High Concentrations Of Arsenic Research Articles

Abstract 745: Molecular landscape of arsenic-induced bladder carcinogenesis

Abstract Introduction: Epidemiological, pre-clinical, and clinical studies have linked chronic arsenic (sodium arsenite: NaAsO2) exposure to a myriad of adverse health dysfunctions including the development of bladder cancer (BCa). However, most of the studies on arsenic-induced BCa have been performed on either unsuitable cell lines or using a higher concentration of arsenic (mM), which does not reflect exposure levels in a real-world setting. We used the telomerase reverse transcriptase (HU-hTERT1) immortalized normal bladder epithelial and a median physiological concentration of NaAsO2 (250 nM: 33 mg/L), to determine the transcriptomic and phenotypic changes during malignant transformation of HU-hTERT1 cells. Methods: HU-hTERT1 cells were exposed to 250nM arsenic for 12 months. To analyze the effect of arsenic exposure we performed cell viability, cellular proliferation, and clonogenic assays. RNA Seq data was used to perform pathway enrichment analysis, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-protein interaction (PPI) studies. Results: BCa patients had significantly higher (4-5 fold) levels of arsenic (20-50 mg/L) in their urine when compared to their healthy counterparts (<8 mg/L). Acute exposure to high concentration of (> 400nM) inhibited the HU-hTERT1 growth, whereas concentrations less than 400nM did not adversely affect the viability of these cells. HU-hTER1 cells began forming colonies after six months of chronic NaAsO2 exposure, with the number of colonies increasing concurrently with the exposure time. GO and KEGG analysis showed a total of 2174 genes that are differentially expressed in arsenic-treated HU-hTER1 transforming cells (0 vs 12 months). The upregulated genes (1392) were involved in cellular response to unfolded protein, response to endoplasmic reticulum stress, proteasome-mediated ubiquitin-dependent protein degradation, autophagy signaling, and tumor angiogenesis(P<0.05). Interestingly, the PPI analysis demonstrated a significant upregulation in histone modification of genes. These genes were enriched for the binding sites of transcription factors that are key regulators of carcinogenic pathways including ataxia-telangiectasia mutated (ATM) kinase and cell cycle regulatory pathways demonstrating a novel link between NaAsO2 exposure and BCa. Conclusion: An in vitro model of NaAsO2-induced malignant transformation was developed. Identifying precise molecular events that lead to arsenic-induced malignant transformation of normal urothelial cells would be an important step in defining therapy for BCa. Citation Format: Ajit Kumar Navin, Vaibhav Shukla, Balaji Chandrasekaran, Ashish Tyagi, Uttara Saran, Murali K. Ankem, Chendil Damodaran. Molecular landscape of arsenic-induced bladder carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 745.

Removal of arsenic in the leachate by a porous carbonaceous solid waste generated from pyrolysis of oily sludge

The leachate derived from lead smelting slag site is a potential hazard to the soil and water nearby due to its excessively high arsenic content. A porous carbonaceous solid waste (PCSW), resulting from the pyrolysis of oily sludge of tank bottom, was proposed to remove arsenic (As) from leachate. According to the results of As removal from simulated solution, PCSW can remove As efficiently and synchronously increase solution pH at equilibrium. The removal efficiency of As was 96.26% and the solution pH at equilibrium was 8.98 under the optimal conditions of PCSW dosage of 3 g⋅L−1, and initial As concentration of 12 mg⋅L−1 with the initial pH of 7.5. The adsorption rate of As was 0.319 g·(mg·min)−1, and the maximum adsorption capacity of As on PCSW was 45.314 mg⋅g−1. The removal of As from the solution was attributed mainly to the formation of stable calcium-arsenate precipitations and Fe–As complexes on PCSW surface. PCSW can also simultaneously and effectively remove the heavy metals (As, Pb, Zn, Cu, Cd) in leachate from lead smelting slag sites, and the residual concentration of all heavy metals were lower than the emission concentration (GB25466-2010, China). It is proved to be feasible for PCSW application in the treatment of leachate containing heavy metals.

