Pesticide and heavy metal concentrations in Great barrier reef sediment, seagrass and dugongs (Dugong Dugon)

Abstract

Dugong populations in the southern Great Barrier Reef Region have undergone a major population decline over the last 10 years. Anthropogenic influences including capture in fishing nets, hunting, loss of seagrass habitat and local water quality degradation caused by coastal and hinterland development all threaten dugong populations. Pesticides including organochlorine compounds have been extensively applied by Queensland’s intensive coastal agriculture industry. The persistent nature of many of these types of compounds raises the potential for continued long-term chronic exposure of Great Barrier Reef seagrasses and dugongs. This is important as organochlorines may affect marine mammal reproduction and immune system functioning, and have been implicated in marine mammal population declines elsewhere. Herbicide runoff from agricultural lands has the potential to impact seagrass, the major food consumed by dugongs.