Occurrence Of Arsenic Research Articles

Geomorphic controls on shallow groundwater arsenic contamination in Bengal basin, India.

The study was conducted to explore the influence of geomorphic features scattered throughout the area on the occurrence and distribution of arsenic in shallow groundwater. GIS techniques were frequently used to identify the geomorphic features and to correlate with arsenic distribution patterns. The study shows that the occurrence of geomorphic features and their distribution have a vital role in the heterogeneous distribution pattern of arsenic in shallow groundwater. The frequency distribution of geomorphic features is found similar to the arsenic distribution pattern. The moderate to highly contaminated zones are mostly consolidated to the central and southeastern part of the study area. Arsenic contamination levels are varying in different fluvial plains of the study area following the trend of Older Deltaic Plain (ODP) > Older Flood Plain (OFP) > Active Flood Plain (AFP). It has also been observed that arsenic contamination along the different geomorphic features follows the trend of abandoned channels > back swamps > other water bodies > swamps > cut-off meanders > meander scars > ponds > oxbow lakes > channel bar > point bars >channel islands. The present study indicates that the geomorphic features play a significant role in the mobilization of arsenic in shallow groundwater by supplying accumulated organic matter.

Seven potential sources of arsenic pollution in Latin America and their environmental and health impacts.

This review presents a holistic overview of the occurrence, mobilization, and pathways of arsenic (As) from predominantly geogenic sources into different near-surface environmental compartments, together with the respective reported or potential impacts on human health in Latin America. The main sources and pathways of As pollution in this region include: (i) volcanism and geothermalism: (a) volcanic rocks, fluids (e.g., gases) and ash, including large-scale transport of the latter through different mechanisms, (b) geothermal fluids and their exploitation; (ii) natural lixiviation and accelerated mobilization from (mostly sulfidic) metal ore deposits by mining and related activities; (iii) coal deposits and their exploitation; (iv) hydrocarbon reservoirs and co-produced water during exploitation; (v) solute and sediment transport through rivers to the sea; (vi) atmospheric As (dust and aerosol); and (vii) As exposure through geophagy and involuntary ingestion. The two most important and well-recognized sources and mechanisms for As release into the Latin American population's environments are: (i) volcanism and geothermalism, and (ii) strongly accelerated As release from geogenic sources by mining and related activities. Several new analyses from As-endemic areas of Latin America emphasize that As-related mortality and morbidity continue to rise even after decadal efforts towards lowering As exposure. Several public health regulatory institutions have classified As and its compounds as carcinogenic chemicals, as As uptake can affect several organ systems, viz. dermal, gastrointestinal, peptic, neurological, respiratory, reproductive, following exposure. Accordingly, ingesting large amounts of As can damage the stomach, kidneys, liver, heart, and nervous system; and, in severe cases, may cause death. Moreover, breathing air with high As levels can cause lung damage, shortness of breath, chest pain, and cough. Further, As compounds, being corrosive, can also cause skin lesions or damage eyes, and long-term exposure to As can lead to cancer development in several organs.

Variability in groundwater flow and chemistry in the Mekong River alluvial aquifer (Thailand): implications for arsenic and manganese occurrence

Arsenic (As) is widespread in alluvial aquifers along rivers draining the Himalayas but has received little attention along the Mekong River upstream of its delta. This study investigates linkages among groundwater recharge, flow, chemistry, and river stage at two sites along the Mekong River in northeast Thailand. Hydraulic head and chemistry were monitored in January and June 2014. In addition, hydraulic head and electrical conductivity were continuously logged at one site from January 2014 to March 2015. During the dry season, groundwater tends to flow toward the river, and saline water from shallow evaporites can intrude the alluvial aquifer. As stage rises, hydraulic-gradient reversals can result in groundwater-river water mixing, thereby promoting geochemical disequilibrium. Groundwater chemistry reflects silicate, carbonate, and evaporite weathering; multiple redox reactions; and spatial and temporal variability in recharge. Concentrations of As and manganese (Mn) in groundwater exceeded drinking-water guidelines by as much as an order of magnitude. Results suggest As is mobilized in groundwater by reduction of ferric (oxyhydr)oxides, consistent with the findings elsewhere in South and Southeast Asia. Upwelling of saline water can increase the solubility of (oxyhydr)oxide phases that sequester Mn and As, can complex Mn and can mobilize adsorbed As oxyanions. Conversely, influxes of oxic river water could promote (oxyhydr)oxide precipitation.

