title: Single and joint effects of pesticides and mercury on soil urease.
abstract: The influence of two pesticides including chlorimuron-ethyl and furadan and mercury (Hg) on urease activity in 4 soils (meadow burozem and phaeozem) was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase (up to 13%-21%) in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship (P<0.05) between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose (ED50) values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.
authors.affiliation: Key Laboratory of Environmental Engineering, Shenyang University, Shenyang 110044, China. ycl_78@yahoo.com.cn
authors.forename: Chun-lu
authors.initials: CL
authors.lastname: Yang
authors.forename: Tie-hang
authors.initials: TH
authors.lastname: Sun
authors.forename: Wen-xiang
authors.initials: WX
authors.lastname: He
authors.forename: Qi-xing
authors.initials: QX
authors.lastname: Zhou
authors.forename: Su
authors.initials: S
authors.lastname: Chen
mesh_terms: D002235:Carbofuran / Q000494:pharmacology*; D008628:Mercury / Q000494:pharmacology*; D010575:Pesticides / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000494:pharmacology*; D013453:Sulfonylurea Compounds / Q000494:pharmacology*; D014510:Urease / Q000378:metabolism*
chemical_list: D010575:Pesticides; D011743:Pyrimidines; D012987:Soil; D012989:Soil Pollutants; D013453:Sulfonylurea Compounds; C112343:chlorimuron ethyl; D014510:Urease; D008628:Mercury; D002235:Carbofuran