Metal pollution in relation to mass outbreaks of Dendrolimus punctatus Walker on Pinus massoniana Lamb.in China

Insects with their ecological superpower have enormous capacity to transform small pollution damage in forests to full scale calamities. Acid rain resulting from extensive coal burning is the chief pollutant in China. Acid rain activates from soil deposits toxic metals, which are transferred to trees and further to insects eating them. We studied the levels of the toxic Cd, its antagonists Zn and Cu, and acid rain indicators Fe and Mn in the forest pest moth Dendrolimus punctatus Walker (Lepidoptera:Lasiocampidae) in variously polluted Pinus massoniana Lamb forests in China. The highest density of D. punctatus, as well as the highest Cd levels developed in the moderately polluted forests. Possibly Cd had there broken down the pest resistance of the pines. The paradoxical coexistence of high Cd level and elevated population density of the pest seems to result from the high accumulation of Cd in its ichneumonid parasitoid. In the most heavily polluted forests the Cd level in needles was low, possibly because the strong acid rain had washed away most of the Cd deposit in the soil. It existed there no D.punctatus population. Absence of pest insects from the most heavily polluted areas is a common phenomenon.     

Acid deposition and its effects in China: an overview

Acid rain is an increasing environmental problem in China. At present SO₂ emission is about 20–22 million tons. However with a growing number of large power plants the long-range transport of air pollutants is expected to increase. The highest acid deposition is near the emission sources. Wind-blown, alkaline soil dust is important in neutralizing the acidity of the emissions, especially in large parts of northern China. In the south, where alkaline soil dust contributes less to acid neutralization, the annual pH in precipitation was below 4.5 at monitoring stations in several provinces and as low as 4.1 in some urban areas. Total sulfur deposition has been estimated to be about 10 g S m−² year⁻¹ in heavily exposed areas. Negative effects on forests, including die-back, have been reported for relatively small areas near large cities. Since large, regional surveys have not been carried out, there are large uncertainties about effects on a regional level. The high concentrations of gaseous pollutants, especially within and near the cities, are likely to have severe effects on human health as well as on materials and vegetation. Several field and laboratory studies, as well as computer simulations, indicate that acidification of soil and soil water has occurred in the past few decades. This has probably caused elevated concentrations of toxic aluminum in soil water. At present, the toxic effect of Al is likely to be counteracted by high concentrations of calcium at many places. The Chinese authorities have recognized air pollution and acid rain as serious environmental problems, however, there are difficulties in implementing effective measures to reduce the problems. With respect to ecological effects we lack a comprehensive regional overview of the extent of the acid deposition problem in China. Such information is necessary before effective countermeasures can be developed.     

Effects of acid rain on forest ecosystem in Southwestern China

The study of effects of acid rain in Southwestern China on forest ecosystems .has been inrestigated since 1984. The results have shown that the ecosystem of Pinus massoniana forest has been damaged severely by acid rain. Comparing the areas where the annual mean pH value is lower than 4.5 with that higher than 4.5, the productivity of the ecosystems decreased 50 percent. Both the percentages of the green leaves and the content of chlorophyll cut down; the acidity of soil increased a bit and the fertility showed the tendency to lower. The microbial population components in surface soil were changed and the total number of soil microbes reduced from 63.5 to 92.6 percent. Besides the direct effects of acid rain, the insect pest, especially, Blastophagus piniperdoz and Monochamus galloprovincialis, seized the opportunity to enter and reproduce in it so as to aggravate the forest dieback of P.massoniana in the areas where the annual average pH value is lower than 4.5.Additionally, the simulation study on the     

