Long-term hydrochemical monitoring and geothermometry:understanding groundwater salinization and thermal fluid contamination in Mila’s basin,Northeastern Algeria

The regular hydrochemical monitoring of groundwater in the Mila basin over an extended period has provided valuable insights into the origin of dissolved salts and the hydrogeochemical processes controlling water salinization.The data reveals that the shallow Karst aquifer shows an increase in TDS of 162 mg L^(-1) while the ther-mal carbonate aquifer that is also used for drinking water supply exhibits an increase of 178 mg L^(-1).Additionally,significant temperature variations are recorded at the sur-face in the shallow aquifers and the waters are carbo-gaseous.Analysis of dissolved major and minor elements has identified several processes influencing the chemical composition namely:dissolution of evaporitic minerals,reduction of sulphates,congruent and incongruent car-bonates’dissolution,dedolomitization and silicates’weathering.The hydrogeochemical and geothermometric results show a mixing of saline thermal water with recharge water of meteoric origin.Two main geothermalfields have been identified,a partially evolved water reservoir and a water reservoir whosefluid interacts with sulphuric acid(H_(2)S)of magmatic origin.These hot waters that are char-acterized by a strong hydrothermal alteration do ascend through faults and fractures and contribute to the contamination of shallower aquifers.Understanding the geothermometry and the hydrogeochemistry of waters is crucial for managing and protecting the quality of groundwater resources in the Mila basin,in order to ensure sustainable water supply for the region.A conceptual model for groundwater circulation and mineralization acquisition has been established to further enhance under-standing in this regard.

Ultrasonic enhancement of persulfate oxidation system governs emerging pollutants decontamination

Emerging contaminants (ECs) are widely present in aquatic environments, posing potential risks to both ecosystems and human health. Theultrasound-assisted persulfate oxidation process has attracted considerable attention in the degradation of ECs due to its ability to generate bothsulfate radicals and cavitation effects, enhancing degradation effects. In this paper, the principle of ultrasonic synergistic Fenton-like oxidationsystem for degrading organic pollutants was reviewed, divided into homogeneous system, non-homogeneous system, and single-atom system toexplore the synergistic effect of ultrasound-enhanced persulfate technology in three aspects, and the effects of environmental factors such asultrasonic frequency and power, system pH, temperature, and initial oxidant concentration on the system's decontamination performance werediscussed. Finally, future research on ultrasonically activated persulfate technology is summarized and prospected.

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular tin-based contamination consisting of micro-and macroparticles was deposited on silicon via physical vapor deposition(PVD).The electrodedriven hydrogen plasma at different power levels was systematically diagnosed using a Langmuir probe and a retarding field ion energy analyzer(RFEA).Moreover,the magnitude of the self-biasing voltage was measured at different power levels,and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage(E_(RFEA)-eV_(self)).XPS analysis of O 1s and Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning.Analysis of surface and cross-section morphology revealed that holes emerged on the upper part of the macroparticles while its bottom remained smooth.Hills and folds appeared on the upper part of the microparticles,confirming the top-down cleaning mode with hydrogen plasma.This study provides an in situ electrode-driven hydrogen plasma etching process for tin-based contamination and will provide meaningful guidance for understanding the chemical mechanism of reduction and etching.

Exploring the mechanical behavior and microstructure of compacted loess subjected to dry-wet cycles and chemical contamination

