is defined as hazardous waste in many countries around the world due to organic and toxic materials and the high leaching ratio of s. The main disposal for is . At present time the ways include silicate cement solidification, melting solidification, plastic material solidification, and chemical medicament solidification. Due to the high properties and big use of waste residue, this paper made a great deal of research on solidification/stabilization of MSWI fly ash by using cement.The fly ash was from Yancheng. The chemical composition, mineral composition, and micro-structure of fly ash were tested. And the cement was used for the solidification/stabilization of raw fly ash, water washing fly ash and thermal treatment fly ash, and the TCLP test was taken.The results showed that: the compressive strength fell quickly with the increase of the content of fly ash when the fly ash was solidified in cement, and the phenomenon of swelling could be seen. With the water washing process, the mass loss of fly ash was 2.7%, indicated that there were some soluble salts in fly ash. The water washing pretreatment had little influence on the effect of compressive strength of the solidification blocks, with the mass addition of 10% of fly ash, the water washing process even had no improvement on the strength of test blocks, and when the mass of fly ash increased, the effect of solidification improved. Then the fly ash was heated at 700℃, 800℃, 900℃and 1000℃respectively for 3h, with the same content of heating fly ash, the compressive strength of solidification blocks improved greatly compared to the blocks with raw fly ash, especially the group of 900℃. When the content of heating fly ash was 30%, compared with the same content of raw fly ash, the compressive strength of 28d increased from 12.4Mpa to 46.0Mpa, and no swelling was found. indicated that the thermal pretreatment maybe an effective way for the utilization of fly ash as the alkaline cementitious material admixture.The s contained in fly ash falls into five formations. The Fe-Mn oxide state is greatest in Pb, Cu, Zn and Cd, and residual state in Cr is the most. The TCLP test was performed on the solidification blocks maintained for 28d, and the extraction toxicity was kept within identification standards for extraction toxicity.
Post about "heavy metal"
Biosorption of nickel and copper ions from aqueous solution onto treated alga biomass Undaria pinnatifida which was artificially cultured in Dalian has been studied and the Langmuir,Freundlich and Temkine equilibrium isotherms,pseudo-first-order,pseudo-second -order and intra-particle diffusion kinetic model were determined respectively.Mechanism andexperiment are brought at the second and final part.Within the test range（initial concentration 5-50 mg/L, doze 0.1-0.5 g,pH 3-7）, performance for metal ions showed an increase in specific metal uptake capacity with an increasing in initial ions concentration and decreasing in biosorbent doze.The optimized condition of pH value for nickel and copper is 4.7 and 4.0 respectively,while contact time is about 100 min.At equilibrium,the maximum total uptake by Undaria pinnatifida was 24.71 mg/g for nickel and 38.82 mg/g for copper.The results for nickel and copper fit well to the Langmuir and the Temkin isotherm respectively.Pseudo-second-order model described well the sorption kinetic of nickel and copper ions in comparison to pseudo-first-order and intra-particle diffusion kinetic model.Then the mechanism about the adsorbent and the ions has been discussed. is deemed to the adsorbent was changed from a catenarian to a retiary structure after treated. is propitious to adsorb the metal ions.Ions of the solution can be considered to be[M2+]than[M（OH）+]at the optimized pH value.FTIR results indicate that the CaCl2 treated biosorbent impacted the -OH and C=O stretching.It means that adsorption is closely contact with the -COOH.It also indicate that the ion on the biomass surface may not only due to the ion exchange but also due to the chelation interaction during the adsorption process.The final part aims at developing a simple and practical methods to study the effect of a submerged membrane adsorption hybrid system.Adsorption kinetic study was first carried out with treated biomass for removing copper ions from a synthetic wastewater.A series of short-term experiments were conducted with preadsorption at different operating conditions such as biosorption time and continuous.Biosorption performance for the show a higher capacity to the higher initial concentration.It has a ion removal of 50%at the intial concentration 45mg/L and 80%at the intial concentration 10mg/L.It is suggested that a multipolar reacter can be used for reclaiming the metal ions.
