20070812 Ver 2_Draft 2008 SEDIMENT DATA REPORT_20090221

DRAFT
REVIEW OF "2008 SEDIMENT DATA REPORT - BADIN LAKE"
DATED: FEBRUARY 2009
PREPARED BY: URS CORPORATION
A Report (Review) Prepared for
Stanly County, NC
By
John H. Rodgers, Jr., Ph.D.
102 Santee Trail
Clemson, SC 29631
and
Department of Forestry and Natural Resources
Clemson University
Clemson, SC 29634
February 21, 2009
This purpose of this report is to provide a scientific review of "2008 Sediment Data
Report - Badin Lake" (prepared by URS Corporation for Alcoa Power Generating Inc.).
This sampling and analysis of sediments in Badin Lake, NC was undertaken in December
2008. The stated objective of this study was "to evaluate the potential presence and
distribution of specific chemicals in sediment from the Badin Boat Access Area and
Badin Lake Swim/Picnic Area to the Narrows Dam." The sampling and analysis were
undertaken in accordance with the "Sediment Sampling Work Plan, Badin Lake, Badin,
North Carolina" (URS 2008) with some exceptions. Comments on this work plan were
submitted previously and are included in this report below in addition to the review of the
final report (URS 2009).
Comments on Study Design/Work Plan
These comments on the "Sediment Sampling Work Plan, Badin Lake, Badin, North
Carolina" (URS 2008) were provided as an Appendix to comments submitted by Stanly
County on February 16, 2009, and are repeated here for ease of reference:
At DWQ's request, the proposal required sampling of sediments in the
vicinity of APGI's permitted discharge outlet to the Lake. The sampling
was to include heavy metals, PCBs and other compounds reported in the
study funded by the County (ESI 2008, p. 1-1). The constituents detected
in the ESI study are summarized in Table 1-1 of the study plan and include
PCBs, PAHs, inorganics and other pollutants (such as cyanide).
2. The proposed study, however, winnowed down the ESI constituents to a
much shorter list of analytes for analysis (in Table 1-2). 1 believe that this
is scientifically unacceptable. For example, how can cyanide be dismissed
from the analysis, if only as a tracer?
3. The RETEC report is used to dismiss toxicity in the sediments in the Lake
(p.1-3). I have previously provided comments on the inadequacy of the
RETEC report for that purpose (in my report dated April 29, 2008).
4. The study proposed to use composite sediment sampling and
homogenization of sediment samples in the boat. These techniques ensure
that no volatile organics are detected, and mask any pattern of movement
of pollutants from the source to the Dam area; the transect approach will
work only if the samples are analyzed separately and discretely. Further,
appropriate QA/QC procedures such as field spikes and recovery
measurements along with appropriate corrections for recovery (to correct
for loss due to volatilization, sorption, etc.) would be crucial to obtain
accurate and scientifically defensible results.
5. I believe that the use of the PCB sampling design in Hartwell Reservoir in
South Carolina as a model is scientifically unsupportable. The Badin Lake
situation is sufficiently unlike that at Hartwell Reservoir to make any
comparison unworkable. Further, I believe that the Hartwell Reservoir
study is also scientifically flawed, such that using the study as a guide is
unwise.
6. The data quality objectives (pages 3-3 and 3-4) presented in the sampling
proposal are inappropriate. The use of certain detection limits that are
higher than the appropriate screening levels means that exceedances could
exist but the test results would not reveal them. Methods can and should
be utilized to ensure that any screening level exceedances can be detected.
7. The study should have analyzed for PCB congeners rather than Aroclors.
Analysis of Aroclors serves to underestimate exposure from PCBs in these
sediments. Understanding the specific congeners, for example, was
critical to evaluating risks in the latest fish study.
Review of 2008 Sediment Data Report - Badin Lake
The following are my opinions on the final sediment study:
This report was intended "to evaluate the potential presence and distribution
of specific chemicals in sediment from the Badin Boat Access Area and Badin
Lake Swim/Picnic Area to the Narrows Dam." As noted above in the
comments on the sampling plan, the report is very limited in scope and thus,
limited in the conclusions that can be drawn from this study.
2. Based upon the design of the study, the data cannot be used to draw
supportable conclusions about transport of sediment-associated contaminants
within the reservoir (Badin Lake) or transport from the reservoir downstream.
The study involved a limited mix of composite and discrete samples (one of
each per transect with ten transects) which has no capability to discern the
distribution of contaminants in sediments. No pattern of contaminant
movement was discerned in this study, and no pattern could have been
discerned based on the nature and handling of the samples .
