community on the right (facing downstream) side of the river below the plant (the 

 waste did not mix laterally very well). Diversity (d) was low (0-2.42) and the numbers 

 of taxa and organisms were reduced. A fish bioassay carried out in 1973 indicated the 

 wastewater discharge to be acutely toxic at a concentration of 34.5% (mixed with 

 65.5% river water). 



In early 1974, FMC Corporation built an activated sludge treatment plant to 

 reduce BOD5 and improve the neutralization and chemical precipitation (zinc 

 hydroxide and liquid-solid separation) facilities that had been in use since 1948. In 

 1975, d values had improved ( 1. 19-3.39), and there were more taxa and organisms 

 (Table 1 ). Wastewater ( 100%) was acutely toxic to fish only once after improvements 

 had been made. The major changes in the wastewater discharge were a 70% reduc- 

 tioninBODsanda 60% reduction in the amount of zinc entering the river (Table 2). 



South River 



The South River in Waynesboro, Virginia, receives wastes from both industrial 

 and municipal discharges (Figure 6 and Table 3). Following a baseline study, '"' du 

 Pont instituted further improvement in wastewater treatment (Table 4). This 

 resulted in a definite improvement in the river biota (Figures 7,8,9). 



Both these studies indicate that the river has improved, though still receiving 

 wastewater discharges. 



FUTURE RESEARCH NEEDS 



The lack of measured evidence leads to a very important question: since so little 

 evidence is presently available (except in terms of species inventories) about most of 

 our ecosystems, what types of evidence should be gathered now in order to be 

 adequately informed should ecosystems be damaged in the future and society wishes 

 to restore them? Clearly, species inventories alone are not adequate if only because 

 the successional process ensures that such inventories will become outdated. This 

 will occur rapidly in some systems but ultimately in all, even the most stable. Perhaps 

 one might want to characterize a community in terms of the functions the various 

 species carry out, such as detritus processing, photosynthesis, predation, etc. If so, is 

 the mere listing of biomass responsible for each of the component activities suffi- 

 cient, or are various rate processes required as well? One would intuitively think both 

 are necessary. 



1 2 3 4 

 ■ I I 1 I 



Kilometers 



Figure 6. Sampling stations on the South River, Virginia forthe 1978 biological survey. 



231 



