ABSTRACT
Selenium (Se) accumulation in wetlands has been studied since the discovery of irrigation-induced selenium poisoning of waterfowl (Ohlendorf, 1989; Weres et a l, 1989; Presser et al., 1994; Zhang and Moore, 1996a, 1997). These studies show that selenium accumulation in wetlands is very complex and is controlled by various environmental conditions. Most studies of selenium accumulation in wetland systems have focused on Kesterson Reservoir in California, where sele nium bioaccumulation was much higher than most other wetlands of the western United States. Bioaccumulation of selenium in wetland organisms in Kesterson Reservoir created serious hazards to fish and waterfowl (Ohlendorf, 1989), finally resulting in closure of the reservoir in 1986. The problems at Kesterson Reservoir led to an increasing concern about the hazards of selenium bioaccumulation at other wetlands (Presser et al., 1994).