Synchrotron X-ray fluorescence and X-ray absorption near edge structure of low concentration arsenic in ambient air particulates

Utilizing the tunability of the synchrotron radiation, the occurrence of arsenic in coarse and fine particulates was investigated. Arsenic is mainly released from industrial sources and tends to settle at its source of provenance.

Footprint of Arsenic Contamination in Sediments and Water from Mining Sites – A case study based on multivariate optimization by GF AAS

Arsenic contamination is worrisome in mineral exploration regions. Efficient arsenic monitoring is dependent on detectability at trace level in environmental matrices. This paper presents a procedure to evaluate the occurrence of arsenic in environmental sediment and water samples collected from a mining area in Catalão, Goiás State (GO), Brazil. The water and sediment samples were analyzed by graphite furnace atomic absorption spectrometry (GF AAS) after appropriate chemical treatment. For the arsenic determination, analytical performance was improved employing multivariate tools. The instrumental conditions were optimized using a 23 factorial design and the response surface methodology (RSM) was applied with a central composite design (CCD). Iridium was used as a permanent modifier. The results for the sediment samples showed arsenic concentrations below the threshold for adverse effects ranging from 2.06 to 3.82 mg Kg-1. The concentrations in water samples were below LOD. The LOD and LOQ were, respectively, 0.33 and 1.09 µg L-1 to water and digested sediment samples. Under the optimal conditions, the dynamic working range was linear of LOQ to 50.0 µg L-1. The method was applied to determine concentrations of arsenic in water and sediments collected from mining sites, which can be used to assess the availability of arsenic in the region.

Spatial distribution, occurrence, and health risk assessment of nitrate, fluoride, and arsenic in Bam groundwater resource, Iran

Evidence shows that exposure to high levels of arsenic, fluoride, and nitrate may be contributing to adverse hygienic effects. This work was carried out to detect the concentration of arsenic (As), fluoride (F−), and nitrate (NO3−) in the groundwater resource of Bam, southeastern Iran and approximate their health risk to citizenships. The GIS-mapping of As, F−, and NO3− concentrations was accomplished. As, F−, and NO3− concentrations in studied drinking water samples have been ranged from 9.26 to 14.65 μg/L, 0.91–1.12 mg/L, and 8.50–10.85 mg/L, respectively. Based on results, all measured concentrations of F− and NO3− were lower than the WHO standard value, while As levels were higher than the allowed value. The acquired findings revealed that the mean risk of As is 5.372 for oral hazard quotient (HQ) and 1.407 for dermal one. For F−, HQ values for children were computed above one for study areas, while all HQ values for adults were below one. The values of dermal and oral HQ for both groups obtained >1 for NO3−. Among studied contaminants, the carcinogenic risk (CR) values of As was more than one. The results showed that the carcinogenicity ratio of ‘children to adults’ is equal to 3.8 for As and 2.33 for NO3−. For all examined pollutants, the health risks of dermal exposure were less than that of oral. The levels of non-cancer and cancer risk for children were greater than those for adults. The highest non-carcinogenic risk in study areas was related to As. This research proposes that any attempt to mitigate the arsenic of the Bam citizenships must consider the health risk of As exposure from potable water.

Natural occurrence of arsenic in the soil and rice plant system in the Bashkandi Block of Barak Valley, Assam, Northeastern India

An effort has been made, perhaps for the first time, to elucidate the concentration of arsenic (As) in soil-rice plant systems in the Bashkandi Block of Barak Valley in Assam, Northeastern India. The present study found that the concentration of As in groundwater is much higher than the WHO permissible limit (10 μg/L) and ranges from 12 to 310 μg/L, and the level of concentration in the soil varies from 5.7 to 12.4 mg/kg. Chemical extraction and its analysis of As in the soil indicate that the pool of As is predominantly associated with organic matter and amorphous Fe-oxides and weakly associated with mobile fractions and loosely bounded As present in the soil. In addition, the extraction result shows a significant amount of As associated with pyrite. The rice plant analysis reveals that the concentration of As content ranges as follows: in grain, 0.9 to 1.51 mg/kg, followed by the husk, 1.1 to 1.35 mg/kg; straw 0.82 to 1.45 mg/kg and 8.2 to 57.9 mg/kg in the root. The root of the rice plant accumulated high amounts of As, followed by straw, husk, and grain. The correlation coefficient calculations indicate the pathway of As translocation along with Fe and S from the soil to the rice grain. The most prominent finding of this work is that the As concentration has a direct entry into the human food chain, and the population in the area seems to be exposed to As toxicity by ingestion of groundwater and rice.

