GROUNDWATER IMPACTS FROM FIVE MILLENNIA OF COPPER MINING - THE LEFKA-XEROS AREA OF CYPRUS

The Lefka-Xeros area encompasses the largest mining/mineral processing complex in Cyrpus, dating to the Chalcolithic period (3500-2500 BC). Post-Roman, industrial-scale mining began around 1920; the Cyprus Mining Corporation (CMC) ultimately operated three mines and processed ores by acid leaching, copper and pyrite flotation, and production of cement copper. In 1974, the plant and all of its mines ceased operations but were left largely intact. This area-wide environmental and hyrdogeologic study was conducted with support of the Bi-Communal Development Programme, funded by the US Agency for International Development (USAID) and United Nations Development Programme (UNDP), and executed by the United Nations Office for Project Services(UNOPS).

Regional data and water analyses indicate that public water supply wells for the town of Lefka are sufficiently upgradient from the impacted areas to avoid contamination. Anomalous Al levels previously observed in monitoring data are an artifact of analytical or collection methodologies. In contrast, the Lefka reservoir, built over the former mine entrance, has shown elevated levels of Fe, SO4, and Cu. Runoff from waste-rock piles, contact with the mine workings, and nearby gypsum deposits are implicated. Agricultural wells screened in coastal plain sediments and Miocene marls have shown elevated sulfate levels but likely reflect natural rather than anthropogenic conditions.

The former CMC plant on the coastal plain at Xeros is an ongoing source of contamination to groundwater. Potential contaminants include metals, sulfate, acidity, VOCs, SVOCs, and cyanide. There are insufficient data with which to determine the extent of impact, although pumping of irrigation wells may draw contaminated groundwater from the plant area. Seawater intrusion is demonstrated, and anthropogenic nitrate and pesticides (including copper sulfate) are potential sources of environmental degradation unrelated to mining or mineral processing activities. Perhaps the most acute concern is the maintenance of earthen-berms that contain 84 hectares of high-moisture content tailings as much as 9 meters above adjacent roads and fields.