We must all eat.

Unfortunately, for the health of the public, the use of toxic chemicals in food production, plus pollution in other forms, goes wider than the fish-farming industry (Fish farm at centre of mystery illness was warned over safety by US agency, News, October 28).

Current farming practices, on land or at sea, are unsound on a wide range of issues. Given the massive vested interest involved and their standard defence of case not proven, is the question too complex for politicians, the various health executives, plus the medical profession, to tackle? Though now a retired farmer, it was obvious to me 50 years ago that in all probability, along with its many other deleterious effects, there is a correlation between chemical agriculture and the increasing rates of cancer.

Iain R Thomson