Arsenic stability and mobilization in soil at an amenity grassland overlying chemical waste (St. Helens, UK).
A 6.6 ha grassland, established on a former chemical waste site adjacent to a residential area, contains arsenic (As) in surface soil at concentrations 200 times higher than UK Soil Guideline Values. The site is not recognized as statutory contaminated land, partly on the assumption that mobility of the metalloid presents a negligible threat to human health, groundwater and ecological receptors. Evidence for this is evaluated, based on studies of the effect of organic (green waste compost) and inorganic (iron oxides, lime and phosphate) amendments on As fractionation, mobility, plant uptake and earthworm communities. Arsenic mobility in soil was low but significantly related to dissolved organic matter and phosphate, with immobilization associated with iron oxides. Plant uptake was low and there was little apparent impact on earthworms. The existing vegetation cover reduces re-entrainment of dust-blown particulates and pathways of As exposure via this route. Minimizing risks to receptors requires avoidance of soil exposure, and no compost or phosphate application.
Hartley
William
W
School of Biological and Earth Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
Dickinson
Nicholas M
NM
Clemente
Rafael
R
French
Christopher
C
Piearce
Trevor G
TG
Sparke
Shaun
S
Lepp
Nicholas W
NW
D000327:Adsorption; D001151:Arsenic / Q000032:analysis*; D004739:England; D004784:Environmental Monitoring / Q000379:methods; D052918:Environmental Restoration and Remediation; D006256:Hazardous Waste; D012037:Refuse Disposal; D018570:Risk Assessment / Q000379:methods; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis
D006256:Hazardous Waste; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D001151:Arsenic