Use of NDVI dataset for a GIS based analysis: A sample study of TAR Creek superfund site

Tar Creek is an Environmental Protection Agency (EPA) designated superfund site in Ottawa County, Oklahoma that is heavily polluted with acid mine drainage (AMD) and pollutant deposits in the form of mine tailings (chat piles). Among several residual heavy metal contaminants, zinc and lead are most prevalent in these chat piles. Approximately 50 million cubic yards or 75 million tons of chat remained in Ottawa County as a result of excessive mining in early 1900's to 1960's. This chat is in addition to the pollution that is leached from open mine shafts that drain contaminants into the groundwater, some of which flows directly into streams and creeks. This paper discusses a methodology for incorporating satellite data (MODIS NDVI) within a GIS framework to perform time series analysis in areas near Tar Creek. GIS functions in Map Algebra and Zonal Statistics were implemented to study changes in spectral reflectance due to vegetation at two locations. One of the locations is a sample plot where remedial action consisted of cleaning up of the chat pile and growing native grass. The second location is along Tar Creek and Elm Creek. The paper describes one of the methods that can be used to combine remotely sensed imagery data and spatial feature data within the GIS framework. The main advantages of combining the two datasets using the described process is that, powerful geoprocessing functions within GIS can be easily applied to remote sensing data and the analysis of vector and raster data can be performed in unison.     

Physical Evidence on the Origin and Fate of the Panhandle Aspect People

Abstract

Comparison of the populations of four Panhandle Aspect sites (Alibates, Antelope Creek, Matthews Ranch, Footprint) using 28 non-metric traits of the skulls indicates generally close similarity among them, but the Panhandle groups show little similarity to Upper Republican. Antelope Creek and Matthews Ranch show some resemblance to the Fort Coffee skulls of the Fulton Aspect. The same two Panhandle site samples also resemble the Washita River people. Footpnnt is even more similar to Washita River.     

The accumulation characteristics and potential health risks of heavy metals in vegetables from reclaimed area of China

The reclamation of subsidence area was regarded as a useful pathway to rebuild landscape and ecosystem. However, the elevated concentrations of heavy metals in the reclaimed area may lead to potential environmental and health risks. This study was aimed at investigating the accumulation of heavy metals in the soils and vegetables, and evaluate the potential health risks to human beings via consuming these vegetables. The concentrations of heavy metals (Cd, Cu, Pb, and Zn) were measured by using inductively coupled plasma mass spectrometry. The elevated concentrations of heavy metals were found in the soil from the reclaimed area when compared with the background value. The concentrations of heavy metals were various among the different vegetable species. The heavy metal tolerance could be found in all the selected vegetables. The elevated concentrations of Cu, Pb, and Zn in the edible part of the selected vegetables indicated that the consumption of these vegetables may lead to potential health risk. The intake of soybean, radish, sweet potato, and mugwort may lead to potential health risks due to the elevated target health quotients. Chinese cabbage and pepper were regarded as the suitable vegetables which may help in reducing the potential health risk.     

Remediation of Contaminated Sediments: A Comparative Analysis of Risks to Residents vs. Remedial Workers

This study weighs the risks to workers of cleaning up a Superfund site against the risks to residents of not cleaning up that site. Risks are measured by the number of deaths and disabilities due to injuries and diseases. We posit a cleanup plan involving 31 occupations and 4,581 person-years of work. We posit 20 hypothetical sites and 99 specific sites with varying numbers of residents and levels of cancer death and cancer disability rates. Depending on the number of residents, and the rates, we find that the risks to workers frequently outweigh the risks to residents. We conclude that risks to workers should be accounted for in EPA judgments regarding whether and how a Superfund site should be cleaned up.     

有机物和重金属复合污染水体的修复植物筛选及修复性能

通过植物的采集、培育和选种,获得了海芋、合果芋、蜘蛛兰和密穗砖子苗等4种同时具备去碳、脱氮、除磷和积累重金属的高效修复植物,并对这些植物修复污染水体的性能进行了研究.结果表明,这4种植物均能有效地处理有机物和重金属复合污染水体.鲜重55-60g的植物,处理10LBOD₅、COD_Cr、TP、TN、Cu²⁺和Cr⁶⁺浓度分别为140、280、6,8、40、10和10mg·L^-1的模拟水样14d后,上述指标的去除率分别高达80%、72%、64%、53%、75%和68%以上,植物的促进作用分别为32%、27%、27%、28%、37%和19%以上.处理后水样的pH和DO分别为6.63～7.63和3.02～3.84mg·L^-1.     

