Arsenic cancer risk still high decades later in Chile

People exposed to very high levels of arsenic in Chilean drinking water back in the 1950s and 60s are still showing a higher-than-normal risk of bladder cancer -- years after the arsenic problem was brought under control, a new study shows. The findings are not surprising, researchers say, since the cancer would take decades to emerge. But the results underscore the importance of continuing to screen high-risk people for bladder cancer, according to lead researcher Dr. Fernando Coz, a professor of urology at the Universidad de Los Andes in Santiago de Chile. The study, reported in the Journal of Urology, focused on people in the Antofagasta region of Chile. In the 1950s and 60s, drinking water in the region became contaminated with high levels of arsenic. Arsenic is semi-metallic element found in rock, soil, water and air. It is also released into the environment through industrial activities, and can be found in products like paints, dyes and fertilizers. High exposure has been linked to several cancers, including tumors of the bladder, liver and lungs. In Antofagasta, a combination of factors led to a huge increase in drinking-water arsenic by the late-1950s: naturally high arsenic levels in the environment, heavy mining and a move to make two rivers the area's main drinking-water sources. Arsenic concentrations reached 800 to 900 micrograms per liter (mcg/L) -- far above the current allowable limit of 10 micrograms per liter recommended by the World Health Organization (WHO) and the U.S. Environmental Protection Agency EPA). The arsenic problem was first reported in 1971, which prompted the first water treatment plants to be set up in the area. Arsenic levels dropped sharply, though it took until about 1990 for levels to fall in line with WHO standards (which at the time allowed for more arsenic than the current standard). But even two decades after the arsenic problem came under control, people in Antofagasta are showing high bladder cancer rates, Coz and his colleagues found.