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Environmental fate & pathways

Biodegradation in soil

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Description of key information

Half-life in soil: 105 days (at 12°C)

Key value for chemical safety assessment

Half-life in soil:
105 d
at the temperature of:
12 °C

Additional information

The fate of 14C-HHCB in soil was studied in microcosms according to protocols described in documents from the U.S. Food and Drug Administration of 1987 (Envirogen, 1998).Samples were taken from an oak forest soil and an agricultural soil, and from a farm with routine sludge applications from a domestic STP. Based on the residues after 1 year, the DT50 was estimated. The half-life of HHCB is 105 days being significantly less than 120 days.

Other available studies showed that fungi commonly found in soil - both in pure cultures (Envirogen, 1997), and in cultures obtained from a variety of 64 soil samples (sand, clay, peat and loam) from various locations in The Netherlands (PFW, 1996) have the capability for primary degradation of HHCB, without mineralization and that HHCB is transformed to polar intermediates by soil-borne fungi.

For the environmental risk assessment, a conservative biodegradation rate constant (expressed as half-life time) of 150 days in the soil compartment (12 °C) is used in accordance with the RAR for HHCB.