Occurrence, predictors and hazards of elevated groundwater arsenic across India through field observations and regional-scale AI-based modeling

Existence of wide spread elevated concentrations of groundwater arsenic (As) across South Asia, including India, has endangered a huge groundwater-based drinking water dependent population. Here, using high-spatial resolution As field-observations (~3 million groundwater sources) across India, we have delineated the regional-scale occurrence of elevated groundwater As (≥10 μg/L), along with the possible geologic-geomorphologic-hydrologic and human-sourced predictors that influence the spatial distribution of the contaminant. Using statistical and machine learning method, we also modeled the groundwater As concentrations probability at 1 Km resolution, along with probabilistic delineation of high As-hazard zones across India.The observed occurrence of groundwater As was found to be most strongly influenced by geology-tectonics, groundwater-fed irrigated area (%) and elevation. Pervasive As contamination is observed in major parts of the Himalayan mega-river Indus-Ganges-Brahmaputra basins, however it also occurs in several more-localized pockets, mostly related to ancient tectonic zones, igneous provinces, aquifers in modern delta and chalcophile mineralized regions. The model results suggest As-hazard potential in yet-undetected areas. Our model performed well in predicting groundwater arsenic, with accuracy: 82% and 84%; area under the curve (AUC): 0.89 and 0.88 for test data and validation datasets. An estimated ~90 million people across India are found to be exposed to high groundwater As from field-observed data, with the five states with highest hazard are West Bengal (28 million), Bihar (21 million), Uttar Pradesh (15 million), Assam (8.6 million) and Punjab (6 million). However it can be much more if the modeled hazard is considered (>250 million). Thus, our study provides a detailed, quantitative assessment of high groundwater As across India, with delineation of possible intrinsic influences and exogenous forcings. The predictive model is helpful in predicting As-hazard zones in the areas with limited measurements.

Arsenic and lead in the indoor residential settings of different socio-economic status; assessment of human health risk via dust exposure.

In the present study, occurrence of arsenic (As) and lead (Pb) is reported in rural and urban household dust (floor and AC filter dust) of the Kingdom of Saudi Arabia (KSA). Several studies have found concerning concentrations of these toxic metals in indoor dust from different countries, but data from this region is missing. The association between studied toxic metals and different socioeconomic parameters was investigated. Furthermore, health risk associated with these toxic metals via dust exposure was evaluated for the Saudi population. Mean concentration of Pb was several times higher than As in both types of dust samples. AC filter dust was more contaminated with these metals than floor dust. Levels of Pb were up to 775ppm in AC filter dust from urban areas, while 167ppm in rural AC filter dust. Different socioeconomic parameters did not influence much on the presence of studied metals in both AC and floor dust. To estimate health risk from contaminated dust hazardous index (HI), hazardous quotient (HQ), and incremental lifetime cancer risk (ILCR) via dust ingestion, inhalation, and dermal contact was calculate using USEPA equations. The ILCR range for both toxic metals was within the tolerable range of reference values of USEPA (1 × 10-5 to 5 × 10-7). Nonetheless, HI was close to 1 for Pb via dust exposure for young urban children, which signifies the risk of non-carcinogenic health problems in studied area. Graphical abstract.

