A REVIEW OF THE CARCINOGENICITY OF CHEMICALS MOST FREQUENTLY FOUND ATNATIONAL-PRIORITIES LIST SITES

Several studies have shown that numerous National Priorities List (NPL ) sites have been contaminated with arsenic (747), cadmium (791), chlo roform (596), or nickel (664). The National Toxicology Program (NTP, 1 991) has classified these substances as known human carcinogens (arsen ic and certain arsenic compounds) or as substances that may reasonably be anticipated to be carcinogens (cadmium and certain cadmium compoun ds, chloroform, and nickel and certain nickel compounds). The general population is probably exposed to low levels of these hazardous substa nces through drinking water, eating food, or inhaling contaminated air . People working or living near industries and facilities that manufac ture and use chloroform, nickel, arsenic, or cadmium may be exposed to higher than background levels of these hazardous substances. Multiple pathways of exposure may exist for populations near hazardous waste s ites. For example, high levels of chloroform (1,890 ppb) were found in well water near a waste site; high levels of cadmium exposure may exi st for individuals living near cadmium-contaminated waste sites.