Heavy metal contamination in river water, sediment, groundwater and human blood, from Kanpur, Uttar Pradesh, India.

Exponential industrialization and anthropogenic activities have resulted in water contamination by various heavy metals in Kanpur city, India. Heavy metal pollution, an issue of great concern, is not only affecting river water, but contamination of groundwater is creating health issues and worries. In the present investigation, blood samples were collected from selected volunteers, water and sediment samples from four sites of river Ganga and drinking groundwater samples from 23 locations of Kanpur city. Heavy metals analysis in river water, sediment, and human blood, was done byinductively coupled plasma optical emission spectroscopy (ICP-OES) and atomic absorption spectroscopy (AAS) was used for groundwater samples. Human blood showed a high concentration of arsenic (As) (66.6 ± 0.00 and 76.9 ± 0.01μg L-1 in males and female subjects, respectively) and thallium (Tl) (13.4 ± 0.004 and 16.6 ± 0.005μg L-1 in males and female subjects, respectively) with higher concentrations in females than males. Other heavy metals (Nickle, Beryllium, Cadmium, Cobalt, Chromium, Lithium, Molybdenum, Lead) were not observed in any of the tested human blood samples. However, in groundwater sampling, iron (Fe), copper (Cu), and arsenic (As) were detected, one sample had the presence of chromium (Cr), and two samples showed lead (Pb) contamination. River water [Cu (32-125μg L-1), Cr (19-725μg L-1), Cd (1-59μg L-1), Pb (37-163μg L-1), As (32-153μg L-1), Th (26.75μg L-1)] showed a high level of the heavy metals, as compared to reference values of BIS, CPCB (2016a), WHO, EPA and USEPA. River sediment [Cu (4168-34,470μg Kg-1), Cr (4040-145,650μg Kg-1), Cd (326-5340μg Kg-1), Pb (1840-19,350μg Kg-1), As (103-188μg Kg-1)] also showed high concentration when compared to reference values of USEPA and PASS. River site 4, with high Cr (725 μg L-1), also showed Cr levels (19.8 μg L-1) in the groundwater samples, indicating Cr contamination in groundwater while Pb was observed at groundwater samples close to two industrial sites. Drinking water might be the primary exposure pathway for As and Tl to enter the human body. The study recommends periodic monitoring of river water, sediment, groundwater, and human blood samples for contamination of heavy metals.

Enhanced expression of lectin‐like oxidized LDL receptor‐1 is implicated in the sodium arsenite‐induced increase in foam cells from murine macrophages

Arsenic is a naturally occurring toxic element that is present in the air, food, soil, and water of many countries, including the U.S. The U.S. Geological Survey reported that about 44 million people in the U.S. use private wells for water and estimated that over 2 million of those people drink from wells with high concentrations (>10 ug/L) of arsenic. Epidemiological studies have shown that chronic arsenic exposure is a significant risk factor for cardiovascular diseases, including atherosclerosis. However, the cellular and molecular mechanisms connecting arsenic exposure to atherosclerosis are not known. It has been established that Macrophage‐derived, lipid‐loaded, foam cells are a key component of atherosclerotic plaques and are essential for their formation. Furthermore scavenger receptors, such as lectin‐like oxLDL receptor 1 (LOX‐1), CD36, and scavenger receptor type A (SR‐A), regulate the lipid uptake of macrophages and are likely key to the transformation of these cells to foam cells. Our previous study showed that in mouse aortic endothelial cells, arsenic exposure stimulated the uptake of oxidized low‐density lipoprotein (oxLDL) by upregulating the expression of LOX‐1. To see if LOX‐1 might play a key role in foam cell formation, in this study, we used Oil‐red‐O assay to show that sodium arsenite (SA) exposure dose‐dependently enhanced the uptake of oxLDL in murine RAW 264.7 macrophages with a commensurate increase in foam cell count. In addition, while we showed that SA treatment caused a significant increase in both LOX‐1 mRNA and protein levels, only slight or no significant increases were observed in CD36 or SR‐A mRNA expression. Our results indicate that in arsenic induced atherosclerosis, LOX‐1 may play a critical and perhaps unique role among scavenger receptors in the production of foam cells. Further studies, including in vivo and in vitro, are warranted to verify and clarify the role of Lox‐1 in a disease model and to identify other cells and components of the disease pathway.