Redox Dependent Arsenic Occurrence and Partitioning in an Industrial Coastal Aquifer: Evidence from High Spatial Resolution Characterization of Groundwater and Sediments

Superlative levels of arsenic (As) in groundwater and sediment often result from industrial pollution, as is the case for a coastal aquifer in Southern Italy, with a fertilizer plant atop. Understanding conditions under which As is mobilized from the sediments, the source of that As, is necessary for developing effective remediation plans. Here, we examine hydrogeological and geochemical factors that affect groundwater As concentrations in a contaminated coastal aquifer. Groundwater has been subject to pump-and-treat at a massive scale for more than 15 years and is still ongoing. Nevertheless, As concentrations (0.01 to 100 mg/L) that are four orders of magnitude more than Italian drinking water standard of 10 μg/L are still present in groundwater collected from about 50 monitoring wells over three years (2011, 2016, and 2018). As was quantified in three different locations by sequential extractions of 29 sediment cores in 2018 (depth 2.5 m to −16.5 m b.g.l.), combined with groundwater As composition, the aqueous and solid partitioning of As were evaluated by partition coefficient (Kd) in order to infer the evolution of the contaminant plumes. Most sediment As is found in easily extractable and/or adsorbed on amorphous iron oxides/hydroxides fractions based on sequential extractions. The study shows that As contamination persists, even after many years of active remediation due to the partitioning to sediment solids. This implies that the choice of remediation techniques requires an improved understanding of the biogeochemical As-cycling and high spatial resolution characterization of both aqueous and solid phases for sites of interest.

Efficient and low-energy mechanochemical extraction of lead from dumped crystal glass waste

Glass waste dumps from crystal glass production is an health issue due to the occurrence of antimony, arsenic, cadmium and lead in crystal glass. Recovery of those elements could both decrease pollution and recycle metals in the circular economy. Pyrometallurgy is a potential recovery method, yet limited by high energy consumption. Here we tested a lower-energy alternative in which glass is mechanically activated in a ball mill and leached with nitric acid. Results show that mechanical activation destabilised the glass structure and resulted in 78% lead extraction during leaching at 95 °C. Temperature had the most significant effect on extraction, whereas acid concentration, from 0.5 to 3 M, and leaching time, from 0.5 to 12 h, had insignificant effects. In each experiment, 75% of the final extracted amount was achieved within 30 min. The study demonstrates potential for lead extraction from glass waste at lower acid concentration, shorter leaching time and lower temperature, of 95 °C, than traditional pyrometallurgical extraction, typically operating at 1100 °C.

ПРИРОДНЫЕ И ТЕХНОГЕННЫЕ ОСОБЕННОСТИ ЗАГРЯЗНЕНИЯ ПРИРОДНЫХ ВОД МЫШЬЯКОМ (NATURAL AND TECHNOGENIC FEATURES OF POLLUTION NATURAL WATER ARSENIC)

The problem of arsenic in drinking water, which causes a violation of human health, is revealed. The main ways of arsenic ingress from the lithosphere into drinking water are shown. In the earth's crust, arsenic is contained in rocky rocks, from where it under the influence of weathering processes passes into sedimentary rocks, alluvium and silts. When underground water passes through a section of the earth's crust containing arsenic in the form of its minerals, the water is saturated with arsenic. Chemical reactions of arsenic transition to easily soluble forms and its main compounds in natural waters are presented. The mechanism of arsenic migration in natural surface and underground waters is explained. In Bangladesh, about 60 million people use arsenic-contaminated groundwater as drinking water and are therefore at risk of poisoning. Detailed map of the world on the risk of arsenic contamination of natural fresh water. It is shown that in Kazakhstan there are numerous geogenic deposits and ore occurrences of arsenic, which naturally infect groundwater. The West Kalba ore belt, which is about 800 km long and 80-100 km wide, has been identified only within Eastern Kazakhstan, and its ore objects are represented by gold-arsenopyrite (with an arsenic content of up to 2-5 %) ores. In addition, Kazakhstan has a significant technogenic component of arsenic water pollution due to the influence of the mining industry: only in the dumps of the Ust-Kamenogorsk metallurgical plant, more than 300 thousand tons of arsenic mineral products have already accumulated, with an annual increase of 11 thousand tons. The method of disposal of such waste, as well as localization of arsenic from underground polluted waters on technogenic geochemical barriers, is described.

Arsenic-contaminated groundwater and its potential health risk: A case study in Long An and Tien Giang provinces of the Mekong Delta, Vietnam.