Due to climatic factors and rapid urbanization,the soil in the Loess Plateau,China,experiences the coupled effects of dry-wet cycles and chemical contamination.Understanding the mechanical behavior and corresponding microstructural evolution of contaminated loess subjected to dry-wet cycles is essential to elucidate the soil degradation mechanism.Therefore,direct shear and consolidation tests were performed to investigate the variations in mechanical properties of compacted loess contaminated with acetic acid,sodium hydroxide,and sodium sulfate during dry-wet cycles.The mechanical response mechanisms were investigated using zeta potential,mineral chemical composition,and scanning electron microscopy(SEM)tests.The results indicate that the mechanical deterioration of sodium hydroxidecontaminated loess during dry-wet cycles decreases with increasing contaminant concentration,which is mainly attributed to the thickening of the electrical double layer(EDL)by Nat and the precipitation of calcite,as well as the formation of colloidal flocs induced by OH,thus inhibiting the development of large pores during the dry-wet process.In contrast,the attenuation of mechanical properties of both acetic acid-and sodium sulfate-contaminated loess becomes more severe with increasing contaminant concentration,with the latter being more particularly significant.This is primarily due to the reduction of the EDL thickness and the erosion of cement in the acidic environment,which facilitates the connectivity of pores during dry-wet cycles.Furthermore,the salt expansion generated by the drying process of saline loess further intensifies the structural disturbance.Consequently,the mechanical performance of compacted loess is sensitive to both pollutant type and concentration,exhibiting different response patterns in the dry-wet cycling condition.

Evaluating bacterial contamination and surgical site infection risks in intracorporeal anastomosis: Role of bowel preparation

We recently read the study by Kayano et al on intracorporeal anastomosis(IA)for colon cancer,which assessed bacterial contamination and medium-term onco-logical outcomes and affirmed that IA is analogous to extracorporeal anastomosis in reducing intraperitoneal bacterial risk and achieving similar oncological results.Our commentary addresses gaps,particularly concerning bowel preparation and surgical site infections(SSIs),and highlights the need for comprehensive details on the bowel preparation methods that are currently employed,including mecha-nical bowel preparation,oral antibiotics(OA),their combination,and specific OA types.We emphasize the necessity for further analyses that investigate these me-thods and their correlation with SSI rates,to enhance clinical protocol guidance and optimize surgical outcomes.Such meticulous analyses are essential for refi-ning strategies to effectively mitigate SSI risk in colorectal surgeries.

Factors Contributing to Contamination of Street Foods in Bamako, Mali

The World Health Organization states that foodborne diseases are a worldwide public health issue. Although street foods can provide nutritious and affordable ready-to-eat meals for city dwellers, their health risks can outweigh the benefits. A cross-sectional study was conducted in the Bamako district, focusing on street food vendors near schools, universities, extensive markets, administrative centers, and major roads. We aimed to sample fifty (50) sellers per municipality, making 300 sellers for the Bamako district. We developed a survey sheet to collect data, and six teams rotated between the municipalities each month. Before starting the collection, the teams were provided administrative papers approved by the municipal authority. The survey revealed three types of sales sites: fixed (65%), semi-fixed (30%), and mobile (4.40%). The proportion of sellers was 26.8%, 23.2%, 19.7%, and 4.2% in municipalities III, IV, and I. In municipalities I, II, III, IV, and VI, respectively, 92%, 95.70%, 93%, 87.2%, and 100% of the sellers were female. The age distribution of sellers was 65.63%, 46.81%, 40.82%, 38.30%, 36.17%, 36%, and 32% in the 25-34 and 35 - 44 age groups. Illiteracy rates were 59.20%, 61.70%, 55.30%, 75%, and 56% in municipalities I, II, III, IV, and VI, respectively. The study identified two categories of sellers: 48.3% in type 1 and 51.7% in type 2. The first category comprised 154 sellers, and the second 165 sellers. The survey found that 66.00%, 56.00%, 48.90%, 44.90%, 38.30%, and 34.40% of municipal V, VI, III, I, II, and IV sales sites were open-air. In municipality I, 63.30% of the sites were under hangars, while in municipalities II and IV, the corresponding percentages were 51.10% and 59.40%, respectively. Moreover, 46.00%, 31.90%, 31.30%, 30.60%, and 27.70% of the sites in municipalities VI, II, IV, I, and III were located next to gutters. In conclusion, this study identified several factors that could compromise the quality of street foods sold in the six municipalities of Bamako.

