Fishes field studies

As noted earlier, OPs are known to be highly toxic to aquatic invertebrates and to fish. This has been demonstrated in field studies. For example, malathion applied to watercress beds caused lethal intoxication of the freshwater shrimp Gammarus pulex located downstream (Crane et al. 1995). Kills of marine invertebrates have been reported following the application of OPs. Accidental release of OPs into rivers, lakes, and bays has sometimes caused large-scale fish kills (see Environmental Health Criteria 63). 

RoUand, R.M. (2000). A review of chemically-induced alterations in thyroid and vitamin A stams from field studies of wildlife and fish. Journal of Wildlife Disease 36, 615-635. 

Varanasi, U., Stein, J.E., and Reichert, W.L. et al. (1992). Chlorinated and aromatic hydrocarbons in bottom sediments, fish and marine mammals in US coastal waters laboratory and field studies of metabolism and accumulation. In C.H. Walker and D.R. Livingstone (Eds.) Persistent Pollutants in Marine Ecosystems, Oxford, U.K. Pergamon Press, 83-118. 

Another example which poses many questions is a study of PCBs in river sediment and fish and PCB transport under varying flow conditions. The objectives of the field study were ... 

The design of this fish study centered on sample collection, preservation, preparation, analysis, and QA/QC. There was no discussion of the effect of compositing on the sample population. No description was given of statistical techniques to be applied to the data for reporting results and for comparison with action levels and future data. Unfortunately, the omission of a statistical framework during planning of the field study is the rule rather than the exception in hazardous waste investigations. 

Haux, C., A. Larsson, G. Lithner, and M.L. Sjobeck. 1986. A field study of physiological effects on fish in lead-contaminated lakes. Environ. Toxicol. Chem. 5 283-288. 

Ankley, G.T., P.M. Cook, A.R. Carlson, D.J. Call, J.A. Swenson, and H.F. Corcoran. 1992. Bioaccumulation of PCBs from sediments by oligochaetes and fishes comparison of laboratory and field studies. Canad. Jour. Fish. Aquat. Sci. 49 2080-2085. 

Once the fish were transferred from fenitrothion-containing water to fresh water,the levels of fenitrothion in fish decreased rapidly to around 0.01 ppm in 5 days (that is, by a factor of 1000). This tendency is apparently in good accord with field studies (13). 

For very hydrophobic compounds, when is very high (10 ), fhere is evidence from field studies involving fish, birds, and animals fhaf fhere is a bioaccumulation or bioconcentration up to food chain [114]. The pesticide DDT is an example of bioaccumulating chemical with a Kqw of —10 . The thermodynamic model for air/water and 1-ocfanol/wafer acfivify coefficients and the importance of the activity coefficient at infinite dilution measurements have been presented as well [114]. 

There have been a few large-scale field studies of PCBs in the food webs of the lakes. These include two EPA mass balance studies, the Green Bay Mass Balance Study and the Lake Michigan Mass Balance Study. The field data collected for these studies was used to calibrate the complex contaminant models, which were developed as the primary goal of the studies. The ultimate objective of these mass balance studies was to predict concentrations of PBTs in top predator fish from only knowing the external loadings of the PBTs. Thus the models linked food web models to fate and transport, hydro-logic, and nutrient models. To calibrate the food web models, an extensive collection of all major trophic levels over both space and time was done and analyzed for PCBs and other selected analytes. 

In studying the balance of matter and eneigy, approaches that determine each part of the triad are especially important. However, because of problems with methods, it is not yet possible to obtain reliable estimates of food consumption in field studies, and existing estimates are not satisfactory. The indirect approach to studying the nutrition of fish is better. 

Accumulations of fluorene in fish were found to be higher than any of the pesticides (Table I). We are not aware of any field study which may have reported the bioconcentration of this particular hydrocarbon, and the results presented here may serve to emphasize the argument that formulation materials are often as desirable research subjects as are the active components. 

Similar to the case with fish, we are not aware of field studies with fluorene in plants. Figure 2 shows the very rapid depuration of label from duckweed in culture, resulting in the high K2 (Table III) and the short half-life (Table V). In view of the volatility of fluorene, and its short half-life it would not be expected to persist long in plants after a spray with a solvent containing fluorene. McLeese et al. (27) examined the uptake and depuration of "585 oil by mussels and found a similar result. The steady state bioconcentration factor was 160 but the half-life was only 0.3 days. 

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