The occurrence of arsenic (As) in groundwater (drilled well water) that were used for drinking, cooking, and personal hygiene and its risks to human health in Long An and Tien Giang provinces (Mekong delta, Vietnam) were evaluated in this study. The average As concentrations were 15.92 ± 11.4μg/L (n = 24, Long An) and 4.95 ± 4.7μg/L (n = 24, Tien Giang). The average concentrations of As in Long An had not reached the WHO and QCVN 01: 2009/BYT healthy drinking water standard (10μg/L). When used as a source of water for drinking and daily activities, arsenic-contaminated groundwater may have a direct impact on human health. The risk assessment from groundwater established by the US Environmental Protection Agency (USEPA) was conducted. The risk assessment showed that the average cancer risk (CR) values were 8.68 × 10-4 (adults) and 2.39 × 10-3 (children) for Long An, and 2.70 × 10-4 (adults) and 7.43 × 10-4 (children) for Tien Giang. These results were significantly higher than the CR (1 × 10-4) proposed by the USEPA. The adverse health effect was therefore specifically warned by the use of arsenic-contaminated groundwater. This research offers valuable knowledge for efficient water management approaches to guarantee local communities' health protection.

Occurrence, speciation analysis and health risk assessment of arsenic in Chinese mitten crabs (Eriocheir sinensis) collected from China

Arsenic (As) is a major hazardous element in natural environments, and arsenic pollution is becoming an issue of concern worldwide. The more toxic inorganic arsenic, such as trivalent arsenite As(Ⅲ) and pentavalent arsenate As(Ⅴ), which normally can transform to organic arsenic compounds, such as arsenobetaine (AsB), arsenocholine (AsC), monomethyl arsenic acid (MMA), dimethyl arsenic acid (DMA), trimethyl arsenic acid (TMA), arsenosugars and arsenolipids. In this study, a total of 2130 individuals of Chinese mitten crabs were collected from seven locations and mixed to 71 samples. Total arsenic and six major species (AsC, AsB, DMA, MMA, As (Ⅲ), and As (Ⅴ)) were determined by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), respectively. The target hazard quotient (THQ) was utilized to evaluate the human health risk. The total arsenic concentration and totals for the six arsenic forms are 0.25–1.66 mg/kg and 0.05–1.19 mg/kg wet mass, respectively. Except for HH and LH, the six arsenic species concentrations accounted for more than 50.0 % of the total arsenic. The less toxic AsB is the most predominant in crabs, comprising 50.0 %–90.0 % of the sum of six types of arsenic. The more toxic inorganic arsenic only range from 0.01 to 0.21 mg/kg wet mass, much less than the limit content of 0.50 mg/kg inorganic As in crustacea. The THQ values of inorganic arsenic through the consumption of Chinese mitten crabs are estimated, and the values are all less than 1, indicating that intaking Chinese mitten crabs collected from China will not cause an appreciable hazard risk to human health.

Coal Mine Water Drainage: The Current Status and Challenges

Any form of mining is a potential threat to the environment. The extent of environmental degradation depends on the status of mine (working/abandoned), type of deposit, mining and processing methods and the geo-atmospheric conditions. Coal mining has huge impacts to local water resources, both surface and ground water. Surface waters are being contaminated through the discharge of mine water, which is also called mine drainage. Ground water is being contaminated due to pilfer of the aquifers. Coal mine drainage is found heavily acidic throughout the world. High acidic water also poses to contaminate with toxic heavy metal ions. Heavy metal pollution comprises the trace occurrences of elements, namely, arsenic, lead, cadmium, cobalt, copper and zinc, coming from the host rock on its exposure to mine drainage water in acidic environment. As the mine water flows over the host rock, metals are leached into the water and mix with the surface waterbodies. These chemicals can be highly toxic to humans and wildlife. Though the heavy metals can dissolve in mine drainage even in non-acidic pH conditions also, but leaching is increased manifold in the acidic environment. From underground coal mines, million liters of mine water is daily disposed to the natural water sources, which are commonly used by the local inhabitants. Most of the Indian coal mines are not generating acidic drainage due to dearth of pyrites in the seams. Thus, it is a common belief that Indian coal mine drainage does not need treatment for heavy metals and is directly discharged into the surface streams. This present study shows that despite the non-acidic mine drainage, Indian coal mine water comprises high heavy metal contaminants and demands immediate attention. It is also revealed that Indian coal mine drainage shows neutral/slightly alkaline water despite having significant iron content.

