Average Concentrations Of As Research Articles

Assessment of some potential harmful trace elements (PHTEs) in the borehole water of Greater Giyani, Limpopo Province, South Africa: possible implications for human health.

The present investigation was conducted in order to evaluate the occurrence and distribution patterns of some potentially harmful trace elements in the borehole water of the Greater Giyani area, Limpopo, South Africa, and their possible implications on human health. Twenty-nine borehole water samples were collected in the dry season (July/August 2012) and another 27 samples from the same localities in the wet season (March 2013) from the study area. The samples were analysed for trace elements arsenic (As), cadmium (Cd), chromium (Cr), selenium (Se), and lead (Pb) using the inductively coupled plasma mass spectrometry technique. The average concentrations of As, Cd, Cr, Se, and Pb were 11.3, 0.3, 33.1, 7.1, and 6.0µg/L in the dry season and 11.0, 0.3, 28.3, 4.2, and 6.6µg/L inthe wet season, respectively. There was evidence of seasonal fluctuations in concentrations of all analysed elements except for As, though Cd and Pb displayed low concentrations (<0.2 and <6.0µg/L, respectively) in almost all sampled boreholes. Se and Cr concentrations slightly exceed the South African National Standard permissible limits for safe drinking water in few boreholes. A total of four boreholes exceeded the water quality guideline for As with two of these boreholes containing five times more As than the prescribed limit. The spatial distribution patterns of elevated As closely correlate with the underlying geology. The findings of this investigation have important implications for human health of the communities drinking from the affected boreholes.

Assessment of heavy metal pollution and human health risk in urban soils of a coal mining city in East China

ABSTRACTThe aims of this study were to determine the concentrations, distribution, potential ecological risk (PER), and human health risk (Risk) of heavy metals in urban soils from a coal mining city in China. A total of 36 topsoil samples from Huainan city, Anhui, East China, were collected and analyzed for As, Hg, Pb, Cd, Cr, and Cu. The PER was calculated to assess the pollution level. The hazard index (HI) and carcinogenic risk were used to assess the human health risk of heavy metals in the study area. The average concentration of As, Hg, Pb, Cd, Cr, and Cu were 12.54, 0.21, 24.21, 0.19, 49.39, and 21.74 mg kg−1, respectively. The correlations between heavy metals indicated that Cu, Cr, Cd, and Pb mainly originated from automobile exhaust emissions, coal gangue, fly ash, and industrial wastewater, and that As and Hg mainly came from coal combustion exhaust. The PER index values of heavy metals decreased in the following order: Hg > Cd > As> Cu > Pb > Cr. The HI and Risk values indicated that the noncarcinogenic and carcinogenic risks of selected metals in the urban soil were both below the threshold values.

Simultaneous Determination of Arsenic, Cadmium, Mercury, and Lead in Raw Ingredients, Nutritional Products, and Infant Formula by Inductively Coupled Plasma Mass Spectrometry: Single-Laboratory Validation.

A method was developed for the determination of As, Cd, Hg, and Pb in raw ingredients, nutritional products, and infant formula using inductively coupled plasma mass spectrometry (ICP-MS). Three raw ingredients (acid casein, maltodextrin, skim milk powder) and three standard reference materials [NIST 1548a (Typical Diet), NIST 1577c (Bovine Liver), NIST SRM 1568b (Rice Flour)] obtained from the National Institute of Standards and Technology were analyzed by two analysts using two ICP-MS instruments in different laboratories. NIST SRM 1568b was used as the control sample. All protocol validation parameters (intermediate precision, accuracy, linearity, quantitation limit, specificity, and robustness) were met. The overall precision (n = 8) for analyte concentrations (2.5-300 ng/g) ranged from 2 to 14% RSD. Spike recoveries ranged from 88 to109% for spike levels between 25 and 200%. The overall average concentration of As, Cd, Hg, and Pb measured in all three NIST SRMs were within the certified value ranges. Good linearity (correlation coefficient (r) = 0.9995 or better) was obtained for all analytes. Control chart results for 8 independent days showed that the method is robust (precision values of 10% and all points within ±3 σ were obtained). Excellent specificity was also demonstrated when the analytes were measured in the presence of high concentrations of the other concomitants.