Arsenic Contamination and its Impact on the Environment

Arsenic (AS) toxicity is considered as one of the biggest environmental issue and a major public health problem. In this chapter we have summarized the impact of AS contamination on human health. A perusal of literature reveals that exposure to higher concentrations of AS is serious for a number of reasons. Such exposure for a longer period leads to ill effect on several organ systems of the human body. The adverse effects of inorganic AS cause many human diseases, human sufferings and increased human mortality and also affect various age groups variously. Population of some countries are more vulnerable to AS contamination problems. Studies have revealed the mechanisms of many AS induced diseases particularly cancer, cardiovascular effects, immunological effects and neurological effects in human. This article presents the scientific information emerged especially during the last two decades in the field of the ecotoxicological properties of AS and the potential mechanism of AS-induced toxicity, with a special emphasis on AS-induced carcinogenesis.

Arsenopyrite Dissolution and Bioscorodite Precipitation by Acidithiobacillus ferrivorans ACH under Mesophilic Condition

Arsenopyrite is the most abundant arsenic-bearing sulfide mineral in the lithosphere, usually associated with sulfide gold ores. The recovery of this highly valuable metal is associated with the release of large quantities of soluble arsenic. One way to mitigate the effects of high concentrations of arsenic in solution is to immobilize it as scorodite precipitate, a more stable form. Hence, we addressed the scorodite formation capacity (under mesophilic conditions) of psychrotolerant Acidithiobacillus ferrivorans ACH isolated from the Chilean Altiplano. Bio-oxidation assays were performed with 1% arsenopyrite concentrate as unique energy source and produced solids were evaluated by X-ray diffraction (XRD) and QEMSCAN analysis. Interestingly, the results evidenced scorodite generation as the main sub-product after incubation for 15 days, due to the presence of the microorganism. Moreover, the QEMSCAN analysis support the XRD, detecting a 3.5% increase in scorodite generation by ACH strain and a 18.7% decrease in arsenopyrite matrix, implying an active oxidation. Finally, we presented the first record of arsenopyrite oxidation capacity and the stable scorodite production ability by a member of A. ferrivorans species under mesophilic conditions.

Stabilization of arsenic and antimony Co-contaminated soil with an iron-based stabilizer: Assessment of strength, leaching and hydraulic properties and immobilization mechanisms

Soils with relatively high concentrations of arsenic (As) and antimony (Sb) in mining areas would impose significant risks to human health and ecosystem. A new stabilizer PFSC composed of polymerized ferric sulfate (PFS) and calcium hydroxide (Ca(OH)2) is proposed to stabilize the soil with co-existed As and Sb sampled at an abandoned arsenic factory site. The effects of stabilizer dosage on the properties of the stabilized soil including leached concentrations of As and Sb, unconfined compressive strength (UCS), and hydraulic conductivity (kw) were investigated. The mechanisms of As and Sb immobilization in the soils were interpreted by Tessier's sequential extraction procedure (SEP), scanning electron microscope (SEM), and X-ray diffraction (XRD) results. The results showed increasing PFSC dosage was effective for reducing leached concentrations of As and Sb. When the PFSC dosage increased from 2% to 10%, the UCS and kw increased from 84 to 206 kPa and decreased from 6.48 × 10−8 to 6.33 × 10−9 m s−1, respectively. Tessier's SEP results showed that the leachable As and Sb fractions decreased from 12% to 5.6% and 7.5% to 3.8%, while the Fe–Mn oxides bound fractions increased from 22.3% to 29.4% and 13.2% to 19.5%. The SEM images and XRD patterns of untreated and PFSC stabilized contaminated soils indicated that hematite and calcite (CaCO3) were the main products of PFSC stabilization processes. Adsorption on ferrihydrite, entrapment in hematite lattices, and co-precipitate with calcite might were the main mechanisms of As and Sb immobilization.

