Pollution and Water pollution is a major environmental concern in Venezuela. Rivers, lakes, and underground aquifers are becoming increasingly polluted due to oil development, untreated sewage wastes, and fertilizer run-off. Lake Maracaibo, Venezuela's largest lake, is suffering from increased pollution, and the resort island of Margarita suffers from frequent water shortages as the island's population exceeds its infrastructure's ability to provide water and treat waste. According to news reports in August 1999, the state oil company, PdVSA, faces about $1.5 billion in environmental liabilities. Cleaning up 15,000 oil pits, which collect contaminated sludge from oil wells, alone could cost $1 billion. Periodic spills have damaged local flora and fauna, with negative implications for biodiversity and for the local economy. Environmental concerns traditionally have not been a major focus of PdVSA, but the company has now adopted an environmental policy and pledges to rank environmental protection as one of its top goals. It now is in the process of cleaning up the most environmentally dangerous oil pits, many of which are seeping into Venezuela's water supplies