Because it targets widely dispersed enzyme reactions, arsenic affects nearly all organ systems. The most sensitive endpoint from arsenic exposure is dermal effects. While several studies may identify effects on other endpoints at the same exposure level that produces dermal effects, the database for dermal effects is stronger than for effects on other endpoints [ATSDR 2007]
Key physiologic effects from arsenic exposure that will be covered in detail later.
- Patchy skin hyperpigmentation, small focal keratoses, and other skin lesions are common effects of heavy chronic exposure.
- It is difficult to establish strong associations between arsenic exposure and disease, as the prevalence and spectrum of diseases linked to chronic arsenic exposure differ not only between countries, but even within countries.
- Arsenic can cause lung and skin cancers and may cause other cancers.
- The association between chronic arsenic exposure and cancer is strongest for skin, lung, and bladder cancer. Liver (angiosarcoma), kidney, and other cancers have limited strength of association [IARC 2004; NRC 2000].
Note that when strength of association (defined as the magnitude of the relative risk in the exposed group compared with that in the control group) is mentioned throughout this section, it refers to one of the five criteria used to decide whether a positive association in epidemiologic studies indicates causality. It is not absolutely required to establish causality. In addition, fulfillment of some criteria may occur when the association is a result of chance or bias. Failure to demonstrate a positive association in an epidemiologic study does not always indicate there is no association between the agent and the effects studied.
In the United States, excess cancer mortality associated with arsenic is not generally seen [Schoen et al. 2004].
Unlike other arsenicals, arsine gas causes a hemolytic syndrome.
