Children at risk 
- More evidence against OPs

How safe is our food supply from pesticide residues? A new report by the US Environment Working Group (EWG) claims that each day one million children under five consume unsafe levels of organophosphate (OP) insecticide residues in the US. The scale of  potential effects is surprising-but the overall message echoes that given by the UK's own Pesticides Safety Directorate last year.

The new EWG report - critical of OPs

Fresh fruit and vegetables are an essential part of any diet, but there is increasing concern about the way these foods are produced. The EWG report Overexposed(1) has found disturbing information in its analysis of US pesticide residue data:

• 1 million children under five consume each day unsafe levels of OP insecticides in the US: this is one child in 20;
• a child has a 25% chance of eating a peach with an unsafe dose; a 13% chance of eating an apple with an unsafe dose; and a 12% chance of eating a nectarine with an unsafe dose;
• more than 100,000 children will exceed the 'reference dose' (a safe lifetime daily dose) by a factor of 10;
• 90% of risks are linked with methyl parathion, dimethoate, chlorpyrifos, pirimiphos-methyl and azinphos methyl;
• most risks are associated with apples, peaches and grapes.

Cumulative and variable risk
The EWG study was prompted by the US 1996 Food Quality Protection Act, which requires the government to consider the total risk posed to people when they are exposed to all pesticides that have a common mode of action and a similar type of effect (such as OPs, see Figure 1). The new law further requires specific protection for children, who are more vulnerable to pesticides and other toxins.
    The US study confirms the findings of the UK Pesticides Safety Directorate (PSD) report(2) in March last year, which also announced unexpectedly high variations in pesticide residues were found in carrots and some fruit. This report noted:

• between 10% and 30% of selected fruit contained OP or carbamate residues but the greatest surprise was the range of variability -the highest residue level was 29 times the mean;
• the risk of eating an apple with a very high residue (that might cause adverse health effect) was 1 in 1000; 

How do these reports compare with each other? There are differences between UK and US pesticide usage:

• the UK does not use the pesticide methyl parathion, associated with the highest risk in the US-but the other four pesticides linked with increased risk in the US are widely used in horticulture and agriculture in the UK; 
• the US report deals only with fruit-but PSD says: "The fact that variable residues seem likely to occur in crops from all sources means that the issue has to be addressed on an international level." This means that Codex risk assessments and maximum residue limits (MRLs) may not be strong enough to protect health.

The EWG report focuses mainly on the longer term OP effects such as cholinesterase inhibition: but the evidence is that there may be other enzymes in the body that are also affected by OPs. The report also only deals with OPs, and it now appears that nearly all pesticides may produce unexpectedly high residues.

Different reactions
The US pesticide industry reacted strongly to the EWG study. In a letter to the US Environmental Protection Agency (EPA) the American Crop Protection Association has expressed their 'serious objection' to the EPA's decision to allocate time at the 24 March Scientific Advisory Panel meeting where the EWG's work will be peer reviewed, and possibly taken up by the EPA.
    Lynn Goldman, assistant EPA administrator, told the Wall Street Journal that the EWG study is "instructive as a 'snap-shot'. In keeping with the 1996 law, the EPA no longer regulates pesticides on a chemical-by-chemical basis. It plans a more sophisticated version of the EWG study to assess the relative risks of combined exposure to pesticides."
    There is even a suggestion that the EPA considers the EWG work to under-estimate risk because it does not take into account household use of OPs.

Consumer concerns
The OP issue and related matters were discussed in London on 20 February at the Food, Children and Health Conference(3). The guest speaker was  John Wargo of Yale University(4). Using data developed from his experience of US regulation and policy over many years, he put forward the argument that we have to rely on ourselves to reduce our exposure to pesticides, because government risk management, residue analysis and data surveillance are not capable of doing the job.

Conclusions
Consumer groups in the UK and the US emphasise that fresh fruit and vegetables are part of a healthy diet. Nevertheless pesticide residue safety issues require urgent attention.
    EWG recommends that the five highest risk OPs methyl parathion, dimethoate, chlorpyrifos, pirimiphos-methyl, and azinphos "must be banned immediately for all agricultural use." This mirrors calls made in the past by many public interest groups in the UK for a moratorium on OP use. However the question remains: are there viable alternatives that do not put human health and/or the environment at risk? (PB) (DB)

1. Richard Wiles, Kert Davies and Christopher Campbell, Overexposed: organophosphate insecticides in children's food, EWG, 1718 Connecticut Avenue NW Suite 600, Washington DC 20009, US, 1998, Fax +1 202 232 2592, also available at www.ewg.org.
2. Unit to Unit Variation of Pesticide Residues in Fruit and Vegetables. PSD, York, 14 March 1997.
3. Food, Children and Health Conference, sponsored by Baby Organix (producers of organic baby food), Fax 01202 479712.
4. John Wargo is Director of the Centre for Children's Environmental Health, and is author of the book Our Children's Toxic Legacy, 1996.

[This article first appeared in Pesticides News No. 39, March 1998, page 3]