Barium and heavy metals in the waters and aquatic plants of the catchment of Bleaberry Gill, North Yorkshire

Abstract

Ca, Zn, Ba and Pb concentrations were measured in the waters and plants of Bleaberry Gill, North Yorkshire. Ba concentrations were compared with those of other streams in Arkengarthdale, considered to be non-contaminated by mining activity. Ba concentrations in bryophytes from Bleaberry Gill were an order of magnitude greater than those from streams uncontaminated with Ba, though aqueous concentrations were only 2-3 X greater. Zn was not present in particularly elevated concentrations, though Pb concentrations were elevated. Concentrations of these elements in bryophytes were not particularly high compared to other mining areas. In a series of experiments Hygrohypnum ochraceum was transplanted between streams with different aqueous metal concentrations. Uptake of Ba was rapid in populations of moss previously exposed to low and medium concentrations of Ba in water. The population from the lower Ba site achieved a lower maximum concentration than the population from the medium Ba site. Loss of Ba was rapid after a short exposure to elevated concentrations but took longer after prolonged exposure. The behaviour of Zn was similar, though both uptake and loss were slower than for Ba. Possible effects of proposed mining developments in the catchment of Bleaberry Gill are considered.