Assessment of heavy metals contamination in deposited street dusts in different urbanized areas in the city of Ma’an, Jordan

190 Street dust samples were collected from nine different localities including high traffic (desert highway), moderate traffic (city center), light traffic (minor streets), residential streets, school gardens, hospital and health centers, industrial sites, parks and background sites (control) of Ma’an area. The concentrations of Fe, Zn, Ni, Pb, Mn, Cu and Cd were analyzed by flame atomic absorption spectrophotometer to assess and to compare road dust contamination levels of metals among the different types of urban environment. The results showed that dust samples from the urban and industrial site contained significant levels of the metals studied compared to the values obtained from the background site. The variation in concentration of the heavy metals determined from different locations was in the decreasing order as: industrial > high traffic > parks > moderate traffic > hospital and health centers > school gardens > light traffic > background sites. The mean concentrations of the metals were in the order of C _Fe > C _Zn > C _Ni > C _Pb > C _Mn > C _Cu > C _Cd where C is the concentration of these metals in solution. Enrichment factor calculations indicated that Cd, Pb, Zn and Ni were highly enriched. Fossil fuel combustion, wear of brake lining materials, traffic emissions and several industrial processes are considered the main sources of these metals. Assessment of the contamination level in dust sample was estimated based on the geoaccumulation index (I _geo), the pollution index, and integrated pollution index (IPI). The values of IPI are in the following order: Pb > Zn > Cu > Ni > Cd > Mn. All the indices for the metals under consideration were either low or corresponded to middle level of contamination. The use of factor analysis showed that anthropogenic activities seem to be the responsible source of contamination for metals in dust samples.     

Assessment of formaldehyde pollution based on Weber exponent and perception of people’s smell

Formaldehyde’s, as the irritant and active gas in atmosphere, pollution assessment by perception of people is significative. Although related study is seldom reported, it is necessary to improve the general contamination evaluation based on Weber–Fischna law and combine with human’s real feeling. Therefore, based on the law, Weber exponents were counted by a convenient optimal calculation, and the results could accurately embody the different standard range of formaldehyde concentration. In addition, by the human smell perception experiment, it was firstly found that the score assessment could also express the pollution condition more practically. According to the scores, expanding exponents could cause the assessment more clearly and closer to human real smell perception.     

Assessment of cement’s dust impact on the soil using principal component analysis and GIS

To evaluate the impact of the cement’s dust emitted by the eastern Moroccan cement factory (Oujda Holcim) and deposited on the soil of the Ain Lahjar commune, 58 samples of soil were collected around the factory on a radius of 3 km approximately. The physicochemical analyses of the upper 3 cm of the soil surface samples correspond to the pH, electrical conductivity, the chlorides and the oxides of Ca, Al, Fe, K, Mn, S and Si which were analyzed by the fluorescence of X-rays. The preliminary results demonstrate that this dust are especially basic and contain a high free lime (43% CaO). The principal component analysis (applied on the 58 samples of soil) allows deducting that the free lime and the sulfur oxide are the tracer elements of this form of pollution. Furthermore, the spatial projection of the factor scores of the principal component analysis using the geographical information system permits to determine the spatial distribution of more polluted areas of soils as well as to estimate their surface (63.3% of the survey zone).     

Assessment of effects of heavy metals combined pollution on soil enzyme activities and microbial community structure: modified ecological dose–response model and PCR-RAPD

A laboratory study was conducted to evaluate the response of soil enzyme activities (namely dehydrogenase, phosphatase and urease) to different levels of trace element pollution in soil representative area. The improved ecological dose model and random-amplified polymorphic DNA (RAPD) were used to assess soil health. The 50% ecological dose (ED₅₀) values modified by toxicant coefficient were calculated from the best-fit model, and determination values from the regression analysis for the three enzyme activities were studied after the incubation periods. The results showed that the elevated heavy metal concentration negatively affects the total population size of bacteria and actinomycetes and enzymatic activity; dehydrogenase (ED₅₀ = 777) was the most sensitive soil enzyme, whereas urease activity (ED₅₀ = 2,857) showed the lowest inhibition; combined pollution or elevated toxicant level would increase disappearing RAPD bands, and the number of denoting polymorphic bands was greater in combined polluted soils. All three mathematical modified models satisfactorily described the inhibition of soil enzyme activities caused by Cd and Pb, by giving the best fit.     