Tubular sites of action of heavy metals, and the nature of their inhibition of amino acid reabsorption

Functional lesions after exposure to heavy metals are reviewed in relation to renal amino acid transport. Such effects may vary from metal to metal but they do not appear to represent general cytotoxicity. In agreement with the conclusion that the rate- and specificity-determining step in amino acid reabsorption is located at the brush border, metals exert their primary effect at that site. The inhibition kinetics resemble those seen with uncompetitive inhibitors but the precise nature of the interaction between metals and carriers remains to be clarified. Peritubular transport of dicarboxylic amino acids is also sensitive to metals, but this action does not influence reabsorption of these acids.     

Hormetic Effects of Heavy Metals in Aquatic Snails: Is a Little Bit of Pollution Good?

Hormesis is the term to describe a stimulatory effects associated with a low dose of a potentially toxic substance or stress. We had anecdotal evidence of hormetic effects in some of our previous experiments concerning the influence of heavy metals on aquatic snail growth and recruitment. We therefore repeated a version of an earlier experiment but this time we expanded our low-dose treatments and increased our sample size. We also explored if metals had a hormetic effect on algae periphyton. We raised snails in outdoor mini-ecosystems containing lead, zinc, and cadmium-contaminated soil from an Environmental Protection Agency Superfund site in the Silver Valley of northern Idaho. The snails came from two sites. One population (Physella columbiana) has evolved for 120 years in the presence of heavy metals and one (Lymnaea palustris) has not. We found that P. columbiana exhibited hormesis with snails exposed to small amounts of metals exhibiting more reproduction and growth than snails not exposed to metals. Naturally occurring Oscillatoria algae also exhibited a hormetic effect of heavy metals but L. palustris did not display hormesis. Large doses negatively impacted all three species. Overall the levels of cadmium, lead, and zinc measured in the tissues of the snails were inversely correlated to the number of snails recruited into the tub populations. Only in comparisons of the lowest metal treatment to the control treatment is a positive effect detected. Indirect effects on competing species of snails, periphyton, and also fishermen, may be less favorable.     

EDTA-Enhanced Phytoremediation of Heavy Metals: A Review

The increase in heavy metal terrestrial ecosystems’ contamination through anthropogenic activities is a widespread and serious global problem due to their various environmental and human implications. For these reasons, several techniques, including phytoremediation of heavy metals, have been extensively studied. In spite of significant recent advancement, ethylene diamine tetraacetic acid (EDTA)-enhanced heavy metal phytoextraction as well as related ecological risks are still topical and remain an important area of research. In fact, EDTA favors the solubilization of metals and metalloids in soils, and was therefore extensively studied during the last two decades in order to improve phytoextraction efficiency and reduce treatment duration. This review highlights the recent findings (2010–2012) and mechanisms behind EDTA-enhanced (1) solubilization of heavy metals in soil, (2) mobilization/transport of soluble metals towards plant root zone, and (3) metal absorption by plant roots and translocation towards aerial parts. The review also presents potential risks associated with EDTA-enhanced phytoextraction: (1) environmental persistence of EDTA and/or metal-EDTA complex; (2) potential toxicity of EDTA and/or metal-EDTA complex to plants; and (3) leaching and contamination of groundwater. Moreover, field-scale cost of EDTA-enhanced remediation and the role of EDTA in time required for heavy metal remediation is discussed.     

