1997: Gunnedah Area Rainwater Tanks. Pesticide: Endosulfan

Ms Christine Robertson, Director, New England Public Health Unit tabled two
documents with the Standing Committee pertaining to tests on water quality in
rainwater tanks in the Gunnedah area conducted by the NSW Environment
Protection Authority and the New England Public Health Unit. A pilot test
was prepared in 1996, followed by a more intensive survey during the 1997
summer cropping season. Water samples from selected rainwater tanks were
tested against maximum residue limits (MRLs) as set out in the National Health
and Medical Research Council’s 1987 “Drinking Water Quality in Australia”
Findings from the surveys were as follows:
•Pesticides were detected in 36 of the 54 (64%) rainwater tanks sampled in the
1997 program;
•The highest endosulfan concentrations were recorded as 0.27 ppb in the 1996
program and0.12 ppb in the 1997 program, these figures were well below the MRL level
of 40 ppb; and
•Endosulfan residues were detected in raintanks up to 3600 metres from the
nearest possible source.