy, in part, the Code of
Virginia, 62.1-44.195, water quality and
reporting requirements, which include expanding
the percentage of river and stream miles
monitored and providing information about trace
levels of toxic organic compounds in riverine
water columns. The focus of the much larger
study, which includes this work, is the
probalistic assessment of benthic
macro-invertebrate populations, standard water
quality chemistry, metals and toxic organic
contaminants in sediments, and dissolved organics
in Virginia water columns. SPMDs were used to
sample the hydrophobic-organic contaminants in
the water columns of selected streams within the
Commonwealth of Virginia. Prior to the advent of
SPMD technology, ultra-trace levels of many
contaminants in water were often below the
detection limits of most commonly employed low
volume (i.e., ? 5 L) sampling methods. Also, the
probabilities of detecting chemicals from
episodic discharge events were very low, because
sampling with conventional methods only provides
concentration data on a single point in time.
When sampling is integrative and uptake is linear
(1 to 10 L/d), residue concentrations in SPMDs
represent time weighted average (TWA)
concentrations of exposure water. SPMDs were
deployed for 27 to 86 days during the Spring
(Deployment 1) and Fall (Deployment 2) of
2003. Extracts of exposed SPMDs were analyzed
(Figure 3) to determine ultra-trace (i.e., lt
ng/L) and trace (ng/L to mg/L) concentrations of
polycyclic aromatic hydrocarbons (PAHs),
polychlorinated biphenyls (PCBs), organochlorine
pesticides (OCPs), and selected current-use
pesticides. Previously developed models (1) were
employed to estimate water concentrations of
contaminants of concern in the water columns of
the rivers studied. Water concentrations were
derived from SPMD levels using published
calibration data and an Excel-based water
concentration calculator. In the case of water
concentrations derived from SPMD data, a maximum
two-fold difference between SPMD derived water
concentrations and independently measured values
would be expected.
SPMD ANALYSIS RESULTS
A number of OCPs were detected in SPMDs at all
sites (Table 1). However, only pentachloroanisole
(PCA) was found at quantifiable levels at every
site analyzed. Although PCA is classified as an
OCP, it is produced in water by the microbial
methylation of the wood-preservative
pentachlorophenol. Figure 4 shows how PCA
concentrations in SPMDs vary from site to site.
SAMPLE PROCESSING
ACKNOWLEDGEMENTS
Figure 2. General Processing Steps for Deployed
SPMDs
Figure 4. Distribution of PCA Concentrations in
Samples (ng/SPMD) Across Sites
We gratefully acknowledge the funding of the
Virginia Department of Environmental Quality and
specifically the support of Roger Stewart and
other Virginia Department of Environmental
Quality personnel involved in the deployment,
retrieval, shipment, and delivery of these
samples to CERC for processing and analysis.
REFERENCES

• Huckins, J.N., Petty, J.D., Booij, K. 2005.
  Monitors of Organic Chemicals in the Environment
  Semipermeable Membrane Devices. Springer
  Publishing Company, New York, NY, USA, In Press.
• Huckins, J.N., Petty, J.D., Lebo, J.A., Almeida,
  F.V., Booij, K., Alvarez, D.A., Cranor, W.L.,
  Clark, R.C., Mogensen, B. 2002. Environ. Sci.
  Technol. 36 85-91.
• 3) NOTE Also see Poster RP210 entitled The
  Occurrence and Geospatial Distribution of Toxic
  Organic Contaminants in a Statewide Stratum
  SETAC North America 26th Annual Meeting,
  Baltimore, MD. Poster Session RP15 on Nov. 17th
  2005.