Benthic invertebrate bioassays with toxic sediment and pore water
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Resource Abstract:
<p><span>The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods
of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a)
Microtox , a 15-min assay of</span><i>Photobacterium phosphoreum</i><span> bioluminescence inhibition by pore water;
(b) 48-h </span><i>Daphnia magna</i><span>lethality test in pore water; (c) 10-d subchronic assay of lethality to and
reduction of weight gain by </span><i>Chironomus tentans</i><span> performed in either whole sediment or pore water;
(d) 168-h acute lethality assay of </span><i>Hexagenia limbata</i><span> in either whole sediment or pore water.
The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water
from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference
location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location,
then using the whole sediment in bioassays. Based on lethality, </span><i>H. limbata</i><span> was the most sensitive
organism to the toxicity of Detroit River sediment. Lethality of </span><i>D. magna</i><span> in pore water was
similar to that of </span><i>H. limbata</i><span> in whole sediment and can be used to predict effects of whole
sediment toxicity to </span><i>H. limbata.</i><span> The concentration required to cause a 50% reduction in </span><i>C.
tentans</i><span> growth (10-d EC50) was approximately that which caused 50% lethality of </span><i>D. magna</i><span> (48-h
LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the
three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response
relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type,
and the dose-response relationship derived from each technique needs to be interpreted accordingly.</span></p>
Citation
Title Benthic invertebrate bioassays with toxic sediment and pore water