title: Fractionation and bioavailability of metals and their impacts on microbial properties in sewage irrigated soil.
abstract: A study was conducted to evaluate the effect of long-term irrigation of sewage contaminated with heavy metals like Cd, Cr, Cu and Pb on microbial and biochemical parameters of soils of West Bengal, India. The microbial parameters included microbial biomass carbon (MBC), microbial metabolic quotient; the biochemical parameters included fluorescein diacetate hydrolyzing activity, beta-glucosidase, urease, phosphatase, and aryl sulphatase activities. A sequential extraction technique was used to quantify water soluble, exchangeable, carbonate bound, Fe/Mn-oxide bound, organically bound, and residual metal fractions. Metal concentrations in the two most labile fractions (i.e., water soluble and exchangeable fractions) were generally low. Total metal concentrations at each site seemed to be associated with soil amorphous Fe and Al minerals. The MBC and the enzymes studied were significantly and negatively correlated with water soluble and exchangeable metals but not significantly correlated with other forms, indicating that water soluble and exchangeable forms exerted a strong inhibitory effect on the soil microbial and biochemical parameters. It was concluded that irrigating soils with metal contaminated sewage seemed to damage soil quality in the long term.
authors.affiliation: BK21 Advanced Geo-Environment Research Team, School of Civil and Environmental Engineering, Kunsan National University, Kunsan, Jeonbuk 573-701, South Korea. b_pradip@rediffmail.com <b_pradip@rediffmail.com>
authors.forename: Pradip
authors.initials: P
authors.lastname: Bhattacharyya
authors.forename: Subhasish
authors.initials: S
authors.lastname: Tripathy
authors.forename: Kalyan
authors.initials: K
authors.lastname: Chakrabarti
authors.forename: Asish
authors.initials: A
authors.lastname: Chakraborty
authors.forename: Pabitra
authors.initials: P
authors.lastname: Banik
mesh_terms: D001682:Biological Availability; D018533:Biomass; D005591:Chemical Fractionation; D004798:Enzymes / Q000378:metabolism; D019216:Metals, Heavy / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D012722:Sewage / Q000737:chemistry*; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D007507:Therapeutic Irrigation; D013997:Time Factors
chemical_list: D004798:Enzymes; D019216:Metals, Heavy; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants