Evaluation of heavy metal concentrations of edible wild-grown mushrooms from China

ABSTRACT

The heavy metal contents (Co, Cu, Fe, Mn, Ni, and Zn) of eight species of wild edible mushrooms from China were determined. The analyses were performed using inductively coupled plasma atomic emission spectrophotometry after microwave digestion. The contents of Co, Cu, Fe, Mn, Ni, and Zn in caps of mushroom samples were 0.7–7.2, 16.2–70.4, 371–1315, 12.5–29.8, 7.1–58.5, and 77.8–187.4 mg kg^?1 dry matter (dm), respectively, while considerable differences were found to be 1.8–25.9, 9.8–36.3, 288–6762, 13.3–103.9, 5.9–78.7, and 38.7–118 mg kg^?1 dm for stipes. The results indicated that higher levels of Co, Fe, and Ni were found in the mushrooms samples analyzed. Zinc and manganese levels were similar to previous reports, whereas Cu was lower than literature values. Correlation analysis suggested that significant correlations were found between the minerals determined and the greatest amount of contamination is associated with Co, Mn, Ni, and Fe. The results of this study indicate that heavy metal contents in mushroom species are mainly related to the mineral resources of sampling sites.     

辽宁省红透山铜矿区土壤中重金属迁移特征研究

采用柱淋溶实验模拟辽宁省红透山铜矿区土壤中重金属的淋溶迁移特征,研究了淋溶液pH、电导率(EC)和重金属含量的变化及其相关性,分析了重金属在淋溶前后的总量和形态变化,并初步探讨其生态与健康风险.结果表明,在1～3次淋溶中,淋溶液pH迅速下降,土样中的部分酸性物质被快速溶出,在第3次淋溶之后,淋溶液pH缓慢上升;淋溶初期淋溶液EC大幅度、迅速降低,此后随着淋溶次数的增加EC缓慢降低;Fe、Mn、Cu、As、Cd均能从土样中溶出进入淋溶液,其中Fe、Mn、Cu、As的溶出主要在淋溶初期,而Cd除了在初期有所溶出外,在淋溶后期还存在二次溶出释放阶段;淋溶后土样中绝大部分重金属总量均有所下降,各重金属的解吸率为Cd＞As＞Fe＞Cu＞Mn＞Zn,其中以Cd、As含量下降最为明显,而Zn基本未溶出;淋溶前后土样中重金属的活性态(弱酸提取态(BCR-1)、可还原态(BCR-2)、可氧化态(BCR-3))含量发生了不同程度的变化,Fe的活性态含量在淋溶后变化很小,Mn、As的活性态含量在淋溶后有所上升,而Cu、Cd的活性态含量在淋溶后有所下降;随着淋溶的进行,土壤中各重金属的赋存形态发生了一定变化,从而可能引起其生态与健康风险的改变.     

利用污泥进行水体中重金属生物吸附研究现状及展望

对国内外利用废水处理等工业过程中所产生的污泥作为生物吸附剂吸附水体中重金属的研究现状进行了综述和分析,包括其预处理技术、反应机理、主要影响因素、处理效果以及反应器工艺等。同时,对该技术未来的发展趋势进行了展望,指出依托现有废水处理设施进行集约化开发将是该工艺的发展方向。     

煤矿复垦区土壤重金属分布特征与质量评价

为保证煤矿复垦区种植农作物的充填复垦土壤的生态安全,以淮南矿区煤矸石充填复垦地为研究对象,通过对研究区内Cd、Cr、Ni、Pb、Cu、Zn和Hg 7种重金属不同深度含量分析,总结其纵向分布特征,并将研究区土壤重金属含量与淮南市土壤背景值、《土壤环境质量标准》(GB 15618-1995)作比较,分析这7种重金属的污染程度.结果表明,这7种重金属都有不同程度的污染,其中土壤受Cd污染最严重,土壤中重金属垂直方向上无确定分布规律.总体而言,土壤重金属潜在生态风险属于强生态危害.从垂直方向来看,重金属潜在生态风险指数(RD随着深度的增加出现先下降后升高的趋势,其中40～60 cm深度的RI最大.重金属生态危害程度依次为Cd＞ Hg＞ Ni＞ Cu＞ Cr＞ Pb＞ Zn,其中Cd为矿区土壤中最主要的重金属污染生态风险因子.     

