Review of the genotoxicity of "Arvin compounds", drinking water contaminants formed by the degradation of UV-stabilizers in polyolefin pipes.

Polyolefin pipes used in drinking water distribution systems require a number of functional additives to ensure stability and durability. Some of these additives and/or their degradation products may migrate from the pipes into the drinking water. Previously, a number of branched chain alkylphenol degradants have been identified in drinking water; these were termed "Arvin substances" and numbered Arvin 1 to 10. As potential genotoxicity is a human health safety concern, the genotoxicity of Arvin substances is reviewed based on comprehensive in vitro and in vivo data available. Results obtained from genotoxicity studies addressing mutagenicity and clastogenicity are available for nine of the ten Arvin substances. These nine Arvin substances were consistently negative in bacterial mutagenicity studies. Divergent results were obtained in clastogenicity assays with some positive responses induced by the branched chain alkylphenols Arvin 1, 2, and 4, often accompanied by significant cytotoxicity. However, Arvin 1, 2, and 4 did not induce micronuclei or genotoxicity in vivo during follow-up testing. The other Arvin compounds did not show genotoxic activity in vitro. In conclusion, regarding human health risk characterization, the Arvin compounds are not considered genotoxic agents based on the available data.