Experiment-based geochemical modeling of Arsenic(V) and Arsenic(III) adsorption onto aquifer sediments from an inland basin

Natural occurrence of groundwater arsenic (As) exists in many aquifers and threatens the health of hundreds of millions of people. Adsorption of As is critical to its distribution in aquifer groundwater, as it can lower dissolved As concentrations and provide a source for As mobilization. However, little is known about As adsorption onto aquifer sediments in inland basins. To fill this gap, we investigated As(V) and As(III) adsorption onto a brown sediment hosting low-As groundwater and two gray sediments hosting high-As groundwater sampled from an approximate flow path of the Hetao Basin, China. Those three sediments had total Fe contents of around 1.3% and As contents of around 9.0 μg/g. Arsenic(III) adsorption were kinetically faster than As(V) adsorption on the sediments. The characteristics of As(V) and As(III) adsorption both exhibited nonlinear isotherms, with adsorption decreasing with increases in pH from around 7 to 9 (typical ambient groundwater pH of inland basins). Generally, As(V) adsorption was greater than As(III) adsorption at pH < 7.5, whereas the opposite was true at pH > 7.5. Phosphate competed more strongly with As(V) adsorption than As(III) adsorption, while HCO3 competed more strongly with As(III) adsorption. Aqueous As(III) was oxidized to As(V) by interaction with the brown sediment, mainly due to its high content of extractable Mn(IV) oxides. Arsenic adsorption onto the sediments was primarily controlled by the content and crystallinity of their Fe(III) oxides. The brown sediment showed weaker affinity for As(V) and As(III) than the gray sediments, possibly due to the better crystallinity of the Fe(III) oxides in the brown sediment. In the two gray sediments containing Fe(III) oxides with similar crystallinities, the As adsorption capacity was related to the content of Fe(III) oxides. Geochemical models were developed to quantitatively simulate As(V) and As(III) adsorption onto aquifer sediments. Experimental data were approximated well by these models, indicating that As(V) adsorption decreases at elevated pH and PO4 concentration, while As(III) desorption is favored at high pH and concentrations of HCO3 and PO4. According to the models, the extent and kinetics of As(III) oxidation are controlled by the number of free oxidation sites in Mn(IV) oxides, pH, and As(III) concentration. This study suggests that the characteristics of As adsorption are highly dependent on the mineral phases existing in the sediments, which must be fully understood to quantify the reactive transport of groundwater As in aquifer systems.

Occurrence of arsenic in ultramafic rocks’ alterites from nickel mines in New Caledonia: implications for the contamination of surface waters

Arsenate As(V) and arsenite As(III) are toxic forms of arsenic in waters. The risk of As toxicity is high in small tropical islands because tap water is often provided from surface water, and As contamination of surface water is rarely studied. For instance, the risk is high in New Caledonia because 61% of the water comes from surface water, and nickel mines induce the dispersal of large quantities of ultramafic rocks’s alterites rich in iron oxide-hydroxide, which are known to be associated with arsenite and arsenate. Levels exceeding the World Health Organization standard of 10 µg L−1 have been detected in rivers downstream of Ni mines, yet there is a lack of systematic assessment. Here, we analyzed total and exchangeable As in alterites collected near three active mines. Arsenate and arsenite adsorption capacity was studied using batch experiments. The results show that alterite contains total As contents ranging from 0.20 to 5.14 mg kg−1, yet the primary mineralogical source of As remains unknown. No exchangeable arsenite was detected. Exchangeable arsenate amounted to 0.16 mg kg−1, thus meaning that 10.3% of the total As is easily mobile. The maximum adsorption capacity of arsenate and arsenite in mining sediments was 1.05 mg kg−1. Overall, our findings reveal that ultramafic rock alterites are a source of arsenic in surface water in the form of suspended particulate matter, 10.3% of which being easily soluble.