3. Any sedimentologist would be cognizant of the patchy distribution of
sediment particulates and contaminants in a reservoir such as Badin Lake.
The contaminants in this study do not move uniformly (or in unison) and
would not be expected to be distributed in the same pattern as the sediments
are distributed.
4. If the study was intended to discern movement of contaminated sediments
downstream, samples of suspended solids could have been collected as they
moved through the dam and they could have been analyzed for contaminants
of concern. This is the appropriate way to conduct the study to address the
401 Water Quality Certification issues. The samples also need to be collected
during "turnover" (destratification) of the reservoir as well as during storm
events with wind and rain when turbidity is maximal. Most of the sediments
transported through the outlet structures is moved on a relatively few days
during storm events.
As illustrated by the recent fish study by NCDHHS, the analysis of Aroclors
underestimates the actual concentrations of PCBs. Since analysis of
sediments and other matrices for Aroclors is relatively insensitive (NRS
2001), it is not surprising or reassuring that PCBs were not detected in these
samples.
6. The presence of relatively low molecular weight PAHs such as naphthalene or
2-methylnaphthalene in sediment samples from three transects is troubling.
The transects containing these contaminants were located from the Badin Boat
Access Area/Badin Lake Swim/Picnic Area and at the Narrows Dam. The
samples were collected and composited in a manner that would make
volatilization of these compounds likely. And since these are compounds that
are relatively readily biodegradable, their presence indicates an ongoing and
recent source. These are analogous to the compounds observed in the
chromatograms from the analysis of PAHs in fish, although the concentrations
in the fish were detected below reportable levels. These compounds are
relatively water soluble and would move with the flow of the water through
and out of Badin Lake. This situation should be further investigated. Although
the data are limited, concentrations of naphthalene in sediments from this
study (-0.7 mg/kg) exceed concentrations triggering concerns for ecological
risks (Buchman 2008). The concentration of 2- methyl naphthalene (0.129
mg/kg) also could contribute to ecological risks in Badin Lake.
7. There is no discernable pattern of mercury in sediments from this study. The
concentrations of mercury in these sediments should be investigated further.
The concentrations of mercury indicated in this report (high of -0.06 mg/kg)
are essentially at background for this region (USGS 2001; Buchman 2008).
This is puzzling since there is a fish consumption advisory for Badin Lake for
mercury. The source of the mercury in fish should be further considered and
investigated.
8. Lead levels in sediments are apparently elevated in the transect located near
the former Alcoa-Badin Works. The concentrations of lead reported in this
study (high of - 40 mg/kg) are well above background for this region (USGS
2001; Buchman 2008). This should be further investigated.
9. The organic carbon levels reported in these sediments are exceptional (1.7-5.7
% or 17,000 - 57,000 mg/kg) and should be investigated further. This could
be contributing to the dissolved oxygen conditions in the hypolimnion and
low dissolved oxygen observed in the outflow from Badin Lake. The bulk
density or moisture content of the sediments also indicates an exceptional
situation in this reservoir (Suedel and Rodgers 1991).
10. The presence of an invasive species, Corbicula fluminea, is also apparent in
the samples from Transects 1 and 2 (Attachment 2; Photographs 1 and 2).
This is further indication of stress in this aquatic system.
11. In summary, these results raise more questions than they answer. Where is
the PAH contamination in sediments coming from? What is the distribution
of PCB congeners in Badin Lake sediments? Do the lead and mercury
concentrations in the sediments pose ecological or human health risks? What
concentrations of other contaminants (e.g. cyanide, ammonia, sulfides, etc.)
are found in the sediments of Badin Lake? Which of these constituents of
concern are causing water quality issues downstream from the dam?
Literature Cited
Buchman, M.F. 2008. NOAA Screening Quick Reference Tables. NOAA OR&R
Report 08=01, Seattle, WA, Office of Response and Restoration Division, National
Oceanographic and Atmospheric Administration. 34 pp.
National Research Council. 2001. A Risk Management Strategy for PCB-
Contaminated Sediments. The National Academies Press. 452 pp.
Suedel, B.C. and J.H. Rodgers, Jr. 1991. Variability of Bottom Sediment
Characteristics of the Continental United States. Water Res. Bull. 27:101-109.
USGS (Gustavsson, B., D.B. Smith and R.C. Severson). 2001. Geochemical
Landscapes of the Conterminous United States - New Map Presentations for 22
Elements. US Department of Interior, US Geological Survey. USGS Professional
Paper 1648.