Contamination, toxicity and risk assessment of heavy metals and metalloids in sediments of Shahid Rajaie Dam, Sefidrood and Shirinrood Rivers, Iran

In this paper, the heavy metals and metalloids (As, Cd, Co, Cr, Ni, Cu, Pb and Zn) levels were studied to investigate their contamination and ecological effects in surface sediments of Shahid Rajaie Dam Lake and two major upstream rivers. Contamination factor and modified degree of contamination values indicate a very low to considerable contamination effects for the studied sediments while pollution load index indicates no pollution (except five stations). The comparison of selected elements concentrations with sediment quality guidelines reveal that the average concentration of As, Cr and Ni in the present sediments is higher than threshold effect level. In addition, Ni shows higher concentration than probable effect level and effect range low values. These sediments based on PELQ and ERMQ calculations, for Cr, As, Cd, Zn, Cu, Ni and Pb are slightly toxic. The result of enrichment factor evaluation similarity to principal component analysis indicates that the main source of Pb, Cd, and Zn for 15.38–42.3 percentages of samples is anthropogenic. PC1 agrees with the measured enrichment factor suggesting a geogenic source for Cu, Mn, As, Cr, Al, Co, Ni and Sc in the sediment samples. Higher positive loadings of P with Ni and Co for a small number of sediment probably indicate amplified concentration due to anthropogenic sources such as application of phosphorus fertilizers in the agricultural lands. High positive loading of Pb, Zn and Cd with organic carbon (OC) and clay reveals a significant role of OC and clay in the dissolution and distribution of Pb, Zn and Cd in the dam’s lake sediments. In summary, the present study has provides a practical baseline data for the long-term monitoring of heavy metals pollution in the study area.

Assessment of metal contamination in groundwater and soils in the Ahangaran mining district, west of Iran.

In this study, 28 groundwater and 13 soil samples from Ahangaran mining district in Hamedan Province, west of Iran were collected to evaluate the level of contamination. Average concentrations of As, Cu, Pb, Zn, Mn, Sb, and Ni in groundwater samples were 1.39, 3.73, 2.18, 9.37, 2.35, 4.44, and 5.50μg/L (wet season), and 11.64, 4.92, 4.32, 14.77, 5.43, 4.12, and 0.98μg/L (dry season), respectively. Results of groundwater samples analysis showed that the average of analyzed metals in the wet and dry seasons were below the permissible limits, except As in the dry season which displays concentrations that exceed US EPA water quality criteria recommended for drinking water. Also, the heavy metal pollution index (HPI) values in each sampling station were less than the critical index limit and were suitable for drinking. Factor analysis revealed that variables influential to groundwater quality in one season may not be as important in another season. Average concentrations of Ag, As, Cd, Cu, Pb, Sb, and Zn in soil samples were 2.61, 31.44, 0.51, 55.90, 1284.9, 21.26, and 156.04mgkg(-1), respectively. The results of the geoaccumulation index (I geo) showed the following decreasing order: Pb > Zn > Cu > As > Sb > Cd > Ag. Potential ecological risk index (RI) suggests that the contamination in the investigated area is moderate to very high risk and the ranking of the contaminants in decreasing order is Ag > Sb > Pb > Cd > As > Cu > Zn.

Polybrominated diphenyl ethers (PBDEs) and heavy metals in road dusts from a plastic waste recycling area in north China: implications for human health.

Road dusts were collected from an area where intense mechanical recycling of plastic wastes occurs in Wen'an, north China. These dusts were investigated for polybrominated diphenyl ethers (PBDEs) and heavy metals contamination to assess the health risk related to these components. Decabromodiphenyl ether (BDE-209) and Σ21PBDE concentrations in these dusts ranged from 2.67 to 10,424 ng g(-1) and from 3.23 to 10,640 ng g(-1), respectively. These PBDE concentrations were comparable to those observed in road dust from e-waste recycling areas but were 1-2 orders of magnitude higher than concentrations in outdoor or road dusts from other areas. This indicates that road dusts in the study area have high levels of PBDE pollution. BDE-209 was the predominant congener, accounting for 86.3% of the total PBDE content in dusts. Thus, commercial deca-BDE products were the dominant source. The average concentrations of As, Cd, Cr, Cu, Hg, Pb, Sb, and Zn in these same dust samples were 10.1, 0.495, 112, 54.7, 0.150, 71.8, 10.6, and 186 mg kg(-1), respectively. The geoaccumulation index suggests that road dusts in this area are moderately to heavily polluted with Cd, Hg, and Sb. This study shows that plastic waste processing is a major source of toxic pollutants in road dusts in this area. Although the health risk from exposure to dust PBDEs was low, levels of some heavy metals in this dust exceeded acceptable risk levels for children and are of great concern.

