Changing contaminant mobility in a dredged canal sediment during a three-year phytoremediation trial.
Metal mobility and degradation of organic pollutants were investigated in a contaminated canal sediment in NW England. Sediment was dredged and exposed above the water surface, planted with multiple taxa of Salix, Populus and Alnus and monitored over 32 months. Short-term metal fractionation and phytotoxicity during sediment oxidation were also evaluated in separate laboratory studies. Zinc and Pb redistributed into more mobile fractions, which increased toxicity of the sediment to plants in the laboratory. In contrast, at the canal site, mobility of most elements decreased and total concentrations of Zn, Pb, Cu and Cd fell. Petroleum hydrocarbon concentrations decreased, but the tree-planted treatments appeared less effective at reducing PAH concentrations than treatments colonised by invasive plants. Tree survivorship decreased over time, suggesting increasing phytotoxicity of the exposed sediment in the longer term. Trees provided little benefit in terms of sediment remediation. Options for future management of the sediment are evaluated.
King
Rosalind F
RF
School of Biological Sciences, Jones Building, Liverpool University, Liverpool L69 3GS, UK. kingr@liv.ac.uk
Royle
Anna
A
Putwain
Philip D
PD
Dickinson
Nicholas M
NM
D001673:Biodegradation, Environmental; D001937:Brassica; D002104:Cadmium / Q000032:analysis; D005591:Chemical Fractionation; D003300:Copper / Q000032:analysis; D004739:England; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis* / Q000633:toxicity; D005618:Fresh Water; D019015:Geologic Sediments / Q000737:chemistry*; D007221:Industry; D007854:Lead / Q000032:analysis; D008129:Lolium; D019216:Metals, Heavy / Q000032:analysis* / Q000633:toxicity; D018517:Plant Roots / Q000254:growth & development; D010944:Plants; D013997:Time Factors; D014197:Trees; D014872:Water Movements; D015032:Zinc / Q000032:analysis
D004785:Environmental Pollutants; D019216:Metals, Heavy; D002104:Cadmium; D007854:Lead; D003300:Copper; D015032:Zinc