Arsenic in drinking water may have a long-term carcinogenic effect, according to results of a study published in the Journal of the National Cancer Institute. By tracking death rates of people exposed to arsenic-contaminated drinking water in one region of Chile, researchers show signs of increased lung cancerof the bladder and kidney even 40 years after exposure to arsenic.
Inorganic arsenic occurs naturally at high levels in groundwater in many countries, creating a significant public health problem, affecting millions of people. Studies have shown that drinking water contaminated with arsenic causes skin, lung, bladder and kidney cancers, as well as cardiovascular illnesses.
The water source in Antofagasta, a city in northern Chile, experienced a sudden increase in arsenic concentrations in 1958, followed by a major reduction in exposure when an arsenic removal plant was installed in 1970. The inhabitants were confronted with high concentrations of arsenic.
Arsenic, a danger 40 years later
This study revealed a clear relationship between arsenic exposure and cancer mortality rates. The increase in lung, bladder, and kidney cancers began to increase about 10 years after exposures to high levels of arsenic began. They only reach their peak 20 years after the beginning of the reduction in exposure. In both men and women, mortality rates for these types of cancers remained high for up to 40 years after the highest exposure ceased.
Arsenic-related illnesses will likely remain very high for many years after exposures to this toxin have ceased. “Possible long-term interventions to reduce mortality and morbidity after high exposures include screening for disease, reducing significant co-exposures, planning treatment and health resources, and raising public awareness of the effects of exposure. ‘arsenic on health’, explain the authors of the study.
Although the researchers plan to continue studying this population, they can already conclude that the delay between exposure to arsenic and the development of related cancers may be one of the longest of all human carcinogens.
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