DOE/ORO/2327 Oak Ridge Reservation Annual Site Environmental ...

Annual Site Environmental Report
Aquatic Resource Alteration Permit or because they had a footprint of greater than 1 acre.
(Construction areas that are part of CERCLA remediation follow substantive requirements of the
appropriate water pollution control permits, but are not required to obtain official permit coverage). Three
of these sites were inspected in 2009 to evaluate overall effectiveness of the best management practices in
use. In general, while some short-term impacts to receiving streams may have been noted, no long-term
adverse impacts were observed.
NPDES outfall drainage areas were also inspected twice in 2009. Land use within drainage areas is
typical of office/industrial settings with surface features including laboratories, support facilities, paved
areas, and grassy lawns. Outdoor material storage is most prevalent in the 7000 Area on the east end of
the main ORNL facility (where most of the craft and maintenance shops are located), with other smaller
outdoor storage areas located throughout the facility in and around loading docks and material delivery
areas at laboratory and office buildings. The types of materials stored outside include metal items
(sheeting, pipes, and parts); equipment awaiting use, disposal, or repair; construction material; and de-icer
product. Flaking paint on some buildings (slated to be dismantled in the near future) also poses a potential
mobile storm water pollutant source.
Some construction activities are performed by third-party contractors working as tenants under
agreement with other local, state, and federal agencies on the DOE reservation. There are mechanisms in
place for ensuring effective storm water controls at these third-party sites, one of which includes staff
from UT-Battelle acting as points-of-contact for communication interface on environmental,
spill/emergency response, and other key issues.
Instream locations identified under the WQPP were monitored twice in 2009 in storm conditions. A
more detailed description of the WQPP wet-weather monitoring scenario can be found in Sect. 5.5.6.
5.5.8 Biological Monitoring
Bioaccumulation Studies
The bioaccumulation task for the BMAP addresses two NPDES permit requirements at ORNL:
(1) evaluate whether mercury at the site is contributing to a stream at a level that will impact fish and
aquatic life or violate the recreational criteria and (2) monitor the status of PCB contamination in fish
tissue in the WOC watershed.
Mercury in Water. In continuation of a monitoring effort initiated in 1997, bimonthly water samples
were collected from WOC at four sites in 2009. Stream conditions were selected to be representative of
seasonal base-flow conditions (dry weather, clear flow) based on historical results that indicate higher
mercury concentrations under these conditions.
The concentration of mercury in WOC upstream from ORNL was < 5 ng/L in 2009. Long-term trends
in waterborne mercury in the WOC system downstream of ORNL are shown in Fig. 5.27. Waterborne
mercury downstream of ORNL declined abruptly in 2008 and remained low in 2009 as a result of
rerouting highly contaminated sump water in Building 4501 to the PWTC in December 2007. The mean
total mercury concentration at White Oak Creek kilometer (WCK) 4.1 was 18.6 ± 2.7 ng/L in 2009
compared with 108 ± 33 ng/L in 2007. The decrease was also apparent but less pronounced at WCK 3.4,
with mercury averaging 16.6 ± 2.2 ng/L in 2009 versus 49 ± 23 ng/L in 2007. In addition to being
significantly lower than levels in 2007, mercury levels at these two sites were also slightly lower than in
2008. A pretreatment system for the sump water started operation on October 22, 2009, which removes
almost all of the mercury prior to sending the water to the PWTC. This system reduces the mercury
concentration in the influent and effluent of the PWTC. Average aqueous mercury concentration at the
White Oak Dam was 38.0 ± 12.7 ng/L in 2009, a level similar to results reported in recent years.
Bioaccumulation in Fish. In WOC, mercury and PCB concentrations in fish are at or near human
health risk thresholds (e.g., EPA ambient water quality criteria [AWQC], TDEC fish advisory limits).
Mercury concentrations in fish collected in the WOC system (WCK 2.9, WCK 1.5) remained within
historical ranges in 2009 (Fig. 5.34). Mercury concentrations in redbreast sunfish at WCK 3.9 (a site
Oak Ridge National Laboratory 5-61