厦门杏林湾表层沉积物重金属污染特征及潜在生态风险评价

论文对杏林湾表层沉积物重金属、有机碳和硫化物含量进行了检测,对数据作了相关性分析和因子分析,并应用潜在生态危害指数法对重金属的潜在生态风险进行了评价。结果表明:重金属之间有显著的相关性,Cu与Ni、Pb与Ni、Pb与Cr以及Cr与Hg之间的相关系数分别为0.786(P﹤0.05)、0.783(P﹤0.05)、0.937(P﹤0.01)和0.770(P﹤0.05)。重金属与有机碳及硫化物的相关性较差,表明该地区重金属污染来源与硫化物和有机碳并不相同。既有人为输入,又有自然的沉积过程。因子分析进一步解释了该水域重金属污染的主要来源。根据E_rⁱ均值大小,Hg的危害风险最大,Cr最小。6种重金属潜在生物毒性风险大小依次为:Hg > Pb > Cu > Cd > Ni > Cr。重金属的生态危害程度均较小,尚属轻微生态危害。     

天山土壤微量(类)重金属的来源解析及潜在生态危害评估

从天山山地3个区段(巴里坤-伊吾、乌鲁木齐-阿克苏、昭苏-特克斯)采集土壤样品,测定了其中(类)重金属Pb、Ni、Cd、Co、Hg、Cu、Mn、Zn、Cr和As的含量.运用经典统计学与多元统计方法分析了这些(类)重金属的来源;同时采用污染指数法与潜在生态风险指数法,并结合天山及新疆土壤背景值、国家土壤质量标准开展了区域土壤微量(类)重金属生态风险的评价.结果表明： 所测10种(类)重金属的平均含量均高于天山或新疆土壤背景值.从变异系数来看,均为中等变异.总体上看,天山山地土壤中10种(类)重金属的含量均较低;主成分分析显示,10种元素可以辨识出 2 个主成分,主成分1(PC1,包括Cd、Pb、Hg、Mn和Zn)为人为源因子,主成分2(PC2,包括Cu、Ni、Cr、Co和As)为自然源因子.Mn 和As在PC1和PC2上均有较大载荷,主要受人为源和自然地质背景的共同控制;污染评价表明, 重金属Hg、Cd在天山中部的乌鲁木齐-阿克苏区段、As在天山西部的昭苏-特克斯区段的单因子污染指数(P_i)属于警戒等级,其他均属于安全等级和清洁水平.从综合污染(P_z)指数来看,天山中部乌鲁木齐 阿克苏区段土壤中10种(类)重金属元素的综合污染程度均属于轻度污染,其他两个区段均属于清洁水平;生态风险评估表明,重金属Hg、Cd在天山中部乌鲁木齐 阿克苏区段,As在天山西部昭苏 特克斯区段的潜在生态风险系数(E_i^r)和生态危害指数(RI)相对较高.     

Heavy metal sorption by microalgae

Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 1) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical.     

Review: Nutritional ecology of heavy metals

The aim of this review is to focus the attention on the nutrition ecology of the heavy metals and on the major criticisms related to the heavy metals content in animal feeds, manure, soil and animal-origin products. Heavy metals are metallic elements that have a high density that have progressively accumulated in the food chain with negative effects for human health. Some metals are essential (Fe, I, Co, Zn, Cu, Mn, Mo, Se) to maintain various physiological functions and are usually added as nutritional additives in animal feed. Other metals (As, Cd, F, Pb, Hg) have no established biological functions and are considered as contaminants/undesirable substances. The European Union adopted several measures in order to control their presence in the environment, as a result of human activities such as: farming, industry or food processing and storage contamination. The control of the animal input could be an effective strategy to reduce human health risks related to the consumption of animal-origin products and the environmental pollution by manure. Different management of raw materials and feed, animal species as well as different legal limits can influence the spread of heavy metals. To set up effective strategies against heavy metals the complex interrelationships in rural processes, the widely variability of farming practices, the soil and climatic conditions must be considered. Innovative and sustainable approaches have discussed for the heavy metal nutrition ecology to control the environmental pollution from livestock-related activities.     

Spatial Distribution and Uncertainty Assessment of Potential Ecological Risks of Heavy Metals in Soil Using Sequential Gaussian Simulation

The objective of this study is to assess the spatial distribution and uncertainty of the potential ecological risks of heavy metals in soil using sequential Gaussian simulation (SGS) and the Hakanson potential ecological risk index (PERI). We collected 130 soil samples in an area of 150 km² in the High-Tech Park of Wuhan, China, and measured the concentrations of five heavy metals in soil (i.e., Cd, Cr, Cu, Pb, and Zn). We then simulated the spatial distribution of each heavy metal using SGS, and calculated Hakanson PERIs for individual metals and multiple metals based on the simulated realizations. The spatial uncertainty of the Cd PERI and its occurrence probabilities in different risk grades were further assessed. Results show that the potential ecological risks of Cr, Cu, Pb, and Zn are relatively low in the study area, but Cd indeed reaches a serious level that deserves much attention and essential treatment. The total PERI of multiple heavy metals indicates a moderate grade in most of the study area. In general, combining SGS and the Hakanson PERI appears to be an effective method for evaluating the potential ecological risks of heavy metals in soil and the priority areas for remediation.     