广东某大型城市生活垃圾焚烧厂9种重金属的迁移特征

采集广东某大型城市生活垃圾焚烧厂一期(WI-A)和二期(WI-B)的进厂垃圾、渗滤液、飞灰、底渣和烟气样品,分析了各样品中砷、镉、钴、铬、铜、汞、镍、铅、锌共9种重金属含量,研究重金属的迁移特征。结果显示,9种重金属呈现4类不同的迁移特征,钴、铜、镍、铬主要迁移至底渣中,锌、砷、铅主要迁移至底渣和飞灰中,镉主要迁移至飞灰中,汞主要迁移至飞灰和烟气中。活性炭吸附和布袋除尘器的组合对除汞以外的重金属治理效果明显。WI-A和WI-B垃圾中的汞分别约有28%、37%随烟气排到环境中。     

水培翅碱蓬对重金属吸收的研究

由于人类活动以及工业化的迅速发展,滩涂湿地正在遭受前所未有的污染和破坏,其中重金属污染是主要污染问题之一。生物修复技术是近年发展起来的新型环境污染治理方法,它在去除污染的同时还具有较高的环保价值,因此受到人们的广泛关注。以中国北方滩涂湿地的优势种植物翅碱蓬(Suaeda heteroptera kitag)为研究对象,通过测定翅碱蓬体内重金属的含量,分别探讨了翅碱蓬对单一Cu、Zn、Pb、Cd及Cu和Zn、Pb和Cd混合重金属的吸收规律、翅碱蓬不同部位对Cu的积累特性。实验结果表明,翅碱蓬对Cu、Zn、Pb、Cd的最大吸收速率分别为31、101、34、62mg/(kg.d);Cu的存在,促进了翅碱蓬对Zn的吸收,翅碱蓬各部位对Cu的积累量大小为根>茎>叶。     

重金属对活性污泥微生物毒性的比较研究

采用发光细菌毒性、活性污泥脱氢酶毒性、硝化抑制毒性3种方法测定Hg、Cd、Zn、Pb 4种重金属对活性污泥微生物的毒性,并对测定结果进行了比较.结果表明,发光细菌毒性测定方法的灵敏度最高,测得的重金属半数有效浓度(ECSO)最低,4种重金属对发光细菌发光强度的抑制程度由大到小顺序依次为Hg>Cd>Zn>Pb;活性污泥脱氢酶毒性和硝化抑制毒性的测定结果与发光细菌毒性测定结果相比,灵敏度相对较低,测得的重金属ECSO相对较高,测得的活性污泥脱氢酶活性的抑制程度由大到小顺序依次为Cd>Hg>Zn>Pb,与测得的活性污泥硝化速率抑制程度大小顺序一致.但2者测得的EC50有所差别.为了更准确的判定重金属对活性污泥微生物的毒性影响.至少应取不同的重金属毒性终点指示指标做一组毒性实验,而不能以发光细菌毒性测定结果作为唯一的判定依据,这可能会过分夸大重金属对污水处理工艺的冲击能力,导致污水处理成本无谓增加.     

层次分析法与地理信息系统在农田土壤重金属污染评价中的应用

以《土壤环境质量标准》(GB 15618—1995)二级标准作为评价标准,采用以改进层次分析法确定权重的加权平均法对南京市郊典型蔬菜地的土壤重金属污染状况进行了评价。结果表明,研究区土壤中Cu、Pb、Cr的单因子污染指数平均值均小于1,含量超标率均不超过10.32%,而Cd的单因子污染指数平均值达2.15,含量超标率为84.13%,急需对该区土壤和受体做进一步的Cd污染深入调查或风险评估;研究区土壤重金属综合污染指数平均值为1.28,属玷污水平;利用ArcGIS 8.3软件进行土壤重金属污染的空间分布特征分析结果表明,研究区各元素的污染程度为Cd>Pb>Cu>Cr,各元素的污染格局较为相似,城市化活动对土壤污染贡献较大;研究区有81.16%的土壤重金属污染级别为玷污,3.78%处于本底级,15.06%处于安全级。     

