A preliminary study on the effect of Cu,Pb and Zn contamination of soils on community structure and certain life-history traits of oribatids from urban areas

The effect of pollution of urban soils by traffic exhausts on oribatid mites was studied along a traffic gradient of the city of Thessaloniki. Although the population density of the main orbatid species appeared increased in polluted areas, the total orbatid numbers were reduced due to the reduction in species richness. The highest species diversity was recorded in moderately polluted areas. The morphometric characteristics as well as certain life-history traits did no correlate with the level of traffic influence. Nevertheless, these characteristics were considered important for the understanding of the pollution impact on life in soils. Moderate body size, sexual reproduction, increased reproductive effort and wide habitat preferences characterize species in urban sites. Scheloribates latipes and Tectocepheus sarekensis can be used as bioindicators for Pb and Zn pollution of soils, respectively.     

Heavy metal contamination of water and fish in peri-urban dams around Bulawayo,Zimbabwe

Urban effluents are significant sources of heavy metal pollution in fresh water. Metal contamination in dams around the city of Bulawayo, Zimbabwe, were monitored during October 2014 to assess ecological and public health risks. Heavy metals were measured in water, sediment and fish in dams located downstream of effluent discharge zones in Bulawayo and were compared to those in a pristine upstream dam. Water conductivity indicated pollution of downstream dams. Levels of lead (0.13–0.28 ppm) and cadmium (0.02–0.06 ppm) in water from downstream dams exceeded WHO safe limits for drinking water. Cadmium levels in polluted dams also exceeded the safe limit for agricultural use. Sediments of effluent-polluted dams had metal contamination factors ranging from 8.8 to 31.2 relative to the control, and fish from the dams had higher metal content and were unfit for human consumption. Metal levels were also measured along an urban stream to establish the sources of metals. The city’s industrial zone had the highest levels of metals, suggesting that industrial effluents were major sources of contamination. The environmental consequences and human health risks of the pollution of peri-urban water bodies from urban effluents are discussed.     

A Survey of Heavy Metal Levels in Eels (Anguilla anguilla) from some Rivers in East Anglia,England: the Use of Eels as Pollution Indicators

A survey was made of mercury, cadmium and lead in the liver and flesh of 517 eels from eleven rivers in East Anglia. Eels from some sites showed high metal levels, indicating sources of metal contamination. Eel liver is a suitable indicator of inorganic pollution and the flesh is a suitable indicator of organic pollution.     

Heavy metal contamination in surface soils of the industrial district of Wuhan,China

The Qingshan district of Wuhan City is a typical Chinese industrial area. An increase in heavy metal pollution in the region's soil, due to industrialization and urbanization, has become a serious environmental problem. Surface soil samples from 155 sites were collected and analyzed. The median concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in soil were 2.3, 46.2, 24.3, 28.2, and 86.8 mg/kg, respectively. Principal component analysis coupled with hierarchical cluster analysis showed that (1) in residential and industrial areas, Pb, Cu, and Zn concentrations were mainly affected by industrial emissions and traffic emissions, whereas in agricultural areas Cu and Zn were less affected by industrial emission and traffic emission, whereas Pb was affected by agricultural activities; and (2) Cd originated from a combination of sources, including industrial activities, traffic emission, and hypergene geochemical characteristics. The integrated pollution index varied from 1.1 to 16.6 with a mean of 3.9, and 70.6% of the area is extremely contaminated, 28.1% is heavily contaminated, and the remainder is moderately contaminated.     

Assessment of Trace Metals Contamination in the Suspended Matter and Sediments of a Semi-enclosed Mediterranean Gulf

This study investigates the distribution of heavy metals in the suspended particulate matter and the sediments of Kavala Gulf, located in Northern Greece. Particulate trace metals were determined in accordance to water column physicochemical parameters. Metals in sediments were related to the textural characteristics, the organic matter, and carbonate contents of surficial sediments. Results illustrated that the diverse human coastal activities influence the distribution of particulate and sediment metal concentrations, since lower trace metal levels were detected along the western (tourism) and eastern (aquaculture) coast, while increased values were observed at the central (urban and industrial). Overall, particulate metals show moderately low levels compared to other similar sites, with the exception of Ni and Cd depicting local peaks along the industrial coastal zone. Significantly increased levels for particulate lead (123.1 μg/g) and chromium (113.9 μg/g) were detected at the sites near the industrial zone. Direct effluents from a fertilizer plant appeared responsible for the increased Pb, Cr, and Cd levels, while the increased values in Zn, Cu, and Hg appear related to phosphogypsum leaching. Sediment contamination assessment indicated that the Kavala Gulf is characterized by clean to marginally polluted sediments, with moderately severe pollution levels along the urban coastline.     