Distributional characteristics and sources of elements in soil from typical area of Pearl River Delta economic zone, Guangdong Province, China

Dongguan City, located in the Pearl River Delta economic zone of China, is famous for its rapid developing township-enterprises in the past 30 years. A total of 759 composite soil samples, including 606 surface soil samples and 153 deep soil samples, have been collected in the city. These samples have been analyzed for 13 elements (Al, As, Cu, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Si, and Zn) and other parameters (pH values and organic matter) to evaluate the influence of anthropic activities on the soil environmental quality and to identify the spatial distribution of heavy metals and their possible sources. The results indicate that the average concentrations of heavy metals in soil were significantly lower than the threshold of the second grade of the Soil Environment Quality Standard in China (GB15618-1995) and the soil environmental quality in this area is comparatively good. But in comparison with local soil geochemical baseline values, As, Cd, Cu, Hg, Pb, and Zn have accumulated remarkably. Specifically, the average concentrations of As, Cd, Cu, and Hg in the small part samples of the west plain and central areas are higher than the national second-grade quality standard, indicating some level of contamination. Multivariate and geostatistical methods have been applied to differentiate the influences of natural processes and human activities on the concentration of heavy metals in surface soils in the study area. Cluster and factor analyses result in the grouping of Al, As, Cr, Cu, Fe, Ni, and Si into factor F1; Co, Mn, Pb, and Zn into F2; and Cd and Hg into F3. The spatial pattern of the three factors may be well demonstrated by geostatistical analysis. It is shown that the first factor could be considered as a natural source controlled by parent material. The second factor could be referred to as “industrial and traffic pollution sources”. The source of the third factor is mainly controlled by long-term anthropic activities, including agricultural activities, fossil fuel consumption, and atmospheric deposition.

Contamination of wetland soils and floodplain sediments from agricultural activities in the Cerrado Biome (State of Minas Gerais, Brazil)

The expansion and intensification of agriculture are responsible for the increase in nonpoint pollution and the release of chemical considered toxic to flora, fauna and human health. Since 1970s, the Cerrado Biome in the State of Minas Gerais (Brazil) has been converted to agriculture. This land use change has not been accompanied by research to evaluate pollution levels associated with inorganic elements in natural wetlands and river sediments. In this study samples were collected in natural wetlands and river sediments recently deposited in floodplain areas to determine the total concentration of inorganic compounds that can be considered potentially toxic and to perform risk assessment. The total concentration of 18 elements (As, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, V, Zn and Zr) and oxides present at the organic soil layer (0–30cm) and at the mineral subsurface horizon (30–60cm) of the wetlands in the upper oxidized layer (0–10cm) of sediments was determined by ICP-OES and XRF. Contamination levels were determined and a risk assessment performed by comparing the obtained values with those proposed by the Guidelines for Agricultural Soils of Brazil (CONAMA no. 420) as well as the pedogeochemical background for soils formed from sandstone. The results showed high average concentrations of As, Cr and Cu in soils and floodplain sediments (as well as of Ba, Pb and Ni in some samples) with values exceeding (p significant at 5%) the pedogeochemical background and the threshold value for clean soil established by CONAMA. The concentrations of As and Cr in the soil were above the threshold level in 100% and 60% of samples, respectively, which may impact the environment and living organisms. The calculated contamination index (Pi) indicates that the wetlands exhibit moderate contamination (2<Pi≤3) by As>Cr>Cu in the topsoil and in the sub-superficial horizons whereas the floodplain sediments exhibit either no contamination (Pi≤1) or low level of contamination (1<Pi≤2). When compared with sediments, the results suggest that the Cerrado wetland soils have a tendency to acquire pollutants and thus store agrochemicals. This poses a real risk to the environment and living organisms if no BMP are established.

