Preliminary investigations of toxicity in the Georges Bay catchment, Tasmania, Australia.
North-eastern Tasmania, Australia has been an area of major production for Pacific oysters (Crassostrea gigas) for over 25 years. Since the mid-1990s, increased oyster mortality has been observed. The purpose of the present study was to identify the agent causing aquatic toxicity and to investigate whether there is a chemical and/or toxicological link between river foam and monoculture timber plantation forests of exotic eucalypts (Eucalyptus nitens) present in the catchment area. Foam samples from the George River catchment demonstrated high toxicity to a freshwater cladoceran and larvae of a marine blue mussel species. After filtration to remove most particulates, foam samples also demonstrated a marked reduction in toxicity to blue mussels, which suggested that the toxicity is particle associated. Foam and leaf extracts ofE. nitenswere then fractionated using HPLC and size exclusion chromatography and the resulting fractions were screened for cladoceran and blue mussel toxicity. Toxicity was detected in fractions common to both the foam and the leaf extracts. This study suggests that there may be a chemical and toxicological relationship between foam andE. nitensleaf components.
Tasmanian Public and Environmental Health Network , PO Box 294, St Helens , Tasmania 7216 , Australia ; National Toxics Network , PO Box 173, Bangalow , NSW 2479 , Australia.
Alison
A
Bleaney
National Institute of Water & Atmospheric Research , Gate 10, Silverdale Rd, Hillcrest , Hamilton 3216 , New Zealand.
Christopher W
CW
Hickey
National Institute of Water & Atmospheric Research , Gate 10, Silverdale Rd, Hillcrest , Hamilton 3216 , New Zealand.
Michael
M
Stewart
Synergistic Coatings Pty Ltd , 21 Mittabah Road, Hornsby , NSW 2077 , Australia.
Marcus
M
Scammell
National Toxics Network , PO Box 173, Bangalow , NSW 2479 , Australia.
Rye
R
Senjen
Eucalypts; Oysters; Plantations; Pollution; Tasmania; Toxicity; Water