Bioaccumulation of metal cations by Saccharomyces cerevisiae

Yeast cells are capable of accumulation of various heavy metals, preferentially accumulating those of potential toxicity and also those of value. They retain their ability to accumulate heavy metals under a wide range of ambient conditions. In the present study it was shown that yeast cells in suspension accumulate heavy metal cations such as Cu²⁺, Co²⁺. The level of copper accumulation was dependent on the ambient metal concentration and was markedly inhibited by extremes of ambient pH. Temperature (5–40°C) and the presence of the alkali metal sodium had much smaller effects on the level of copper accumulation. This suggests that in waste-waters of pH 5.0–9.0, yeast biomass could provide an effective bioaccumlator for removal and/or recovery of the metal. During bioaccumulation and subsequent processes it is necessary to retain the biomass. It was shown in the present study that this could be achieved by cell immobilization. Immobilization allowed for complete removal of Cu²⁺, Co²⁺, and Cd²⁺ from synthetic metal solutions. The immobilized material could be freed of metals by use of the chelating agent ethylenediamine tetraacetic acid (EDTA) and recycled for further bioaccumulation events with little loss of accumulation capacity.Correspondence to: J. R. Duncan     

Bioaccumulation and translocation of heavy metals by nine native plant species grown at a sewage sludge dump site

In the present study, nine native plant species were collected to determine their potential to clean up nine heavy metals from soil of a sewage sludge dump site. Almost all nine plant species grown at sewage sludge dump site showed multifold higher concentrations of heavy metals as compared to plants grown at the reference site. All the investigated species were characterized by a bioaccumulation factor (BF) > 1.0 for some heavy metals. BF was generally higher for Cd, followed by Pb, Co, Cr, Cu, Ni, Mn, Zn, and Fe. The translocation factor (TF) varied among plant species, and among heavy metals. For most studied heavy metals, TFs were <1.0. The present study proved that the concentrations of all heavy metals (except Cd, Co, and Pb) in most studied species were positively correlated with those in soil. Such correlations indicate that these species reflect the cumulative effects of environmental pollution from soil, and thereby suggesting their potential use in the biomonitoring of most heavy metals examined. In conclusion, all tissues of nine plant species could act as bioindicators, biomonitors, and remediates of most examined heavy metals. Moreover, Bassia indica, Solanum nigrum, and Pluchea dioscoridis are considered hyperaccumulators of Fe; Amaranthus viridis and Bassia indica are considered hyperaccumulators of Pb; and Portulaca oleracea is considered hyperaccumulator of Mn.     

Rhamnolipid biosurfactant-enhanced soil flushing for the removal of arsenic and heavy metals from mine tailings

Mine tailings containing high contents of arsenic and heavy metals are potential environmental contamination sources. Column experiments were conducted in this study to evaluate the feasibility of using a rhamnolipid biosurfactant (JBR425) to enhance the removal of arsenic and heavy metals from an oxidized mine tailings sample collected from Bathurst, Canada. Capillary electrophoresis (CE) analyses indicated that arsenate [As(V)] was the only extractable arsenic species in the mine tailings. The addition of rhamnolipids did not change the oxidation state of arsenic. It was found that a 0.1% rhamnolipid solution (initial pH adjusted to 11) could significantly enhance the removal of arsenic and heavy metals (i.e., Cu, Pb and Zn) simultaneously. The accumulative removal of arsenic, Cu, Pb and Zn reached 148, 74, 2379, and 259 mg/kg after a 70-pore-volume flushing, respectively. Moreover, the mobilization of arsenic and heavy metals by rhamnolipids was found to be positively correlated with that of Fe, and the mobilization of arsenic was also positively correlated to that of the heavy metals. The mobilization of co-existing metals, to some extent, might enhance arsenic mobilization in the presence of rhamnolipids by helping incorporate it into aqueous organic complexes or micelles through metal-bridging mechanisms.     

