Sediment organic matter content as a confounding factor in toxicity tests with Chironomus tentans

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1897/1551-5028(1999)018<0231:SOMCAA>2.3.CO;2· OSTI ID:361925

Lacey, R; Watzin, M C; McIntosh, A W ^[1]

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1. Univ. of Vermont, Burlington, VT (United States). School of Natural Resources

Physicochemical characteristics of sediment unrelated to contaminant levels and bioavailability may influence the outcome of toxicity tests. In particular, sediment organic matter content has the potential to be a confounding factor in toxicity tests using the midge larva Chironomus tentans because the larvae are infaunal and feed on organic matter in the sediments. To examine the possibility, the authors conducted a series of tests using formulated sediments with varying organic matter contents following the standard US Environmental Protection Agency (US EPA) 10-day C. tentans growth and survival protocol. Formulated sediments made with peat moss, {alpha}-cellulose, and maple leaves were tested. An organic-rich natural sediment diluted with formulated sediment to achieve a range of organic matter contents was also examined. In a final experiment, sediments containing each of the four organic matter sources at the same concentration were tested against one another. Survival was not greatly affected by concentration of organic matter, except at the lowest concentrations in natural sediment, where survival dipped below 70%. In experiments using peat moss, {alpha}-cellulose, and maple leaves, significant differences in C. tentans growth were found at different organic matter concentrations. In contrast, concentration of organic matter in the natural sediment dilution series had little effect on growth, perhaps because much of this material was highly refractory. In the comparison experiment, growth differed significantly among the four sediments, with best growth achieved with {alpha}-cellulose and leaves. These results suggest that both organic matter quantity and quality can be confounding factors in toxicity tests using C. tentans.

• Sponsoring Organization: USDOE
• OSTI ID: 361925
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 2 Vol. 18; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
AQUATIC ORGANISMS
BIOASSAY
BIOLOGICAL AVAILABILITY
BIOLOGICAL INDICATORS
FLIES
SEDIMENTS
WATER POLLUTION