DEFORMITIES OF AQUATIC LARVAL MIDGES (CHIRONOMIDAE, DIPTERA) IN THE SEDIMENTS OF THE BUFFALO RIVER, NEW-YORK

We conducted an extensive survey of the benthic macroinvertebrate fauna of the heavily polluted Buffalo River (New York) Area of Concern (AOC), with specific emphasis on assessment of morphological deformities of aquatic larval midges (Chironomidae: Diptera). Sediments were sampled on seven occasions during 1990 - 1991, from as many as 20 sites. Abnormal mouthparts (menta) were most frequent among larvae of the genus Chironomus, occurring in 29.0% of all specimens in the Buffalo River (n = 755), and 22.4% in the adjacent Ship Canal (n = 98). Individual sites in the downstream section of the river yielded even higher deformity frequencies; 36.9% (n = 84), 48.1% (n = 27), and 66.7% (n = 9). The frequencies of abnormalities in this genus at all sites within the AOC were well above levels normally observed (0 - 3%) at non-industrial sites. Additionally, abnormal mouthparts (ligulae) were seen in 3.1% of larvae of the genus Procladius (n = 1,677). While individual downstream samples of Procladius were occasionally as much as 15.4% abnormal (n = 26), this genus was much less prone to morphological deformities than Chironomus. Abnormal menta were also noted in the genera Polypedilum, Cryptochironomus, and Dicrotendipes, but were infrequent. Community parameters such as richness and diversity of the chironomid fauna, and the prevalence of oligochaetes, provide further evidence of decreased environmental quality within the downstream reaches of the Buffalo River. The data presented here provide one biologically relevant measure against which to gauge the effectiveness of pollution abatement strategies within the AOC.