A comparative study of heavy metal contamination and pollution in four reservoirs in the English Midlands,UK

Chemical and palaeoecological analysis of lake and fluvial sediments reveals a range of human impact on the sediment chemistry of four reservoirs in the English Midlands. Atmospheric pollution is recorded in both inner city and rural sites over the last 150 years. Catchment derived heavy metals at one urban site reveals high contamination factors for Pb, Cu, Ni, Zn and Cd. From the phosphorus record and from reconstructions based on macrofossil remains, eutrophication is recorded at all sites. Recent attempts to evaluate rehabilitation programmes for the inner city sites have proved problematical owing to two major problems. First, their shallow nature results in a high cost of desilting and, secondly, heavy metal contamination makes treatment and disposal of the sediment expensive.     

Using tree leaves and barks collected from contaminated and uncontaminated areas as indicators of air metallic pollution

Abstract

The aim of this study was to show the usefulness of woody species in assessing air pollution by cadmium, copper, lead, and zinc. For this, washed leaves, unwashed leaves, and barks of a coniferous species (Cupressus sempervirens var. fastigiata) and a broadleaved one (Eucalyptus cladocalyx F. Muell) were analyzed for cadmium, copper, lead and zinc contents. A transect sampling approach was carried out during spring 2016. Fifty stations were selected along an intensive traffic road, and three in a control area. The results showed that the highest concentrations were recorded in barks for copper (21.86?µg/g, 23.33?µg/g) and lead (14.53?µg/g, 63.33?µg/g), and in unwashed leaves for cadmium (0.57?µg/g, 1.19?µg/g) and zinc (48.94?µg/g, 47.6?µg/g) for E. cladocalyx F. Muell, and C. sempervirens var. fastigiata, respectively. Lead and zinc are the most accumulated metals compared to cadmium and copper in all samples. The studied metal contents in urban area were significantly higher than that of the control one. This represents that traffic road has influenced the metals contamination of the surrounding area. Results of the bioconcentration factor (BCF) for both species indicate that the studied species could be used as biomonitors to identify ecological problems and to predict effect on wildlife habitats. The highest values of metal accumulation index (MAI) indicate the effectiveness of these trees for controlling the air metals in the polluted areas. Result shows too that the studied species could be used for phytoextraction of heavy metals from the polluted soils and/or air.     

A Study of Air Pollution with Heavy Metals in Athens City and Attica Basin Using Evergreen Trees as Biological Indicators

Concentrations of five metals (cadmium, chromium, copper, nickel and lead) were determined in tree leaves collected from 13 areas of the Attica basin and Athens city, Greece. Geographical distribution patterns were investigated, and factors affecting toxic element accumulation in trees were discussed. The mean heavy metal content in the tree leaves is described in the descending order of copper>lead>nickel>chromium>cadmium. Generally, the most damaged areas have been proved to be those near the city center and in the vicinity of the Attica highway. The geomorphological relief of the area plays an important role in the dispersion of airborne particles from pollution sources to the surrounding area. Areas on the NE region are also polluted mainly due to wind directions. In Citrus aurantium leaves, with relatively impermeable cuticle, high chromium, copper and nickel concentration would be possibly caused only by significant stomatal uptake. The conifer tree Pinus brutia providing a rough leaf surface also showed elevated concentrations, especially of cadmium and lead. The thick waxy cuticle of the sclerophyllous broad-leaved Olea europaea forms a smooth sheet increasing the barrier properties of the leaf epidermis and causing a reduction in leaf permeability. The dense trichomes of the abaxial epidermis of Olea europaea also act as a pollution screen keeping away the air particles from the epidermis stomata. The presence of a certain metal within the leaf cells could reduce the uptake or toxicity of some others.     

