Registration Dossier

Environmental fate & pathways

Biodegradation in soil

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Administrative data

Link to relevant study record(s)

Description of key information

The environmental distribution model indicates that deposition of trichloroethane to soil and sediments will be negligible.  It is also well-documented that the vapour pressure of trichloroethane will mitigate against persistence in soil.  it is therefore considered highly unlikely that the material will persist long enough to undergo any biological degradation as it is anticipated that vaporisation will be rapid (vaporisation from water has been estimated by the UK government reviewers to be 90% in two hours - vaporisation from soil will be quicker). 

Key value for chemical safety assessment

Additional information

The key study included in this section really relates to testing for effects following contamination of soil. Primary contamination of soil is likely to arrise following deposition from the atmosphere in rainfall. The UK 1996 review estimated that deposition following severe rainfall events would be of the order of 12 to 13 ppb. The results from this study show that as the concentrations expected to be achieved following severe weather events are appreciably less than the IC50 value recorded for surrogate soil bacteria in this study. It is however interesting to note that the results obtain in this study indicate that the toxicity to soil bacteria is appreciably higher than to methanogenic bacteria in sewage treatment plants. However, as registration is sought for a transported intermediate the probability of direct contamination of soil is considered remote.