Persistent organic pollutants (POPs) in food are a worldwide problem demanding urgent worldwide government action, say the authors of a study in the US.

The authors analysed data held by the FDA, looking for the 12 most dangerous POPs listed for phasing out by the Stockholm Convention: residues of all 12 were in all food types—fruit and vegetables, meat, poultry, and dairy and baked foods. They estimated that, at worst, adults could be exposed to 63 to 70 daily “hits” by these residues, depending on where in the US they lived—north east, south east, western states, or the Midwest. The amounts present were above thresholds considered safe for adults for individual POPs and way above thresholds for children, whose sensitivity to POPs is greater. This despite bans on POPs in the US decades ago.

POPs are linked to cancer, learning disorders, impaired immunity, and reproductive disorders, and since their use surveillance studies have reported increases in them all. The evidence is that POPs—even in tiny amounts—are a serious health hazard.

POPs comprise organochlorine pesticides—DDT, dieldrin— industrial chemicals or process byproducts—PCBs, dioxins. The danger lies in their longevity, accumulation in food chains, and ability to spread far and wide in water and within air currents; POPs occur in human blood and breast milk around the world.

The Stockholm Convention was set up in May 2001 to stop the use of POPs. Fifty ratifications of the treaty are needed for it to take effect; by April 2002 just five governments had signed up. Other governments need to catch up—fast.