title: Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time.
abstract: The anionic surfactant linear alkylbenzene sulfonate (LAS) may inhibit soil microorganisms and may occur in agricultural soil through the application of sewage sludge. For five microbial parameters (microbial biomass C and the potentials of iron reduction, ammonium oxidation, dehydrogenase activity, and arylsulfatase activity), we compared the effects of aqueous LAS and LAS-spiked sewage sludge added to existing levels of 0, 3, 8, 22, 22, 62, 174, and 488 mg/kg soil (dry wt) in a Danish sandy agricultural soil that was incubated for 5 d to eight weeks. Arylsulfatase activity (measured after four weeks of incubation) was rather insensitive to LAS, with an EC 10 of 222 and more than 488 mg/kg in soil samples treated with aqueous LAS and LAS-spiked sewage sludge, respectively. For the other microbial parameters, the short-term effects (approximately one to two weeks) of aqueous LAS were characterized by an EC10 in the range of 3 to 39 mg/kg. Application of LAS via sewage sludge generally reduced the short-term effects for the microbial parameters, and the EC10 for LAS in sludge-amended soil after approximately one to two weeks of incubation ranged from less than 8 to 102 mg/kg. Recovery potential was seen for most microbial parameters as a result of prolonged incubation, both under conditions of LAS persistence (anaerobic conditions, the iron-reduction test) and LAS depletion (aerobic incubations, all other assays). In conclusion, the short-term inhibitory effects of LAS on soil microbiology were decreased in the presence of sewage sludge and by a prolonged (two to eight weeks) laboratory incubation period.
authors.affiliation: Danish Institute of Agricultural Sciences, Department of Crop Physiology and Soil Science, Tjele. lars.elsgaard@agrsci.dk
authors.forename: L
authors.initials: L
authors.lastname: Elsgaard
authors.forename: S O
authors.initials: SO
authors.lastname: Petersen
authors.forename: K
authors.initials: K
authors.lastname: Debosz
mesh_terms: D017738:Alkanesulfonic Acids / Q000009:adverse effects*; D001192:Arylsulfatases / Q000032:analysis; D018533:Biomass; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D018570:Risk Assessment; D012722:Sewage / Q000737:chemistry*; D012988:Soil Microbiology; D013501:Surface-Active Agents / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D017738:Alkanesulfonic Acids; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D013501:Surface-Active Agents; C030641:alkylbenzyl sulfonic acid; D007501:Iron; D010088:Oxidoreductases; D001192:Arylsulfatases