Rapid Determination of Arsenic in Traditional Chinese Medicine by Laser-Induced Breakdown Spectroscopy (LIBS)

High arsenic (As) content in medicine may threaten health and its determination is necessary. However, traditional methods cannot achieve rapid analysis because of complex digestion procedures. Exploring rapid and accurate methods for the determination of As is urgent. In this study, the As concentration in niuhuangjiedu tablets (NHJDTs) was accurately and rapidly determined by laser-induced breakdown spectroscopy (LIBS). Furthermore, comprehensive health risks of As were analyzed combined with solubility measurements to evaluate the impact on humans. The results showed that the relative standard deviation and relative error of the LIBS results were less than 10% for detection period of less than 0.3 h, which meets the requirements for rapid, accurate, and convenient As determination. The indices for non-carcinogenic and carcinogenic risk for total As and soluble As in niuhuangjiedu tablets were 966.67, 0.15, 4.37, and 6.72 × 10−4, respectively, indicating the presence of potential health risks. This work provided support for further investigation for quality control of pharmaceutical products.

Quantification of potentially toxic element contamination in groundwater using the novel particle-induced X-ray emission (PIXE) technique and human health impacts

The particle-induced X-ray emission system is an extremely responsive multi-elemental diagnostic practice uses to analyze thin films, air, water, archaeological and biological samples. This complicated system was used to quantify heavy metals presented in groundwater in the South-Central part of Bangladesh. Contaminates in tube-well water are related in a straight line with human health hazard. The study was designed to scrutinize heavy metal concentrations in 170 groundwater samples collected from densely settled area of Gopalganj District, Bangladesh. The samples were collected from 96 No. Fukra, Kurulia and Kandi Tilchara Mouza. The study represents that the highest arsenic concentration was 260 μg/L, iron was 17.21 mg/L, manganese was 0.94 mg/L, zinc was 1.71 mg/L and copper was 0.07 mg/L. The end result evidently showed that almost 5.0 times elevated arsenic concentration, 17.0 times higher iron concentration, 9.0 times elevated manganese concentration were found in the study area as compared to standard value approved by Bangladesh. The peak concentration of arsenic was found in Kandi Tilchchara Mouza, which was along the bank of Madhumati River. The spatial distribution showed that arsenic concentration was relatively towering in Kandi Tilchchara Mouza. Majority of water sources were unsuitable for drinking and cooking in terms of arsenic and manganese concentrations. The cumulative ingestion of drinking water along the study area imposes high non-carcinogenic and very high cancer risk to the residents’ health.

Groundwater arsenic content in quaternary aquifers of the Red River delta, Vietnam, controlled by the hydrogeological processes

