Bioindicator Studies

The biological indicator task is designed to evaluate the effects of water quality and other environmental variables on the health and reproductive condition of individual fish and fish populations in EFPC. Redbreast sunfish are sampled from four sites in EFPC (upstream of Lake Reality, EFK 23, EFK 19 and EFK 14) and from two reference streams (Brushy Fork and Hinds Creek) in the spring prior to the onset of the breeding season. 

The health and reproductive condition of sunfish from EFPC sites upstream of Bear Creek Road continue to lag behind those of fish from reference sites and lower EFPC sites. For example, the induction of detoxification enzyme systems in liver tissue, has shown little improvement in upper EFPC over the last few years. However, overall trends in many other contamination-related bioindicators suggest there has been a distinct improvement in overall fish health in upper EFPC in recent years (Figure 1). 
Water sampled throughout the length of EFPC during 1998 remained toxic to developing fish embryos in the medaka test. The specific cause(s) for this toxicity has not yet been identified, but medaka embryos, like the embryos of many other species of fish, are quite sensitive to many chemical constituents originating within the Y-12 Plant, including various metals (particularly mercury), ammonia and other nitrogenous wastes, and apparently even the chemicals involved in or the byproducts of chlorination/dechlorination water treatment procedures. 
Flow management has reduced, but not significantly ameliorated, the toxicity of EFPC water to fish embryos as measured in this developmental toxicity test (Figure 2).

Figure 1. Temporal response of bioindicators to contaminants in the upper sections of East Fork Poplar Creek. All three indictors demonstrate a gradual improvement in fish health from 1990-2000 as the water quality in the stream improved following remediation activities.

Figure 2. Comparison of medaka embryo survival in grab samples of water collected from EFK 23.4 downstream of Lake Reality when flow management was either operational ("with flow management") or nonoperational ("without flow management").

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Last Modified: April 17, 2001