Spatial and Temporal Distribution of Dust‐Bound Trace Metal Elements around Kuhdasht Watershed Area in Iran

Dust, as a source of trace metal elements, affects the health of society. The spatial and temporal concentrations of dust‐bound trace metals (Cd, Pb, Ni, Zn, Cu, and Mn) in Kuhdasht watershed (456 km²), Lorestan Province, Iran, is investigated. Dust is collected using glass traps placed in ten research stations in the region. The spatial and temporal distribution of dust trace metals are plotted using ARC‐GIS. The highest and the lowest concentrations of Zn (9751150 mg kg^?1), Pb (46.352.9 mg kg^?1), and Cd (2.443.30 mg kg^?1) are obtained in winter, of Ni (98110 mg kg^?1) and Cu in autumn (16.053.5 mg kg^?1), and of Mn in summer (385505 mg kg^?1). The spatial concentrations of dust‐bound trace metals indicate all, except Cu, show a decreasing trend from the mountains toward the plains, similar to that of soil and of dust, except for Zn, which shows higher concentrations in dust than in soil. The potential sources of dust‐bound trace metals and their rate of contamination are also investigated using the enrichment and contamination factors. The major sources of Cd and Zn in the dust of watershed are due to anthropogenic activities or from activities outside the borders.     

Natural and Enhanced Concentrations of Trace Metals in Sediments of Cleveland Bay, Great Barrier Reef Lagoon, Australia

Natural variation in concentrations of Cd, Co, Cu, Ni, Pb, and Zn in sediments of Cleveland Bay can be modelled by linear regression by using the concentration of Al recovered by strong acid digestion as an independent variable. Samples that exceed the upper 95% prediction interval of regression models are classified as enhanced. Enhancement of trace metals occurs in the intertidal zone and near-shore sediments of western Cleveland Bay, in sites that are characterized by high accumulation rates of fine grained terrigenous sediment. There is a strong positive relationship between increasing enhancement of Cu and Pb and the recovery of these metals by weak HCl digestion, which suggests that for these metals the modelled enhancement is environmentally meaningful. In contrast, at least 60%, and generally greater than 80% of Cd is recovered by weak HCl digestion irrespective of modelled enhancement, and suggests that the statistically modelled enhancement of Cd may be more meaningful than weak HCl soluble concentrations.     

Assessment of heavy metal contamination in the surficial sediments from the lower Meghna River estuary,Noakhali coast,Bangladesh

Sediment samples were collected from ten selected sites of the lower Meghna River estuary,and six heavy metals were analyzed with Atomic Absorption Spectrophotometry(AAS)to assess the contamination level and the metals’association with sediment grain size.The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron(Fe)(1.29×103 mg/kg)>zinc(Zn)(42.41 mg/kg)>lead(Pb)(12.48 mg/kg)>chromium(Cr)(10.59 mg/kg)>copper(Cu)(6.22 mg/kg)>cadmium(Cd)(0.28 mg/kg).The geo-accumulation,contamination,and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe,Zn,Pb,Cr,and Cu.The mean size of the sediment ranged from 28.92 to 126.2 mm,and the Pearson correlation coefficient showed a significant association between Fe and Pb(coefficient of determination,r2=0.836;p<0.05),and no significant correlation was found between individual metals and grain size,indicating no or low influence on the metals distribution.     

Ecological risk assessment of trace metal accumulation in sediments of Veraval Harbor,Gujarat, Arabian Sea

In this study, different types of indices were used to assess the ecological risk of trace metal contamination in sediments on the basis of sediment quality guidelines at Veraval Fishery Harbor. Sediment samples were collected from three sectors in pre-, post-, and monsoon seasons in 2006. Trace metal concentrations were higher in the inner sector during post-monsoon, and it showed the highest statistical significance (p < 0.01) among the stations. Pollution load index was higher than unity, indicating alternation by effluent discharge from industries. Enrichment factor and geo-accumulation index showed that Cd, Pb, and Zn were enriched in the northern part of the harbor and Pb had accumulated in the harbor sediment. The ecological risk assessment index revealed that Ni, Zn, and Pb were higher than the effect range median values, indicating their potential toxicity to the aquatic environment in the Veraval Harbor. Hence, the harbor is dominated by anthropogenic activities rather than natural process.     