Trace elements in major marketed marine bivalves from six northern coastal cities of China: Concentrations and risk assessment for human health

One hundred and fifty nine samples of nine edible bivalve species (Argopecten irradians, Chlamys farreri, Crassostrea virginica, Lasaea nipponica, Meretrix meretrix, Mytilus edulis, Ruditapes philippinarum, Scapharca subcrenata and Sinonovacula constricta) were randomly collected from eight local seafood markets in six big cities (Dalian, Qingdao, Rizhao, Weifang, Weihai and Yantai) in the northern coastal areas of China for the investigation of trace element contamination. As, Cd, Cr, Cu, Hg, Pb and Zn were quantified. The risk of these trace elements to humans through bivalve consumption was then assessed. Results indicated that the concentrations of most of the studied trace element varied significantly with species: the average concentration of Cu in C. virginica was an order of magnitude higher than that in the remaining species; the average concentration of Zn was also highest in C. virginica; the average concentration of As, Cd and Pb was highest in R. philippinarum, C. farreri and A. irradians, respectively. Spatial differences in the concentrations of elements were generally less than those of interspecies, yet some elements such as Cr and Hg in the samples from different cities showed a significant difference in concentrations for some bivalve species. Trace element concentrations in edible tissues followed the order of Zn>Cu>As>Cd>Cr>Pb>Hg generally. Statistical analysis (one-way ANOVA) indicated that different species examined showed different bioaccumulation of trace elements. There were significant correlations between the concentrations of some elements. The calculated hazard quotients indicated in general that there was no obvious health risk from the intake of trace elements through bivalve consumption. But care must be taken considering the increasing amount of seafood consumption.

Current status and developing trends of the contents of heavy metals in sewage sludges in China

It is essential to determine the heavy metal concentrations in sewage sludge to select appropriate disposal methods. We conducted a national survey of heavy metal concentrations of sewage sludge samples from 107 municipal sewage treatment plants located in 48 cities covering the 31 provinces and autonomous regions, as well as Hong Kong, Macao and Taiwan by Xinjiang Production and Construction Corps in 2006, and identified the temporal trends of heavy metal contents in sewage sludge by comparison with surveys conducted in 1994–2001. In 2006, the average concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in sewage sludge were 20.2, 1.97, 93.1, 218.8, 2.13, 48.7, 72.3, and 1058 mg·kg−1, respectively. Because of the decreased discharge of heavy metals into industrial wastewater in China and the increasingly stringent regulations governing the content of industrial wastes entering sewers, the average concentrations of Cd, Cr, Cu, Hg, Ni, Pb, and Zn have decreased by 32.3%, 49.7%, 54.9%, 25.0%, 37.2%, 44.8%, and 27.0%, respectively, during the past 12 years. The concentrations of Cd, Cr, Cu, Ni, and Zn in the samples exceeded the heavy metal limits of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant in China (GB 18918-2002) by 6.5%, 3.7%, 6.5%, 6.5%, and 11.2%, respectively. From these results, 85 of the 107 municipal sludges analyzed would be considered suitable for land application.

Characterization of Soil Contamination in Miduk Mining District, SW Iran

In this study, 30 soil samples were collected from 0–5 cm and 15–20 cm depths in the vicinity of the Miduk Porphyry Copper Mine in Kerman Province, southeast Iran. The samples were analyzed for total concentrations of eight potentially toxic elements. The bioavailability of trace elements is determined using sequential extraction analysis. Average concentrations of As, Cd, Cr, Cu, Mo, Ni, Pb, and Zn in soil samples are 26.9, 0.49, 56.31, 201.18, 1.77, 45.6, 83.87, and 191.94 mg kg−1, respectively. Also, to assess the bioaccumulation of the analyzed elements, the roots and the leaves of three plant species were sampled and analyzed. The mobility of the analyzed trace elements shows the following decreasing order: Cd > Mo > Ni > Zn > Cu > Cr >Pb> As. The distribution pattern of elements indicates that elemental concentration in Miduk soils is highly influenced by bedrock composition, while soil pollution is mostly affected by ancient mining.

