Award details

Soil pollution, protection and remediation

Reference	BBS/E/C/00034070
Principal Investigator / Supervisor	Professor Stephen Paul McGrath
Co-Investigators / Co-Supervisors
Institution	Rothamsted Research
Department	Rothamsted Research Department
Funding type	Research
Value (£)	35,661
Status	Completed
Type	Institute Project
Start date	01/08/1998
End date	31/03/1999
Duration	8 months

Abstract

There is often no relation between the total concentration of a pollutant and any adverse biological effects. We aim to identify the soil factors that contribute to pollutant solubility and model these so that they can be predicted using standard soil information. Ecotoxicological methods for measuring effects of pollutants on soil systems in soil are poorly developed. Gradients of well characterised equilibrated metal pollutants are available to us, making it possible to examine the robustness and sensitivity of various methods for measuring effects on: single species. To decide whether soil is polluted, or is a threat to offsite receptors through mobility into groundwater or dispersal of dust, we seek to extract, break down or immobilise the pollutants. This work focuses on the basic properties of hyperaccumulation. At present, the distinctive physiological or biochemical properties that distinguish hyperaccumulator from non- hyperaccumulator species are not understood. In the case of organic pollutants immobilisation and biodegradation are applicable, depending on the nature of the compounds. Soils from three field experiments that received metal- contaminated sewage sludges in the past will be sampled and the following measured: Total metal concentrations Soil pH Soil organic carbon Iron and aluminium oxide content Soil texture. The pH, dissolved organic C, soluble total metals and free ionic concentrations of Zn, Cd and Cu will be measured. The data will be modelled to determine which factors are most important determinants of metal solubility and speciation. Biological pollution assessment. We have marked soil bacterium Pseudomonas fluorescens with the lux cassette. The luminescence of this type of biosensor decreases with increasing metal pollution. In this study, two long-term field trials will be sampled and a cation exchange resin system used to calculate the free ion concentrations of Zn2+ and Cd2+ in soil solution. The total metal concentrations in the bulk soil will also be determined. This assessment of chemical availability will then compared with a bioluminesence- based screening assay. By combining a chemical and biological approach to interpreting soil ecotoxicological responses it should be possible to enhance our understanding of the chemical species likely to induce toxic effects. Soil remediation. Samples of soil & plants will then be analysed for physical, chemical and biological parameters. Parameters to be measured include: soil texture, dry bulk density, organic matter content, water holding capacity, pH, available nutrients (N, P, K), and heavy metal concentrations. Seed of the most efficient metal hyperaccumulator crops will be multiplied. Culture conditions for their growth in hydroponics will also be established. Two techniques will then be used to investigate cellular compartmentation of Zn in leaves of the metal hyperaccumulator Thlaspi caerulescens. Work on biodegradation of organic pollutants in the rhizosphere will focus on PAH compounds. Potentially suitable former coking and tar plants will be selected by an industrial partner and screened for the presence of suitable grasses and legumes. Legumes will be sampled such that their root mass and nodules will be recovered. The physical and chemical parameters measured will include: particle size distribution (sand/silt/clay), dry bulk density, organic matter content, water holding capacity, pH, and extractable nutrients (N, P, K). Analysis of organic pollutants (PAHs, phenols, cyanide) will be conducted. Short-term (2-3 months) experiments in small pots with industrially-polluted soils and simplified systems with spiked soils will be used to study PAH- biodegradation in the rhizosphere of a) plants with or without rhizobia, b) mycorrhizal and non-mycorrhizal plants (grass and/or legume).

Summary

unavailable

Committee	Closed Committee - Plant & Microbial Sciences (PMS)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search