模拟酸雨下土壤中铜、镉行为及急性毒性效应

本文论述模拟酸雨下红壤、黄棕壤和黑土中Cu、Cd行为及急性毒性效应.试验表明:(1)模拟酸雨对添加性土壤Cu、Cd的淋溶有一定的影响,随着降水酸度的增大,土壤中Cu、Cd的淋出量增加,但增加的程度与土壤类型、添加金属的浓度和种类有关,相同酸度下,红壤中Cu、Cd的淋出量远大于黄棕壤和黑土,淋出率随着沉降酸度而改变的程度也最显著,酸雨对黑土中Cu、Cd淋溶影响最小.Cd对酸雨淋溶的敏感性大于Cu.(2)模拟酸雨对土壤中Cu、Cd形态影响较为明显,随着酸雨pH的降低,黄棕壤和黑土中部分Cu、Cd形态明显地向着交换态转化,红壤中部分Cu、Cd形态明显地向着水溶态转化.(3)模拟酸雨对土壤中Cu、Cd的生物毒性影响很大,但这种影响同时又受土壤类型相当大的制约,红壤中毒性影响最大,黑土中毒性影响最小,表明三类土壤的抗酸能力顺序为黑土>黄棕壤>红壤.     

土壤-植物系统中模拟酸雨与Cd复合污染的短期环境效应--黄豆盆栽试验

通过盆栽实验,研究了在黄豆(Glycne max)的一个生长周期内,模拟酸雨与Cd复合污染对土壤基本性质的影响,模拟酸雨作用下土壤-植物系统中Cd的迁移转化规律以及模拟酸雨与Cd复合污染对黄豆生长与生理特性的影响,探讨了土壤-植物系统中这种复合污染的短期环境效应.结果表明,短期内模拟酸雨和Cd污染对土壤-植物系统都有致害作用,但Cd污染的效应大于模拟酸雨的效应,模拟酸雨与Cd复合污染环境效应大于这2种污染物的单因素效应,且表现出明显的协同作用.在本试验条件下,pH值为3.5的模拟酸雨和20 mg·kg-1Cd的处理组合对土壤-植物系统的危害最严重.尽管在短期内,协同作用仅在土壤交换态Cd含量、黄豆茎和根中的Cd含量这3项指标上得到一定程度的体现,但这种复合污染的化学机制和环境效应值得关注,这2种污染物长时期共同作用对土壤-植物系统的影响也值得深入研究.     

费氏弧菌发光法对Cd^2＋及镉污染土壤的检测

采用发光细菌法（费氏弧菌,Vibrio．fisheri）对镉污染的土壤及Cd^2＋进行毒性检测,分析了不同浓度Cd^2＋和不同镉污染梯度的土壤对发光细菌发光抑制率的影响。结果表明,在0．32～48mg·L^-1这个浓度区间,Cd^2＋对费氏弧菌的剂量一效应关系为CUBIC曲线,相关系数在0．92～0．96之间。镉污染土壤的临界浓度为10mg·kg^-1;土壤镉污染程度越重其pH值越高。     

Cu和Cd复合重金属污染土壤修复后对地下水的安全性研究

以修复前污染土壤为对照,对化学固化修复后的铜(Cu)、镉(Cd)复合重金属污染土壤进行了模拟酸雨淋溶实验和SPLP浸出实验,研究了修复后土壤中Cu、Cd的释放特征,应用模糊综合评级法,评价了修复后土壤对地下水安全的风险级别。在十年酸雨淋溶下,污染土壤Cd释放总量为14.06 mg,Cu为7.27 mg,对地下水安全的风险级别为11;修复后土壤中的Cu和Cd 10年释放总量都为0,对地下水安全的风险级别为1。Cu、Cd复合重金属污染土壤经化学固化修复后对地下水的风险较低。     

Risk assessment of heavy metals in soils and vegetables around non-ferrous metals mining and smelting sites, Baiyin, China