Chemometric study of trace elements in hard coals of the upper Silesian Coal Basin, Poland.

The objective of the study was the analysis of trace elements contents in coals of the Upper Silesian Coal Basin (USCB), which may pose a potential threat to the environment when emitted from coal processing systems. Productive carbon overburden in central and southern zones of the USCB is composed mostly of insulating tertiary formations of a thickness from a few m to 1,100 m, and is represented by Miocene and Pliocene formations. In the data study the geological conditions of the coal seams of particular zones of the USCB were taken into account and the hierarchical clustering analysis was applied, which enabled the exploration of the dissimilarities between coal samples of various zones of the USCB in terms of basic physical and chemical parameters and trace elements contents. Coals of the northern and eastern zones of the USCB are characterized by high average Hg and low average Ba, Cr, and Ni contents, whereas coals of southern and western zones are unique due to high average concentrations of Ba, Co, Cu, Ni, and V. Coals of the central part of the USCB are characterized by the highest average concentration of Mn and the lowest average concentrations of As, Cd, Pb, V, and Zn.

Environment Quality Evaluation of Heavy Metals in Agricultural Soils of Shilou Town in Fangshan District of Beijing

Concentration of 7 heavy metals in 269 topsoil samples were determined which collected from Shilou town of Fangshan district in Beijing, and the data was analyzed by the single factor index and the Nemerow index for the soil environment quality evaluation. The mean values of the heavy metals were 8.24 ± 1.42, 0.209 ± 0.07, 62.99 ±8.89, 0.133 ± 0.11, 25.29 ± 5.02, 23.91 ± 5.72 and 86.29 ± 28.13 mg kg-1 for As, Cd, Cr, Hg, Cu, Pb, and Zn, respectively. Average concentration of As, Cd, Cr, Cu and Zn exceeded the background value of Beijing area. It was found that all heavy metals were not in normal distribution. The soil environment quality was evaluated by single factor pollution index and Nemerow index of heavy metals. The order of single factor index was Cd, Zn, Hg, Cu, Cr, Pb, As in decreasing. Average Nemerow index of soil was 0.918. This value was reached to the grade III standard of soil environmental quality assessment classification.

Origin identification method by multiple trace elemental analysis of short-neck clams produced in Japan, China, and the Republic of Korea

The correlations among the contents of trace elements in the shells of short-neck clams collected from Japan, China, and the Republic of Korea were examined. Origin-specific elemental content patterns were seen in clams originating from Japan, China, and the Republic of Korea. The crushed shells were decomposed with nitric acid–hydrogen peroxide, and the concentrations of ten elements (Li, V, Mn, Co, As, Rb, Mo, Ba, Pb, and U) in the shells were measured by inductively coupled plasma mass spectrometry. Some of the metal concentrations in the samples displayed clear geographical trends. The average concentration of Pb in Japanese clam shells was one-half to one-quarter that seen in Chinese or Korean clams. Average concentrations of As, Rb, and Ba in shells of Japanese origin were one-half those observed in Chinese or Korean clams. Linear discriminant analysis was applied to these analytical data, and four discriminant models were constructed. These discriminant models were able to distinguish the geographic origins of short-neck clams with 80.0–100 % accuracy. In particular, clams of Japanese origin were classified correctly ≥90 % of the time. Therefore, the trace elemental analysis of a short-neck clam shell is useful for identifying the country of origin of the clam.

DISTRIBUTION PATTERN OF HEAVY METALS IN THE SURFACE SEDIMENTS AND ENVIRONMENT QUALITY EVALUATION FOR THE YANGTZE RIVER DELTAIC ECONOMIC ZONE

This paper,based on the 1871 of geochemical data of surface sediments and other geological data,deals with the contents and distribution pattern of heavy metals in the Yangtze River Delta Economic Zone.The results show that,in the surface sediments of the study area,the average contents of As,Cd,Cr,Cu,Hg,Pb,Zn are 8.12×10-6,101.53×10-9,74.79×10-6,19.33×10-6,34.87×10-9,22.31× 10-6,and 67.13×10-6respectively.The higher values of heavy metal elements appear in the area from the Xiangshan to the Yueqing Bay,while the lower values occur along the Jiangsu coast.The comprehensive index method was adopted for environmental quality assessment.It is revealed that the heavily polluted area is located along the channel of the Yangtze River,while slightly polluted area is near the Yangtze River Estuary and the area off Ningbo and Wenzhou.The area along the Jiangsu coat is rather clean.