Lead and cadmium concentrations in seawater and algae of the Tunisian coast

Both lead and cadmium are toxic trace metals, even in very weak concentrations. The aim of this study was to estimate lead and cadmium pollution in various sites of the Tunisian coast and to verify the possibility of modification of the algae bioconcentration power according to water physico-chemical conditions. Our study concerned 99 samples of algae and 99 samples of seawater, taken in different sites of the Tunisian littoral. The analysis was realized by atomic absorption spectrophotometry (oven graphite). In algae, Sfax site presented the highest concentrations of lead when Sousse site showed the lowest ones. In seawater, the most amounts of lead were observed in Bizerte, Mahdia and Sfax sites, and those of cadmium in Bizerte and Medenine coasts. Bizerte's coast seems to be the most exposed zone to pollution. Indeed, the intensification of sea traffic may take place on this pollution because hydrocarbons derived from petroleum contain some tetraethylic lead characterised by its great toxicity. Sousse's region is the least polluted zone; it might be due to the development of tourism and a strict regulation of pollution in this district.     

Spatial patterns,hotspot, and risk assessment of heavy metals in different land uses of urban soils (case study: Malayer city)

A study on identification of hotspots, spatial patterns, and risk evaluation of heavy metals in urban soils of Malayer city (Iran) was carried out. Fifty-nine composite surface soil samples were collected from six different land uses (urban parks, streets, and squares, boulevards, residential and agricultural areas) in Malayer city, and the total heavy metals were measured by atomic absorption spectroscopy. Average concentrations of Cd, Pb, Cu, and Zn, As, Cd, and Pb were 0.66, 15.51, 12.25, and 96.8 mg/kg, respectively. Among the six land uses, heavy metal contamination was heavier for street, while low contamination could be found for residential and urban parks. The spatial distribution of Pb in surface soil was similar to those of Cd, and Cu was similar to those of Zn with decreasing values from the central areas to the suburb. Also, there were several hotspots for studied heavy metals that Cd and Pb were mainly occurred in locations of heavy traffic in the city center and Cu and Zn in the west and northwestern in the city. The calculated result of risk evaluation showed that much of the city suffered from moderate to severe pollution by four of these heavy metals.     

Using wild plant species as indicators for the accumulation of emissions from a thermal power plant, Candiota, South Brazil

The impact of Candiota coal-fired thermal power plant on air quality was evaluated during two years by means of passive biomonitoring. The monitoring consisted of the quarterly collection of leaf samples of Baccharis dracunculifolia, Elephantopus mollis, Eryngium horridum, Paspalum notatum and Piptochaetium montevidense or the shoot of Baccharis trimera at five sites located in the area around the power plant. The element load of these plants was used as indicator for atmospheric pollution. In the samples collected, sulphur and heavy metal cadmium contents were measured. Among the species evaluated, E. mollis presented the highest potential to accumulate metal, followed by B. trimera. The Aeroporto and AFUCAN sampling sites, located in the prevailing wind directions, presented the highest level of metal contamination.     

Heavy metal contamination of sediments in the Upper Connecting Channels of the Great Lakes

In 1985, sampling at 250 stations throughout the St. Marys, St. Clair, and Detroit rivers and Lake St. Clair — the connecting channels of the upper Great Lakes — revealed widespread metal contamination of the sediments. Concentrations of cadmium, chromium, copper, lead, mercury, nickel, and zinc each exceeded U.S. Environmental Protection Agency sediment pollution guidelines at one or more stations throughout the study area. Sediments were polluted more frequently by copper, nickel, zinc, and lead than by cadmium, chromium, or mercury. Sediments with the highest concentrations of metals were found (in descending order) in the Detroit River, the St. Marys River, the St. Clair River, and Lake St. Clair. Although metal contamination of sediments was most common and sediment concentrations of metals were generally highest near industrial areas, substantial contamination of sediments by metals was present in sediment deposition areas up to 60 km from any known source of pollution.Contribution 735 of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

