, is less toxic and does not dissolve as easily. The students have also discovered a microbe that consumes arsenate and releases arsenite. (See figure 5-A) Another student has also found a bacterium that does the opposite by converting arsenite to arsenate. They hope to use these microorganisms to help clean up arsenic contamination. (Brown 1997) Other studies have led toxicologists to suggest lowering the federal limit of 50 parts per billion to two parts per trillion. This is especially recommended for California because of the high concentration levels of arsenic here. (Turkington 1994) Some experts, however, dispute the idea that arsenic causes cancer, namely bladder cancer due to drinking arsenic tainted water. Studies have been done in Taiwan where the water is naturally contaminated with high levels of arsenic. The studies concluded that the tainted water could be linked with an acutely heightened chance for bladder cancer. Although this study has aroused concern in the United States, because bladder cancer is among the nine most prevailing cancers in America, some have pointed out that the risk may be overestimated. There is the possibility of other contributing factors to the cancer such as "an underlying genetic vulnerability to the cancer, the malnutrition endemic in arsenic-tainted Taiwan, and the presence of other water pollutants." (Raloff 1966)A new study, however, seem to strengthen and prove the idea that arsenic is directly linked with bladder cancer. The study was conducted in Crdoba, a province in Argentina whose water is without the additional pollutants such as in the case of Taiwan. In addition, the inhabitants of the province have an ethnic background similar to the United States and a low occurrence of malnutrition. The study was led by Claudia Hopenhayn-Rich from the University of California, Berkeley. The water in Crdoba has high levels of naturally occurring arsenic and the residents there have a...