土壤小麦根系系统重金属迁移控制因子的辩识研究

相关与回归分析发现,大田条件下土壤理化性质与共存元素同小麦根系重金属含量间存在密切关系;多元与逐步回归数学模型均达到显著水平,但逐步回归分析显示对重金属迁移起主导作用的不是所选全部控制因子。非必需元素Cd、Pd主要取决于同种元素在土壤中的含量;而必需元素Cu、Zn则受同种元素在土壤中含量的影响相对较小。控制因子的辨识,无疑有利于制定合理的土壤修复及环境管理方案。     

Selective removal of heavy metals from metal-bearing wastewater in a cascade line reactor

Goal, Scope and Background This paper is a part of the research work on ‘Integrated treatment of industrial wastes towards prevention of regional water resources contamination — INTREAT’ the project. It addresses the environmental pollution problems associated with solid and liquid waste/effluents produced by sulfide ore mining and metallurgical activities in the Copper Mining and Smelting Complex Bor (RTB-BOR), Serbia. However, since the minimum solubility for the different metals usually found in the polluted water occurs at different pH values and the hydroxide precipitates are amphoteric in nature, selective removal of mixed metals could be achieved as the multiple stage precipitation. For this reason, acid mine water had to be treated in multiple stages in a continuous precipitation system-cascade line reactor. Materials and Methods All experiments were performed using synthetic metal-bearing effluent with chemical a composition similar to the effluent from open pit, Copper Mining and Smelting Complex Bor (RTB-BOR). That effluent is characterized by low pH (1.78) due to the content of sulfuric acid and heavy metals, such as Cu, Fe, Ni, Mn, Zn with concentrations of 76.680, 26.130, 0.113, 11.490, 1.020 mg/dm³, respectively. The cascade line reactor is equipped with the following components: for feeding of effluents, for injection of the precipitation agent, for pH measurements and control, and for removal of the process gases. The precipitation agent was 1M NaOH. In each of the three reactors, a changing of pH and temperature was observed. In order to verify efficiency of heavy metals removal, chemical analyses of samples taken at different pH was done using AES-ICP. Results Consumption of NaOH in reactors was 370 cm³, 40 cm³ and 80 cm³, respectively. Total time of the experiment was 4 h including feeding of the first reactor. The time necessary to achieve the defined pH value was 25 min for the first reactor and 13 min for both second and third reactors. Taking into account the complete process in the cascade line reactor, the difference between maximum and minimum temperature was as low as 6°C. The quantity of solid residue in reactors respectively was 0.62 g, 2.05 g and 3.91 g. In the case of copper, minimum achieved concentration was 0.62 mg/dm³ at pH = 10.4. At pH = 4.50 content of iron has rapidly decreased to < 0.1 mg/dm³ and maintained constant at all higher pH values. That means that precipitation has already ended at pH=4.5 and maximum efficiency of iron removal was 99.53%. The concentration of manganese was minimum at pH value of 11.0. Minimum obtained concentration of Zn was 2.18 mg/dm³ at a pH value of 11. If pH value is higher than 11, Zn can be re-dissolved. The maximum efficiency of Ni removal reached 76.30% at a pH value of 10.4. Discussion Obtained results show that efficiency of copper, iron and manganese removal is very satisfactory (higher than 90%). The obtained efficiency of Zn and Ni removal is lower (72.30% and 76.31%, respectively). The treated effluent met discharge water standard according to The Council Directive 76/464/EEC on pollution caused by certain dangerous substances into the aquatic environment of the Community. Maximum changing of temperature during the whole process was 6°C. Conclusion This technology, which was based on inducing chemical precipitation of heavy metals is viable for selective removal of heavy metals from metal-bearing effluents in three reactor systems in a cascade line. Recommendations and Perspectives The worldwide increasing concern for the environment and guidelines regarding effluent discharge make their treatment necessary for safe discharge in water receivers. In the case where the effluents contain valuable metals, there is also an additional economic interest to recover these metals and to recycle them as secondary raw materials in different production routes. ESS-Submission Editor: PhD Hailong Wang, hailong.wang@ensisjv.com     