is studied for the routine of cumulate and of three s（Cu, Cd, Pb）by four kinds of seashll （Tegillarca granosa、Ruditapes philippinarum、Sinonovacula constricat canarck、Monodonta labio）in the lab. The bioconcentration of three s for four kinds of seashll also is studied. Ii is discussed for heavy metal concentration between water quality standard and seashll quality standard. The test is carried out through law-hydrostatic method. The salinity of sea water is 28.5-29.0, pH is 8.1-8.3. [Cu2+], [Pb2+] and [Cd2+] is 0.015mg/L、0.001 mg/L and 0.0001 mg/L in the sea water. The shell length of Tegillarca granosa, Ruditapes philippinarum, Sinonovacula constricat canarck, Monodonta labio is （2.2-3.5）cm, （3.0-3.6）cm, （1.8-2.8）cm and （8.0-12.5）cm, the avoirdupois is （4.8-7.2）g, （6.0-7.8）g, （3.6-5.2）g, （11.0-20）g. The range of [Cu2+] is （0.0150.115）mg/L , the range of [Pb2+] is （0.0010.051）mg/L and the range of [Cd2+] is （0.00010.050）mg/L in the experiment. is set 6 group for evry kind heavy metal and every seashell. The seashell is taken out for detect heavy metal with GF-AAS in 0d, 1d, 3d, 5d, 10d , 15d, 20d, 25d and 30d.The test results shows:（1） Four kind of seashell have bioconcentration effect to Cu, Pb and Cd in seawater. The bioconcentration of Tegillarca granosa is obvious when [Cu2+]≥0.035mg/L or [Pb2+]≥0.0035mg/L. Similarly, the bioconcentration of Ruditapes philippinarum is obvious when [Cu2+]≥0.025mg/L or [Pb2+]≥0.006mg/L. The bioconcentration of Sinonovacula constricat canarck is obvious when [Cu2+]≥0.025mg/L or [Pb2+]≥0.011mg/L. The bioconcentration of Monodonta labio is obvious when [Cu2+]≥0.035mg/L or [Pb2+]≥0.011mg/L. Another, the bioconcentration of four kinds of seashell is obvious to Cd when [Cd2+]≥0.050mg/L. The sequence of bioconcentration ability and speed is: Cu>Pb>Cd. The bioconcentration ability of four kind of seashell isn’t distinguished.（2）As a whole, the residue of heavy metal in seashell body is increase if the concentration of heavy metal is increase in water. The relation of residue in seashell body with concentration in water is positive correlation. But is decrease when [Cu2+] is （0.0250.035）mg/L, [Pb2+] is （0.0060.011） mg/L,[Cd2+] is （0.00260.0051）mg/L. When the seashell is input to seawater which is added heavy metal, the residue of heavy metal in seashell body is higher when the time is longer. But the residue is lower more than some time ago in about 3d. Maybe it is the result of inhibition of seashell. When the concentration of heavy metal is increase, the inhibition is appearing and part of heavy metal is discharged. When the concentration of heavy metal is continue to increase or the time is prolong , The seashell will adapt the environment and the cumulating and ing will be in gear with the passage of time.（3）When [Cu2+] is （0.0350.115）mg/L, uptake rate constant（k1） is 2.70-22.3, extract rate constant（k2） is 0.008-0.126, bioconcentration factor （BCF） is 176.8-854.6,the maximal metal contents in test organism（CAmax） at steady-state is （7.4-53.9）mg/kg. The change of k1 , k2 and BCF is no relation with [Cu2+]. Cmax is increase when [Cu2+] is increase. When [Pb2+] is （0.0060.051）mg/L, uptake rate constant（k1） is 1.79-35.5, extract rate constant（k2） is 0.009-0.151, bioconcentration factor （BCF） is 139.4-1429,the maximal metal contents in test organism（CAmax） at steady-state is （2.06-16.5）mg/kg. K1 , k2 and BCF is decrease when [Pb2+] is increase.. Cmax is increase when [Pb2+] is increase. When [Cd2+] is 0.050mg/L, uptake rate constant（k1） is 2.41-7.97, extract rate constant（k2） is 0.044-0.148, bioconcentration factor （BCF） is 55.0-166,the maximal metal contents in test organism（CAmax） at steady-state is （5.69-8.32）mg/kg.（4）The water quality standard and seashll quality standard is not consistency about heavy metal. It is suggested increasing the request about Pb and Cd in water quality standard. It is can be aceepted that decreasing the request about Pb and Cd in seashll quality standard.