The relation between arsenic groundwater concentrations and hydrogeological processes was investigated in the proximal part of the Red River delta, Vietnam, west of the depression cone formed by the exploitation of groundwater in Hanoi. Flow paths in the Quaternary aquifers were modeled based on previously interpreted geological structure and hydrogeological data gathered during field work in 2014–2017. Sedimentary structures and simulated flow patterns were compared with the spatial distribution of the groundwater arsenic concentration.The regression of the sea in the area started 4 ka BP in the Holocene. The low tectonic subsidence rate of the Red River delta led to intensive erosion and replacement of fine grained sediments of the sea level high stand by sandy channel belts, resulting in hydraulic connections between the Pleistocene and Holocene aquifers. The Pleistocene aquifer is recharged by both regional flow paths and naturally occurring vertical recharge through Holocene sand and clay layers. Young groundwater (<40 a) in the shallow Holocene aquifer generally discharges to surface water bodies. The shallow flow system is also seasonally recharged with surface water, as indicated by δ18O enrichment of groundwater and oscillating groundwater ages in wells in the vicinity of water channels. The deeper flow system discharges into the Red River and Day River or flows parallel to the rivers, toward the sea.The overall pattern of arsenic groundwater concentrations (decreasing with increasing sediment age) is modified by groundwater flow. The arsenic contamination of the Pleistocene aquifer of the Red River delta is not only caused by the intensive groundwater abstraction in Hanoi, as reported previously, but also by the natural flow of high arsenic groundwater from Holocene to Pleistocene aquifers in areas located outside of the depression cone. Groundwater with < 50 µg L-1 arsenic is found in the Pleistocene aquifer close to the recharge zone in the mountains bordering the Red River delta and in the Holocene and Pleistocene aquifers where clay deposits were eroded. Close to the recent Red River channel, recharge of older Holocene and Pleistocene sediments occurs partially by arsenic-contaminated groundwater from the youngest Holocene aquifers, and here arsenic concentrations exceed 50 µg L-1. A high arsenic concentration is also present in the early Holocene-Pleistocene aquifer, beneath thick clay layers, indicating a limited extent of flushing and the inflow of fresh organic matter.

Rice Industry By-Products as Adsorbent Materials for Removing Fluoride and Arsenic from Drinking Water—A Review

In drinking water, high concentrations of fluoride and arsenic can have adverse effects on human health. Waste deriving from the rice industry (rice husk, rice straw, rice bran) can be promising adsorbent materials, because they are (i) produced in large quantities in many parts of the world, (ii) recoverable in a circular economy perspective, (iii) at low cost if compared to expensive conventional activated carbon, and (iv) easily manageable even in developing countries. For the removal of fluoride, rice husk and rice straw allowed to obtain adsorption capacities in the range of 7.9–15.2 mg/g. Using rice husk for arsenic adsorption, excellent results were achieved with adsorption capacities above 19 mg/g. The best results both for fluorides and arsenic (&gt;50 mg/g) were found with metal- or chemical-modified rice straw and rice husk. Identifying the next steps of future research to ensure the upscaling of biochar from recovered by-products, it is fundamental to perform: (i) tests on real waters for multicomponent adsorption; (ii) experiments with pilot plants in continuous operation; (iii) cost analysis/real applicability of modification treatments such as metal coupling or chemical synthesis; (iv) more studies on the biochar stability and on its regeneration or recovery after use.

Possibility of direct rapid determination of inorganic contaminant elements in paints by LA-ICP-MS method

In this work content of inorganic major and trace elements were directly determined in produced in China, Russia, and Germany household use purpose oil, асгуI, and ochre paint samples using laser ablation-inductively coupled plasma-mass spectroscopy (LA_ICP_MS) technique. A sample preparation was simple and rapid: an oil and acryl paint droplets were dried on glass substrate for several hours on a hot plate at 60° C and few mg ochre paint powder samples were solidified with pure paraffin wax on the glass substrate. Dried oil and acryl paint droplets were ablated locally, drilling the hole way, while ochre paint powders were ablated using surface rastering method. Contents of inorganic elements were calculated using the NIST 610 glassy standard sample as the reference. Parallel determination results of lead and chromium in oil paint samples by atomic absorption technique correlates with that of by LA_ICP_MS acceptably (correlation coefficient for lead is 0.85 and for chromium is 0.95). Because of sample organic - reference inorganic matrix difference, the measured by the LA_ICP_MS content of each element must be adjusted being multiplied in some quantity, value of which are different for each element. For lead and chromium value of the quantity found correspondingly as 6.4 and 9.3. The average relative standard deviation (RSD) of measured content of the mostly high content elements Ca, Al, Mn, Pb, Sr, S, Mg, Fe, Sb, Na, Co, Si, Zn, Cu, P, Y, K, CI, Ce, and La is less than 10%, the RSD for elements Ti, Cr, Sn, Ba, Zr, Rb lies between 10 and 20%, and the RSD for trace elements Gd, Nb, Sc, V, U. Pr, Ni, Ga, Eu, As, Th B, Mo, Cd, Li lies in interval from 20 to 50 %. High level of concentration 309 - 24300 ppm for lead, 950- 3134 ppm for chromium are detected by LA-ICP-MS method in samples of red, yellow and green color oil paints produced in China and bestselling in Mongolia certain brand products. Up to 1900 ppm alarming high content of arsenic is tovnd in the Chinese origin yellowish red, brown red color ochre paints. As shows our measurements, the LA-ICP-MS method is possible to use as alternative rapid semi-quantitive detection method with acceptable accuracy and precision for basic inorganic additives in oil, acryl and ochre paints using glassy standard sample.