Geochemical investigation of selected elements in coastal and riverine sediments from Ube, Kasado, and Suo-Oshima Bays in the western Seto Inland Sea, Southwest Japan

This paper presents the geochemical study of sediments along Ube, Suo-Oshima, and Kasado Bays in the Seto Inland Sea of Japan. We examined the distribution and abundances of 13 elements (As, Pb, Zn, Cu, Ni, Cr, Sr, Ca, Fe, Ti, P, Mn, and total S) in 40 coastal and river sediment samples, to evaluate the factors controlling their abundances, possible sources, and environmental implications. Average concentrations of As, Pb, Zn, Cu, Ni, and Cr at Ube were 12, 26, 86, 16, 43, and 92 mg/kg, 6, 25, 31, 8, 9, and 29 mg/kg at Kasado, and 5, 20, 28, 3, 5, and 18 mg/kg at Suo-Oshima, respectively. Average As, Pb, Zn, and Cr concentrations at Ube were comparable or enriched relative to those of the upper continental crust and Japan upper crust, whereas most major elements, Cu, and Ni were depleted at Kasado and Suo-Oshima. Enrichment factor values show low to moderate enrichment of Zn, Ni, and Cr, whereas As and Pb show significant contamination at some sites, suggesting contributions from anthropogenic sources. Anthropogenic contributions of most metals mainly originate from natural processes; however, As and Pb ranges of 73–79 and 66–81 %, respectively, confirm their anthropogenic contribution. Factor analysis and correlation matrices suggest that elevated metal concentrations at Ube, especially in samples located in the river basin, may be controlled by Fe–Mn oxy-hydroxides. Deposition of metals at Kasado and Suo-Oshima might be controlled by non-ferrous metal (i.e., aluminosilicates), sediment grain size, or source rock composition (granite and gneiss).

국내 유통 버섯 중 중금속 함량 조사 및 위해성 평가

BACKGROUND: Many edible mushrooms are known to accumulate high levels of heavy metals. This research was focused on health risk assessment to investigate the mushrooms in Korea, arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) contaminations in edible mushrooms in cultivated areas were investigated, and health risk was assessed through dietary intake of mushrooms. METHODS AND RESULTS: The heavy metals in mushrooms were analyzed by ICP/MS after acid digestion. Probabilistic health risk were estimated by Monte-Carlo simulation techniques. The average contents of As, Cd, Pb, and Hg were mg/kg, mg/kg, mg/kg, and mg/kg, respectively. The results showed that contents of Cd and Pb did not exceed maximum residual levels established by European Uion regulation (Cd 0.20 mg/kg and Pb 0.30 mg/kg). For health risk assessment, estimated intakes in all age populations did not exceed the provisional tolerable daily intake of As and Hg, provisional tolerable monthly intake of Cd, provisional tolerable weekly intake of Pb. The Hazard Index (HI) were ranged from for As, for Cd, for Pb, and for Hg at general population. CONCLUSION: The HI from the ratio analysis between daily exposure and safety level values was less than 1.0. This results demonstrated that human exposure to heavy metals through dietary intake of mushrooms might not cause adverse effect.

Can a River Heal Itself? Natural Attenuation of Metal Contamination in River Sediment

