Minnesota Department of Health (MDH) has developed new drinking water guidance for 2-methylnapthalene. The new Risk Assessment Advice (RAA) value is 8 parts per billion (ppb) or µg/L. MDH believes that exposure to 2-methylnaphthalene in drinking water at or below 8 ppb over a lifetime will pose little or no risk of health effects.
2-methylnaphthalene is found naturally in crude oil and coal and is used for making detergents, dyes, solvents, and some pesticides. 2-methylnaphthalene is released into the environment when wood or fossil fuels are burned or when there are spills of products containing fossil fuels. 2-methylnaphthalene can evaporate or break down quickly in soils exposed to air or containing certain microorganisms, but can persist under other conditions in certain sediments or soils.
The Minnesota Pollution Control Agency has found 2-methylnaphthalene in some Minnesota waters, but has not been found in Minnesota public drinking water systems. It is most often reported in leachate from landfills and in groundwater at hazardous waste sites. Leachate concentrations range from 0.8 to 400 parts per billion (ppb), and groundwater concentrations near clean-up sites range from 0.004 to 455 ppb. The highest concentrations in groundwater were reported at former wood treatment sites.