It is tempting to conclude that wealthy nations worry about global changes whose consequences may be two or more generations away, while poor nations do not have the cash to provide clean water and proper waste removal in desperately polluted towns filled with toxic dust and fumes. In a global survey of heavy metal pollution, Nriagu concluded that over 150 million people experienced elevated lead in their blood, 250000-500000 suffer renal failure of cadmium poisoning, and another 500000 are believed to have skin cancer as a result of arsenic poisoning. In developing countries generally, Nriagu concludes: