Persistent organochlorines and metals in estuarine mud crabs of the Great Barrier Reef

Abstract

Contamination of the Great Barrier Reef (GBR) with metals, pesticides and persistent organic pollutants (POPs), such as DDT and dieldrin, is primarily due to effluent discharge, urban stormwater and agricultural and industrial runoff (Haynes and Johnson, 2000). Pesticides currently used in GBR catchments, including the herbicides diuron and atrazine, have been detected in water and sediments from the GBR lagoon ([Haynes et al., 2000], [Mitchell et al., 2005] and [Kapernick et al., 2006]). Contamination of GBR sediments by polyaromatic hydrocarbons (PAHs), trace metals and metalloids has also been reported near marinas and port facilities ([Smith et al., 1987] and [Reichelt and Jones, 1994]). The hydrophobic POPs are more often detected in association with biota, and measuring contaminants in the tissues of organisms is critical to demonstrate exposure and uptake in natural environments (Phillips and Rainbow, 1993). On the GBR, polychlorinated biphenyls (PCBs) have been detected in dugong tissue (Haynes et al., 1999), while the organochlorines (OCs) dieldrin, DDT and its breakdown products have been detected in crabs from a range of nearshore environments ([Russell et al., 1996], Mortimer and Cox, 1999 Mortimer, M., Cox, M., 1999. Contaminants in mud crabs (Scylla serrata) from the Maroochy River. Queensland Environmental Protection Agency Technical Report No 25. Brisbane, 19p.[Mortimer and Cox, 1999] and [Mortimer, 2000]). The mud crab Scylla serrata has great potential as a tropical biomonitoring species because of its capacity to bioaccumulate a range of contaminants such as POPs and metals ([Mortimer, 2000] and [Andersen and Norton, 2001]). S. serrata is an important target species for subsistence, commercial and recreational fisheries and males of this species have limited territorial ranges (Ryan, 2003) and are large enough to provide ample tissue for chemical analysis. Although runoff presents a potentially significant source of pesticides and trace metals to the GBR, no comprehensive survey of bioaccumulation within GBR catchments has been previously performed. This baseline report presents the concentrations of pesticides, PCBs, PAHs, metals and metalloids in S. serrata collected following the wet seasons (2004/2005 and 2005/2006) from 11 north Queensland rivers and creeks that flow into the GBR lagoon.