A field survey was conducted to investigate the metal and arsenic contamination in soils and vegetables on four villages （Shuichuan （SCH）, Beiwan （BWA）, Dongwan （DWA） and Wufe （WFE）） located along, Baiyin, China, and to evaluate the possible health risks to local population through foodchain. Results show that the most significantly contaminated soils occurred upstream at SCH where Cd, Cu and As concentrations exceeded maximum allowable concentrations for Chinese agricultural soil. Further downstream the degree of contamination semi-systematically decreased in concentrations of metal. Generally, the leafy vegetables were more heavily contaminated than non-leafy vegetables. Chinese cabbage is the most severely contaminated, the concentrations of Cd exceeded the maximum permit levels （0.05 mg/kg） by 4.5 times. Bio-accumulate factor also shows that an entry of Cd to food chain plants is the greatest potential. Furthermore, the estimated daily intake amounts of the considered toxic elements （Cd, Pb and Cu） from the vegetables grown at SCH and BWA and DWA have exceeded the recommended dietary allowance levels. Thus, the vegetables grown in three villages above, which affected by Baiyin mining and smelting have a health hazard for human consumption.     

宝鸡市麟游县煤矿区周边农田土壤重金属污染安全评价

文章选取麟游县的北马坊煤矿、郭家河煤矿和北王煤矿为研究区域,对其周边的农田土壤进行野外采样和室内分析,测定Zn、Cr、Pb、Cu、Cd、Hg、As 7种重金属的污染状况。结果表明:测定的7种重金属元素的最大值均超过了陕西省土壤背景值和当地的土壤环境背景值。单因子污染指数评价得出,三矿区周边的土壤Hg元素的污染较严重,局部地区已经达到了重度污染;综合污染指数法评价得出,三矿区均达到了中度到重度污染水平,其中北王煤矿污染水平较高;地质累积指数法评价得出,三矿区Hg元素的累积程度属于中度污染到强污染等级,Cd元素次之。因此3矿区周边的耕地土壤已不同程度的受到重金属的污染,相关部门应该采取一定的措施治理该区的土壤。     

西南某铅锌矿区农田土壤重金属空间主成分分析及生态风险评价

以西南某铅锌矿区周边农田土壤作为研究对象,采集土壤表层(0~20 cm)149个土壤样品,分析测定了As、Cd、Cr、Cu、Hg、Ni、Pb、Zn共8种重金属含量.采用多元统计分析,揭示了研究区农田土壤重金属污染的主要来源及各元素之间的相关性;并应用Hakanson潜在生态风险指数法,对农田土壤生态风险进行评价.结果表明,研究区农田土壤重金属Cd、Pb、Zn含量相对处于极高水平,均值分别为15.56、419.4、933.4 mg·kg~(-1),污染十分严重;Hg和As的均值分别为0.13 mg·kg~(-1)和37.3 mg·kg~(-1),属于中度污染;Cu、Ni、Cr的均值分别为26.1、14.3、33.4 mg·kg~(-1),未超过云南省土壤环境背景值;多元统计分析结果显示Cd、Pb、Zn、Hg、As这5种元素来源相似,主要来源于矿山开采和工业活动;Cu、Ni、Cr这3种元素来源相似,主要是自然来源;研究区综合潜在生态风险指数RI的均值为2 294.8,整体上处于极高生态风险水平.矿区开采和工业活动对农田土壤造成了严重的重金属污染.     

