THE Ferret’s article in the Sunday National (Limit for toxic sea lice chemical increased after industry lobbying) raises fundamental issues. The use of toxic chemicals both in agriculture and the fish farming industry may well harm other forms of life. Is there any absorption by the animals or fish so treated?

As a hill shepherd in the 1950s, to deal with the sheep tick problem, on orders from the UK’s Department of Agriculture we dipped the flock using a product based on arsenic. To ensure compliance a dipping form was completed and the operation was sometimes watched by the local policeman hoping for a cup of tea.

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Did the sheep so treated absorb even a tiny fraction of the product? Perhaps not, but when dipping finished the used water was tipped on the ground.

A vet who investigate the sudden death of my previous shepherd’s milk cow pointed at an empty sheep dip drum. Humans are now polluting the planet with an ever wider range of chemicals, perhaps most maybe safe, if checked in isolation. Chemicals do mix. Common sense might one day wonder who will be capable of checking their worldwide synergistic impact.

Iain R Thomson