778 



BRADT 



Biological Parameters 



Total numbers, wet weight, and number of taxa of benthic 

 macroinvertebrates peaked at station 10 (Fig. 2). Diversity was 

 highest at station 28 and lower at stations 12, 10, and 2. According 

 to Wilhm and Dorris (1968), station 28 would be classified as clean 

 water (x = 3.42, SD = 0.40), whereas stations 12, 10, and 2 would be 

 classified as mildly polluted (station 12, x = 2.89, SD = 0.50; station 

 10, X = 2.97, SD = 0.32; and station 2, x = 2.87, SD = 0.55). 



16 



14 



12 



1.7 — 



— 1.3 — 



— 0.9 — 



0.5 



3.4 



3.2 



3.0 



2.8 



28 



12 10 



STATION 



Fig. 2 Mean total numbers, N, ; wet weight, W, . . . . ; total 



taxa, T, ; and diversity of macroinvertebrates, D, • — 



per 0.092 m^. 