广东清远电子垃圾拆解区农田土壤重金属污染评价

简单粗放的电子垃圾回收活动给周边环境带来了一系列污染问题,污染物通过食物链的累积最终将对人体健康产生危害.为了解广东省清远市电子垃圾拆解地周边农田土壤重金属污染现状,在该市龙塘镇和石角镇电子垃圾拆解区域内采集22个农田土壤样品,并分析了土样中重金属的含量水平、空间分布特征和化学形态.结果表明,与广东省土壤背景值相比,农田表层0~20 cm土壤中Pb、Cu、Cd、Zn、Ni和Cr元素含量表现出不同程度的富集.从单项污染指数来看,72.7%的表层土壤样品存在一种或几种重金属超标,以Cd、Cu、Pb和Zn污染为主,其中Cd污染比例最高,其次是Cu,最后是污染比例相当的Pb和Zn.内梅罗综合污染指数分析发现68.2%的土壤样品受到重金属污染,其中更有53.3%为重污染等级.大部分重金属之间具有良好的相关性,简单粗放的回收活动成为电子垃圾拆解地周边农田重金属污染的重要来源.Cd、Pb、Zn和Cu在表层土壤中含量较高,深层土部分(20~100 cm)并未表现出随深度增加而显著降低的趋势.Cr和Ni元素在整个采样剖面中含量基本一致,无统计学意义上的差别.重金属化学形态分析结果显示Pb、Cu和Cd的活性形态比例范围分别为36.9%~90.6%、39.6%~93.9%和43.7%~99.6%,平均值分别为61.3%、65.3%和80.7%,绝大多数土壤样品中3种重金属活性形态在总量中的比例占到一半以上,具有极大的生态风险.     

北江流域横石河-翁江沿岸土壤重金属污染特征分析

采集了北江流域翁源县境内受大宝山矿区影响的横石河-翁江沿岸13个土壤剖面共49个土样,分析了河流沿岸土壤中重金属As、Cd、Cr、Cu、Fe、Mn、Ni、Pb和Zn的含量,讨论了土壤重金属含量的空间变化特征、污染程度以及潜在生态风险.结果表明:横石河沿岸(I区)土壤重金属污染较翁江沿岸(II区)严重,I区As、Cd、Cu、Zn的含量分别为26.6~430,1.99~11.9,31.7~765,63.5~646mg/kg; II区As、Cd、Cu、Zn的含量分别为4.16~51.3,0.830~4.67,3.99~103,17.6~83.7mg/kg;重金属含量差异分析显示,土壤重金属污染与污染源类型(大宝山矿山开采、农业、交通污染、生活垃圾等)、河水-地下水交互作用以及土壤理化性质(有机质含量、微粒组分)有关;As、Cu、Cd是研究区内主要的重金属污染元素,尤其以Cd污染最为严重,I区、II区Cd的地累积系数分别为6.13和4.84,属于极度污染和强-极度污染水平;土壤毒性单位评价结果显示,I区土壤(S23除外)剖面毒性单位(∑TU)均大于4,属于中毒性;II区土壤剖面∑TU普遍较低.     

湖北某铅锌矿区农用地重金属调查与类别划分

以鄂东南某铅锌矿区147.3 hm2农用地土壤为研究对象,通过现场采样及实验室测试,对土壤重金属Cu、Cr、Ni、Zn、Pb、Cd、As和Hg含量进行分析和评价。结果表明:Cu、Zn、Pb、Cd和As的点位超标率分别为33.7%、49.0%、73.5%、95.9%和85.7%,单因子污染指数顺序为Cd>As>Pb>Zn>Cu;通过内梅罗综合污染指数评价,重度污染、中度污染、轻微污染的点位比例分别为59.18%、12.24%、27.55%;通过土壤和农产品综合质量指数法评价,矿区农用地土壤大部分呈重度污染状态(土壤综合质量影响指数IICQ_S>5),与Pb、Cd和As含量高值并集区域分布一致;而农产品大部分属于清洁或轻微污染状态(农产品综合质量影响指数IICQ_AP<2),超标点位分布无明显规律;IICQ_S值与IICQ_AP值无显著相关性;IICQ值与IICQ_S值的分布相一致,研究区内农用地IICQ均值为7.84,属于重度污染。结合现场调查及数据分析,对矿区农用地土壤污染概念模型提出了初步构想。根据《农用地土壤环境质量类别划分技术指南(试行)》,结合农产品调查结果,将矿区农用地中的耕地划分为优先保护Ⅱ类(21.4 hm2)、安全利用Ⅰ类(57.8 hm2)、安全利用类荒地(29 hm2)、安全利用Ⅱ类(1.2 hm2)、严格管控类(37.9 hm2)。     