Assessment of the Potential of Umbrella Thorn [Vachellia tortilis (Forssk.) Galasso &amp; Banfi] for the Rehabilitation of Sub-Sahelian Mining Sites at Essakane, North-Eastern Burkina Faso

Establishment of plant communities at mine sites with significant disturbance depends upon factors such as the presence of efficient mycorrhizal fungi and rhizobia. Field and greenhouse experiments were conducted to assess growth performance of umbrella thorn as a potential tree species for reforestation of mine sites in arid areas. In the first experiment, seedlings were transplanted onto waste rock stockpile (WR) and tailings (TLG) with high arsenic (As) content on sites at the Essakane gold mine. Trees were assessed for growth and survival 3 years after planting. In experiment 2, soil was sampled on four sites across a disturbance gradient from mining waste (WR and TLG) and artisanal gold mining to undisturbed natural soil (NS). Each soil was planted with two separate leguminous trap crops (cowpea and umbrella thorn) in pots to check for microsymbionts. At 3 years, trees grew better on TLG soils with greater arsenic contamination than WRs in the field. Although tree establishment was moderate, with &amp;lt;50% survival, overall results suggest the ability of umbrella thorn to tolerate As contamination levels up to 1,300 ppm and, therefore, its potential for reforestation. Soil pH has shown strong effects on soil nutrient content. In particular, ammonium was the dominant form of mineral nitrogen (N) in the more neutral pH NS soils, while nitrate was present in the more alkaline WRs. Denitrification likely resulted in high N loss where nitrate dominates, reflecting the poor performance of N-deficient trees on WRs compared to TLG soils. Growth trends of umbrella thorn in potted-soils were consistent with those reported on TLG and WR soils in plantations.

Arsenic speciation analysis in honey bees for environmental monitoring

Arsenic can be toxic to living organisms, depending not only on the concentration, but also its chemical form. The aim of this study was to determine arsenic concentrations and perform arsenic speciation analysis for the first time in honeybees, to evaluate their potential as biomonitors. Highest arsenic concentrations were determined in the vicinity of coal fired thermal power plants (367 µg kg−1), followed by an urban region (213 µg kg−1), with much lower concentrations in an industrial city (28.8 µg kg−1) and rural areas (41 µg kg−1). Until now, honey bees have never been used to study different arsenic species in the environment. For this reason, four extraction procedures were tested: water, hot water at 90 °C, 20% methanol, and 1% formic acid. Water at 90 °C was able to extract more than 90% of the total arsenic from honey bee samples. Inorganic arsenic (the sum of arsenite and arsenate) accounted for 95% of arsenic species in bees from three locations, except the industrial city, where it represented only 80% of arsenic species, while 15% was present as DMA.

