Study of colloidal content and associated heavy metals in landfill leachate: a case study of El-Akader landfill site: Jordan

Landfill leachate samples were collected anaerobically at six locations at the El-Akader landfill site in North Jordan. The collected leachate samples were separated into size fractions with special attention to the distribution of colloids and associated heavy metals. The fraction sizes were 1.2 μm. The maximum concentrations of heavy metals in the analysed leachate samples were Cd 0.6 μg/l, Ni 25 μg/l, Zn 245 μg/l, Cu 15 μg/l and Pb 2.50 μg/l. In the dissolved particular matter the heavy metals concentration ranges were Cd 0.1–1.1 μg/l, Ni 0.35–1.5 μg/l, Zn 85–105 μg/l, Cu 0–0.95 μg/l and Pb 0.5–2.5 μg/l.     

高速公路路面沉积物的污染特性

对湖南省长潭西高速公路不同采样点的路面沉积物进行取样分析,并检测了样品的颗粒级配、COD、重金属(Cu、Zn、Pb和Cd)和有机质。结果表明,路面沉积物主要以粒径<0.15 mm的颗粒为主;较小颗粒物中的COD含量高于较大颗粒中的COD含量;粒径在0.15 mm以下的颗粒物所含重金属Cu、Zn、Pb和Cd的浓度普遍高于所选的土壤标准值,降雨一旦形成径流将会产生严重的污染危害;沉积物中的有机质含量对重金属的吸附有一定的影响,有机质含量越高,沉积物中重金属含量相对也高。     

Size-resolved trace metal characterization of aerosols emitted by four important source types in Switzerland

In central Switzerland five types of emission sources are mainly responsible for airborne trace metals: traffic, industrial plants burning heavy oil, resuspension of soil particles, residential heatings and refuse incineration plants. The particulate emissions of each of these source types except refuse incineration were sampled using Berner impactors and the mass and elemental size distributions of Cd, Cu, Mn, Pb, Zn, As and Na determined.Cd, Na and Zn are not characteristic for any of these source types. As and Cu, occurring in the fine particle fractions are characteristic for heavy oil combustion, Mn for soil dust and sometimes for heavy and fuel oil combustion and Pb for traffic aerosols. The mass size distributions of aerosols originating from erosion and abrasion processes show a maximum mass fraction in the coarse particle range larger than about 1 μm aerodynamic equivalent diameters (A.E.D.). Aerosols originating from combustion processes show a second maximum mass fraction in the fine particle range below about 0.5μm A.E.D.Scanning electron microscopy combined with an EDS analyzer was used for the morphological characterization of emission and ambient aerosols.     

Partitioning and mobility behavior of metals in road dusts from national-scale industrial areas in Korea

In this study, we investigated the characteristics of heavy metal contamination in road dusts collected from industrial areas in Korea. A total of 12 sampling sites, including nine sites in three different industrial complexes (ICs), two IC vicinity areas and one background area, were selected for this study. The collected road dusts were divided into four categories. The heavy metals (Cd, Cu, Pb, Zn, and Ni) were extracted from the road dust by an aqua regia extraction method and analyzed by atomic absorption spectrometry. The highest concentrations of Cd, Cu, and Pb were identified in road dusts from areas near the non-ferrous metal IC, followed by those from the petrochemical IC. The petrochemical IC and the mechanical/shipbuilding IC showed the highest concentrations of Ni and Zn in their road dusts, respectively. The concentration of heavy metals in the road dusts collected from the IC vicinity areas, even those located in a rural environment, were very high. The concentration of heavy metals increased with decreasing particle size of the road dusts. This study also analyzed the mobility of the heavy metals in the road dusts using partial sequential extraction with the Tessier procedure. The order of mobility identified, based on exchangeable and carbonate fractions of the heavy metals, was Cd > Zn > Pb > Cu > Ni.     

