Ongoing work at CNFRL includes considerable effort in continued acute 

 and chronic toxicity testing (Figure 2), monitoring and surveillance of con- 

 taminants in the environment, and continued methods development in analyti- 

 cal chemistry to better enable us to identify and quantitate a wide spectrum 

 of contaminants in the environment. We are placing additional emphasis on 

 ecosystem approaches, behavior studies, highly sophisticated analytical ap- 

 proaches to identify unknown contaminants in the environment, and assessment 

 of biological or biochemical indicators of contaminant stress. 



Contamination of the aquatic environment by agricultural and industrial 

 chemicals, oil spills, mine effluents, and other forms of pollution has been 

 recognized for many years. Evaluating the impact of the many contaminants 

 on aquatic organisms has been limited mainly to short-term laboratory 

 studies. Only recently have long-term laboratory studies been used to 

 evaluate growth, reproduction, mortality and residue dynamics in relation to 

 the environment. Although these studies strongly indicate safe toxicant 

 concentrations, their disadvantages include the length of time required to 

 complete partial and chronic toxicity studies, cost, and the limited number 

 of aquatic species that can be cultured in laboratory or artificial environ- 

 ments. Much of the laboratory research lacks field verification, and the 

 true impact of chemical contaminants on aquatic organisms in the natural 

 environment is poorly understood. New techniques are needed that can be 

 used as biological indicators or predictors in both laboratory and field in- 

 vestigations for estimating the health or status of a particular resource. 



Development and validation of analytical capabilities must accompany 

 laboratory studies dealing with the toxicological effects of contaminants. 

 New analytical procedures have been implemented for di-2-ethylhexyl phtha- 

 late, pentachlorophenol , mirex, and Kepone in water and fish, and for mixed 

 Arochlors (PCBs) in sediments from the Upper Mississippi River. The use of 

 adsorbents has greatly facilitated the analysis of certain trace organics 

 and led to the development of a new multichromatographic material that may 

 permit one-step purification of many aromatic compounds, including dioxins 

 and dibenzofurans. 



Routine methods currently used in monitoring and surveillance programs 

 enable us to measure fewer than 50 kinds of residues in fish. Thus, it is 

 essential to develop a comprehensive strategy to detect and measure contami- 

 nants in fish and other sample material. Recent advances in chemical detec- 

 tion, sample extraction, and clean-up procedures make it possible to iden- 

 tify and quantitate a greater number of the components that make up the com- 

 plex contaminants in aquatic systems. 



Techniques are under development to fractionate complex mixtures of con- 

 taminants present in samples from aquatic environments into classes of 

 chemicals to simplify the detection and to provide more comprehensive resi- 

 due data (Figure 3). By using advanced scientific instruments, such as the 

 mass spectrometers and the inductively coupled plasma emission spectrophoto- 

 meter, we are gaining the ability to perform comprehensive analyses with 

 much greater precision and accuracy. Separations of contaminants into 

 classes, combined with new instrumentation, have helped identify several 



