Evaluation on Soil Heavy Metal Pollution of Agricultural Habitat Environment in Xi'an City

[Objective] This study aimed to understand and grasp the soil heavy metal pollution status of agricultural habitat environment in Xi＇an City. [Method] The soil heavy metal pollution status of pollution-free agricultural products-producing areas in 9 counties （districts） of Xi＇an City was investigated. A total of 609 soil samples were collected, and their Cd, Hg, As, Pb and Cr contents were determined. In addition, the heavy metal pollution status of the collected soil samples was evaluated by Nemerow index method. [Result] The pollution in Baqiao, Chang＇an; Gaoling, Lan- tian, Lintong and Yanliang was of grade I, belonging to clean level; the pollution in Hu County, Weiyang and Zhouzhi was of grade II, near the warning line, belong to relatively clean level. There was no large-area soil heavy metal pollution overall. The investigated areas could be used as production bases of pollution-free agricultural products and even high-quality agricultural products. However, the heavy met- als contents in some individual areas exceeded relevant soil environmental quality standards, and they should be avoided or forbidden during regional planning and selection of production area. [Conclusion] Soil heavy metal pollution of agricultural habitat environment in Xi＇an City is generally at good status. Targeting at the future development plan of Xi＇an City, feasible and scientific suggestions are put forward.

Analysis and Assessment on the Heavy Metals in a Severely Degraded Subtropical Red Soil Region

5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects.

Evaluation of Heavy Metals Contamination on Representative Fruits in Nanning

[ Objective] The research aimed to analyze the contents of heavy metals in the typical fruits of Nanning and evaluate the pollution status of heavy metals in fruits of Nanning. [ Method] Five kinds of typical fruits （litchi, longan, dragon fruit, mangosteen and pineapple） in Nanning were collected to measure contents of heavy metals including Cd, Pb, As and Hg. According to standard of pollution-free fruits （GB18406.2 -2001 ）, pollution evaluation was conducted, and cumulative degrees of different fruits on a variety of heavy metals were contrasted. [ Result ] The heavy metal contents of all fruits were qualified. Comprehensive pollution index of dragon fruit was the maximum, and its cumulative capability on various heavy metals was the strongest. [ Conclusion] The pollution degrees of all fruits were safety in Nanning, and pollution level was clean.

Evaluation of Antibiotic Pollution in Soil of Vegetable Base in Yangling District,Shaanxi Province

[Objectives]To evaluate the pollution status of antibiotics in the soil of vegetable bases in Yangling District.[Methods]The contents of 19 antibiotics in 4 categories of quinolones,tetracyclines,sulfonamides and macrolides in soil samples from 20 bases were detected and analyzed using HPLC-MS/MS.[Results]The quinolones,sulfonamides and tetracyclines were all detected in 100%of soil samples,and the detection rate of macrolides was 62%.The average contents of the four antibiotics from high to low were quinolones(51.76μg/kg)>tetracyclines(12.77μg/kg)>sulfonamides(1.14μg/kg)>macrolides(0.28μg/kg),and norfloxacin,oxytetracycline,sulfamethazine and erythromycin were the main contents,respectively.According to the trigger value of ecological toxic effect of antibiotics in soil(100μg/kg)proposed by the Steering Committee of the International Coordinating Committee for Veterinary Medicine(VICH),the contents of the four classes of antibiotics in the soil of the study area were all lower than the trigger value,indicating a small ecological risk.[Conclusions]Compared with other domestic research reports,the vegetable bases in this study area are also at a relatively low level of antibiotic pollution.

Investigation and Analysis of Soil Pollution of Heavy Metals(Hg,As) in Duanzhou District,Zhaoqing City

The soil heavy metals(Hg and As)in Duanzhou District of Zhaoqing City were determined by AFS200 T atomic fluorescence spectropho-tometer,and the soil environment in Duanzhou District was evaluated by several evaluation methods of soil heavy metal pollution,such as single factor index method,pollution load index method and Nemerow comprehensive pollution index method.Finally,according to the data and conclu-sions,the soil pollution situation in Duanzhou District of Zhaoqing was analyzed.The results will let more people pay attention to the changes of the environment and realize the harm of the environment,and the government can formulate a new plan conducive to the coordinated development of the environment and economy.

Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier(PC-PRB)

The passive convergence-permeable reactive barrier(PC-PRB)was proposed to address the limitations of traditional PRB configurations.To evaluate the hydraulic and pollutant removal performance of the PC-PRB system,we developed a simulation code named PRB-Trans.This code uses the two-dimensional(2D)finite element method to simulate groundwater flow and solute transport.Case studies demonstrate that PC-PRB technology is more efficient and cost-effective than continuous permeable reactive barrier(C-PRB)in treating the same contaminated plume.Implementation of PC-PRB technology results in a 33.3%and 72.7%reduction in PRB length(L_(PRB))and height(H_(PRB)),respectively,while increasing 2D horizontal and 2D vertical pollutant treatment efficiencies of PRB by 87.8%and 266.8%,respectively.In addition,the PC-PRB technology has the ability to homogenize the pollutant concentration and pollutant flux through the PRB system,which can mitigate the problems arising from uneven distribution of pollutants in the C-PRB to some extent.The L_(PRB)required for PC-PRB decreases as the water pipe length(L_(p))increases,while the H_(PRB)required initially decreases and then increases with increasing L_(p).The effect of passive well height(Hw)on H_(PRB)is not as significant as that of L_(p)on H_(PRB).Overall,PC-PRB presents a promising and advantageous PRB configuration in the effective treatment of various types of contaminated plumes.

City level CO_(2) and local air pollutants co-control performance evaluation: A case study of 113 key envir on mental protection cities in China

‘Co-control',or synergistically reducing CO_(2)and local air polluta nt emissions,is an important strategy for cities to achieve'low carb on'and'blue sky'simultaneously.However,there were few studies to evaluate and compare the level of co-control of CO_(2) and local air pollutants in cities year.The present study proposed qualitative and quantitative methods to evaluate the level of co-control of CO_(2)and three local air pollutant(SO_(2).NOX,and particulate matter PM)emissions in key environmental protection cities in China over two periods(2012-2015 and 2015-2018).Statistical analysis found that,though three local air pollutant emissions positively correlated with CO_(2) emission,no significantly positive correlation was found between local air pollutants emission reductions and CO_(2) emission reductions,indicating that co-control effects were poor in general.By using the co-control effect coordinate system,qualitative evaluation showed that less than half of the sample cities could achieve co-control of the total amount of CO_(2) and local air pollutants.By employing the indicator of emission reduction equivalence(EReq),quantitative evaluation showed that the co-control level of the sample cities improved in 2015-2018 compared with 2012-2015.Further regression analysis showed that,reducing coal consumption and economic development significantly enhanced the co-control performance of the observed cities.The present case study proved that the proposed methods for evaluation and comparison of the city co-control performance works well,and can be used in other countries and regions to promote global cities racing to carbon and local air pollutants co-control.

Evaluation of occupational noise pollution and attitudes of exposed workers in two metal industries

The purpose of the present study was to determined noise levels and to show the annoyance reaction, hearing loss, hearing impairment by the workers due to the occupational noise exposure according to Iran development of Environment （IDE） and also awareness about effects of noise and use of hearing protective devices （HPD） in the two manufacturing electronic equipment （metal） industries. The present study was carried out among industrial workers and included a sample of lao workers, site 1 （n = 52） and site 2 （n = 78） from two metal industries located in south eastern Iran province of Kerman. In order to attend the objectives of the current study, noise levels evaluation was determined throughout all different work stations in both industries. The results of the study revealed that noise levels in 75% of the stations are higher than limits used for assessment of noise for community response. The result of the study indicated that noise levels in the workplace are （66%） very high, （28%） high and only 6% low. Workers having higher education are much aware of the health impact due to occupational noise. Chi-square analysis indicated that the difference in educational background and not wearing HPD was significant and also a significant relationship was also observed between the impact of occupational noise on the health and education status. This research has clearly demonstrated that the workers in both the metal industries included in this study are at high risk of developing noise induced hearing loss and other associated ailments due to excessive occupational exposure to noise. There is a need to develop and apply a well-defined, comprehensive and enforceable training programs and noise regulation. The study revealed that the workers having higher education （9-12 grades） are much aware of the health impact due to occupational noise exposure. There is a need to establish a hearing conservation programs in both industries, the components of such program include noise assessment, use of hearing protection devices, audiometric and increasing awareness among the workers about the adverse effects of noise.

Water quality assessment in Qu River based on fuzzy water pollution index method

A fuzzy improved water pollution index was proposed based on fuzzy inference system and water pollution index. This method can not only give a comprehensive water quality rank, but also describe the water quality situation with a quantitative value, which is convenient for the water quality comparison between the same ranks. This proposed method is used to assess water quality of Qu River in Sichuan, China. Data used in the assessment were collected from four monitoring stations from 2006 to 2010. The assessment results show that Qu River water quality presents a downward trend and the overall water quality in 2010 is the worst. The spatial variation indicates that water quality of Nanbashequ section is the pessimal. For the sake of comparison, fuzzy comprehensive evaluation and grey relational method were also employed to assess water quality of Qu River. The comparisons of these three approaches＇ assessment results show that the proposed method is reliable.