Sediment sampling of bed sediment from a large river contaminated by mining and smelting was used to determine rates of natural attenuation of metal concentrations. A "natural decay model" was developed from high-resolution temporal data and used to predict when restoration guidelines would be met without restoration and with various degrees of restoration success. The natural decay model estimates that in the most contaminated reaches it will take about 90 years for average concentrations of As, Cd, Cu, Pb, and Zn to fall below "probable effects concentrations" (PEC), i.e. levels above which we expect to see adverse environmental effects. At sites farther downstream, all metals will fall below PEC in <35 ± 8 years. It will take longer to reach "threshold effects concentrations" (TEC), i.e. concentrations at which no effects are expected. But, even in the most contaminated reaches, Cd, Pb, and Zn will reach TEC in <80 ± 57 years, while Cu and As will take ~200 years. Model simulations with different levels of remediation success show that recovery is highly dependent on source reduction and how far the goal is from the basin background concentration. Furthermore, beneficial effects of restoration may be unexpectedly small: for example a likely decrease of ~20% in the source concentration would shorten the time to reach the Cu PEC by only 13 years. We argue that conducting analyses like these can provide insight into remediation approaches and ultimately decrease the cost of restoration by identifying the role of natural attenuation in restoration design and implementation.

Measuring and Modeling Atmospheric Arsenic Pollutants, Total As, As(III), and As(V), at Five Characteristic Sampling Sites

This investigation determines ambient air arsenic (As), As(III), and As(V) concentrations in total suspended particulates (TSP) and dry deposition. Calculated/measured dry deposition flux ratios of ambient air As, As(III) and As(V) were evaluated using two dry deposition models at five characteristic sampling sites during 2009-2010.The highest average concentrations of As, As(III) and As(V) in TSP and dry deposition were measured at the Quan-xing industrial sampling site during August-January. The Quan-xing site, with many industrial factories under process around there regions, its air is extremely polluted. In addition, the average dry deposition velocities for ambient air total arsenic (As) at Bei-shi, Chang-hua, He-mei, Quanxing and Gao-mei were 0.60 (cm/sec), 0.57 (cm/sec), 0.73 (cm/sec), 0.67 (cm/sec) and 0.66 (cm/sec), respectively at these five characteristic sampling sites. The highest average seasonal variation for As, As(III) and As(V) in TSP and dry deposition were in winter and fall due to emissions from fossil fuel combustion by the nearby Taichung Thermal Power Plant (TTPP) and for household heating. The Noll and Fang model can be applied to predict dry deposition of As, As(III), and As(V) at these sampling sites.

Speciated arsenic in air: Measurement methodology and risk assessment considerations

Accurate measurement of arsenic (As) in air is critical to providing a more robust understanding of arsenic exposures and associated human health risks. Although there is extensive information available on total arsenic in air, less is known on the relative contribution of each arsenic species. To address this data gap, the authors conducted an in-depth review of available information on speciated arsenic in air. The evaluation included the type of species measured and the relative abundance, as well as an analysis of the limitations of current analytical methods. Despite inherent differences in the procedures, most techniques effectively separated arsenic species in the air samples. Common analytical techniques such as inductively coupled plasma mass spectrometry (ICP-MS) and/or hydride generation (HG)- or quartz furnace (GF)-atomic absorption spectrometry (AAS) were used for arsenic measurement in the extracts, and provided some of the most sensitive detection limits. The current analysis demonstrated that, despite limited comparability among studies due to differences in seasonal factors, study duration, sample collection methods, and analytical methods, research conducted to date is adequate to show that arsenic in air is mainly in the inorganic form. Reported average concentrations of As(III) and As(V) ranged up to 7.4 and 10.4 ng/m⊃, respectively, with As(V) being more prevalent than As(III) in most studies. Concentrations of the organic methylated arsenic compounds are negligible (in the pg/m3 range). However, because of the variability in study methods and measurement methodology, the authors were unable to determine the variation in arsenic composition as a function of source or particulate matter (PM) fraction. In this work, the authors include the implications of arsenic speciation in air on potential exposure and risks. The authors conclude that it is important to synchronize sample collection, preparation, and analytical techniques in order to generate data more useful for arsenic inhalation risk assessment, and a more robust documentation of quality assurance/quality control (QA/QC) protocols is necessary to ensure accuracy, precision, representativeness, and comparability. Implications: The detailed review of the speciation techniques for arsenic in air samples presented in this study showed that (1) a variety of efficient methods (sampling, extraction, and analytical) developed across research studies were available for the determination of arsenic species in air; (2) arsenic species in the air were predominantly inorganic forms; and (3) the organic forms in air were largely below detection limits. Despite these general findings, more consistent methods must be developed to understand potential risks from arsenic in ambient air. Research needs to advance air arsenic risk assessment are identified.