固体废物中重金属浸出毒性评价方法的研究进展

浸出毒性是固体废物的重要特性之一,亦是判别固体废物是否属于危险废物的重要评价指标.根据与溶液接触方式的不同,固体废物浸出毒性评价方法可以划分为批处理实验、柱淋滤实验和恒pH滴定(pH-stat)实验等.对这3种方法的应用方向、特点和缺陷等进行了系统总结.最后还指出,在评价固体废物中重金属的浸出毒性时,可采用几种方法进行对比,还可以根据实验目的和需求对各个实验参数进行改进,从而得出更全面、客观的评价结果.     

土壤重金属的植物污染化学研究进展

针对中国土壤重金属污染加剧的趋势,为改善土壤环境质量和保障农产品安全,提出了土壤重金属的植物污染化学研究领域.结合多年的研究工作,从土壤重金属的植物根际化学行为、土壤重金属的植物吸收与解毒机制和重金属污染土壤的植物-微生物交互作用等方面简要阐述了土壤-植物系统中重金属的分布、存在形态、迁移转化、累积及生物学效应和控制规律的研究进展,并对将来的植物污染化学理论研究提出了展望.     

盐城市不同功能区地表灰尘重金属污染特征及评价

为了解盐城市不同功能区地表灰尘中重金属污染特征,以工业区、交通区、居民区、商业区、学校区、公园区的地表灰尘作为研究对象,分析地表灰尘中重金属的含量分布及氮磷、有机质的含量变化,并以此为基础,对重金属的生态风险进行评价,探索重金属污染的成因与来源,为城市的地表灰尘污染防治提供理论依据。结果表明:(1)工业区地表灰尘中总氮、总磷最低;公园区和学校区地表灰尘中总氮最高,分别达到2.03、2.43g/kg,公园区地表灰尘中总磷最高,达到1.59g/kg。(2)地表灰尘中有机质呈现出和总氮、总磷一致的趋势,同样是工业区地表灰尘中有机质最低,公园区地表灰尘中有机质最高(34.0g/kg)。(3)地表灰尘中重金属和总氮、总磷、有机质总体呈现负相关关系,公园区地表灰尘中重金属最低,工业区地表灰尘中重金属最高。各个功能区地表灰尘中重金属全部高于土壤背景值。(4)地表灰尘中不同重金属元素的单因子污染指数依次为CdCuPb;不同功能区地表灰尘中重金属综合污染指数依次为工业区交通区居民区学校区商业区公园区,呈中污染(除公园区、商业区呈轻污染外)。     

垃圾焚烧飞灰有毒重金属固化稳定技术研究综述

采用焚烧法处理生活垃圾正呈快速增长的趋势,焚烧过程产生的飞灰中所含有的大量有毒重金属对自然环境和人类生存都造成极大影响。阐述了目前常用的几种固化稳定垃圾焚烧飞灰有毒重金属的方法,综合分析了其固化特点和优缺点,并初步探索了一种低能耗环境下实现高温熔融处置技术的有效途径,从而为垃圾焚烧飞灰高温固化稳定有毒重金属的实施提供一定的理论基础和技术支持。     

氧化亚铁硫杆菌对电子垃圾焚烧迹地重金属形态的影响

采用生物淋滤法处理电子垃圾焚烧迹地重金属严重污染的土壤。所用氧化亚铁硫杆菌是从矿坑废水中通过一系列培养、分离和纯化得到。实验结果表明,生物淋滤法可以有效地去除土壤中重金属Cu、Ph和Zn,去除率的大小顺序为Zn〉Cu〉Pb;采用五步连续提取法分析处理前后土壤中重金属的存在形态,结果表明,通过氧化亚铁硫杆菌处理受重金属污染的土壤,可以促使易移动的重金属结合态的溶解（可交换态、碳酸盐结合态和Fe—Mn氧化物结合态）,并使难移动的重金属结合态向易移动的重金属结合态转变。     