酸性降水对我国森林的影响

综述了近几年来酸雨对我国森林影响的主要调查和实验研究成果,所涉及的内容包括酸雨对木本植物的直接伤害,酸雨对森林生长和生产力的影响,以及对森林土壤、土壤微生物、病虫害的影响等方面。      

改性生物质电厂灰钝化修复南方镉污染土壤及其长效性研究

选取我国南方生物质发电厂的灰渣为原料,经物理和化学改性制成重金属钝化剂,针对我国南方重金属Cd污染的土壤开展钝化修复研究.底灰中Cd等重金属含量明显低于其对应的飞灰,这是选择底灰作原料的重要原因.用其制备的BFA型钝化剂在水中对Cd的吸附量可达16mg/g以上.室内盆栽试验中,添加土壤干重1%的钝化剂,第一季稻米Cd含量降低80%以上,从超标2.8倍降至达标;第二季小麦籽粒Cd降低70%,从超标0.9倍降至达标.在我国南方Cd重度污染的农田中开展的原位修复试验表明,添加1%的钝化剂,稻米和小麦籽粒中Cd降低70%~90%,其中稻米Cd持续降低,2017年降低率相较2016年继续提升10%~20%,最终从超标20倍降至达标;Ni降低60%以上,且保留有益的Cu、Zn元素不受明显影响;此BFA型钝化剂还能促进作物生长,第一季稻米产量提高40%~60%,第二季仍有一定的增长效果.综合安全性考虑,我国南方生物质电厂的灰渣重金属含量很低,经过改性加工可制成安全高效的重金属钝化剂.可为钝化修复我国南方重金属污染农田提供一种经济有效的方法,也为现阶段难以处置的灰渣提供一个重要的利用途径.     

南京城郊某典型退耕农用地土壤重金属含量特征与污染评价分析

通过对比土壤背景值、筛选值,对南京城郊某典型退耕农用地45个点位深度至6 m的166个土壤样品中Cu、Ni、Cd、As、Pb、Hg、Be、Sb、Co、V 10项重金属含量特征进行分析与污染评价。结果表明:1)10种重金属含量最大值均超过背景值;Cu、Cd、As、Pb、Hg含量最大值均超过GB 15618-2018《土壤环境质量 农用地土壤污染风险管控标准》;As、Co含量最大值超过GB 36600-2018《土壤环境质量 建设用地土壤污染风险管控标准》;Cd含量变异系数最大,Hg次之;2)Hg、Cd、Pb含量最大值在上层(A或B层)的频次明显较高,As、V含量最大值在下层(C层或D层)的频次明显较高;Hg含量在最大值与中位值上均呈A层递减至D层趋势,Cd含量呈U形;3)单因子指数评价发现,Cu、Cd、As、Pb、Hg存在重度污染,污染程度大于其他重金属;内梅罗指数评价发现,对比GJA,JSA,NJ 3种背景值、NY筛选值、JSH1筛选值,评价结果分别呈70%以上各层样品为轻度污染等级,90%以上各层样品为安全等级,100%各层样品为安全等级;4)重金属相关性上,As-Sb(0.810)相关性最高,Hg与其他重金属相关性较弱;结合主成分分析,重金属主要来自自然成土过程、农业耕作类强人为源以及城郊大气沉降类弱人为源3个来源;土壤中Cu、Ni、Cd、As、Pb、Sb含量主要受成土过程影响,其次为人为源,同时Co、V基本未受人为源影响;Hg、Be含量除受成土原因影响外,受人为源影响大。     

Simulating study on the effect of acid precipitation on forest soil weathering

The effect of acid rain on the forest soils in China was discussed on the basis of simulating studies. The soils were collected from five typical areas, including Chongqing in Sichuan Province and Guiyang in Guizhou Province, where there has been heavier acid rain in southwest China, and Huitong in Hunan Province, Zhouzhi in Shaanxi Province, and Xinglong in Hebei Province, all of which were selected as control. Field investigation and sampling were made in the typical forests in all the above five areas. The relationship between pH values in precipitation and rates of soil weathering, the difference between the rates of soil weathering in different areas, and the cause of such a difference, have been worked out. The prediction was also conducted on the supply dynamics of nutrient and toxic elements in various forest ecosystems which were affected by acid deposition in order to understand the long-term effects of acid precipitation on the forest ecosystems studied.     

