3
Toxic Effects of
Selenium in Fish
Introduction
One of the most extensive and prolonged cases of selenium poisoning
in freshwater fish occurred at Belews Lake, NC in the United States
(Fig. 3.1). Belews Lake was contaminated by selenium in wastewater
released from a coal-fired electric generating facility. From 1974 to
1986, water was withdrawn from the lake and mixed with bottom ash
from the coal burners and fly ash collected by electrostatic precipitators. This slurry was pumped from the power plant and discharged into
a 142 ha ash basin, where suspended solids were collected by gravitational settling. Selenium-laden (150-200 J,lg SelL) return flows from
the ash basin entered the west side of Belews Lake through an ash
sluice water canal (Lemly 1985).
Selenium bioaccumulated in aquatic food chains and caused severe tissue pathology and reproductive impairment in the resident
fish community, leading to the elimination of 19 of the 20 species
originally present in the reservoir (Lemly 1985; Sorensen 1986). In
late 1986, the power plant stopped discharging selenium-laden
water into the lake, and a period of natural recovery began, augmented with artificial stocking of fish. However, monitoring studies revealed that the rate of recovery was slow; elevated selenium
residues and associated biological effects in fish were still present
a decade later (Lemly 1997).
The Belews Lake pollution event provides a wealth of information
on aquatic cycling, long-term persistence, and hazard of selenium to
freshwater biota. It is an excellent case for examining the biological
symptoms and ecological consequences of selenium toxicity. This chapter
utilizes that database to present a concise review of the effects of selenium poisoning in fish and discuss the environmental lessons learned
from Belews Lake.
39
Toxic Effects of
Selenium in Fish
Introduction
One of the most extensive and prolonged cases of selenium poisoning
in freshwater fish occurred at Belews Lake, NC in the United States
(Fig. 3.1). Belews Lake was contaminated by selenium in wastewater
released from a coal-fired electric generating facility. From 1974 to
1986, water was withdrawn from the lake and mixed with bottom ash
from the coal burners and fly ash collected by electrostatic precipitators. This slurry was pumped from the power plant and discharged into
a 142 ha ash basin, where suspended solids were collected by gravitational settling. Selenium-laden (150-200 J,lg SelL) return flows from
the ash basin entered the west side of Belews Lake through an ash
sluice water canal (Lemly 1985).
Selenium bioaccumulated in aquatic food chains and caused severe tissue pathology and reproductive impairment in the resident
fish community, leading to the elimination of 19 of the 20 species
originally present in the reservoir (Lemly 1985; Sorensen 1986). In
late 1986, the power plant stopped discharging selenium-laden
water into the lake, and a period of natural recovery began, augmented with artificial stocking of fish. However, monitoring studies revealed that the rate of recovery was slow; elevated selenium
residues and associated biological effects in fish were still present
a decade later (Lemly 1997).
The Belews Lake pollution event provides a wealth of information
on aquatic cycling, long-term persistence, and hazard of selenium to
freshwater biota. It is an excellent case for examining the biological
symptoms and ecological consequences of selenium toxicity. This chapter
utilizes that database to present a concise review of the effects of selenium poisoning in fish and discuss the environmental lessons learned
from Belews Lake.
39