A comparison of the responses of benthic invertebrate individuals, populations, and communities to creosote contamination, with emphasis on Chironomidae (Diptera).

Environmental management strategies include the use of aquatic biota for environmental monitoring and assessment. There exists a need for reliable early warning indicators of impending environmental degradation. This study evaluated the toxicity of creosote as indicated by a 48-h acute toxicity sediment bioassay and various measures of the benthic invertebrate community and chironomid populations in artificial ponds, to which creosote was added. The study also evaluated the potentially useful early warning indicator, chironomid morphological deformities, in determining a toxic response. In the laboratory, a 48-h spiked-sediment toxicity test was conducted by placing 4th instar Chironomus riparius Meigen larvae in formulated sediment (sand, sculptor\u27s clay, potting soil) spiked with creosote (a PAH mixture). The estimated median lethal concentration (LC50) value was 437 $\mu$g creosote/g sediment. A toxicity study was conducted in 10,000-L artificial ponds (mesocosms) located at the Turfgrass Institute, University of Guelph, Guelph, Ontario. Ponds received a single application of creosote to produce a logarithmic series of nominal concentrations ranging from 0.053 $\mu$L/L to 100 $\mu$L/L water. Four community attributes (total invertebrate density, family richness, chironomid density, chironomid generic richness) and two population measures (Procladius density, Psectrocladius density) were tabulated and regressed against creosote concentration. Combined triplicate samples of Procladius larvae from each pond were examined for deformities of various cephalic structures (ligula, paralabial combs, and mandibles). (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .P37. Source: Masters Abstracts International, Volume: 37-01, page: 0220. Adviser: J. J. H. Ciborowski. Thesis (M.Sc.)--University of Windsor (Canada), 1997