A Tropical Sediment Toxicity Test Using the Dipteran Chironomus crassiforceps to Test Metal Bioavailability with Sediment pH Change in Tropical acid-Sulphate sediments

摘要

The wetlands of the Magela floodplain of northern Australia, which is the major sink for dissolved metals transported in the Magela Creek system, contain acid-sulfate sediments. The rewetting of oxidized acid-sulfate soil each wet season produces acidic pulses that have the potential to alter the bioavailability of sediment-associated metal contaminants. Acute toxicity tests(72- h mean lethal concentration[LC50]) using the tropical chironomid Chironomus crassiforceps Kieffer showed that copper toxicity decreased from 0.64 mg/L at pH 6 to 2.30 mg/L at pH 4.