Health Risk Assessment of Heavy Metals in Soils and Vegetables from a Typical Greenhouse Vegetable Production System in China

There is growing concern about food safety and environmental contamination due to potential health risks to consumers. The aims of this study are to elucidate the accumulation status, influencing factors, and potential risk of selected heavy metals in soils and vegetables from a typical greenhouse vegetable production system in China. The potential health risks of heavy metals through soil contact and vegetable consumption were evaluated for greenhouse and corresponding open field production. The results indicated that the mean concentrations of Hg, Pb, Cu, and Zn in greenhouse vegetable soils were greater than those in open field soils. Leaf vegetables had relatively higher concentrations and transfer factors of heavy metals than root and fruit vegetables, especially for Cd. The target hazard quotient of heavy metals through vegetable consumption was greater than 1 for leaf vegetables, and was also higher for greenhouse vegetables than those from open field. The risk of exposure to heavy metals through direct contact with soil and vegetable consumption was higher for children than for adults and seniors. Planting patterns with different vegetable types and soil properties can affect bioavailability and crop accumulation of heavy metals.     

The effects of heavy metals pollution of the upper Arkansas River on the distribution of aquatic macroinvertebrates

Water quality, types, and diversity of aquatic macroinvertebrates show that heavy metal pollution of the upper Arkansas River is presently moderately severe and conditions for aquatic life are generally poor, particularly in the Leadville area. A 2 year study was done on a 30 km section of the upper Arkansas River, Colorado, to determine the effects of heavy metals pollution on the distribution of the aquatic macroinvertebrates. Physical and chemical water parameters were measured, and aquatic macroinvertebrates were collected. The major sources of heavy metal-laden inflows are Leadville Drain, California Gulch, and a number of intermittent flows entering the Arkansas River between Lake Fork and Lake Creek. Important freshening flows are Tennessee Creek, Lake Fork (containing Halfmoon Creek), and Lake Creek.     

重金属污染可能改变稻田土壤团聚体组成及其重金属分配

采集了太湖地区污染与非污染稻田表土,采用原状土低能量分离-分散技术提取土壤团聚体粒组,分析土壤中不同粒径团聚体颗粒组质量组成和Pb、Cd、Hg、As等重金属元素的含量, 讨论重金属污染下土壤团聚体组成和重金属团聚体分配的变化.结果表明：在重金属污染下,供试水稻土砂粒级团聚体减少,而较细粒径团聚体相对增多;4种重金属元素在不同粒径团聚体颗粒组中的含量存在差异,但随粒径的变化趋势基本一致,即在<0.002 mm粒径的颗粒组中最高, 其次是0.2～2 mm粒径的颗粒组,而在0.02～0.2 mm和0.002～0.02 mm粒径的团聚体中呈现亏缺现象（富集系数为0.56～0.96）.表明重金属污染可能减弱了较大土壤团聚体的形成,导致细粒径团聚体相对增多,从而明显提高了重金属元素在粉砂和粘粒组团聚体中的分配,这可能进一步提高了污染农田重金属的水迁移和大气颗粒物迁移的风险.对于重金属污染对稻田土壤生物物理和生物化学过程的影响及其机制还需要进一步研究.     

石墨烯的环境行为及其对环境中污染物迁移归趋的影响

石墨烯是当前研究最热的碳纳米材料,具有独特的理化特性,在各领域具有广阔的应用前景.随着其生产和使用量的不断增大,石墨烯不可避免地会进入到环境中,从而给生态环境和人类健康带来风险.深入理解石墨烯在环境中的行为和归趋,探讨石墨烯对污染物环境行为的影响,对于科学客观评价石墨烯的环境风险具有十分重要的意义.本文对石墨烯的环境行为及其对污染物迁移归趋的影响进行了综述,主要介绍了石墨烯在水环境中的胶体特性和稳定性,以及在多孔介质中的迁移,重点探讨了石墨烯与重金属和有机物之间的相互作用,并从吸附机理、石墨烯与土壤组分之间的相互作用、石墨烯对污染物在环境中迁移及生物有效性的影响、石墨烯的定量方法等方面对该研究领域的前景和重点进行了展望,以期为该领域的深入研究提供借鉴并拓展新的思路.