Cytological and Physiological Biomarker Responses from Green Mussels, Perna viridis (L.) Transplanted to Contaminated Sites in Hong Kong Coastal Waters

Biological monitoring of marine contaminants often involves the analysis of metals accumulated in mussel tissues. Critiques of this type of monitoring suggest that although relatively good indications of ambient metal concentrations are determined, actual biological harm is not elucidated. Biomarkers, techniques originally developed in medicine, have recently been employed in an attempt to ascertain the health of marine mussels. Biomarkers have been used with good effect in temperate marine pollution monitoring programmes. The use of biomarkers in the toxicological evaluation of tropical and subtropical waters is, however, generally lacking, which is somewhat surprising, as considerable industrialisation and environmental degradation is taking place in the Pacific-rim countries of Southeast Asia. In the present study, a suite of cytological and physiological biomarkers have been measured from mussels (Perna viridis: Mytilidae) transplanted within the coastal waters of Hong Kong. Mussels from contaminated sites, had labile lysosomal membranes, whereas animals from a cleaner reference site had more stable membranes. These cytological responses have been related to metal-induced stress and are simple, cost-effective markers of pollution. Cardiac activity from mussels transplanted to polluted sites was generally similar to that of individuals from the reference site, although a mild tachycardia was associated with one site. The cause of the tachycardia and the use of heart rate in mussels as a biomarker is discussed. Integrated physiological responses to stress, condition indices, revealed mussels from a clean reference site had higher indices than animals from contaminated sites. The relative sensitivities of the cytological and physiological biomarkers deployed in this study and their application to pollution monitoring is discussed.     

Relationships between magnetic susceptibility and heavy metals in urban topsoils in the arid region of Isfahan, central Iran

Electromagnetic induction (EMI) method results are shown for vertical magnetic dipole (VMD) configuration by using the EM38 equipment. Performance in the location of metallic pipes and electrical cables is compared as a function of instrumental drift correction by linear and quadratic adjusting under controlled conditions. Metallic pipes and electrical cables are buried at the IAG/USP shallow geophysical test site in São Paulo City, Brazil. Results show that apparent electrical conductivity and magnetic susceptibility data were affected by ambient temperature variation. In order to obtain better contrast between background and metallic targets it was necessary to correct the drift. This correction was accomplished by using linear and quadratic relation between conductivity/susceptibility and temperature intending comparative studies. The correction of temperature drift by using a quadratic relation was effective, showing that all metallic targets were located as well deeper targets were also improved.     

西藏羊卓雍错流域水体水质评价及主要污染因子

水质是流域生态系统的重要指标,水质评价则是开展流域水体污染防治等工作的基础.基于2010-2014年羊卓雍错流域湖泊、河流水质及2012-2014年流域居民饮用井水、自来水水质监测资料,结合单因子污染评价法和内梅罗污染指数法,对流域水质现状进行分析和评价.结果表明,12处地表水体中,羊卓雍错和巴纠错受中度污染,其他水体清洁或尚清洁,硒及氟化物为主要污染因子;9处居民饮用水体中,自来水水质明显好于井水,但也仅有3处自来水达清洁标准,硒、铝及硝酸盐为主要超标项.污染因子通过水-土-植被-动物系统破坏流域生态环境、阻碍农业生产发展,并直接或间接影响人类身体健康.因此,必须做好流域环境的综合整治、控制农业面源污染、完善饮用水基础设施建设,同时继续加强水质监测.     

太湖近代沉积物中重金属元素的累积

利用210Pb、137Cs定年技术,对来自太湖不同生态和沉积特征的三个湖区的沉积物柱状样品进行了定年,用ICP—AES分析了沉积物中重金属等元素的含量,分析了太湖沉积物中重金属的累积特征及其成因.污染较重、蓝藻水华暴发频繁的梅梁湾沉积物中的重金属含量在近25年来逐年增加;太湖上游风浪较大的夹浦湖区表层10cm沉积速率大、粒度粗,除表层1cm外,1—10cm沉积物中各种重金属含量都较低,且层间变化剧烈;下游湖区正逐渐草型化的胥口湾除表层3cm外,沉积物中重金属的含量自底层向表层大致呈不断下降的趋势.研究表明,不同年代的太湖沉积物中重金属含量差异很大,明显大于不同湖区间沉积物重金属平均含量间的差异.水动力作用引起的沉积物粒度分异很可能是影响沉积物中重金属积累的一个重要因素.总体上太湖沉积物中重金属的污染比较轻微,但已经有一定程度的Cd污染,梅梁湾沉积物中自上世纪70年代开始明显积累Cd,其他重金属元素的积累也逐渐增加,值得关注.     