The sorption of heavy metal species by sediments in soakaways receiving urban road runoff

Infiltration facilities are designed for both the retention of non-point pollutants and the replenishment of groundwater in urban areas. In this study, sorption tests were conducted to evaluate the speciation of heavy metals and their behaviour in infiltration facilities receiving urban road runoff containing high DOC concentrations and stable heavy metal organic complexes. Road dust and three soakaway sediments were collected from heavy traffic areas and a residential area with an infiltration-type sewerage system in Tokyo, Japan. Sequential multiple batch tests were conducted by adding prepared road dust leachate (artificial road runoff) or deionised water to soakaway sediment to obtain soakaway sediment leachate (artificial percolating water from soakaway sediment), which mimicked the sorption by sediments in soakaways receiving urban road runoff. Heavy metal speciation was assessed by means of a combination of anion-exchange resin measurements and MINTEQA2 model calculations, and further validated by chelating resin measurements. In road dust leachates and soakaway sediment leachates, Cu predominantly existed as organic complexes and carbonates, whereas most Mn, Zn and Cd were found to exist in the form of free ions and carbonate complexes. Stable organic complexes of Cu in road dust leachates were strongly adsorbed by soakaway sediments despite the limited adsorption of DOC. On the other hand, desorption of free Mn, Zn and Cd ions from the sediment receiving road dust leachates was observed, indicating that heavy metals such as Mn, Zn and Cd may ultimately reach groundwater as free ions.     

Dry deposition (downward, upward) concentration study of particulates and heavy metals during daytime, nighttime period at the traffic sampling site of Sha-Lu, Taiwan

Downward, upward dry deposition fluxes and total suspended particulate of particulate heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) were measured in daytime and nighttime period in Sha-Lu, a small city in the central Taiwan during summer period of 2003. The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 g/m3) were higher than in nighttime period (averaged 560.7 g/m3). And the downward dry deposition fluxes (averaged 54.07 g/m2s) were about two times as that of upward dry deposition fluxes (averaged 26.48 g/m2s) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.22 g/m2s) were also about two times as that of upward dry deposition fluxes (averaged 12.11 g/m2s) in the nighttime period. In addition, the average downward dry deposition fluxes are greater than the upward dry deposition fluxes for all the heavy metals in either daytime or nighttime period. The proposed reasons are that the wind speed and concentration difference for daytime and nighttime period lead to these results at the traffic sampling site of central Taiwan. In addition, the deposition velocity for mass, heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) during daytime and nighttime period were also calculated. The average daytime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 5.56, 2.66, 1.71, 0.18, 1.06, 0.24, 0.47 and 0.11 (cm/s), respectively. And the average nighttime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 4.70, 2.11, 1.66, 0.18, 0.86, 0.23, 0.32 and 0.07 (cm/s), respectively at traffic sampling site of central Taiwan.     

Trace metal contents in Parmelia caperata (L.) Ach. compared to bulk deposition,throughfall and leaf-wash fluxes in two holm oak forests in Montseny (NE Spain)

The metal concentrations of V, Cr, Co, Ni, Cu, Zn, Cd, Hg and Pb were analysed in distilled water extracts of Parmelia caperata and in bulk deposition, throughfall and an experimental in situ washing of leaves at two forests at Montseny (NE Spain) submitted to differential exposure to the industrial and traffic activities around Barcelona. Lichen concentrations of Zn, Cu, V, and Cd were higher at the site of greater exposure to pollutants. Consistently, there was higher dry deposition of these metals at the more exposed site. The order of abundance of trace metals in the lichen was similar to that in the deposition variables, although Pb and Cu had intermediate concentrations in the lichen but were very low in the deposition measurements. This indicated the higher affinity of Pb and Cu for the exchange sites in the lichen cell wall and the fact that lichens accumulated Pb for the last 12–18 y when emissions were much higher than today. The ability of Parmelia caperata to indicate the deposition of heavy metals, together with its easy sampling and handling, its broad distribution and its easy identification suggest that the lichen extract procedure described here could be used to establish gradients of atmospheric deposition of heavy metals at a general geographic level.     

Date palm (Phoenix dactylifera L.) leaves as biomonitors of atmospheric metal pollution in arid and semi-arid environments

The leaves of date palms were evaluated as a possible biomonitor of heavy metal contamination in Ma’an city, Jordan. Concentrations of (Fe), (Pb), (Zn), (Cu), (Ni), and (Cr) were determined in washed and unwashed leaves and soil samples collected from different sites with different degrees of metal contamination (urban, suburban, industrial, highway and rural sites); separate leaves were taken from outside the city to be used as a control sample. Samples collected from industrial sites were found to have high concentrations of all metals except those of Cu, Ni and Pb, which were found at high levels in the highway site samples which is associated with the road traffic. The difference between unwashed and washed samples showed that metal pollutants exist as contaminants, particularly Pb, Zn and Ni, which varied in concentration, depending on the source of the metal.     

