'Too Little, Too Late.'
A Tennessee Valley Authority employee surveyed damage caused by the Monday failure of a retention pond. (J. Miles Cary/knoxville news sentinel/Associated Press)
...Chen and her team were curious to learn how arsenic and mercury, two toxic environmental metals, moved through the food web in a freshwater ecosystem known to be polluted and contaminated. In a process called bioaccumulation, mercury and arsenic were found throughout the food web, from the water, into the algae, through the tiny algae-eating zooplankton, to the fish. As expected, the researchers found that more nutrient-rich environments supported larger algal blooms, which resulted in lower concentrations of mercury and arsenic in the water due to uptake by the algae....
Long-term exposure (click here) to inorganic arsenic in drinking water in Taiwan has caused blackfoot disease, in which the blood vessels in the lower limbs are severely damaged, resulting eventually in progressive gangrene. Its occurrence in Taiwan may be influenced by factors such as poor nutrition. However, arsenic exposure has caused other forms of blood vessel disease in the limbs in several other countries.
...Regrettably, this new source of drinking water was not tested for toxic metals. In 1993, Dhaka Community Hospital first diagnosed chronic arsenic poisoning caused by drinking Bangladesh's groundwater [British Geological Survey (BGS) 1999a]. In 1997, our team produced the first national-scale map of As concentration in Bangladesh's groundwater [Frisbie et al. 1999; U.S. Agency for International Development (USAID) 1997]. This map showed that 45% of Bangladesh's area had groundwater with As concentrations greater than the 50 µg/L national standard (Frisbie et al. 1999; USAID 1997). In 2003, a risk assessment estimated that 28 million Bangladeshis were drinking water with As concentrations greater than this national standard (Yu et al. 2003). As a result of this exposure, skin cancer, melanosis, leukomelanosis, keratosis, hyperkeratosis, and nonpitting edema from chronic As poisoning are common in Bangladesh (BGS 1999b; Frisbie et al. 2002). In addition, the rates of bladder cancer, liver cancer, and lung cancer are expected to increase in Bangladesh based on an analysis of death certificates for As exposures in Taiwan (Morales et al. 2000)....
