\04
R.R. Turner and G.R. Southworth
the adjacent tidal marsh (Lipsky et al. 1981). Results of analysis of mercury in fish
and shellfish (Santoro and Koepp 1986) collected from the area in 1979-80 did
not suggest an immediate human health hazard (values were elevated but not
above levels requiring consumption advisories). These authors and others who
conducted investigations at the site (Berman and Bartha 1986) speculated that the
sulfide-rich marsh sediments may have reduced the bioavailability of mercury. In
contrast to the early findings of relatively low biotic contamination, analysis of
biota conducted in the mid 1980s (HMDC 1987, 1989) revealed high average
concentrations in a number of fish (white perch, killifish, eel, catfish, pumpkinseed) and crab. Previously, Berman and Bartha (1986) had speculated that
improved water quality due to a planned sewage diversion could potentially
increase the bioavailability of mercury. Whether such improved water quality
actually accounted for the differences in biotic contamination between the two
sampling periods is undetermined. This site is particularly interesting in the
context of the hypothesis that general improvements in water quality at such sites
may lead to paradoxical trends in biotic contamination. Hopefully, more
information about this site will appear in the accessible literature in the future.
Lavaca Bay, a secondary embayment of Matagorda Bay in Texas, was
contaminated by mercury releases from a chloralkali plant which operated on the
shore of this bay between 1966 and 1979. The plant was razed in 1985. Today, the
bay is one of the few marine systems with a partial closure to fishing due to
mercury contamination. Releases to the bay were greatly reduced in 1970 after
high concentrations of mercury were found in oysters and crabs. Mercury in
these organisms decreased rapidly after releases were reduced. Regular monitoring of mercury in fish (red and black drum) began in 1977 and has shown
moderately elevated concentrations which have changed little since monitoring
began. Concentrations of mercury in sediment, water, and biota (including fish,
crabs, oysters, and benthic invertebrates) have been highest rather consistently
among many studies at sampling locations closest to the site of the former
chloralkali plant (Locarnini and Presley 1996; C. Dobbs, pers. comm.). King et al.
(1991) found somewhat higher mercury residues in eggs from terns and black
skimmers collected from Lavaca Bay in 1984 compared with a reference area, but
residues were not correlated with nesting success. Recent intensive studies at
Lavaca Bay have redefined the focus of potential corrective actions. Results of
these intensive studies are scheduled for publication in the open peer-reviewed
literature (C. Dobbs, pers. comm.). As with some other sites reviewed here, the
possibility of continuing releases from the former plant site has been examined
more closely and found to be a credible explanation for slow further recovery of
the site.
Turtle Creek near Brunswick, Georgia, received effluent from a chloralkali
plant between 1957 and 1989. Winger et al. (1993) reported that sediments (with
Hg up to 27 ~Lg g-I) and sediment pore water (Hg not measured) immediately
below the site were toxic, but they could not unambiguously attribute the toxicity
to mercury. The sediments also contained elevated concentrations of polychlorinated biphenyls and other metals. This site is currently under intense
investigation and some corrective actions (e.g., soil removal and groundwater
treatment) are in progress or have already been completed. The site is one of
R.R. Turner and G.R. Southworth
the adjacent tidal marsh (Lipsky et al. 1981). Results of analysis of mercury in fish
and shellfish (Santoro and Koepp 1986) collected from the area in 1979-80 did
not suggest an immediate human health hazard (values were elevated but not
above levels requiring consumption advisories). These authors and others who
conducted investigations at the site (Berman and Bartha 1986) speculated that the
sulfide-rich marsh sediments may have reduced the bioavailability of mercury. In
contrast to the early findings of relatively low biotic contamination, analysis of
biota conducted in the mid 1980s (HMDC 1987, 1989) revealed high average
concentrations in a number of fish (white perch, killifish, eel, catfish, pumpkinseed) and crab. Previously, Berman and Bartha (1986) had speculated that
improved water quality due to a planned sewage diversion could potentially
increase the bioavailability of mercury. Whether such improved water quality
actually accounted for the differences in biotic contamination between the two
sampling periods is undetermined. This site is particularly interesting in the
context of the hypothesis that general improvements in water quality at such sites
may lead to paradoxical trends in biotic contamination. Hopefully, more
information about this site will appear in the accessible literature in the future.
Lavaca Bay, a secondary embayment of Matagorda Bay in Texas, was
contaminated by mercury releases from a chloralkali plant which operated on the
shore of this bay between 1966 and 1979. The plant was razed in 1985. Today, the
bay is one of the few marine systems with a partial closure to fishing due to
mercury contamination. Releases to the bay were greatly reduced in 1970 after
high concentrations of mercury were found in oysters and crabs. Mercury in
these organisms decreased rapidly after releases were reduced. Regular monitoring of mercury in fish (red and black drum) began in 1977 and has shown
moderately elevated concentrations which have changed little since monitoring
began. Concentrations of mercury in sediment, water, and biota (including fish,
crabs, oysters, and benthic invertebrates) have been highest rather consistently
among many studies at sampling locations closest to the site of the former
chloralkali plant (Locarnini and Presley 1996; C. Dobbs, pers. comm.). King et al.
(1991) found somewhat higher mercury residues in eggs from terns and black
skimmers collected from Lavaca Bay in 1984 compared with a reference area, but
residues were not correlated with nesting success. Recent intensive studies at
Lavaca Bay have redefined the focus of potential corrective actions. Results of
these intensive studies are scheduled for publication in the open peer-reviewed
literature (C. Dobbs, pers. comm.). As with some other sites reviewed here, the
possibility of continuing releases from the former plant site has been examined
more closely and found to be a credible explanation for slow further recovery of
the site.
Turtle Creek near Brunswick, Georgia, received effluent from a chloralkali
plant between 1957 and 1989. Winger et al. (1993) reported that sediments (with
Hg up to 27 ~Lg g-I) and sediment pore water (Hg not measured) immediately
below the site were toxic, but they could not unambiguously attribute the toxicity
to mercury. The sediments also contained elevated concentrations of polychlorinated biphenyls and other metals. This site is currently under intense
investigation and some corrective actions (e.g., soil removal and groundwater
treatment) are in progress or have already been completed. The site is one of