Date of Award

1994

Degree Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

First Advisor

Ciberowski, J. J. H.

Keywords

Environmental Sciences.

Rights

CC BY-NC-ND 4.0

Abstract

Chironomids are potentially important indicators of the effects of sediment-bound contaminants. I evaluated mouthpart (mentum) deformities of larval chironomids collected from six locations varying in the amounts and types of organochlorine contaminants. Two thousand and six larvae belonging to 18 genera were collected. The overall incidence of deformities varied from 1.3% at an uncontaminated site (Anchor Bay, Michigan) to 11.4% at a more contaminated site (Peche Island at Windsor/Detroit). Five genera were widely distributed among sites (Chironomus, Cryptochironomus, Polypedilum, Stictochironomus, Phaenopsectra). The incidence of deformities varied significantly among genera (G-statistic Goodness of fit test, G = 43.68, p $<$ 0.001). Cryptochironomus, Polypedilum, and Stictochironormus showed uniformly low incidences of deformities among sites. The incidences of deformities in Chironomus and Phaenopsectra varied significantly among sites (G = 43.27, p $<$ 0.001 and G = 10.77, p $<$ 0.05 respectively), and reflected gross levels of sediment contamination. In a laboratory study, I exposed Chironomus salinarius Kieffer larvae to mixtures of contaminated Trenton Channel (near Detroit, Michigan) sediment diluted with uncontaminated, synthetic sediment (sand, sculptor's clay, potting soil). Groups of 20 second instar C. salinarius were grown to 4th instar (10 d) in water-filled 1-L jars containing 300 mL of Trenton Channel sediment: synthetic sediment mixture in ratios of 1:0, 1:1, 1:3, 1:7, 1:15, or 0:1. Larval head capsules were examined for mentum deformities. Giant chromosomes, located in the salivary glands were examined for (i) incidence of puffs occurring in atypical locations, a reflection of stress protein production and (ii) reduction in relative size of the nucleolus, reflecting inhibition of RNA synthesis activity. Our results show that chironomids are good indicators of sediment contamination and can be used to identify toxic stress before community effects become visible. (Abstract shortened by UMI.) Source: Masters Abstracts International, Volume: 34-02, page: 0698. Adviser: Jan J. H. Ciborowski. Thesis (M.Sc.)--University of Windsor (Canada), 1994.

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