Speciation distribution and mass balance of copper and zinc in urban rain, sediments, and road runoff

Heavy metal pollution in road runoff had caused widespread concern since the last century. However, there are little references on metal speciation in multiple environmental media (e.g., rain, road sediments, and road runoff). Our research targeted the investigation of metal speciation in rain, road sediments, and runoff; the analysis of speciation variation and mass balance of metals among rain, road sediments, and runoff; the selection of main factors by principal component analysis (PCA); and the establishment of equation to evaluate the impact of rain and road sediments to metals in road runoff. Sequential extraction procedure contains five steps for the chemical fractionation of metals. Flame atomic absorption spectrometry (Shimadzu, AA-6800) was used to determine metal speciation concentration, as well as the total and dissolved fractions. The dissolved fractions for both Cu and Zn were dominant in rain. The speciation distribution of Zn was different from that of Cu in road sediments, while speciation distribution of Zn is similar to that of Cu in runoff. The bound to carbonates for both Cu and Zn in road sediments were prone to be dissolved by rain. The levels of Cu and Zn in runoff were not obviously influenced by rain, but significantly influenced by road sediments. The masses for both Cu and Zn among rain, road sediments, and road runoff approximately meet the mass balance equation for all rainfall patterns. Five principal factors were selected for metal regression equation based on PCA, including rainfall, average rainfall intensity, antecedent dry periods, total suspended particles, and temperature. The established regression equations could be used to predict the effect of road runoff on receiving environments.     

Road traffic emission factors for heavy metals

Quantifying the emissions and concentrations of heavy metals in urban air is a prerequisite for assessing their health effects. In this paper a combination of measurements and modelling is used to assess the contribution from road traffic emissions. Concentrations of particulate heavy metals in air were measured simultaneously during 1 year at a densely trafficked street and at an urban background site in Stockholm, Sweden. Annual mean concentrations of cadmium were 50 times lower than the EU directive and for nickel and arsenic concentrations were 10 and six times lower, respectively. More than a factor of two higher concentrations was in general observed at the street in comparison to roof levels indicating the strong influence from local road traffic emissions. The only compound with a significantly decreasing trend in the urban background was Pb with 9.1 ng m^?3 in 1995/96 compared to 3.4 ng m^?3 2003/04. This is likely due to decreased emissions from wear of brake linings and reduced emissions due to oil and coal combustion in central Europe.Total road traffic emission factors for heavy metals were estimated using parallel measurements of NOx concentrations and knowledge of NOx emission factors. In general, the emission factors for the street were higher than reported in road tunnel measurements. This could partly be due to different driving conditions, since especially for metals which are mainly emitted from brake wear, more stop and go driving in the street compared to in road tunnels is likely to increase emissions. Total emissions were compared with exhaust emissions, obtained from the COPERT model and brake wear emissions based on an earlier study in Stockholm. For Cu, Ni and Zn the sum of brake wear and exhaust emissions agreed very well with estimated total emission factors in this study. More than 90% of the road traffic emissions of Cu were due to brake wear. For Ni more than 80% is estimated to be due to exhaust emissions and for Zn around 40% of road traffic emissions are estimated to be due to exhaust emissions. Pb is also mainly due to exhaust emissions (90%); a fuel Pb content of only 0.5 mg L^?1 would give similar emission factor as that based on the concentration increment at the street. This is the first study using simultaneous measurements of heavy metals at street and roof enabling calculations of emission factors using a tracer technique.     

Estimation of atmospheric trace metal emissions in Vilnius City, Lithuania, using vertical concentration gradient and road tunnel measurement data

A new approach for the estimation of trace metal emissions in Vilnius city was implemented, using vertical concentration profiles in the urban boundary layer and road tunnel measurement data. Heavy metal concentrations were examined in fine and coarse particle fractions using a virtual impactor (cut-off size diameter 2.5 μm). Negative vertical concentration gradients were obtained for all metals (Ba, Pb, V, Sb, Zn) and both fractions. It was estimated that the vertical concentration gradient was formed due to emissions from an area of about 12 km². Road tunnel measurements indicated that trace metal concentrations on fine particles were lower than those on coarse particles, which suggested that re-emitted road dust was highly enriched in trace metal due to historic emissions within the tunnel. Emission rates of different pollutants in the road tunnel were calculated using pollutant concentration differences at the tunnel entrance and exit and traffic flow data. Heavy metal emission rates from the area of Vilnius city were estimated using the vertical gradient of heavy metal concentrations and the coefficient of turbulent mixing, as derived from meteorological measurement data. The emission values calculated by the two different methods coincided reasonably well, which indicated that the main source of airborne trace metals in Vilnius city is traffic. The potential of the vertical concentration gradient method for the direct estimation of urban heavy metal emissions was demonstrated.     

