The impact of long-term biosolids application (>100 years) on soil metal dynamics

Biosolids application to arable land is a common, and cost-effective, practice but the impact of prolonged disposal remains uncertain. We evaluated the dynamics of potentially toxic elements (PTEs) at a long-established ‘dedicated’ sewage treatment farm. Soil metal concentrations exceeded regulation...

Full description

Saved in:
Bibliographic Details
Published in:The Science of the total environment 2020-06, Vol.720, p.137441-137441, Article 137441
Main Authors: Mossa, Abdul-Wahab, Bailey, Elizabeth H., Usman, Abida, Young, Scott D., Crout, Neil M.J.
Format: Article
Language:English
Subjects:
Biosolids
Isotopic dilution
Lead isotopes
Metal lability, trace elements
Metals, Heavy
Sewage
Soil
Soil Pollutants
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Biosolids application to arable land is a common, and cost-effective, practice but the impact of prolonged disposal remains uncertain. We evaluated the dynamics of potentially toxic elements (PTEs) at a long-established ‘dedicated’ sewage treatment farm. Soil metal concentrations exceeded regulations governing application of biosolids to non-dedicated arable land. However, measurement of isotopic exchangeability of Ni, Cu, Zn, Cd and Pb demonstrated support for the ‘protection hypothesis’ in which biosolids constituents help immobilise potential toxic metals (PTMs). Metal concentrations in a maize crop were strongly, and almost equally, correlated with all ‘capacity-based’ and ‘intensity-based’ estimates of soil metal bioavailability. This was attributable to high correlations between soil factors controlling bioavailability (organic matter, phosphate etc.) on a site receiving a single source of PTMs. Isotopic analysis of the maize crop suggested contributions to foliar Pb from soil dust originating from neighbouring fields. There was also clear evidence of metal-specific effects of biosolids on soil metal lability. With increasing metal concentrations there was both decreasing lability of Cd and Pb, due to interaction with increasing phosphate concentrations, and increasing lability of Ni, Cu and Zn due to weaker soil binding. Such different responses to prolonged biosolids disposal to arable soil should be considered when setting regulatory limits. [Display omitted] •Long-term effects of biosolids application on arable soils was investigated.•Substantial metal accumulation in soil was not accompanied by increased metal lability.•Metal-specific effects of biosolids application on metal lability were observed.
ISSN:0048-9697
1879-1026
DOI:10.1016/j.scitotenv.2020.137441