Mobility and speciation of Cd,Cu,and Zn in two acidic soils affected by simulated acid rain

Through a batch experiment, the mobility and speciation of heavy metals(Cd, Cu, Zn) in two acidic forest soils from Hunan Province were studied. The results showed that the release and potential active speciation of Cd, Cu, and Zn in the tested contaminated red soil(CRS) and yellow red soil(CYRS) increased significantly with pH decreasing and ion concentrations increasing of simulated acid rain, and these effects were mainly decided by the pH value of simulated acid rain. Cd had the highest potential nsk on the environment compared with Cu and Zn. Cd existed mainly in exchangeable form in residual CRS and CYRS, Cu in organically bound and Mn-oxide occluded forms, and Zn in mineral forms due to the high background values.     

中国193个城市规划区土壤微量元素污染与健康风险

随着城市化进程的加快,城市表层土壤微量元素含量发生了不同程度的变化,城市土壤污染所引发的环境问题进一步凸显.为了系统研究我国31个省（自治区、直辖市）193个地级以上城市规划区表层土壤13种微量元素的含量特征、污染水平和暴露风险,利用地累积指数（I_geo）和综合污染指数（IPI）对土壤微量元素的污染水平进行了评价,采用美国环保署（USEPA）推荐的健康风险评估方法量化了居民暴露于城市土壤的健康风险.研究结果显示：城市规划区表层土壤As、Be、Cd、Co、Cr、Cu、Hg、Ni、Pb、Se、Tl、V和Zn等13个元素含量中位值分别是9.25、2.14、0.174、12.4、68.4、28.2、0.095、27.7、31.1、0.29、0.61、82.7和82.2 mg·kg^-1,相比于城市土壤背景值,Cd、Hg和Se是含量变化比较显著的元素.I_geo值表明城市规划区表层土壤污染最严重的是Hg,其次是Se和Cd,污染程度介于无污染至中度污染之间,其他元素无污染.综合污染指数IPI_N显示：全国有22个城市规划区土壤已达到重度污染,16个城市达到中度污染,湖南省株洲市是全国土壤污染最严重的城市.健康风险评估结果表明：郴州市、黄石市、株洲市、湘潭市和龙岩市等5个城市规划区土壤暴露对未成年人具有潜在非致癌风险,其中土壤Pb摄入是引发风险的主要因素.建议在综合污染已达中度到重度污染的城市开展详查,摸清土壤污染状况及污染地块分布,建立污染地块清单和优先管控名录,实施污染调控和修复治理.     

中国城市土壤重金属空间分布与污染研究

研究对比分析了中国城市土壤重金属的空间变异、时间差异、污染水平以及环境风险,研究结果表明,中国城市土壤重金属含量均超过了中国土壤背景值,尤其是Cd和Pb的污染严重,其含量分别是中国土壤背景值的91.37倍和41.91倍,Ni的污染较轻,其含量是中国土壤背景值的1.59倍。中国城市土壤重金属的含量存在明显地区差异,东部、中部和西部地区的城市土壤重金属含量差异较大,省会城市和地级城市的污染程度不一,城市不同功能区之间也存在明显区别。同时,城市土壤中金属含量也因城市发展时间的长短而又一定差异。中国城市土壤重金属总体内梅罗综合污染指数是45.404,属于重度污染,中国城市土壤重金属综合潜在生态风险指数为71.56,潜在生态风险程度为高级。不同等级的城市污染程度不一,造成的环境风险也不同。