The Drinking Water Inspectorate (DWI), has
published a report of the UK water companies' analysis of nitrate, pesticides
and lead data for 1991 to 1994.
In 1991 the total number of determinations (tests) for
individual pesticides in drinking water was 828,990 of which 23,159 exceeded the
European Union (EU) standard of 0.1µg/l. By 1994 the number of tests had
increased to 1,112,269 but the number exceeding the standard had fallen to
12,875. This represents a decrease in the number failing the standards from 2.8%
to 1.2% over the four year period.
The percentage of tests breaching the standard is increasing
for isoproturon and chlorotoluron. The DWI is at a loss to explain the reason
for a rise in the failure rate of chlorotoluron from 1.4% in 1991 to 2.5% in
1994 despite a massive reduction in use from 695 tonnes in 1989/99 to 130 tonnes
in 1993/4. With isoproturon, measures co-ordinated by the government to restrict
its use in 1995 may be reflected in lower levels in future reports.
The herbicides atrazine, simazine isoproturon, diuron and
mecoprop were most frequently detected above the EU standard. There were
declines in the percentage of tests breaching the standard for atrazine,
simazine, diuron, mecoprop and 2,4-D.
Hydes, O.D., (Ed), Nitrate, Pesticides
and Lead, 1991-1994, Drinking Water Inspectorate, Romney House, 43 Marsham
Street, London SW1P 3PY, December 1996, 126pp.
[This
article first appeared in Pesticides News No. 35,
March 1997, page 21]