可渗透反应复合电极法对土壤重金属的电动去除

将零价铁(Fe0)、沸石等活性材料附着在电极上形成可渗透反应层并构成可渗透反应复合电极,采用不同的复合电极对Cd2+、Ni 2+、Pb2+和Cu2+等4种阳离子型重金属污染土壤进行了电动力学修复。研究了不同可渗透反应复合电极对土壤pH的控制效果以及对重金属的去除作用,分析了迁移到复合电极中的重金属形态变化。结果表明,复合电极中添加酸、碱性沸石并适时更换,可有效中和、截留阴阳极电解产生的OH-和H+,避免或减缓土壤酸碱迁移带的形成,防止重金属离子的过早沉淀及土壤过度酸化,极大提高了重金属的去除率。复合电极中Fe0可将迁移进来的重金属离子进行还原稳定,实现重金属污染物的捕获与固定,与迁移到沸石复合电极中的4种重金属不稳定态相比,"Fe0+沸石"复合电极中重金属不稳定态分别下降了61.4、60.5、61.4、57.1百分点。结果还显示,阴极采用"Fe0+沸石"复合电极并适时进行更换,施加1.5V/cm的直流电压修复10d后,土壤中Cd、Ni、Pb、Cu的总去除率分别为44.5%、41.5%、33.5%和36.7%,且进一步延长修复时间和持续更换电极可获得更为理想的修复效果。     

Speciation of heavy metals in estuarine sediments in the northeast of Brazil

An analytical procedure involving a three-step sequential extraction was used to determine the chemical association of heavy metals (Zn, Cr, Mn and Fe) with the major phases (exchangable, reducible and oxidizable) in samples from a fishpond of estuarine sediments. The pond is located in the Capibaribe River estuary, within the boundaries of the city of Recife, in the State of Pernambuco in the northeast of Brazil. The total metal content was determined as well. All metals were extracted from the residual fraction at a percentage greater than 50%.     

不同湿地植物凋落物对汞铊矿废弃物浸出酸性废水中重金属的吸附研究

研究了不同湿地植物(稻草(Oryza sativa L.)、风车草(Cyperus involucratus Rottb.)、芦竹(Arundo donax L.)、美人蕉(Canna indica L.)、水葱(Scirpus validus Vahl.)、香蒲(Typha orientalis C.Presl)和鸢...     

柠檬酸浸出土壤中铜、锌的优化设计

以某工业废弃地土壤为供试材料,采用批次实验方法,研究了柠檬酸对重金属Cu、Zn的浸出效果。并在单因素实验基础上,探讨不同pH值、柠檬酸浓度、固液比和浸提时间等对浸出效果的影响,进而对实验条件进行正交优化组合,确定优化工艺参数为：pH值为3.2,柠檬酸浓度为0.4 mol/L,壤土固液比为1/10,土壤中Cu、Zn接近平衡的时间分别为1 h和1.5 h。结果表明,在此条件下,对这2种金属来说,Cu较Zn易释放,Cu、Zn的最大浸出率分别为74.8%和65.3%。柠檬酸浸提前后,土壤中有机质含量下降范围为0.61%~3.16%。单从土壤有机质含量来看,柠檬酸对土壤质量影响较小,具有较好的应用前景。     

渤海南部表层沉积物重金属污染及潜在生态风险评价

利用电感耦合等离子体/质谱仪(ICP/MS)测定了渤海南部21个站位表层沉积物中Cr、Cu、Zn、Cd和Pb共5种重金属浓度,比较分析了重金属来源及分布特征,同时应用Hakanson潜在生态危害指数法进行潜在生态风险评价.结果表明,调查区域沉积物中Cr、Cu、Zn、Cd、Pb的平均质量浓度分别为43.67、17.27、...