基于城市微气候模拟软件的城市道路绿化带对PM2.5消减作用的研究

随着经济的快速发展及机动车保有量的持续增长,车辆造成的道路污染问题日益严重。广州作为中国重要的经济发展城市,交通源排放问题高度集中,机动车排放是城市PM2.5的主要来源之一,开展减缓城市道路污染危害的研究具有重要意义。本研究为调查绿化带对广州城市道路PM2.5的影响,运用实测与城市微气候模拟软件（ENVI-met）模拟结合的研究方法,实测并分析城市道路空间PM2.5的浓度分布及其影响因素,使用实测数据对模拟软件进行验证分析,模拟研究理想道路模型下不同高宽比、风向等因素及绿化带植配类型对PM2.5的消减作用。研究表明：（1）城市道路空间PM2.5浓度分布受污染源、街道高宽比、风速风向、绿化带等综合影响,自然消减情况下,其主要受风速风向和高宽比双因素影响;（2）通常街道高宽比越大,越有利于道路空间PM2.5的扩散;（3）城市道路空间PM2.5自然沉降最小距离为12 m,0-12 m范围内应保持无障碍物的开敞环境,PM2.5消减的关键范围是12-24 m,此范围内可以利用生态手段沉降颗粒物;（4） PM2.5消减率受绿化带和风向的双控制,应根据主导风向选择绿化带植配方式。在主导风平行面和垂直迎风面绿化带对PM2.5有正消减效应,建议植配类型为"乔-乔+灌+草";在主导风垂直背风面绿化带对PM2.5呈负消减效应,植配类型为"乔-灌"绿化带消减率接近于自然消减率,而植配类型为"乔-灌+草"和"乔-乔+灌+草"的绿化带加重了颗粒物在该区域的积聚。     

Spatial Distribution and Correlative Study of the Total and the Available Heavy Metals in Soil From a Typical Lead Smelting Area,China

Representative soil samples (n = 453) were collected from a lead smelting area in central China. The total and the available contents of several hazardous elements, including lead, cadmium, arsenic and mercury were determined. Inorganic acid were used for the pretreatment of the total element analysis. DTPA (Diethylene triamine pentacetate acid) digestion, an effective pretreatment procedure for the biological availability assessment of heavy metals, was used for bio-available assessment in this study. Graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma-optical emission spectrometer (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) were employed for the instrumental analysis. The results indicated that the soil samples were seriously polluted by mercury, arsenic, lead and cadmium around the smelting factories, comparing to many other cities in China. Spatial distributions of the metal contents were then illustrated with maps. For 220 samples in pollution areas, average bio-effectiveness rates of cadmium, lead, mercury and arsenic in soils were 25.9%, 17.2%, 0.58% and 0.11%, respectively. The relationships of the total and the available contents of metals were investigated, among which lead and cadmium were found to can be expressed as linear and power function. These equations were tested inversely and further verified by the data from six randomly selected sites. The results will be helpful to assess the bioavailable contents of lead and cadmium fast and accurately only by the total contents and functional calculation in similar study.     

土壤中镉、铅、锌及其相互作用对作物的影响

通过作物盆栽模拟试验(砂壤质褐土、pH值8.2)揭示：土壤中分别施入镉(CdCl2)、铅[Pb(CH3COO)2]或锌(ZnSO4)其影响表现为,植物各器官镉的含量超过对照植物的数倍至500倍。土壤镉浓度<5ppm和<10ppm分别造成某些蔬菜和水稻的污染。铅主要积累在植物根部,土壤铅污染对作物的影响较小。锌主要积累在植物叶片和根部,对水稻产生生长抑制的土壤锌浓度临界值不大于200ppm,此浓度对旱作无影响。土壤中同时施入镉和铅,植物对镉的吸收增加。而土壤中镉的增加却减少了植物体内铅的含量。土壤中由于镉、锌或铅、锌相互作用的结果,水稻对它们的吸收都有增加。在旱地土壤锌浓度的增高,降低了植物对镉、铅的吸收。镉、铅、锌同时施入土壤由于相互作用的结果,除锌之外,植物对镉、铅的吸收有明显下降。评价土壤重金属污染,不仅要看它们的含量及其存在形态,而且要分析它们之间的相互作用(促进或拮抗)特点。     

Application of in situ cage cultures of phytoplankton for monitoring heavy metal pollution in two Norwegian fjords

A simple apparatus for in situ use of the cage culture technique for growing planktonic algae has been developed and used to follow growth and metal uptake of three diatoms in two Norwegian fjords polluted by heavy metals. Continuous pumping of sea water through a chelating resin and continuous water sampling was used to obtain average values for dissolved and particulate heavy metal content at the various test sites. The metals investigated (zinc, copper, lead, cadmium, and mercury) showed differences in the proportion of dissolved to particulate fractions.The three species of diatoms tested gave systematic growth responses to heavy metal pollution in the moderately polluted fjord; one alga died, one showed reduced growth rate at the more contaminated site compared with those at less polluted sites, while the most tolerant alga was apparently not affected. In the heavily polluted fjord only the most tolerant alga survived, showing decreasing growth rate with increasing pollution.Uptake of heavy metals increased generally with increasing heavy metal content in the sea water. The contents in the algae grown in the most polluted fjord were much higher than those obtained in the less polluted fjord, which were higher than the contents reported for algae from non-contaminated areas.     

