New Toxicological Profiles Available for Five Substances
The Agency for Toxic Substances and Disease Registry (ASTDR) has published new toxicological profiles for acrylonitrile, creosote, 1-2-dichloroethene, nickel, and vinyl acetate. The profiles are peer-reviewed compilations of information that characterize a substance’s toxicology and adverse health effects. The profiles may also identify minimal risk levels, which are intended as screening levels for the identification of contaminants and potential health effects at hazardous waste sites. According to ASTDR, an MRL is “an estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse non-cancer health effects over a specified duration of exposure.”
Acrylonitrile is used in the manufacture of acrylic fibers, plastics, and other chemicals. Based on studies of laboratory animals, ASTDR identified health effects that include nasal legions following inhalation exposure, forestomach damage following oral exposure, neurological effects, and cancer. The tox profile for acrylonitrile proposes provisional MRLs of 0.0009 ppm for intermediate-duration inhalation exposures, 0.09 mg/kg/day for acute oral exposures, 0.02 mg/kg/day for intermediate oral exposures, and 0.00009 mg/kg/day for chronic oral exposures.
The tox profile for creosote discusses wood creosotes and coal tar products, which are complex mixtures with hundreds or thousands of chemical components. Wood creosotes were previously used in disinfectants, laxatives, and expectorants, but are no longer major pharmaceutical ingredients, and there is limited information about their health effects. Coal tar creosote is used as a wood preservative pesticide and has applications as a fungicide, insecticide, and sporicide. It is not available for public purchase in the United States and may only be used by certified pesticide applicators. Health concerns related to coal tar and coal tar products include adverse respiratory and developmental effects as well as an increased risk for cancer. The tox profile for creosote does not identify any MRLs.
1,2-Dichloroethene is used as a chemical intermediate and industrial solvent. It exists as two geometric isomers with distinct properties: trans-1,2-dichloroethene and cis-1,2-dichloroethene. The health effects of trans-1,2-dichloroethene include eye irritation and skin damage from inhalation exposure and immune system effects from oral exposure. For trans-1,2-dichloroethene, the tox profile identifies provisional MRLs of 3 ppm for acute inhalation exposures and 0.2 mg/kg/day for intermediate oral exposures.
Nickel has many uses, primarily in stainless and alloy steels, nonferrous alloys and superalloys, and electroplating. Occupational exposures typically involve dusts or powders containing nickel or nickel compounds. Exposure is presumed to lead to a range of respiratory effects as well as immunological effects such as contact dermatitis. The tox profile identifies MRLs of 0.00003 mg/m3 for intermediate inhalation exposures and 0.00001 mg/m3 for chronic inhalation exposures.
The synthetic compound vinyl acetate is used in the production of polymers and copolymers as well as in adhesives, paint and powder coatings, plastics and resins, rubber foam, packaging, sporting equipment such as ski boots and bicycle seats, auto-related films, and intermediates in construction and building materials. Vinyl acetate can also be used as a food additive and in some food packaging. The health effects of vinyl acetate exposure can include nose and throat irritation. The tox profile identifies provisional MRLs of 1 ppm for acute inhalation exposure, 0.7 ppm for intermediate inhalation exposure, and 0.3 ppm for chronic inhalation exposure.
ASTDR is accepting public comments on the new tox profiles through Nov. 28. An index of tox profiles is available on the agency website.