English Abstract To evaluate, and indicate possible adjustment of, the
current Dutch Intervention Values for cyanides (CN) a review has been made
of sources of CN soil contamination, behaviour of CN species and present
environmental concentrations related to soils contaminated before 1987.
Knowledge on ecotoxicological effects of CN species in soils is insufficient
to derive Intervention Values. Consequently these have to be based on human
exposure. Consumption of crops is the major contributing factor to the
current soil Intervention Values. Recent plant physiological studies
indicate that soil contamination will not lead to CN concentration in crops
which effect human health. Critical human exposure can occur via inhalation
of free CN in ambient air, or after a one time peak ingestion by children of
soil contaminated with complex CN. Therefore provisionally 25 ug/m3 HCN in
soil air or in ambient air is suggested as a possible soil Intervention
Value, equal to the Tolerable Concentration in Air. Further research is
indicated to obtain a sound base for CN Intervention Values for soil.
Consumption of untreated groundwater contaminated with ferrohexacyanide or
thiocyanate can lead to critical exposure. For thiocyanate the Tolerable
Daily Intake for children will be reached with 75 ug total CN per dm3, which
may be proposed as an Intervention Value for
groundwater.