The mine exploit, industry wastewater, garbage treatment and other human activity have a serious affection on our country’s under water. So,is a critical time todevelop a technology of low cost and high treatment effection. A study of Ag+、Co2+、Sr2+、Cs+ five ions adsorpted by S. cerevisiae on huge volume and low ions consistency wastewater which has been polluted by s. Creative points of the study are as follows:1、The experimental results indicated that, Cu2+ and Ag+ both uptake took place at the best pH range was 4-5; the best biosorption temperature of Cu was 20℃-30℃, temperature had no effect on the progress of Ag+ biosorption; there were two progresses of Cu2+ and Ag+ adsorption, the first was fast and happened on the cell face mainly was physics adsorption and ion exchange, the second was slow, enter cell through initiativr transport and consume metabolism energy. The capacity of Cu2+ almost 93.38% uptake was completed within the first ten minutes and the one of Ag+ almost was 86.6%; both ions biosorption time was 3 hours.2、The Langmuir and Freundlich adsorption isotherms can well described the progress biosorption of Cu2+, but the Langmuir adsorption isotherm was best, it’s related coefficient was 0.999 42 and the adsorption equation was: q =7.928 33·c/（c +1/0.986 7）; the isoadsorption of Ag+ accorded Langmuir isotherms, and Fredulich isotherm wasn’t suit, the adsorption equation was: q = 49.7265·c/（c +1/0.00825） and its related coefficient was 0.98572.3、The adsorption ability of Sacchromyces cerevisiae on s was Sr2+>Co2+>Cs+ through comparation two of them mixed solitio, this maybe related with their moving morphology and the morphology of Cs+was simple ion Cs+、the one of Co2+ was mainly CoHCO3+ and C02+·xH2O、the one of Sr2+ was mainly SrHCO3+and Sr2+·6H2O.
PM10 and radioactive radon gas are the main pollutants in Uranium ore mining activities. The pollutants of PM10 including radionuclides,s and organic pollutants and so on. These airborne particles contaminated the environment through the settlement and Air-proliferation.they （especially the diameter of less than 10μm of respirable particulate matter）are easily inhaled in the human body so as to have a serious impact on .PM10 samples were taken at Uranium mining area of east China in july of year 2007,and analyzed for Uranium、thorium、 and by ICP-MS、ICP-AES and High Performance Lipuid Chromatography（HPLC）. The characteristics of pollution were studied, And investigate the thorium and uranium enrichment characteristics of the s in the moss plants. Followed is the main conclusion that thesis has got:（1） The differences of concentrations are very large in different spatial distribution. The concentration of particles is 60～80μg/m3 in sampling points 1, 2 and,and 130μg/m3、200μg/m3 in points 4 and 5.The main factors is single source of particulate matter, mainly from TSP of uranium mining and natural particulate matter in sampling points 1, 2 and 3. The source of particulate matter is more complicated in the points 4 and 5, not only uranium mining of the particles brought about long-range transport of pollution, the major is subject to the impact of human life.（2） The chemical elements of PM10 is similar, the main element is composed of inorganic Al, Ca, Mg, which accounting for 75 percent of the sum elements mass, they are rich in the crust of the elements, mainly from the mine dust. In the high concentration of PM10, each element content accordingly higher, but the percentage of PM10 are not necessarily high quality.（3） Through enrichment factor analyzed, wo know that the enrichment factor of Cr, Cu, Pb, Ni,and Zn are more than 10,they are obvious enrich in the respirable particulate matter （PM10） and are the main the inorganic elements of PM10 Pollution, which may be caused by the coupling of participation of ground ore dust and dust （4） The highest concentration of uranium was 3 sampling points,but the concentr-ation of particulate matter （PM10） only 72.61μg/m3, the maximum concentration of thorium was 1 sampling point, and the concentration of particulate matter （PM10） only 70.02μg/m3. The highest PM10 was the sampling points 4 and 5, but content of thorium and uranium are relatively low. is thought that uranium andthorium are from uranium mining, and the source of particulate matter is more complicated.