Monitoring of Fluoride, Arsenic and Other Heavy Metals in the Shallow Aquifers of Small Tea Gardens Belt of Biswanath District, Assam, India

Abstract: The Biswanath district is one of the most important tea growing district of Assam. There are big tea estates (under multinational companies) as well as a large number of small tea gardens growing which is like a green revolution. In these gardens heavy amount of artificial agrochemicals are used which contaminates soil as well as drinking water sources. Ground water is an essential and vital component of our life support system. The groundwater resources are being utilized for drinking, irrigation and industrial purposes. There is growing concern on deterioration of groundwater quality due to geogenic and anthropogenic activities. Groundwater, being a fragile must be carefully managed to maintain its purity within standard limits. In tea gardens belt the agro-chemicals affect the quality of groundwater so this investigation has been carried out to assessment the quality of water in this area. Now the Fluoride and Arsenic are major problems in ground water in India and Bangladesh, the heavy metals also affect the chronic health hazards of the people in this area so it is very important to investigation of ground drinking water sources. The ground water of this area is of high iron, manganese, fluoride and arsenic concentration is observed. Finally, stress zones in the study area were delineated using Arc GIS spatial analysis. Keywords: Groundwater quality, Heavy metals, Small tea gardens, Biswanath

Aqueous Arsenic Speciation with Hydrogeochemical Modeling and Correlation with Fluorine in Groundwater in a Semiarid Region of Mexico

In arid and semiarid regions, groundwater becomes the main source to meet the drinking water needs of large cities, food production, and industrial activities. For this reason, necessary studies must be carried out to estimate its quantity and quality, always seeking sustainable management, thus avoiding social conflicts or a decrease in the productive activities of humanity. This research explains the behavior of groundwater quality concerning arsenic speciation and its relationship with fluoride. The average total arsenic concentration of 19.95 µg/L and 20.29 µg/L is reported for the study period from 2015 to 2020, respectively, according to the Mexican standard. If the population drinks water directly, it is exposed to possible damage to health. The predominant arsenic species is As (V), with 95% and As (III) with 5%, this finding will allow us to define in greater detail the type of remediation that is required to reduce the content of this element in the water. Regarding the relationship between arsenic and fluorine, very small Pearson correlation coefficients of the order of 0.3241 and 0.3186 were found. The estimation of the space–time variation made it possible to identify the areas with the highest concentration of arsenic and fluorine, allowing the definition of the operating policies of these wells, thereby protecting the health of the inhabitants who consume this water.

Arsenic Contamination in Groundwater and Potential Health Risk in Western Lampang Basin, Northern Thailand

This research aimed to investigate the spatial distribution of arsenic concentrations in shallow and deep groundwaters which were used as sources for drinking and domestic and agricultural uses. A geochemical modeling software PHREEQC was used to simulate equilibrium geochemical reactions of complex water–rock interactions to identify arsenic speciation and mineral saturation indices based on groundwater quality and hydrogeochemical conditions. In addition, the potential health risk from arsenic-contaminated groundwater consumption was assessed based on the method developed by the U.S. Environmental Protection Agency. The study area is located at the western part of the Lampang Basin, an intermontane aquifer, Northern Thailand. The area is flat and situated in a floodplain in the Cenozoic basin. Most shallow groundwater (≤10 m depth) samples from dug wells were of Ca-Na-HCO3 and Ca-HCO3 types, whereas deep groundwater from Quaternary terrace deposits (30–150 m depth) samples were of Na-HCO3 and Ca-Na-HCO3 types. High arsenic concentrations were found in the central part of the study area (Shallow groundwater: &lt;2.8–35 mg/L with a mean of 10.7 mg/L; Deep groundwater: &lt;2.8–480 mg/L with a mean of 51.0 mg/L). According to geochemical modeling study, deep groundwater contained toxic As(III), as the dominant species more than shallow groundwater. Arsenic in groundwater of the Lampang Basin may have been derived from leaching of rocks and could have been the primary source of the subsurface arsenic in the study area. Secondary source of arsenic, which is more significant, could be derived from the leaching of sorbed arsenic in aquifer from co-precipitated Fe-oxyhydroxides in sediments. Quantitative risk assessment showed that the average carcinogenic risk values were as high as 2.78 × 10−3 and 7.65 × 10−3 for adult and child, respectively, which were higher than the acceptable level (1 × 10−4). The adverse health impact should be notified or warned with the use of this arsenic-contaminated groundwater without pre-treatment.

Evaluation of arsenic effects on Paracyclops novenarius Reid, 1987: a cyclopoid copepod in central-north of Mexico.