Characterization of arsenic-contaminated groundwater and human health risk assessment in Vietnam

The characteristics of arsenic-contaminated groundwater were investigated and the potential risks from groundwater were evaluated in Vietnam. Arsenic contamination in groundwater was found in Ha Nam Province in the northern part of Vietnam. Since groundwater has been used as one of the main drinking water sources in this region, groundwater （n=10） and hair （n=15） samples were collected in the Vinh Tru district, Ha Nam Province, during February of 2006. At the site, the concentrations of anions and silica were analyzed and As（Ⅲ） and As（Ⅴ） species in groundwater were separated with disposable arsenic speciation cartridge. The concentrations of arsenic in groundwater ranged from 13 to 582 μg/L （mean=366 μg/L）. According to the results of arsenic speciation, approximately 90% of arsenic in groundwater existed as As（Ⅲ） species. Average concentrations of iron and manganese were 18 and 0.7 mg/L, respectively. All samples exceeded the Vietnamese drinking water standard of 10μg/L for arsenic and 0.5 mg/L for iron. Also 70% of the groundwater samples were above the Vietnamese drinking water standard of 0.5 mg/L for manganese. However, a real intake of arsenic to human is less than analyzed arsenic concentration because sand filtration units are used to remove iron and arsenic in groundwater in this region. After treatment, arsenic concentrations decreased from 〈1 to 82 μg/L （mean=33 μg/L）. The concentrations of arsenic in hair samples and treated groundwater were compared. Especially, arsenic concentrations in female hair samples and treated groundwater had significantly positive correlation with the Spearman correlation of 0.88 and the P-value of 0.001. Based on the arsenic concentrations in treated groundwater, the assessment of human health risks was conducted.     

Assessment of spatial distribution and possible sources of heavy metals in the soils of Sariseki-Dörtyol District in Hatay Province (Turkey)

In this study, total heavy metal content of soil and their spatial distribution in Sar?seki-Dörtyol district were analyzed and mapped. Variable distance grids (0.5, 1.0 and 2.0 km) were established, with a total of 102 soil samples collected from two different soil depths (0–5 and 5–20 cm) at intersections of the grids (51 sampling point). Soil samples were analyzed for heavy metals (Cd, Co, Cr, Cu, Pb, Zn, Mn, Fe, and Ni). The most proper variogram models for the contents of all heavy metal were spherical and exponential ones. The ranges of semivariograms were between 1.9 and 31.1 km. According to the calculated geoaccumulation (I _geo) values, samples from both soil depths were classified as partly to highly polluted with Cd and Ni and partly polluted with Cr and as partly polluted-to-not polluted with Pb and not polluted with Cu, Fe and Mn. Similar results were also obtained when evaluated by the enrichment factor. The contamination levels of the heavy metals were Ni > Cd > Cr > Pb > Zn > Cu > Co > Fe > Mn in decreasing order. The soils in the study area are contaminated predominantly by Cd and Ni, which may give rise to various health hazards or diseases. Cadmium pollution results primarily from industrial activities and, to a lesser extent, from vehicular traffic, whereas Ni contents in the study area result from parent material, phosphorus fertilizer, industries, and vehicles.     

Modeling transfer of heavy metals in soil–rice system and their risk assessment in paddy fields

Many studies have been conducted on model transfer in soil–plant systems. However, relatively little information is available on modeling metal transfer in soil–rice system and associated risk assessment in real paddy fields. Based on a random sampling method from Nanxun, Shengzhou and Wenling in Zhejiang province, China, 15 pairs of rice and the corresponding soil samples were respectively collected for analysis of heavy metals and soil pH. The results showed that the accumulation ability of rice for different heavy metals was significantly different (p < 0.05), and was in the order of Cd > Zn > Cu > Ni > Cr > Pb. The relationships of heavy metals in rice with those in soil, along with soil pH, were well described by linear regression models. Except for Pb, the contents of most metals in rice were positively correlated with those of the soil. Soil pH was negatively correlated with the contents of Cd, Zn and Ni in rice, and positively correlated with Pb in rice; however, it had less effect on Cr and Cu. Based on risk reference dose (R_fD), the risk assessment data indicated that the rice grown in Zhejiang paddy fields does pose some potential Cd and Cr contamination risk to food safety; rice in Shengzhou posed light Ni risk.     