（5） The heavy metal content of value the moss which in same environment was compared, the different habitats moss plants is not the same of the enrichment of heavy metals,tree>stone>soil.Bryophytes in nutrition mainly from the precipitation and atmospheric particles in the settlement, but the matrix can also affect the moss on the sensitivity of pollutants and enrichment capability, bryophytes matrix for the growth of certain elements of the absorption and assimilation.（6） Through the enrichment capacity of the moss can know that the Entodon compressus C. Mutll on the enrichment of uranium is relatively high, Haplocladium microphyllum, Hypnum plumaeforme the second level of enrichment, Plagiomnium Cuspidatum T. kop on uranium Enrichment is not too good. Haplocladium microphyllum on the thorium higher degree of enrichment, Entodon compressus C. Mutll, Sematophyllaceae Pylaisiadelpha yokohamae general enrichment, Plagiomnium Cuspidatum T. kop enrichment performing poorly. In different sampling points, with a moss on the uranium, thorium not the same degree of enrichment, with the main points of the pollutant concentration and the surrounding environment. The whole of Entodon compressus C. Mutll, Haplocladium microphyllum on the absorption of uranium thorium are strong.（7） The individual are below 100ng/m3, with the lowest concentration occurring at anthracene（0.21ng/m ） and the highest at benzo[b]fluoranthene（2.31ng/m3）.The overall average concentrations of fluoranthene, chrysene,benzo[b]fluoranthene, benzo[k]fluoranthene, imdeno[1, 2, 3-cd]pyrene, benzo[ghi]perylene are higher, and those of phenanthrene, pyrene, benzo[a]anthracene, benzo[a]pyrene are in the middle, and those of acenaphthylene, acenaphthene, fluorine, anthracene, dibenzo[a, h]anthracene are comparatively lower. The pattern of higher abundance of four and more aromatic rings PAHs in the samples is an indicat or of incomplete combustion process of fossil and fuel at high temperature.
Research on the Evaluation of Soil Heavy Metal Pollution of the Black Soil Region in Jilin Province Based on GIS
With the rapid industrial development, urban pollution and the increase ofchemicals types, the increasing number of soil pollution is becoming increasingly serious. Heavy metal pollutants in soil with poor mobility, stranded in a long time and not be microbial degradation, toxic and cumulative effect of strong characteristics of the crop growth, yield and quality have a greater impact, and through the food chain affect human , soil Once the subject of pollution, is to eliminate an extremely easy. Therefore, investigation and evaluation of heavy metals in soil environment pollution and its risk profile, find out the soil quality of the environment, strengthen the comprehensive control of soil pollution, protection of human is of great practical significance.Eight kinds of heavy metals (Hg, As, Cu, Pb, Zn, Cr, Ni and Cd) in the black soil region (Dehui)in Jilin receive the sampling for survey and test analysis in this paper. With the aid of Global Positioning System, Geographical Information System and evaluation model integration technology of soil heavy metal pollution, following the national soil environmental quality standard and the value of the local soil background for the evaluation criteria, the single pollution index was used to elevate the pollution degree of single element, and comprehensive pollution index was used to implement the general evaluation of soil environmental quality. And then the single evaluation maps and the comprehensive evaluation map was obtained by GIS technology respectively. Studies have shown that the use of geographic information systems black soil area in Jilin Province of heavy metal pollution assessment, the evaluation method is feasible, visual effects and strong. This paper tries to use two standard evaluation to make up for the evaluation of the possible lack of previous studies and this is the difference.Base on the research results, the spatial distribution low of heavy metal content of soil in study region was revealed, providing scientific basis to the governance of heavy metal pollution and the sustainable utilization of the black soil.
