Research On The Performance Of Heavy Metal Emissions From Industrial Wastewater In China

Since the industrial revolution in the second half of the18th century,environmental pollution hasspread rapidly from the local to global scale.From the "10big event" and "eight major public hazard" ofworld environmental pollution to the "limits to growth" of Roman club, environmental problems havebecome the most important factor which restrict the sustainable development of human society.China isnow in the middle stage of industrialization and urbanization,the rapid economic growth is accompanied byserious environmental pollution problems.The contradiction between economic development andenvironmental protection has become increasingly acute.In recent years the heavy metal contaminationwere frequently occured in our country, which seriously affected the people’s living environment and lifeand health,whether the socio-economic development is sustainable are questioned.Heavy metal pollution inour country is mainly caused by related industrial activity and emissions of industrial wastewater is themain way. This paper mainly used environmental DEA method，evaluated and analysed the emissionefficiency of5kinds of key monitoring heavy metals from the industrial wastewater on provincial scale inChina,and further studied on the regional differences and main influencing factors of the result,providereference for reasonable preventing and controlling the heavy metal pollution and making regionalenvironmental policy.Firstly,this paper based on the equal-standard waste load method,in the aspects of pollution load(environmental impact intensity) and unit industrial production pollution load (environmental impactstrength),studied the classification and spacial distribution and industrial characteristics of heavy metalpollutants from industrial wastewater in China’s31provinces and cities in2010.Results shows thatCadmium(Cd) has the largest load ratio,the following are Arsenic(As) and Lead(Pb),the accumulation loadof these three kinds of heavy metal account for75%of the total load.From the view of spatial distributioncharacteristics,corresponding with the distribution of the heavy metal resources and regional industrialtradition in China, Hunan province as “the hometown of nonferrous metals” have the highest load ratio inboth Mercury(Hg), Cadmium(Cd) and Arsenic(As),which account for50%respectively in China.Theprovince which have the highest load ratio in Hexavalent chromium(Cr6+) and Lead(Pb) are Fujian andGansu,which account for14.94%and24.44%of the total load respectively.So the emission area of Hg,Cd, As are relatively concentrated,while the emission area of Cr6+and Pb are relatively scattered.This iscoincide with the spatial distribution characteristics of heavy metal pollution events in China.From the viewof industrial emission characteristics,the industry of non-ferrous metals mining and dressing,non-ferrousmetal smelting and rolling processing,chemical raw materials and chemical products manufacturing,metalproducts,black metal smelting and rolling processing,Leather, fur, and feathers (fine hair) and its productsare the main industries which discharge wastewater with heavy metal,the load ratio of the top threeindustries account for more than15%of the total load respectively,and their cumulative load ratio is80.85%.Secondly,based on the environmental DEA efficiency measurement method,constructed theMalmquist Heavy Metal Emission Performance Index(MHPI).(1)By measuring the MHPI of theindustrial wastewater of29provinces in China from2003to2011,results shows that the average annualgrowth rate of MHPI is6.2%,and the change of MHPI is mainly affected by technological progress,whilethe influence of technical efficiency which stands for chase effect is not prominent enough,which reflectsthe technology and management experience etc. is not flow smoothly enough between areas, the learningeffect is not obvious.In terms of provincial change of MHPI,87%of the province have improved,thisillustrate that the overall efficiency of industrial wastewater emissions of heavy metal is improving inChina.There are22provinces obtained technical progress and technical efficiency at the sametime,specifically,although the technological catch-up effect promoted the MHPI more smoothly,but theeffect were not strong enough.The change of the MHPI were largely affected by technicalprogress.(2)Combined the result of the traditional DEA-Malmquist index method to measure theperformance index of industrial production,analysis display that the traditional DEA model which fail toconsider the undesirable output overestimate the performance of the industry.Combined the results of thetwo algorithms,classified the provinces according to their industrial development efficiency andenvironmental efficiency, results shows that,because of China puted emphasis on prevention and control ofheavy metal pollution and related environmental policy were introduced in recent years,the industrialdevelopment of most provinces belonged to the " improve" type.Only Qinghai, Ningxia, Guizhou andJiangsu four provinces whose industrial development were "environmental retrogress",and the industrialdevelopment performance of Jiangsu province even had a certain degree of recession.Inner Mongolia was the leader in both of the environmental performance and industrial performance.Most provinces belongedto the middle level in which the environmental performance is good and the industrial performance isrelatively prominent,this illustrate that the heavy metal pollution has been contained to some extent.Inspecific,MHPI changes of different types of provinces respectively presents the continuous improvement,continued to deteriorate and fluctuating these three types.From the perspective of the regional differencesof the MHPI change, the MHPI of China’s four major economic regions were all improved,theaccumulative improvement rate of central region was53.6%,followed by eastern region and westernregion,whose accumulative improvement rate were also exceeded50%.While the northeast region had thelowest accumulative improvement rate of28.4%.Judging from the decomposition of MHPI,theimprovement of technical efficiency and technical progress all played a significant role in the efficiencyimprovement of heavy metal emissions in four regions,but the contribution degree was different in eachregion.Using the economic convergence theory to measure the convergence of the regional MHPI,resultsshows that there exists catch-up effect,the regional emissions performance level of heavy metals have atendency to convergence.The convergence performance of the central region is most obvious,while thewest and northeast region are characterized by a weak convergence,this also confirms the former resultsthat the technical efficiency shows weak catch-up effect on the average.Finally,this paper used the panel regression method to study the underlying influencing factorswhich account for the provincial differences of emissions performance of the heavy metals from theindustrial wastewater.Results shows that,on behalf of the economic development level,the per capita GDPindex had significantly negative effects on the efficiency of the heavy metal emissions. From theperspective of environmental kuznets inverted u-shaped curve(EKC),this illustrate that the economicdevelopment of our country are still in the left side of the inverted u-shaped curve,the development of theeconomy have not reached to the level in which the environmental damage can be fullycompensated.People’s overall preference still lies on economy rather than the environment. The positiveinfluence that the upgrading of the industrial structure on the efficiency of the heavy metal emissions is notstrong,which shows that the effect of China’s industrial upgrading and change of economic growth patternwas preliminary revealed, but the effect is not prominent.The increase of the opening-up degree slightlyinhibited the promotion of the emission efficiency of the heavy metals,because trade have double environmental impact effect on the change of economic structure,at present for the heavy metalemissions,the two effect force still favor of the "pollution haven".The enhancement of the industrialproduction efficiency have a significant positive impact on heavy metals emission efficiency. Theagglomeration and synergistic effect of urbanization play an significant indirect role in promoting the heavymetal emission performance.Increase of the proportion of state-owned enterprises have a significantnegative effect on the heavy metal emission efficiency, which indicates that the heavy metal resourceallocation is distorted to some extent,and need further combining with the market mechanism.Thepromotion of people’s educational level can indirectly supervise and urge the improvement of the heavymetal emission performance.Therefore,besides government and market,in the process of prevention andcontrol of heavy metal pollution, citizen’s participation and supervision will also have an positive effect.