- RAIN IS NOT what it used to be. A new study reveals that much of the precipitation
in Europe contains such high levels of dissolved pesticides that it would
be illegal to supply it as drinking water.
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- Studies in Switzerland have found that
rain is laced with toxic levels of atrazine, alachlor and other commonly
used crop sprays. "Drinking water standards are regularly exceeded
in rain," says Stephan Müller, a chemist at the Swiss Federal
Institute for Environmental Science and Technology in Dübendorf. The
chemicals appear to have evaporated from fields and become part of the
clouds.
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- Both the European Union and Switzerland
have set a limit of 100 nanograms for any particular pesticide in a litre
of drinking water. But, especially in the first minutes of a heavy storm,
rain can contain much more than that.
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- In a study to be published by Müller
and his colleague Thomas Bucheli in Analytical Chemistry this summer, one
sample of rainwater contained almost 4000 nanograms per litre of 2,4-dinitrophenol,
a widely used pesticide. Previously, the authors had shown that in rain
samples taken from 41 storms, nine contained more than 100 nanograms of
atrazine per litre, one of them around 900 nanograms.
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- In the latest study, the highest concentrations
of pesticides turned up in the first rain after a long dry spell, particularly
when local fields had recently been sprayed. Until now, scientists had
assumed that the pesticides only infiltrated groundwater directly from
fields.
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- Müller warns that the growing practice
of using rainwater that falls onto roofs to recharge underground water
may be adding to the danger. This water often contains dissolved herbicides
that had been added to roofing materials, such as bitumen sheets, to prevent
vegetation growing. He suggests that the first flush of rains should be
diverted into sewers to minimise the pollution of drinking water, which
is not usually treated to remove these herbicides and pesticides.
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- Meanwhile, Swedish researchers have linked
pesticides to one of the most rapidly increasing cancers in the Western
world. Non-Hodgkin's lymphoma, which has risen by 73 per cent in the US
since 1973, is probably caused by several commonly used crop sprays, say
the scientists.
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- Lennart Hardell of Orebro Medical Centre
and Mikael Eriksson of Lund University Hospital found Swedish sufferers
of the disease were 2.7 times more likely to have been exposed to MCPA,
a widely used weedkiller, than healthy people (Cancer, vol 85 p 1353).
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- MCPA, which is used on grain crops, is
sold as Target by the Swiss firm Novartis. In addition, patients were 3.7
times more likely to have been exposed to a range of fungicides, an association
not previously reported.
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- The patients were also 2.3 times more
likely to have had contact with glyphosate, the most commonly used herbicide
in Sweden. Use of this chemical, sold as Round-Up by the US firm Monsanto,
is expected to rocket with the introduction of crops, such as Roundup-Ready
soya beans, that are genetically modified to resist glyphosate. The researchers
suggest that the chemicals have suppressed the patients' immunity, allowing
viruses such as Epstein-Barr to trigger cancer.
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