摘要
Heavy metals are widely distributed in the environment and have caused serious pollution problems in nowadays. Particular anthropogenic sources can frequently lead to increase concentrations of toxic metals,which present a serious health hazard for human and animals. Generally the toxicity of heavy metals results from the formation of bonds to thiol groups in proteins,which can directly cause deleterious effects on microbial growth and indirectly reduce microbial activity and functioning by modifying processes such as plant growth.So the assessment of the toxicity of heavy metal is important,At the moment,most toxicity bioassays are conducted on invertebrates,fish,plant and algae,however,these conventional analytical techniques are often expensive,require large sample volumes ,time-consuming and not suitable for on-site measurements[3]. For all of above disadvantages,the indicator systems,which are rapid,simple,sensitive and,at the same time,applicable to monitoring on-line are required to offer specific analytical information and evaluation of effects. Consequently,a range of acute toxicity bioassays have been developed to establish the toxicity levels of compounds for aquatic organisms. Biosensors have been considered as competitive tools for the detection of toxic compounds that can be used as early warning systems because of their specificity,fast response and low cost.