Water treatment residuals as soil amendments: Examining element extractability, soil porewater concentrations and effects on earthworm behaviour and survival

摘要: Abstract Drinking water treatment residuals (WTRs), the by-product of clarification processes, are routinely disposed via landfill however there is a growing body research that demonstrates material has great potential for beneficial use in environmental applications. Application to agricultural land one option showing promise (i.e. low cost disposal route provides organic matter input soils and other benefits), questions remain as impact such applications may have on earthworm survival behaviour also effects it soil porewater chemistry. This study examined leachability elements within two types WTRs (one Al- Fe- based) from England 0.001 M CaCl 2 solution, at varying pH, Community Bureau Reference (BCR) sequential extraction scheme. Earthworm avoidance, survival, growth, reproduction element concentrations were WTR-amended sandy (0%, 5%, 10%, 20% w/w), while porewaters recovered experimental units concentrations. The results revealed leachable be very both tested so leaching these would unlikely pose any threat ecosystems under typical conditions. However, when pH was lowered 4.4 substantial release Al Al-WTRs (382 mg/kg). Soil influenced some degree by WTR addition, warranting further examination terms implications nutrient supply or limitation. avoidance only observed maximum applied rate (20% earthworms not affected either type application rate. growth (cocoon production) statistically significant level but this needs over longer period exposure. Increased assimilation Fe into tissues rates (maximum fresh weight 42 mg/kg 167 mg/kg Fe), levels likely concerns.