Microorganisms in Lianxian lateritic gold deposit in Guangdong and their effects on leaching of heavy metals

Microorganisms in the lateritic profiles of the Lianxian gold deposit in Guangdong were cultured, isolated and identified. The microorganisms include bacteria such as Bacillus, Enterobacter, Pseudomonas, Lactobacillus, Actinetobacter, Aeromona, Listeria, Agrobacteriura, Cotyttebacteriurn, and Moraxella, fungi such as Penicillium, Alter naria, Cladosporium, Saccharcornyces, Mucor, and the chemoautotrophic Thiobacillu.~. It is shown in a leaching experiment that the microorganisms can accelerate the leaching of Cu, Cd, Zn, and that the G- bacteria are most efficient for leaching Cu, Zn and the G^ bacteria are better for leaching Cd.     

Evaluation of the frequency of micronucleus in epithelial cells of children exposed to arsenic and heavy metals pollution in a mining area of Mexico

Mining industry is one of the most important economical activities of Latin America, where As, Pb and Cd are commonly associated with the extraction of precious and base metals. Mining activities become a source of contamination if control measures are no…     

Evaluation of the frequency of micronucleus in epithefial cells of children exposed to arsenic and heavy metals pollution in a mining area of Mexico

Mining industry is one of the most important economical activities of Latin America, where As, Pb and Cd are commonly associated with the extraction of precious and base metals. Mining activities become a source of contamination if control measures are not adapted to avoid the pollution of soils by these potentially toxic elements （PTE） for the human, because they have the capacity to produce damage to the DNA generating a genomic instability in the individual and this directly can lead to the development of chronic diseases like cancer. The considered population of greater risk is the infantile since they have an exceptional vulnerability to the acute or chronic effects of environmental toxics and in addition have a higher susceptibility to these PTE compared with the adults. For that reason, it is assumed that the infantile population exposed to soil contaminated by the mixture of As, Pb and Cd, has damage in the DNA of its cells and this provokes a greater susceptibility to develop neoplasics processes or other environmental diseases. Individual sensitivity to the cytogenetics effects produced by the polluting agents or their metabolites is based on the differences in the magnitude of the repair systems induction, reason why it is necessary to determine the genotoxicity in exposed children by means of the evaluation of a damage biomarker that allows to establish a biological meaning to predict the adverse effects in health.     

Heavy metals contamination and assessment in gas station dust of Xi’an,a mega-city of China

The dust samples from 30 gas stations located in Xi’an are analyzed for Mn, Ni, Co, Cr, Cu, Cd, Pb and Zn by using atomic absorption spectrometry. The concentration, spatial distribution, source and the contamination levels provide scientific basis for urban planning and environmental renovation in Xi’an. The results indicate that the mean values of Ni, Cr, Co, Cu, Pb, Zn and Cd in the dust are 1.15, 1.19, 8.13, 3.94, 4.42, 5.09 and 15.62 times higher than the corresponding background values of Shaanxi soil, respectively. The high concentration of heavy metals is located in the inner and second ring road of Xi’an, China. Furthermore, the contents of metals in the south are higher than in the north. In addition, the concentrations of the gas station dust metals in the west are higher than in the east, particularly in the southwest. Three main sources of heavy metals of gas station dusts are identified in Xi’an. Mn and Ni mainly originate from a natural source; Cr, Cu, Pb, Cr and Zn mainly originate from traffic flow; and Co is mainly from industrial sources. The results of the potential ecological risk assessment indicate that the potential ecological risk index (RI) of Co is moderate; Cd is very high ecological risk, and the other analyzed metals belong to low ecological risk. The mean RI value of eight heavy metals in the gas station dusts from Xi’an is considerable ecological risk.     

Geochemistry of sulfur and hazardous trace elements in coals and its bearing on human health

Hazardous air pollutants, including compounds of sulfur and toxic trace elements, are emitted during coal combustion. Geochemical studies of these constituents in coals provide information about their species, regional distribution and origins. The data are useful in understanding the cause and scope of human health problems related to these hazardous elements and in designing preventive or remedial measures. Sulfur in coal is a problem because sulfur dioxide emitted during coal combustion is a main source of acid rain. The sulfur isotopic evidence shows that sulfur in low-sulfur coal is derived primarily from parent plant materials. Sulfur enrichment in medium- and high-sulfur coals is caused by the sulfate in seawater that flooded the peat swamp during coal formation. The sulfur content of a coal is controlled primarily by the depositional environment of coal seams. Only pyritic sulfur can be removed by physical coal cleaning processes （coal preparation）. Sulfur dioxide emission can be reduced using clean coal technologies, such as flue-gas desulfurization, fluidized-bed combustion, and integrated gasification and combined cycle.     

