The Fauna of the River Melindwr, a Lead-Polluted Tributary of the River Rheidol in North Cardiganshire, Wales
1940; Wiley; Volume: 9; Issue: 2 Linguagem: Inglês
10.2307/1455
ISSN1365-2656
Autores Tópico(s)Ecology and biodiversity studies
ResumoFROM prehistoric times until the beginning of the twentieth century, leadmining and the crushing and washing of the ore (galena) was one of the chief industries of north Cardiganshire. During the first half of the nineteenth century the industry flourished, but after 1872 it declined under the influence of foreign competition and in 1900 nearly all the mines had been closed down. A small number were reopened during the period of the Great War, but this revival was temporary and at the present time lead-mining in Cardiganshire is a dead industry. The extraction of the ore was accomplished by crushing or grinding the mined material into a fine state of division and washing the crushed material with running water which carried off the lighter earthy impurities leaving behind the heavy galena. As might be expected, the separation of galena and earthy particles was not complete, so that the washing water carried off quantities of galena in a fine state of division. Apparently it was the ancient practice to allow the washing water to flow directly into the neighbouring rivers and streams, which carried the finely divided ore for considerable distances before it was finally deposited on their beds, or, at flood time, on land bordering their banks. Later, when the poisoning of domestic animals, especially horses, poultry and ducks, and the wholesale destruction of pasture land which resulted from this practice had aroused serious concern, the
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