The Evaluation and Regional Differentiation Rules of Heavy Metal Pollution in Farmland Soils, Nong’an County
Nong’an County, as the keyCounty of the State, not only produces products for local residents, but also supplies and processes the mainly production for its capital city, Changchun, and also supplies millions of tons of marketable grains for our Country. In recent years, with the increasing of population and developing of economy, the pollution problem in farmland soils in Nong’an County has been increasingly serious. Researching on contamination in farmland soils will play a very important role in protecting more effectively and utilizing rationally the existing land resources, speeding up agricultural restructuring, developing pollution-free agricultural production to achieve standardization of agricultural production, and guaranteeing food and grocery security.Based on the environmental science principles, geography principles, and SPSS technology, geographic information system (GIS), taking farmland soils in Nong’an County as study area, the author evaluated roundly the contamination in farmland soils, and disscussed deeply the spatial variation of heavy metals and impact mechanism. The following conclusions were drawn from the analysis.Ⅰ.The quality of the most soil environment was good in Nong’an County. In the 162 soil samples, the single pollution indexes, single-factor composite indexes and multi-factor integrated indexes of Pb, As, Cd, Cr all reached NY/P391-2000 standard. As for Hg, the single index is that 107 samples met NY/P391-2000 standard, 157 samples met GB/T18407-2001 standard and 5 samples failed; the multi-factor integrated index is that 103 samples met NY/P391-2000, in the safe and clean level, 157 samples met GB/T18407-2001, in the safe and clean level, and 5 samples failed, in the alert level but still clean; the single-factor composite index is that 7 townships met NY/P391-2000 standard, 15 townships only met GB/T18407-2001 standard.Ⅱ.The spatial variation trend of five heavy metals in farmland soils, Nong’an County, was that the index values of five heavy metals were mainly high in northwest and southeast. The high value of As concentrated in the central, northwest and southeast; Cd focued on the edge of north, northwest and southwest area; the distribution trend of Cr was interphase from the northeast to southwest; the distribution trend of Pb was interphase from west to east with low and high value; the distribution of Hg was similar to the multi-factor integrated pollution ratings map, which generally concentrated on the west, northwest and southeast.Ⅲ.The regional differentiation rules of heavy metal contamination in Nong’an County farmland soils related natural factors (the soil attribute, hydrological distribution) and human factors (rural townships, transportation, agricultural production, land use types), which were mainly affected by hydrological distribution and the livestock and poultry breeding in the agricultural production. The influence order of all influencing factors was: hydrological distribution>livestock and poultry industry>urban, transportation>plastic sheeting>soil attributes>land use types>fertilizer>pesticide.
Heavy metals in the soil accumulate to a certain amount will lead to soilpollution, s in vegetables to a certain extent would seriously affect their quantity and quality, and affect human through the food chain. This paper assesses the posed by heavy metal content in both soil and in . The results could be used to guide vegetable safety evaluation. samples of 0~20 cm layer and leaf and fruit were collected from greenhouse in , carrying on laboratory analysis to study the soil Cd, Cu and Zn form distribution, Cd, Cu and Zn distribution in tomato leaf and fruit, the effect of Cd, Cu and Zn on the rhizospheric microorganism number, preliminary research Cd, Cu and Zn . The results were as follows:1. Accumulate coefficient of Cd, Cu and Zn is 2.50, 0.498 and 1.08 respectively, Cd accumulated significant, Zn accumulated small, Cu in soil below background level. There were no obvious interaction between Cd, Cu and Zn.2. To HJ/T 333-2006 for an comprehensive contamination index standard , Cd contamination index raged from 0.7 to 1, were alert levelⅡ, is still clean. Cu, Zn contamination index below 0.7, were security levelⅠ, soil is clean. The study area had not received soil Heavy metals pollution, but Cd had the potential pollution tendency. Need to avoid external Cd into the soil, leading to increased soil pollution. In turn affect food security, cause even greater harm.3. The form alalysis of heavy metals in the greenhouse soil showed that Cd mainly exist in Fe-Mn oxide-bound factions and organically bound form, and Cu mainly exist in residual faction and organic form, with 88.9% in all, Zn mainly exist in Fe-Mn oxide and residual faction, with 75.6% in all. Exchangeable, carbonate, Fe-Mn oxide and residual faction of Cd, Cu and Zn accounted 88.2, 52.4 and 46.1% in the total content separately. Most of heavy metals were in these four forms, which have highly potential risk to the environment, may affect the quality of products and the agro-ecological environment.4. The content of heavy metals (Cd, Cu and Zn) in the tested tomato fruit were measured all lower to the Chinese Food Hygiene Standard. No sample exceeded the standard, the pass rate of greenhouse tomato fruit content of heavy metals was 100%, meet Chinese Food Hygiene Standards.5. The tomato leaf Cd enrichment capacity is influenced by the available Cd content in soil,and the ability increases along with the available soil Cd content in increase. And the correlations are not obvious between the tomato fruit Cd and each Cd forms in soil. Cu content in soil do not influence the tomato Cu content in leaf and fruit. has certain relevance between Zn in leaf and fruit of tomato and Zn in soil, and the relevance of different locations not identical. Clearly, the bioavailability was not exactly the same of heavy metals in the soil.6. The proportion of bacteria was more than 90 percent in soil microbial community structure, followed by actinomycetes, at least the number of fungi in the soil. The correlations correlation coefficient between total Cd and the microbes in the soil were negative. And the correlation coefficient between total Zn and microbes were positive. There was no relationship between Cu and the number of soil microorganisms. Heavy metal in soil can affect the soil microbial community structure.