太湖宜溧河水系沉积物的重金属污染特征

用ICP方法分析了太湖宜溧河水系沉积物中主要重金属含量,以太湖宜溧河口下层沉积物作背景样品,用均根法对沉积物中重金属进行了污染综合指数计算,并根据划分的污染等级对宜溧河水系沉积物污染状况进行了分析和评价。结果表明：宜溧河及其入湖口沉积物平均呈轻污染状态,北部支流未受污染,南部支流和太湖沿岸呈轻污染,干流河段污染最为严重,呈偏中度污染水平,在个别测点综合评价已达到重度污染状态。全水系Cu,Zn,Cd和Pb的污染指数略高。其中仅有Cd含量高出我国土壤一级自然背景值,表现为Cd污染型,其原因能与该地区水泥制造业和有色金属冶炼的污染排放有关。     

Characterization and Application of Dried Plants to Remove Heavy Metals,Nitrate, and Phosphate Ions from Industrial Wastewaters

Low cost adsorbents were prepared from dried plants for the removal of heavy metals, nitrate, and phosphate ions from industrial wastewaters. The efficiency of these adsorbents was investigated using batch adsorption technique at room temperature. The dried plant particles were characterized by N₂ at 77 K adsorption, scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, and phytochemical screening. The adsorption experiments showed that the microparticles of the dried plants presented a good adsorption of heavy metals, phosphate, and nitrate ions from real wastewaters. This adsorption increased with increasing contact time. The equilibrium time was found to be 30 min for heavy metals and nitrate ions and 240 min for phosphate ions. After the adsorption process, the Pb(II) concentrations, as well as those of Cd(II), Cu(II), and Zn(II) were below the European drinking water norms concentrations. The percentage removal of heavy metals, nitrates, and phosphates from industrial wastewaters by dried plants was ～94% for Cd²⁺, ～92% for Cu²⁺, ～99% for Pb²⁺, ～97% for Zn²⁺, ～100% for ${\rm NO}_{{\rm 3}}^{{-} } $ and ～77% for ${\rm PO}_{{\rm 4}}^{3{-} } $ ions. It is proved that dried plants can be one alternative source for low cost absorbents to remove heavy metals, nitrate, and phosphate ions from municipal and industrial wastewaters.     

Distribution and fate of metals in the Montenegrin part of Lake Skadar

Skadar Lake,the largest lake on the Balkan Peninsula,is famous for a wide range of endemic and rare,or even endangered plant and animal species.Different anthropogenic pressures have,however,influenced the fragile equilibria of the lake ecosystem,with metal pollution as one of the primary concerns.Therefore,this study investigated spatial distribution of metal pollutants in the water and sediment phase of Skadar Lake,and anthropogenic and environmental factors affecting this distribution.A sieving analysis showed that sediment in Skadar Lake is mainly distributed in the three smallest fractions（colloid,clay and silt）.Eleven metals were analyzed in the lake surface and bottom water,and only six of them were detected：potassium,magnesium,calcium,nickel,aluminum and manganese.They were all present at low concentrations.In contrast,sediments contained elevated levels of some metals with concentrations between 28.1-126.8 mg kg~（-1） for Ni,23.6-79.2 mg kg~（-1） for Cr,9.2-36.9 mg kg~（-1） for Cu,199-878 mg kg~（-1） for Mn and 9.6-23.1 g kg~（-1） for Fe.Nickel exceeded consensus-based guidelines for safety towards freshwater dwelling organisms.The organic matter content of the sediment fluctuated between 4.7 and 21.5%.No correlations were found between metal concentrations,organic matter and sediment particle size fractions,suggesting that the latter are not the main factors controlling metal accumulation in Skadar Lake.     

Correlation assessment and monitoring of the potential pollutants in the surface sediments of Pyeongchang River, Korea

The study provides a baseline for the assessment of the organic and inorganic pollution specially, heavy metal contamination in the surface sediments of Pyeongchang River,South Korea.The assessment of the study areas was done with respect to metal pollution load,ecological risk and geoaccumulated risk.Based upon the used indices,a priority index(P_index) was used to rank the utmost contaminated sites.Though the concentrations of mercury in all sediments were below the guideline, the significant enriched contamination was observed by all applied indices.As expected,the values of pollution load index（PLI）,ecological risk index（RI） and geoaccumulation risk index(I_geo) demonstrated lower heavy metal contamination in upstream areas compared to the downstream. Admittedly,sediments were unpolluted to slightly-polluted according to PLI while high to extremely high ecological risks were observed in several sediment samples.Furthermore,all the samples were uncontaminated as per I_geo.After simplification of I_geo,the P_index,showed the utmost contaminated sediments with a value of 2.537.Notably,protective measures should be taken to the highly contaminated areas which are prioritized by P_index Admittedly,the maximum concentrations of total organic carbon,total nitrogen,inorganic nitrogen,total phosphorous,inorganic phosphorous,calcium, magnesium,sodium and potassium were significantly observed as 7.8×10⁴,3,185,36,1,032,3.7, 1,5163,2,881,669 and 4,076mg/kg accordingly.