Phytoremediation Strategies for Heavy Metal Contamination: A Review on Sustainable Approach for Environmental Restoration

Current globalization trends and important breakthroughs globally need a complete study of heavy metal contamination, its causes, its impacts on human and environmental health, and different remediation strategies. Heavy metal pollution is mostly produced by urbanization and industry, which threatens ecosystems and human health. Herein, we discuss a sustainable environmental restoration strategy employing phytoremediation for heavy metal pollution, the carcinogenic, mutagenic, and cytotoxic effects of heavy metals such as cadmium, copper, mercury, selenium, zinc, arsenic, chromium, lead, nickel, and silver, which may be fatal. Phytoremediation, which was prioritized, uses plants to remove, accumulate, and depollute pollutants. This eco-friendly method may safely collect, accumulate, and detoxify toxins using plants, making it popular. This study covers phytostabilization, phytodegradation, rhizodegradation, phytoextraction, phytovolatilization, and rhizofiltration. A phytoremediation process’s efficiency in varied environmental circumstances depends on these components’ complex interplay. This paper also introduces developing phytoremediation approaches including microbe-assisted, chemical-assisted, and organic or bio-char use. These advancements attempt to overcome conventional phytoremediation’s limitations, such as limited suitable plant species, location problems, and sluggish remediation. Current research includes machine learning techniques and computer modeling, biostimulation, genetic engineering, bioaugmentation, and hybrid remediation. These front-line solutions show that phytoremediation research is developing towards transdisciplinary efficiency enhancement. We acknowledge phytoremediation’s promise but also its drawbacks, such as site-specific variables, biomass buildup, and sluggish remediation, as well as ongoing research to address them. In conclusion, heavy metal pollution threatens the ecology and public health and must be reduced. Phytoremediation treats heavy metal pollution in different ways. Over time, phytoremediation systems have developed unique ways that improve efficiency. Despite difficulties like site-specificity, sluggish remediation, and biomass buildup potential, phytoremediation is still a vital tool for environmental sustainability.

Assessment of Heavy Metals Contamination of Topsoil and Street Dust around Cement Factory in Southern Jordan

Evaluation of assessment of the metal processes governing the metals distribution in soil and dust samples is very significant and protects the health of human and ecological system. Recently, special attention has given to the assessment of metals pollution impact on soil and dust within industrial areas. This study aims to assess the metal contamination levels in the topsoil and street dust around the cement factory in Qadissiya area, southern Jordan. The levels of seven metals (namely Fe, Zn, Cu, Pb, Cr, Cd, and Mn) were analyzed using Flame Atomic Absorption Spec-trophotometer (FAAS) to monitor, evaluate, and to compare topsoil and road dust pollution values of metals of the different types of urban area. The physicochemical parameters which believed to affect the mobility of metals in the soil of the study area were determined such as pH, EC, TOM, CaCO3 and CEC. The levels of metal in soil samples are greater on the surface but decrease in the lower part as a result of the basic nature of soil. The mean values of the metals in soil can be arranged in the following order: Zn > Pb > Mn > Fe > Cu > Cr > Cd. The relatively high concentration of metals in the soil sample was attributed to anthropogenic activities such as traffic emissions, cement factory and agricultural activities. Correlation coefficient analysis and the spatial distribution of indices and the results of statistical analysis indicate three groups of metals: Fe and Mn result by natural origin, Zn, Pb, Cu and Zn result by anthropogenic origin (mainly motor vehicle traffic and abrasion of tires) while Cd is mixed origin. The higher content level values of metals of anthropogenic source in soil samples indicate that it is a source of contamination of air in the studied area. .