Distribution of heavy metals in urban soils – a case study of Danang-Hoian Area (Vietnam)

 This work is part of a research study which is intended to study the degree of anthropogenic influences of the trace metal distribution of soils from Danang-Hoian area (Vietnam). Cu, Ni, Zn and Zr show significant effects in most of the cultivated soil categories, especially in the industrial soils. Extremely high levels of Pb (up to 742 μg/g) are observed in the industrial soil category, which shows an enrichment factor 114 as compared to rural soils. Cd shows only a relative local enrichment with the maximum level of 4.6 μg/g in urban soils. Sequential extraction was performed in selected samples to evaluate the geochemical trace metals. The result indicates that Zn and Cr are mainly found in the crystal and amorphous Fe oxide bounded forms. The contents of Cr in these fractions comprise more than 94% of total extractable Cr. In the case of Zn, 85% of total extractable Zn is in fractions F_V and F_VI. Cu is mainly found in the organic fraction at an average of 39.3% of total extractable content. On the other hand, heavy metal contents show an increasing tendency in the fine fraction (silt and clay). Received: 4 February 1998 · Accepted: 26 November 1998     

Evolution of the dust envelope of Sakurai’s star (V4334 Sgr) in 1997–1999

We have studied the structural evolution of the dust envelope of V4334 Sgr, starting with the onset of its condensation in 1997. A model with complete cloud cover, with the optical depth growing until the end of 1999, gives the best fit to the photometric data in the optical and IR. The inner radius of the dust layer remained virtually constant, whereas its thickness increased due to expansion. The deep minimum in the visual light curve of V4334 Sgr in October 1998 is attributed to the arrival at the dust-grain condensation zone of a density discontinuity in the circumstellar envelope. The discontinuity was probably formed early in 1997 due to an increase in the mass-loss rate by a factor of about four, possibly associated with an increase in the luminosity of V4334 Sgr during its transformation into a carbon star. After this luminosity increase, the mass-loss rate was $\dot M \approx 2 \times 10^{ - 6} M_ \odot /yr$ . In the summer of 1999, the mass of the dust envelope was $M_{dust} \approx 2 \times 10^{ - 7} M_ \odot (M_{gas} \approx 4 \times 10^{ - 6} M_ \odot)$ . In the complete-cloud-cover model, the envelope consists of graphite grains with a _gr=0.05 µm, to ～85% per cent in terms of the number of grains. The remaining ～15 per cent of the grains have sizes a _gr=0.1 and 0.25 µm. To reproduce the small hump in the spectral energy distribution of V4334 Sgr near 11 µm, some silicon carbide grains must be added to the graphite mixture. Their contribution to the V optical depth is ≤4%. The first deep minimum in the visual light curve could also be reproduced using a model in which the dust cloud has condensed along the line of sight, but a detailed analysis of the resulting characteristics of the cloud and envelope indicates that this model is improbable.     

Potential hazardous elements (PHEs) in atmospheric particulate matter (APM) in the south of Xi’an during the dust episodes of 2001–2012 (NW China): chemical fractionation,ecological and health risk assessment

Atmospheric pollution from atmospheric particulate matter (APM) deposition is one of the major sources of potential hazardous elements (PHEs) contamination. In this study, 68 total APM samples were collected from the local areas of southern Xi’an (NW China) during the long-term period of the 2001–2012 dust campaign. The chemical fractionation of PHEs (Cr, Cu, Ba, Sr, As, Pb, and Zn), their contamination levels, and ecological health risk were examined. The mobility sequence based on the sums of the first three fractionations of the modified BCR (the European Community Bureau of Reference) sequential extraction stages was: Cu (77.83 %) > Pb (74.50 %) > Zn (55.40) > Sr (52.93) > Ba (40.89) > Cr (30.09) > As (21.59). The contamination levels of APMs from these sites, calculated from the total content indices ICF, were uniformly moderate in degree. The obtained single-metal model MI_MERSS (speciation index) values had allowed for classification of elements as a function of their potential ecological risk as As (64.00 mean value) > Pb (43.86) > Sr (37.50) > Cu (11.53) ? Ba (11.32) > Zn (7.68) > Cr (1.88). The results presented that the toxic As posed a moderate to considerable risk; Pb and Sr varied from low to a moderate risk, while others posed low risk. However, a new developed multi-metal model GRI_IERMS (speciation index) indicated that the PHEs in most of the APMs posed moderate ecological risk. The result was consistent with that of ICF indexes. Combined with the US Environmental Protection Agency, we developed models of (ingestion, dermal and inhalation) hazard index (HI), children’s health risk due to PHEs exposure from APM was higher than that for adults. Much attention should be paid to the PHE As (HI = 0.864, close to 1) for children. While, carcinogenic risk for adults was higher than that for children. Although cancer risk because of As, Cr and Pb exposure were within an acceptable range, the PHEs exposed to the highest density of the population in residential and educational villages in south of Xi’an would be much more concerned. The moderate ecological risk and the higher risk for children’s health illustrated that special attention has to be taken to the mentioned PHEs from APMs in the local ecosystem, and their health risk impact should continue to be checked carefully. The new developed GRI_IERMS index method was to be useful for risk assessment of PHEs combining with their chemical fractionations.     

