Chemical categorization carcinogens

A comprehensive search (295) of the STORET water quaUty database, maintained by the U.S. EPA Office of Water, is used to evaluate the potential water quaUty implications of various herbicides. This database contains information on contamination of surface water (SW) and groundwater (GW) suppUes. The data are provided to give a general impression of the occurrence of a given herbicide in SW and GW (269). The U.S. EPA scheme for categorizing a chemical s carcinogenic potential is used for herbicides for which healthy advisory information (HA) is available. The U.S. EPA is continually issuing HAs for various environmental contaminants HAs available in Reference 269 were used in preparation of this article. 

In Table 6.1 are listed some of the chemicals and occupational settings lARC has categorized as carcinogenic to humans - the data from... 

Bolt HM, Foth H, Hengstler JG, Degen GH. 2004. Carcinogenicity categorization of chemicals — new aspects to be considered in a European perspective. Toxicol Lett 151 29-41. 

The U.S. EPA has categorized chemical substances into six groups of conhrmed or suspected carcinogens ... 

Unfortunately, many of the compounds dropped from these lists come from chemical classes that are known to contain examples that are of concern to human health (Figure 1). Some, for example, show evidence of carcinogenicity and reproductive toxicity in humans and/or experimental animals (as categorized by the International Agency for Research on Cancer [IARC]) others show a large potential environmental impact and have been slated for inclusion on the EPA s ground water contamination survey (5). 

In Table 4 are presented some of the chemicals and occupational settings IARC has categorized as carcinogenic to humans - the data from all the available epidemiology studies and case reports were considered sufficient by the expert groups to conclude that a causal relationship exists between exposure to the chemical or occupational setting and some form of human cancer. 

Lock, E. A., and Hard, G. C. (2004). Chemically induced renal tubule tumors in the laboratory rat and mouse Review of the NCI/NTP database and categorization of renal carcinogens based on mechanistic information. CritRev Toxicol 34, 211-299. 

Because of the odor and taste of the groundwater due to MTBE, residents in southern California were supplied with bottled water. MTBE is not a particularly toxic chemical—it would be categorized as practically nontoxic using the scale shown on table 2.1. However, one report from a laboratory in Italy indicated it could cause kidney tumors in laboratory rodents. After much additional research in the United States failed to confirm the Italian study, it was recently concluded (by state of Ccd-ifornia toxicologists) that MTBE is not a carcinogen. The U.S. EPA considers MTBE to be a possible human carcinogen, but research is still ongoing. 

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