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A STUDY OF THE FAUNA OF RIVERS POLLUTED BY LEAD MINING IN THE ABERYSTWYTH DISTRICT OF CARDIGANSHIRE
Author(s) -
CARPENTER KATHLEEN E.
Publication year - 1924
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1924.tb05689.x
Subject(s) - fauna , lead (geology) , streams , biology , ecology , galena , sphalerite , computer network , paleontology , computer science , hydrothermal circulation
Summary.1 The relative poverty of the fauna and flora of certain streams in the Aberystwyth district can only be related to their pollution by lead mining and lead washing operations. 2 Such operations affect the rivers by the discharge into their waters of galena particles in all stages of division, and also by the formation of lead salts in diffusible form through chemical interaction with the natural water. 3 Only a single case is known of the clogging of fish‐gills by adhering particles of galena‐grit: there is no definite evidence that this is a usual cause of death. 4 Statistics locally collected shew, however, that such lead grit is present in practically all the streams of the neighbourhood, particularly in the Lower Clarach, where a rich fauna, including Fishes, subsists. 5 The correlation of fauna lists with tables of analyses of water samples shews that poverty of fauna, with absence of fishes in particular, always accompanies the presence of lead salts in diffusible form. 6 The cessation of the last of the lead mining and washing operations affecting the Rheidol and Ystwyth was followed by a marked and rapid increase in the flora and fauna of the rivers, which was accelerated by the spring drought of 1922. At this season, the amount of lead in diffusible form in these waters was, if any, too small to be estimated, while the proportion of lead grit remained high. 7 Observations made since May, 1922, shew that the original proportion of lead in diffusible form has not been restored, while the flora and fauna have continued to increase. 8 The general inference is that, while the presence of lead grit is no doubt in some cases directly harmful to Fishes, the general fauna of the rivers is undoubtedly impoverished by the presence of lead salts in diffusible form.