Research And Application Of Baseline For Soil Environmental Damage Identification And Assessment In Contaminated Sites

Soil is not only an integral part of the ecological environment,but also the basis of human survival.Damage compensation and related litigation disputes caused by soil environmental problems must be solved through damage identification and assessment.Accurate and reasonable baseline enables the plaintiff and defendant to reach an agreement as soon as possible and saves evaluation time.Taking the baseline as the research center,on the basis of the existing baseline determination methods,this thesis puts forward a new idea of baseline determination,establishes the working procedure of baseline determination,develops the application program of baseline determination,and carries out case verification.According to the definition of baseline and the calculation principle of historical data method,the determination principle of original site point method is proposed.The calculation results of the two sites show that the baselines determined by the original site point method and the control data method are similar,and the results of the standard benchmark method are much higher than those of the two methods.Through two application cases,this thesis discusses the applicability of the original site point method,and establishes the steps for determining the baseline in the case of known pollution: preliminary investigation →determination of the baseline calculation area→setting up sampling points in the calculation area → determining the baseline.The steps for determining the baseline in the case of unknown pollution are preliminary investigation→determination of the baseline calculation area → detailed investigation →setting up sampling points in the calculation area and other areas→verify rationality of calculation area→determine baseline.The principle of using risk assessment model to deduce the baseline is proposed,and benzo [a] pyrene is taken as an example to deduce the baseline.The result of the baseline is close to the screening value and control value,which verifies the feasibility of the method.According to the calculation principle and the results of the verification example,the steps of the risk assessment model to deduce the baseline are established.By analyzing the accuracy and rapidity of the baseline determination method,it is concluded that the recommended working procedure for baseline determination is historical data method > original site point method > control data method > standard benchmark method > special research method.The soil background values of 8 heavy metal elements in33 provinces and 9 soil environmental standards at home and abroad were summarized.The calculation principles of determining the baseline after removing the outliers by Grubbs criterion and deducing the baseline by risk assessment model were put forward.According to the available data resources and the calculation principle of determining baseline,the application program of determining baseline is developed.Taking a pharmaceutical site in Shenyang City of Liaoning Province as a case study,through data collection,field survey,sampling survey and other work,the baseline of heavy metals in the site was determined by using the average value of the results determined by the control data method and the original site point method,which verified the accuracy and applicability of the original site point method and the baseline determination procedure.According to the baseline,the pollution degree of the site is calculated,and the pollution range of the site is predicted.The pollution degree of Cd is the highest,and the pollution range is the largest,and the pollution degree of Cu is the lowest,and the pollution range is the smallest.