An evaluation of Australian sediment quality guidelines

Interim sediment quality guidelines (ISQGs) adapted recently to Australia from North American effects-based guidelines were evaluated with matching chemical and toxicological data collected for sediments (n = 103) from Sydney Harbour and south coast estuaries of New South Wales. The incidence of toxicity for the test battery was low (7%) among samples with all chemical concentrations below ISQG-Low values, indicating these guidelines are accurate and protective of non-toxic conditions. The incidence of toxicity increased greatly (to 73%) when one or more ISQG-Low values were exceeded, suggesting that ISQG-Low guidelines are appropriate for compliance. Frequent toxic effects (in >75% of samples) were associated with chemical concentrations exceeding ISQG-High guidelines. As expected, the high guideline values were more predictive of adverse effects than the low guidelines. Predictive abilities of ISQGs were not markedly affected by normalization of organic compounds to organic carbon or the use of dilute acid extractions for metals, suggesting that the guidelines are applicable to a wide range of conditions.