The Study of Health Risk Assessment on Heavy Metals of Crops in City Reclaimed Water Irrigation Area
With the increase of water shortage and water pollution in China, the lack ofirrigation water becomes an important factor which hampered China’s production. The is an important alternative source of water for irrigation. is an effective method to use city reclaimed water to resolve water shortage in agriculture, but s in the water may be absorbed by human body through food chain; the excessive amount of them will be harmful, and ultimately affect human . So is necessary to use risk assessment technology to evaluate the impacts on human’s caused by s in reclaimed water, and then provide the theoretical basis for the using of .This research was based on the demonstrative of for irrigation of farmland in Wuqing District, Tianjin. Corn and wheat were chosen as the experimental crops in the experiment. The impact on soil and crops caused by heavy metals in the reclaimed water irrigation area was analyzed. Monte Carlo method was used to calculate human risk probability distribution about the heavy metals in crops, then health risk assessment was made, and the key risk factors were decided. The results will contribute to provide referenced basis for the safe use of reclaimed water for irrigation of farmland.The main conclusions will be draw as following:(1) During the experiment, the heavy metals in soil do not show obvious residue; the heavy metal proportion in plant irrigated by municipal reclaimed water is higher than that in control area, but the difference was not significant; seven kinds of heavy metals in the crops were lower than corresponding food hygiene standards and national food hygiene standards, the content of heavy metal is always higher in wheat than in corn, so it is necessary to evaluate the risks.(2)Through the compared among enrichment coefficient of different metals, certain crop has different enrichment capacity of different kinds of metal. Different crops have different enrichment capacity to a certain metal; wheat has stronger enrichment capacity to heavy metal than corn.(3)The health risks analysis of heavy metals in crops:In accordance with international standards, harmful heavy metals could be divided into two kinds: one is chemical carcinogenic metal; the other is non-chemical carcinogenic metal. Lifetime carcinogenic risks of arsenic, cadmium, chromium and lead are less than maximum acceptable level of risk recommended by the International Commission on Radiological Protection (ICRP). Each of the non-carcinogenic heavy metals in the lifetime risks is less than the maximum acceptable level of risk recommended by British Royal Society, the Swedish Environmental Protection Agency and the Netherlands Ministry of Environment. For the individual carcinogenic risk and non-carcinogenic risk of heavy metals, the risk of wheat is higher than that to corn. Based on the assumption that a variety of chemical pollutants have additive risks to human health, the total risk of heavy metal carcinogenic risk and heavy metal non-carcinogenic risk is less than the recommended maximum acceptable level of risk; The total risk of wheat is higher than that of corn, and chromium carcinogenic risk of the total risk is over 70 percent.
With the rapid increase of sewage treatment plants, the disposal and the environmental impact ofhave been paid more and more attention. Now, of has become an important way for sewage sludge disposal duo to its lower cost and higher efficiency. But s are the key factor that affects the of sewage sludge. So we have done some researches on the monitoring of nutrient and concentration and the phytoavailability of heavy metal in soil treated of sewage sludge by a pot experiment. Also the impacts of soil environmental and heavy metal contents in wheat by land applications of sewage sludge were evaluated to assess the agronomic benefits and environmental impacts of sewage sludge application to soils. The main results obtained were as the following:1. The content of organic matters, nitrogen, phosphorus and potassium in sewage sludge from Beijing is 35.5%, 2.7%, 3.8% and 0.2%, respectively. Except potassium, those are higher than organic fertilizer as pig manure and chicken manure.2. The mean concentrations of Zn, Cu, Cr, Pb, Ni, As and Hg in sewage sludge from sludge disposal plant are 1665 mg/kg, 238 mg/kg, 98 mg/kg, 79 mg/kg, 46 mg/kg, 20 mg/kg and 13 mg/kg, respectively, and are 821 mg/kg, 149 mg/kg, 31 mg/kg, 35 mg/kg, 40 mg/kg, 21 mg/kg, 14 mg/kg respectively from sewage treatment plant. Compared with the heavy metal limits of sewage sludge for land application in china, Zn, Cu, Cr, Pb, Ni and As concentrations in sewage sludge are lower than the limits value, and Hg concentrations in sewage sludge is overran the limits value for pH