In the 1990s, increasing awareness of health problems experienced by sheep farmers led to reductions in the use of organophosphates for sheep dipping. An unfortunate side effect was increased use of the synthetic pyrethroid cypermethrin. Cypermethrin is around a thousand times more toxic to invertebrates and large quantities are used in sheep dipping. There are numerous points in this process when spills, leaks and drips from dipped sheep can pollute rivers and fields. Buglife, a charity focusing on invertebrate biodiversity, has drawn attention to this outmoded and polluting practice, and has achieved a temporary suspension of the use of cypermethrin for sheep dipping (page 3).

A controversy has been brewing in the United States (US) over the use of human dosing studies by agrochemical companies. Although such studies are carried out in the US, a moratorium has prohibited the US Environmental Protection Agency from considering them as part of a pesticide registration
package. This moratorium was lifted in April of this year. In this issue we review these developments and consider the ethical implications, and the motivation of companies conducting such studies. Although human dosing studies are not required to register a pesticide in Europe it is legal to conduct such studies and they will be considered if submitted to regulators as part of a registration package (page 6).

The role of pesticides in the development of certain chronic health problems remains controversial. In this issue we carry an article reviewing evidence that pesticide exposure may be involved in the development of prostate cancer, non- Hodgkin’s lymphoma, testicular cancer and childhood cancers. The authors conclude by arguing for greater precaution in the licensing and use of chemicals such as pesticides (page 12). A second article reviews multiple chemical sensitivity (MCS), a condition whose biological basis is recognised in countries such as Germany and Australia, but which is still not recognised in the UK. The author argues for recognition of MCS as an illness and discusses evidence that chemicals such as pesticides may have a role in its aetiology (page 9).

We have frequently reported on problems caused by large stockpiles of obsolete pesticides in Africa. An integral part of the solution is to ensure that, once current stockpiles are removed, future stockpiles are not allowed to accumulate.We report on a project in Mozambique identifying the historic reasons for stockpile accumulation and work to prevent this problem arising again (page 18).

One of the unavoidable consequences of pesticide use is the generation of hazardous waste most frequently in the form of empty pesticide containers. Tens of thousands of tonnes of such waste is generated every year. In developing countries empty containers often find secondary uses most notoriously for carrying drinking water and sometimes with catastrophic effect. It is essential that pesticides are managed throughout their whole lifecycle and schemes for managing pesticide containers safely and sustainably are a vital part of this. Technical and financial considerations in establishing such schemes are reviewed along with examples of successful schemes (page 16).