Toxic Responses Of Five Species Of Soil Collembola To Heavy Metals Lead And Chromium In North China

Heavy metal pollution continue to break the ecological equilibrium,and became a major threat to human health,therefore,it is particularly important to study soil heavy metal ecological risk assessment and pollution monitoring.This paper studied toxicity responses of five species of soil springtails from China to different concentration of lead?II?and chromium???for purpose of selecting appropriate Collembola species as soil monitoring standard insect and to found tolerant and sensitive species.The ecological toxicity test data of soil Collembola can support soil ecological risk assessment.To study the sensitivity of diverse species of springtails response to the heavy metal plumbum???,five Chinese collembolans species Sinella curviseta Brook,Ceratophysella duplicispinosa Yosii,Proisotoma minuta Tullberg,Homidia similis Szeptycki and Lepidocyrtus sp.were exposed to six centrations of Pb??? for 7d subacute,28d chronic–LC₅₀ measurements respectively.The results of 7d-LC₅₀ were calculated by the bliss method were 122.13,34.05,132.61,99.54,164.14g·L^-1;while the 28d-LC₅₀ values were 1.08,0.002,49.15,0.01,42.14 g·L^-1 respectively.To study the sensitivity of diverse species of springtails response to the heavy metal chromium???,five species of Chinese springtailsspecies Ceratophysella duplicispinosa,Homidia similis,Sinella curviseta,Proisotoma minuta,Lepidocyrtus sp.were exposed to six centrations of chromium for 7d subacute,21d chronic–LC₅₀ measurements respectively.The results for 7d-LC₅₀ were calculated by the bliss method were 2.31,1.99,2.48,2.09,2.16g·L^-1;while the 21d-LC₅₀ values were 0.011,0.013,0.169,0.026,0.163g·L^-1respectively in the chronic toxicology test,the survival of the larval reproduction was studied.The results show that toxic effects of Pb??? to Collembola is long-term effects,in which P.minuta and Lepidocyrtus sp.shows the highest tolerance against Pb??? ,followed by S.curviseta,while H.similis and C.duplicispinosa ranks last.In addition,P.minuta and Lepidocyrtus sp.show the stimulatory effect of low dose in lead concentration was 0.01 g·L^-1;within a short time,there are no significant difference between several springtails tolerance to chromium,after a long time,S.curviseta and Lepidocyrtus sp.shows the highest tolerance against Cr???,followed by C.duplicispinosa,while H.similis and P.minuta ranks last.increasing Pb??? and Cr??? concentration shows inhibition effect to the spawn and hatch of springtails.Finally,a comprehensive analysis is conducted on results of China springtails response to heavy metal toxicity show that S.curviseta,C.duplicispinosa represent two exremes of tolerance,therefore,S.curviseta can be used as China standard insect for the study of toxicity principle of heavy metals and C.duplicispinosa can be used as the standard insects for Chinese soil heavy metals pollution degree.