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Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time
Author(s) -
Elsgaard Lars,
Petersen Søren O.,
Debosz Kasia
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620200807
Subject(s) - sewage sludge , environmental chemistry , chemistry , incubation , sewage , sewage treatment , soil water , arylsulfatase , ecotoxicology , environmental engineering , environmental science , ecology , biology , biochemistry , enzyme
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, 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 EC10 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.