Assessment of atmospheric pollution from toxic heavy metals in two cities in India

Atmospheric concentrations of Pb, Cd, Cu and Zn have been measured at different locations in Bombay. The concentration levels of these metals in blood and teeth of Bombay residents were also measured to assess the current and integrated exposure. Higher atmospheric concentrations were observed in higher vehicular traffic zones in Bombay. Environmental monitoring of Pb, Cd, Cu and Zn was also carried out at Moradabad, the largest production and exporting centre of brass wares in India. Surface soil concentrations of these metals were also measured in Moradabad and Bombay. The analysis of samples was carried out by differential pulse anodic stripping voltammetry (DPASV). The study indicates that automobile exhaust is the dominant source for heavy metals in the environment of Bombay whereas the brass industry is responsible for enhanced concentrations of these metals in Moradabad.     

Potentially toxic metal contamination of urban soils and roadside dust in Shanghai, China

A detailed investigation was conducted to understand the contamination characteristics of a selected set of potentially toxic metals in Shanghai. The amount of Pb, Zn, Cu, Cr, Cd and Ni were determined from 273 soil/dust samples collected within urban area. The results indicated that concentration of all metals except Ni in soils was significant, and metal pollution was even severer in roadside dust. A series of metal spatial distribution maps were created through geostatistical analysis, and the pollution hotspots tended to associate with city core area, major road junctions, and the regions close to industrial zones. In attempt of identifying the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Pb, Zn and Cu mainly originated from traffic contaminants; soil Ni was associated with natural concentration; Cd largely came from point-sourced industrial pollution; and Cr, Ni in dust were mainly related to atmospheric deposition.     

Geofractionation of heavy metals and application of indices for pollution prediction in paddy field soil of Tumpat, Malaysia

The present study investigates the concentration of Pb, Cd, Ni, Zn, and Cu in the paddy field soils collected from Tumpat, Kelantan. Soil samples were treated with sequential extraction to distinguish the anthropogenic and lithogenic origin of Pb, Cd, Ni, Zn, and Cu. ELFE and oxidizable-organic fractions were detected as the lowest accumulation of Pb, Cd, Ni, Zn, and Cu. Therefore, all the heavy metals examined were concentrated, particularly in resistant fraction, indicating that those heavy metals occurred and accumulated in an unavailable form. The utilization of agrochemical fertilizers and pesticides might not elevate the levels of heavy metals in the paddy field soils. In comparison, the enrichment factor and geoaccumulation index for Pb, Cd, Ni, Zn, and Cu suggest that these heavy metals have the potential to cause environmental risk, although they present abundance in resistant fraction. Therefore, a complete study should be conducted based on the paddy cycle, which in turn could provide a clear picture of heavy metals distribution in the paddy field soils.     

Metal contamination of short-term snow cover near urban crossroads: correlation analysis of metal content and fine particles distribution

Snow samples were collected near crossroads in Novi Sad, Serbia, during December 2009 to assess metal concentrations (Ca, K, Zn, Fe, Cu, Mn, Al, Pb and Na), fine particle distribution and pH value. The filtered samples of melted snow were analysed, with a focus on particles smaller than a few μm. The most common values of the frequency number distribution curve were either in the range of 0.05-0.07 μm or one order of magnitude higher (0.2-0.5 μm). At examined locations metal concentrations varied from 0.0004 mg L⁻¹ for Pb to 18.9 mg L⁻¹ for Na. Besides Na, which mostly originated from de-icing salt, Ca is found to be the most abundant element in snow indicating the dominant influence of natural factors on snow chemistry. No significant difference was found in concentration of the elements at locations near crossroads with either low or high traffic volume, except for Na and Zn.To investigate how metals were related a correlation analysis was done for the concentrations of metals and with respect to the particle size distribution parameters and pH values. The major influence on the fine particle volume (mass) was concluded to be due to the elements from anthropogenic sources. This conclusion was based on the significant positive correlation between Fe, Zn and Al and the fine particle volume based distribution parameters.     

