New Zealand Journal of Marine and Freshwater Research abstracts
Short communication
Survey of pesticides in New Zealand groundwaters, 1994
MURRAY E. CLOSE
Institute of Environmental Science and Research
P. O. Box 29-181
Christchurch, New Zealand
Abstract A survey of pesticides in groundwater throughout New
Zealand was conducted in 1994 by the Institute of Environmental Science and
Research for various Regional and District Councils. Wells were selected on the
basis of the importance of each aquifer to the region, the proximity of
particular land uses, and the extent of application of pesticides in the
area--recognising that shallower, unconfined aquifers would be more at risk
than deeper aquifers. Throughout New Zealand, 79 wells were sampled plus 39
wells sampled during a more intensive survey in Marlborough. There were no
wells with pesticides detected above the Maximum Acceptable Value (MAV) for
drinking water, indicating that all the water tested was suitable for drinking.
Pesticides were detected in 13 out of the total of 79 wells (16.5%) excluding
the Marlborough survey. If this survey is included, then 16 out of a total of
118 wells (13.6%) showed detectable pesticides. Most (78%) pesticide
concentrations were below 1 mg m-3 with 52% below 0.25 mg
m-3. In total 10 different pesticides were detected, with the
triazine group occurring most often. Contaminated wells were significantly
shallower, had higher water tables, had less depth between the water table and
the well screen, and had slightly lower temperatures than uncontaminated
wells.
Keywords pesticide; groundwater; New Zealand; maximum
acceptable value; triazine
New Zealand Journal of Marine and Freshwater Research, 1996: Vol 30:
455-461
0028-8330/96/3004-0455 $2.50/0 (c) The Royal Society of New Zealand
1996
PDF file of entire paper: medium quality (520K); (scanned from paper original: notes about this process)
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