Mining & industrial pollution

At MayarÕ zone, northeast Cuba, important lateritic deposits have been exploited since 1943. The mineral is used as raw material in a nickel-processing plant which discharges its untreated solid and liquid wastes into Levisa Bay. Similarly to the adjacent Nipe and Cabonico bays, fluvial currents from the mining areas convey a significant mineral load into this bay. To assess the environmental impact caused by the mining and the metallurgical activities, the distribution of Ni, Co, Fe, Mn, Cu, Pb and Zn was investigated in surface and core sediment samples. Uni- and multivariate statistical methods as well as different indices and pollutant factors were used to interpret results. These revealed significant environmental impacts in some areas of the three bays with high concentrations of Ni, Co, Fe and Mn, whose values are up to two orders of magnitude greater than the zone baseline levels. The metal concentrations decreased with increasing distance from discharges. A comparison with other Cuban bays and coastal zones, confirmed that the main source of metal pollution in these three bays was not urban and industrial activities, but lateritic mining and metallurgy.

The effect of nickel mining and metallurgical activities on the distribution of heavy metals in Levisa Bay, Cuba

The distribution of Ni, Co, Fe, Mn, Cu, Pb and Zn was investigated in surface and core sediment samples and i n the leaves of the red mangrove (Rhizophora mangle) from Levisa Bay, an area affected by nickel mining and metallurgical activities. The results revealed that these activities have seriously polluted the sediments, especially by Ni. Fe, Co and Mn, with concentrations decreasing with increasing distance from discharge sources. The concentrations of Fe (0.64-22.66%) and Co. Mn and Ni (7.7–324, 125–2957 and 69–4764 μ/g, respectively) were up to two orders of magnitude greater than those of non-polluted coastal areas in Cuba. Rhizophora mangle was shown to be a useful bioindicator of heavy metal pollution in the studied ecosystem.