Description and morphological analysis of copepods inhabiting a water body with high arsenic concentrations (32.79 to 62.29mg L-1) were performed to identify some effect on the development of individuals due to the arsenic concentrations. Detailed morphology of prosomal and urosomal appendages along the development of the specimens was considered. The results showed that the freshwater copepod Paracyclops novenarius Reid, 1987 inhabits this water body, and previously, it was recorded as Paracyclops chiltoni (Thomson GM, 1882) on this site. Moreover, this becomes the first record of P. novenarius in Mexico. Morphological analysis showed a normal and stable development along the different instars, different arsenic concentrations in the media, and different sampled dates between the analyzed specimens, suggesting that the high arsenic concentrations do not affect the morphology of P. novenarius, including all its development and adult instars, which differs from other copepods and other groups such as Cladocera and Rotifera, where morphological changes due to metals and metalloids have been observed but in low concentrations of these elements. The results of this study contribute to the existing reports of the genus Paracyclops (Claus 1893) in Mexico and could provide information for environmental impact assessments on aquatic systems.

Arsenic Mineral in Volcanic Tuff, a Source of Arsenic Anomaly in Groundwater: City of Chihuahua, Mexico

Arsenic is a naturally occurring trace element that causes many health effects when present in drinking water. Elevated arsenic concentrations in water are often attributed to nearby felsic volcanic sequences; however, the specific rock units to which the groundwater anomalies can be accredited are rarely identified. The groundwater from wells around the city of Chihuahua, Mexico, contains high arsenic content. Arsenic in groundwater increases toward the base rock containing Tertiary volcanic rocks. Through detailed scanning electron microscope (SEM) and electron microprobe (EMP) work, arsenic minerals are identified in the cavities of the Tertiary volcanic tuff from the northeast part of the Tabalaopa Basin, city of Chihuahua. Arsenic minerals, the As–Sr–Al phase (a possible arsenogoyazite–arsenoflorencite group mineral) crystallized in the vesicles of the tuff and the As–Y bearing phase included in biotite, prevail in the studied Tertiary volcanic outcrops. Based on the current study, the arsenic anomaly in the Tabalaopa–Aldama aquifer corresponds to these arsenic phases in the Tertiary volcanic rocks.

Growth and biosorption of Purple guinea and Ruzi grasses in arsenic contaminated soils.

Increasing mining and industrial discharge of untreated wastewater, as well as excessive use of fertilizers for agricultural purposes, and heavy metal contamination in soil have become one of the serious environmental problems worldwide. In the present study, pot experiments were conducted to evaluate the influence of arsenic contamination and other factors on the growth and development of local forage grasses like Purple guinea and Ruzi grasses under controlled conditions. Influence of arsenic concentration, soil properties, and fertilizers on biosorption and withstanding potential of grasses was studied using model soil and real-time arsenic-contaminated mine soil. High arsenic contents in soil significantly affected the growth as well as biomass production of grasses and declined the overall biomass production concerning exposure durations. Purple guinea and Ruzi grasses showed growth tolerance in arsenic-contaminated soils with concentrations of 100 and 150 mg/kg respectively. Grass species, soil compositions, and properties, fertilizers, growth duration, etc. potentially influenced arsenic accumulation in grasses. Both local forage grasses showed <1 bio-accumulation factor (BAF) and bio-concentration factor (BCF) after 45 days that indicates the minimum harvesting time of 45 days, and biosorption rate was found significant to the exposure duration. Maximum translocation factor (TF) values observed in Purple guinea and Ruzi grasses were 0.65 and 0.95, respectively which are < 1, therefore, these local forage grasses could be labeled as arsenic-metallophytes and ability to tolerate high levels of heavy metals without much biosorption. The results confirmed that local forage grasses have much growth tolerance potential against arsenic in real-time mine soil with desired fertilizers and these species could be used for sustainable management of ecological health of the Thung Kum gold mine area in Thailand.