Dichloromethane: Environmental effects
Description
Dichloromethane evaporates when exposed to air. It dissolves when mixed with water and also evaporates from the water. In animals, as well as humans dichloromethane is metabolised into carbon monoxide, which results in depriving the body of oxygen. Very high levels of dichloromethane (25,300 parts per million concentration of air breathed) were lethal to 50% of the rats tested. Lower long-term concentrations caused problems with the liver and kidneys in rats. Dichloromethane has low acute toxicity to aquatic organisms.
Entering the environment
Industrial emissions of dichloromethane can produce elevated, but still low level concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere dichloromethane is expected to be confined to the local area within which it is emitted. Because dichloromethane is used in many consumer products, short-term indoor concentrations may be elevated above the levels considered safe for workers.
Where it ends up
Dichloromethane quickly evaporates to a gas if released as a liquid. It will then degrade by reacting in the air with photochemically produced products. The expected lifetime in the air is 130 days. Dichloromethane has low acute toxicity to aquatic organisms. There is not enough information to predict the effect dichloromethane has on land animals and birds. Dichloromethane is not expected to bio-accumulate. It is not expected to react with ozone in the upper atmosphere since most of it will decompose in the lower atmosphere.
Environmental guidelines
The 1992 Australian Water Quality Guidelines for Fresh and Marine Waters reports halogenated methanes should be limited to 0.016 milligrams per litre (that is, 0.000016 grams per litre) of water in order to protect human consumers of fish and other aquatic organisms.
Key
Links to an another web site
Opens a pop-up window