Assessment of Cyclone Lehar’s impact on seagrass meadows in Ross and Smith Islands,North Andaman

Cyclonic storms are large-scale disturbances which cause extensive damage in coastal ecosystems. On 25 November 2013, Cyclone Lehar made a significant impact on the coastal areas of Andaman and Nicobar Islands. We observed the pre- and post-Lehar cyclonic effects on the seagrass meadows at Ross and Smith Island, North Andaman. The study indicates that the seagrass meadows are composed of Halodule uninervis, Halophila ovalis, Halodule pinnifolia and Thalassia hemperichii species. Seagrass beds of approximately 1.96 ha (approx. 63 %) were destroyed in the cyclone.     

Spatial distribution of heavy metals and arsenic in soils of Aragón (northeast Spain): controlling factors and environmental implications

Legal regulation of heavy metal contents is an important issue in many European countries, where laws still do not exist establishing the heavy metal levels permitted in soils. As a first step to determine the reference levels of heavy metals, it is necessary to know their contents in soils under natural conditions. To achieve this goal in the Autonomous Community of Aragón, a total of 133 sites have been sampled. A balanced allotment of the sampling sites, according to soil spatial distribution in the region, has been carried out by selecting 9 soil types that represent 97.5% of its surface area. Fifteen elements (Cr, Cu, Ba, As, Sb, Hg, Sn, Mn, Fe, Al, Zn, Ni, Co, Cd and Pb) have been analysed by (ICP–AES) after a partial acid extraction. The content of analysed elements has been correlated to some soil parameters such as organic matter, pH, and granulometric fractions. Results of the statistical analyses have shown a large variety and complexity in some of these relationships. The main factors for variation in the heavy metal contents are both the soil type and the lithology. Gypsisols and Calcisols developed on sedimentary rocks have the lowest contents while Leptosols overlying metamorphic and igneous rocks have the highest contents. The spatial distribution of heavy metal contents shows a large variability with the highest contents in the mountain ranges (Iberian and Pyrenees) and the lowest in the plains of the central Ebro valley.     

Krieger’s conceptualization and measurement of discrimination and internalized oppression in studies of adverse health outcomes

Embodiment is a central concept in Krieger’s ecosocial theory, and is said to be of relevance to the understanding of the relationship between social conditions and a variety of adverse health outcomes. The most detailed empirical investigation of this in Krieger’s work is to be found in her studies of the relationship between racial discrimination and high blood pressure. Of especial relevance here is the idea of internalized oppression which is said to explain the observed association between self-reports of no racial discrimination and increased levels of blood pressure among working-class African Americans. Here we critically examine the empirical evidence pertaining to internalized oppression. Specifically, we focus on the measurement of the construct and the quality of the empirical evidence that has been presented in support of the hypothesis that there is an association between internalized oppression and adverse health outcomes. We argue that the validity of the concept has yet to be established and that the available data linking it to poor health outcomes are open to alternative explanations, notably measurement error and misclassification.

---

Special and seasonal variations of trace metals in PM_(10) in Chongqing

1Introduction Tracemetalsarereleasedtotheatmosphereduring combustionoffossilfuelsandwood,aswellasemis sionsfromavarietyofprocessesactingoncrustalmin erals,includingvolcanism,erosionandsurfaceweath ering.Onaglobalscale,resuspendedsurfacedusts havemadeagreatcontributiontothetotalnaturale missionoftracemetalstotheatmosphere,withCr,Mn andVaccountingfor>50%andCu,Mo,Ni,Pb,Sb andZnaccountingfor>20%,whilevolcanicactivity probablygeneratedasmuchas20%atmosphericCd,Hg,As,Cr,Cu,Ni,PbandSb(Pacyna,19…