土壤复合污染的联合修复技术研究进展

复合污染是土壤污染的主要存在形式,其中重金属、有机污染物等是主要的污染源。例如,共存于土壤中铅和镉会发生交互作用,从而增强了镉的迁移能力。此前单一的物理、化学、生物等修复手段对复合污染的修复效果并不明显。联合修复技术的使用可以在一定程度上克服使用单一的修复手段存在的缺点,提高修复效率、降低修复成本。最近有研究表明,综合利用化学氧化和超声波方法可以在很短的时间内将土壤中的甲苯和二甲苯完全氧化为CO和CO2。介绍了综合利用物理、化学、生物等方法对土壤复合污染修复的进展,并对研究中需要注意的问题及未来的发展趋势说明。     

Anthropogenic Influence on Selected Heavy Metal Contamination of Urban Soils of Akure City,Nigeria

Levels of Cd, Ni, and Pb in topsoil (0–5 cm) taken from seven different sites of the urban city of Akure, Nigeria, were determined using flame atomic absorption spectrophotometer after the wet digestion method. This was with a view to appraising the influence of various anthropogenic activities on heavy metal contamination of the urban soil. Results show that the range of Cd was 6.27–10.34 ppm, Ni 7.17–14.78 ppm, and Pb 9.22- 46.19 ppm. This analytical data indicated a significant accumulation of heavy metals above background levels, with highest concentrations found in mechanic/battery charger workshops. The level of accumulation was assessed using accumulation factor (AF), and the values obtained exceeded 4 in all sites. This implies that the heavy metals are not from the natural geochemistry of Akure but from human activities. The classes of contamination were differentiated using geoaccumulation index (I _geo). The I _geo performed revealed that Cd (2< I _geo<3: Class 3), Ni (2< I _geo<4: Class 3 and 4) and Pb (3< I _geo<5: Class 4 and 5) belong to different classes of geoaccumulation index, but the contamination patterns (moderately to strongly contaminated) are similar in all sites, except the mechanic battery/charger workshop (moderately to extremely contaminated). The differences observed in the metal concentrations among the sites are statistically significant (P < 0.05).     

Morpho-anatomical responses ofTrigonella foenum graecum Linn. to induced cadmium and lead stress

Effect of different concentrations of cadmium (0, 5,15, 30, 50 μg/g of soil) and lead (0,25, 50,100,200 μg/g of soil) on morphological and anatomical features ofTrigonella foenum graecum Linn, was studied at pre-flowering, flowering and post flowering stages. Morphological attributes, like number of leaves per plant, total leaf area of the plant and single leaf area, dry mass of stem, root and leaf, length of shoot, root and plant, size of stomata and stomatal pore, and the density of stomata on both epidermises were significantly reduced under metal stress at all the developmental stages. Trichome length on both epidermises increased while their density decreased under metal stress. Under cadmium stress, proportion of pith and vasculature decreased but cortex increased in the stem. Under lead stress, proportion of pith and vasculature increased but cortex decreased in the stem. In the root, proportion of vasculature and pith increased and cortex decreased in response to both cadmium and lead stresses. Dimensions of vessel element and xylem fibre in the wood of stem and root decreased under the cadmium and lead stresses. Decrease in density of vessel element in the stem and root with advancement of age was more pronounced in plants grown under cadmium and lead stresses.     

The recovery of heavy metals using encapsulated microbial cells

We prepared capsules containingSaccharomyces cerevisiae andZoogloea ramigera cells for the removal of lead (II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. TheS. cerevisiae cells grown in the capsule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell exopolymer density of encapsulatedZ. ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell exopolymer ofZ. ramigera was 55 mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulatedS. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulatedS. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model. 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.