Occurrence of platinum and additional traffic related heavy metals in sediments and biota

Non-point sources play an important role in metal emissions into surface waters. One of the most important non-point sources is automobile traffic. Recent studies determining traffic related heavy metals in surface waters have concentrated mainly on worst case scenarios by analyzing heavy metal loads in waters and sediments close to storm-water overflow inlets. The present study aims at identifying traffic related heavy metals in moderately polluted sites, as they occur in highly urbanized regions. Therefore, the concentrations of eight traffic related metals (Pt, Sb, Mo, Cd, Pb, Cu, Cr and Zn) were determined in sediment and crustacean samples from eight different aquatic habitats in the Ruhr district, Germany. Traffic related heavy metals could be identified in sediment and biota samples as a combination of heavy metals (Pt, Sb, Cd, Pb for sediments and Pt and Sb for crustacean samples). Pt concentrations received special attention due to the relatively recent occurrence of anthropogenically emitted Pt in the environment. At six sampling sites, Pt was detected in sediment and/or biota samples. The uptake of Pt compared to other traffic related heavy metals by Asellus aquaticus and Gammarus pulex is relatively high and can be compared with the uptake rates of essential metals like Zn.     

Heavy metals in soils along unpaved roads in south west Cameroon: Contamination levels and health risks

Soils enriched with heavy metals from vehicular emission present a significant exposure route of heavy metals to individuals using unpaved roads. This study assessed the extent of Cd, Cr, Co, Cu, Ni, Pb and Zn contamination of soils along unpaved roads in Cameroon, and the health risks presented by incidental ingestion and dermal contact with the soils using metal contamination factor (CF) pollution load index, hazard quotients (HQ) and chronic hazard index (CHI). CF values obtained (0.9–12.2) indicate moderate to high contamination levels. HQ values for Cr, Cd and Pb exceeded the reference doses. Moderate health hazard exists for road users in the areas with intense anthropogenic activities and high average daily traffic (ADT) volume according to CHI values (1–4) obtained. The economy and quality of life in cities with unpaved roads could be threatened by health challenges resulting from long-term exposure to heavy metal derived from high ADT volumes.     

Heavy metal content in vegetables and fruits cultivated in Baia Mare mining area (Romania) and health risk assessment

Information about heavy metal concentrations in food products and their dietary intake are essential for assessing the health risk of local inhabitants. The main purposes of the present study were (1) to investigate the concentrations of Zn, Cu, Pb, and Cd in several vegetables and fruits cultivated in Baia Mare mining area (Romania); (2) to assess the human health risk associated with the ingestion of contaminated vegetables and fruits by calculating the daily intake rate (DIR) and the target hazard quotient (THQ); and (3) to establish some recommendations on human diet in order to assure an improvement in food safety. The concentration order of heavy metals in the analyzed vegetable and fruit samples was Zn?>?Cu?>?Pb?>?Cd. The results showed the heavy metals are more likely to accumulate in vegetables (10.8–630.6 mg/kg dw for Zn, 1.4–196.6 mg/kg dw for Cu, 0.2–155.7 mg/kg dw for Pb, and 0.03–6.61 mg/kg dw for Cd) than in fruits (4.9–55.9 mg/kg dw for Zn, 1.9–24.7 mg/kg dw for Cu, 0.04–8.82 mg/kg dw for Pb, and 0.01–0.81 mg/kg dw for Cd). Parsley, kohlrabi, and lettuce proved to be high heavy metal accumulators. By calculating DIR and THQ, the data indicated that consumption of parsley, kohlrabi, and lettuce from the area on a regular basis may pose high potential health risks to local inhabitants, especially in the area located close to non-ferrous metallurgical plants (Romplumb SA and Cuprom SA) and close to T?u?ii de Sus tailings ponds. The DIR for Zn (85.3–231.6 μg/day kg body weight) and Cu (25.0–44.6 μg/day kg body weight) were higher in rural areas, while for Pb (0.6–3.1 μg/day kg body weight) and Cd (0.22–0.82 μg/day kg body weight), the DIR were higher in urban areas, close to the non-ferrous metallurgical plants SC Romplumb SA and SC Cuprom SA. The THQ for Zn, Cu, Pb, and Cd was higher than 5 for <1, <1, 12, and 6 % of samples which indicates that those consumers may experience major health risks.     

Heavy metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.     

Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206Pb/207Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary.