Your Daily Poison - Pesticide Action Network UK

3 Pesticides in water
In this section we compare official data from
the government’s Drinking Water Inspectorate
(DWI) with the results we have obtained from
questionnaire survey of both the water
companies who report to the DWI, summarised
in Table 4 (Appendix 6a and 6b), and local
authorities, summarised in Table 6 (Appendix
6c). Local authorities are responsible for
private water supplies, but conduct only a
small number of tests. Indications of ubiquitous
contamination of drinking water at low levels
are confirmed through the PAN UK survey. A
gap in the protection of health from potentially
harmful pesticides in water, due to the limited
number of pesticides tested for, is revealed.
According to the official data from the
government’s Drinking Water Inspectorate,
pesticides in water are a minor and diminishing
cause for concern 26 . The legal limit, set by the
European Commission, is 0.1 micrograms per
litre, or one part in ten billion, for a single
pesticide, 0.5 micrograms per litre for the sum
of detectable concentrations of individual
pesticides, and 0.03 micrograms per litre for
the pesticides aldrin, dieldrin, heptachlor and
heptachlor epoxide 27 (persistent organochlorine
pesticides now banned in the UK and globally
under the Stockholm Convention, but still
detected many years after their use). Only 18
‘exceedances’ of the legal limit for pesticides
were detected in 2004. This is a decrease from
31 in 2003 and 72 in 2002. However, data
gathered in the PAN UK survey (see Table 4)
indicates that drinking water contains low
levels of pesticides. Looking in detail at both
the public and private water supply, the
presence of pesticides is confirmed in both raw
Table 4. Pesticides in the public water supply.
Summary of PAN UK survey – Appendix 6a, page 39
PAN UK Questionnaires sent to: All 26 water companies in England and
Wales, Scottish Water, and the
Northern Ireland Drinking Inspectorate
Number of responses received: In 2004 (2002 data) In 2005 (2004
data)
12 12
Number of companies reporting
10 or more pesticides found
above 0.01 micrograms per litre
(below the legal limit) in raw
(untreated) water
4 5
Number of companies reporting
10 or more pesticides found
above 0.01 micrograms per
litre (below the legal limit)
in drinking (treated) water
4 5
12
(untreated), and drinking water at levels which
are below the legal limit, but above the limit of
detection. As the EC legal limit was intended to
achieve zero pesticides in drinking water on a
precautionary basis 28 , our evidence indicates
that, to maintain this objective, the legal limit
needs to be lowered to the levels at which
pesticides can now be detected. Harmful
effects are suspected to risk, in particular, the
foetus. The health effects of a lifetime’s
exposure to a mixture of chemicals at low
levels is unknown.
Of the twelve water companies who received
and responded to our survey, seven companies
completed the section in our questionnaire
which asked them to report the levels of
pesticides found below the legal limit, but
above the limit of detection. In Appendix 6b we
present the highest occurrences: atrazine,
isoproturon, mecoprop, propyzamide and
simazine are all being detected in a high
number of tests. According to Southern Water,
atrazine occurred in 62.6 per cent of drinking
water samples, and simazine in 43.2 per cent
of drinking water samples. Numerous other
pesticides are routinely detected in a lower
percentage of tests. The water companies
varied in their facility to extract data in the
format of our information request.
According to the Drinking Water Inspectorate,
aldin, dieldrin, heptachlor and heptachlor
epoxide are ‘generally are not found in water
sources 29 ’. These are obsolete pesticides,
banned since the 1980s on health grounds,
which have not had approved uses in the UK
for many years. However, the PAN UK survey
showed that these pesticides are present in
water.
Of the respondents to PAN UK’s survey who
disclosed details about pesticides tested for,
and detected at levels below the legal limit, but
above the limit of detection, the following water
companies reported in their questionnaire
return the presence of these pesticides in raw
or treated water: Bristol, Dee Valley, Essex &
Suffolk, Mid Kent, Northumbrian, Southern,
South Staffordshire, Sutton & East Surrey,
Wessex. Aldrin, dieldrin and heptachlor are
classified carcinogens and endocrine
disruptors according to international
authorities 30 . Some studies have found banned
pesticides, including these, occurring in
rainwater 31 indicating that they persist in the
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