Co-culturing Hydrilla verticillata with rice (Oryza sativa) plants ameliorates arsenic toxicity and reduces arsenic accumulation in rice

Abstract Widespread occurrence of arsenic (As) in paddy agricultural fields and consequent accumulation of As in rice grains poses a great threat to human health. In the present study, the approach of co-culture of rice (Oryza sativa) and Hydrilla verticillata was studied to evaluate arsenic toxicity amelioration in rice. Rice plants of two varieties, Pooja and CO-50, grown under As stress (25 μ M) for 10 d showed significant decline in growth, photosynthetic pigments and protein content while an increase in malondialdehyde (MDA) and non-protein thiol (NP-SH) contents and guaiacol peroxidase (GPX) activity. The effects were attributable to significant As accumulation in both Pooja (185.35 μ g g−1 dw in root and 23.49 μ g g−1 dw in shoot) and CO-50 (846.61 μ g g−1 dw in root and 167.32 μ g g−1 dw in shoot). In rice-Hydrilla co-culture, significant improvement in growth and various biochemical parameters were observed in both varieties of rice as compared to As alone treatments. A significant decrease in As accumulation was also noticed in both Pooja (93.23 μ g g−1 dw in root and 8.37 μ g g−1 dw in shoot) and CO-50 (566.19 μ g g−1 dw in root and 94.36 μ g g − 1 dw in shoot). Hydrilla plants itself showed significant As accumulation when grown in co-culture with Pooja (476.36 μ g g−1 dw) or CO-50 (439.43 μ g g−1 dw). In conclusion, the co-culture of hydrilla plants with rice can be used as a low-cost, sustainable and feasible technology to ameliorate As toxicity and to reduce As accumulation in rice.

Occurrence of Trace Metals in Food Crops Grown on the Mbale Dumpsite, Uganda, and Human Health Risks.

Food crops can be used as biomonitors to assess potential public health food safety hazards from contaminated agricultural environments. Globally, more than 800 million people grow fruits, vegetables, and grains on urban garden soils with unknown health risks. This worldwide practice has exposed consumers to pathogenic and carcinogenic risks from locally grown and imported contaminated foodstuffs such as Amaranthus cruentus and Zea mays, traditional and widely consumed crops across the globe. This study used Z. mays and A. cruentus crops to investigate the occurrence and spatial variations of aluminum (Al), chromium (Cr), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations across the Mbale dumpsite, Uganda. Mean concentrations for Fe, Al, Zn, Mn, and Cu were high in both crops, whereas Pb, Cr, Co, Cd, As, Hg, Se, and Ni occurred in trace amounts. Using the 2 crops as biomonitors, significant variations for Al, Zn, Fe, Cr, and Co concentrations in individual crops were identified across the dump center, hill slope, and riverbank. The variations in Al, Zn, Fe, Cr, and Co concentrations were specific for crop types, crop parts, and location. The highest overall accumulation of metals was at the dump center and in crop leaves. Except Pb concentrations in Z. mays seeds, Cr, Pb, Zn, and Al concentrations in other crop parts were above World Health Organization/Food and Agricultural Organization consumer food safety limits. Therefore, Z. mays and A. cruentus consumption could pose health risks to consumers. Further health assessments and potential regulations are recommended to reduce potential health risks from metals in crops for human consumption. Integr Environ Assess Manag 2020;16:362-377. © 2019 SETAC.

Dimension Reduction and Analysis of a 10-Year Physicochemical and Biological Water Database Applied to Water Resources Intended for Human Consumption in the Provence-Alpes-Côte d’Azur Region, France

The SISE-Eaux database of water intended for human consumption, archived by the French Regional Health Agency (ARS) since 1990, is a rich source of information. However, more or less regular monitoring over almost 30 years and the multiplication of parameters lead to a sparse matrix (observations × parameters) and a large dimension of the hyperspace of data. These characteristics make it difficult to exploit this database for a synthetic mapping of water quality, and to identify of the processes responsible for its diversity in a complex geological context and anthropized environment. A 10-year period (2006–2016) was selected from the Provence-Alpes- Côte d’Azur region database (PACA, southeastern France). We extracted 5,295 water samples, each with 15 parameters. A treatment by principal component analysis (PCA) followed with orthomax rotation allows for identifying and ranking six principal components (PCs) totaling 75% of the initial information. The association of the parameters with the principal components, and the regional distribution of the PCs make it possible to identify water-rock interactions, bacteriological contamination, redox processes and arsenic occurrence as the main sources of variability. However, the results also highlight a decrease of useful information, a constraint linked to the vast size and diversity of the study area. The development of a relevant tool for the protecting and managing of water resources will require identifying of subsets based on functional landscape units or the grouping of groundwater bodies.