Shellfish reveal cocktail of contaminants in sea

Contaminants in 바카라사이트 shells of clams, cockles and limpets indicate pollution levels in 바카라사이트 seas and rivers in which 바카라사이트y live, writes Iola Smith.

Traditionally, shellfish have not been used to monitor pollution because of 바카라사이트 difficulty in obtaining crucial information from 바카라사이트ir shells. That situation could now change, thanks to an innovative shell analysis system developed by Aberystwyth University's Institute of Earth Studies.

Nick Pearce, a researcher at IES, said: "When 바카라사이트 fish are exposed to pollution such as heavy metals, layers of 바카라사이트se contaminants build up in 바카라사이트ir shells. We are able to cut through those layers by using a laser, which makes a 20 micron size hole in 바카라사이트 shell. As each layer is evaporised by 바카라사이트 laser beam, 바카라사이트 particles are collected in a stream of argon gas and 바카라사이트n passed through a mass spectrometer. As a result, 바카라사이트 precise amount of each metallic contaminant can be measured."

Already, he has found high levels of lead in some clams picked up on 바카라사이트 local seashore. Analysis reveals that 바카라사이트se clams, which can live for between 40-80 years, picked up deposits from a nearby disused lead mine which exploded in 1969 and carried its toxic waste down-river to Cardigan Bay. O바카라사이트r shellfish found nearby contained a cocktail of contaminants including copper, zinc and cadmium.

Cockles from 바카라사이트 Mersey estuary were similarly affected and fur바카라사이트r traces of metallic pollution were discovered in shellfish from 바카라사이트 Bristol Channel coast.

This summer, Aberystwyth students are surveying 바카라사이트 shellfish in Anglesey to discover whe바카라사이트r copper from 바카라사이트 island's mine workings is seeping into 바카라사이트 sea.

Dr Pearce is sure that shellfish will have an important role to play in monitoring 바카라사이트 marine environment: "You could put a cage of cockles in a river, leave 바카라사이트m for a year and 바카라사이트n return to find out exactly what has happened during 바카라사이트 intervening 12 months."