Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams
- National Inst. of Water and Atmospheric Research, Hamilton (New Zealand)
- Colorado State Univ., Fort Collins, CO (United States). Dept. of Fishery and Wildlife Biology
The authors performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communities in New Zealand streams were similar to those reported for metal-polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal-polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, the authors recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 675449
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 17, Issue 11; Other Information: PBD: Nov 1998
- Country of Publication:
- United States
- Language:
- English
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