Study on Preservation of Boar Semen and Bacteria Contamination in Kandal Province

The breeding program is progressing steadily,with increasing the awareness among farmers regarding the its critical role in improving productivity,promoting rapid growth,enhancing disease resistance,and boosting household income.At the same time,the dissemination of AI(Artificila Insemination)technique among farmers has been active and effective.For the application of the AI,the quality of boar semen is extended in BTS(Belts Ville Thawing Solution)for more longer preservation period.The study purpose is to evaluate sperm survival time and bacterie contamination in boar semen.Six boars with different breed around 3 years old were used for this study as two Durocs,two Landraces and two Yorkshires.In evaluation sperm survival time in extender on each boar was designed by CRD(Completely Randomized Design)and calculating the survival time of spermatozoa was done after semen dilution and the sperm mobility was determined.The experimental BTS compositions are glucose,sodium bicarbonate acid,trisodium citrate,ethylenediaminetetraacetic acid,potassium chloride and distill water.In the same time,eighteen sample semen ware collected and used for detection of bacterial contamination.The results showed that the survival time of spermatozoa with its straight mobility more than 50%between the commercial BTS and BTS-KH was from 52 to 56 h.They are not significantly different(p>0.05).And the total survival time of spermatozoa was from 92 to 98 h,they are also not significantly different(p>0.05).The survival time of spermatozoa with its straight mobility more than 50%between the Yorkshire,Landrace and Duroc was 55 h 5 min,54 h 25 min and 50 h 18 min respectively.They are significantly different(p>0.05).The total survival time of spermatozoa between the commercial BTS and BTS-KH was 97 h 19 min,91 h 29 min and 92 h 26 min respectively.They are also not significantly different(p>0.05).The main bacteria isolated from the diluted semen were gram-negative bacteria,Escherichia coli 27.78%was contaminated with an average 6.4×106 CFU/mL,and the family Pseudomonaceae was 11.11%with 8.3×106 CFU/mL.In conclusion,the comparative results of the survival time of spematozoa during the breeding period(t=0.5)between the breeds and extender are similar.For bacteria contamination isolate from the semen all breeds may be due to direct and environmental factors.It is a rainy season with heavy rains that can cause infections.

Agricultural Contamination of the Surface Waters of the Upper Ouémé in Benin: The Case of Heavy Metals and Pesticides

Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10-4 mg/L;2.2 × 10-1 mg/L;1.2 × 10-4 mg/L;2 × 10-4 mg/L), Cadmium (4.4 × 10-5 mg/L;1.1 × 10-2 mg/L;10-4 mg/L;4 × 10-4 mg/L). Then Copper (7 × 10-4 mg/L;3 × 10-3 mg/L;7 × 10-4 mg/L;1 × 10-4 mg/L), Iron (1.51 mg/L;6.4 × 10-1 mg/L;2.0012 mg/L;2.9 × 10-1 mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10-3 mg/L;1.5 × 10-3 mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.

基于MICP法的巴氏生孢八叠球菌固化镉污染土的试验研究

以重金属污染土的治理为背景,通过毒性浸出、无侧限抗压强度、土柱淋滤试验并结合镉形态分析等其他微观测试方法,探讨了Ca^(2+)的添加、Cd^(2+)浓度、养护时间等因素对驯化巴氏生孢八叠球菌固化镉污染土特性的影响.结果表明:Ca^(2+)对固化土中Cd^(2+)浸出特性影响显著,不添加Ca^(2+)时,当尿素浓度为0.5 mol·L^(-1),固化土的Cd^(2+)浸出质量浓度(0.42~5.64 mg·L^(-1))最低;添加Ca^(2+)后,Cd^(2+)浸出浓度略有增大,胶结液中尿素和Ca^(2+)浓度均为0.5 mol·L^(-1)时,Cd^(2+)的固化效果较好.延长养护时间,固化后土体的抗压强度增加,Cd^(2+)浸出浓度降低且固化效果提高;增大Cd^(2+)浓度,固化后土体的抗压强度降低,Cd^(2+)浸出浓度提高;添加Ca^(2+)有助于增强镉污染土的固化效果,在养护时间为28 d时,当Cd^(2+)浓度为100 mg·kg^(-1)时,添加Ca^(2+)的试样强度达到312 kPa,相较于未添加Ca^(2+)试样强度(234 kPa)提升了33.3%;当Cd^(2+)浓度增大至1600 mg·kg^(-1)时,添加Ca^(2+)的试样强度达到269 kPa,相较于未添加Ca^(2+)试样强度提升了57.3%,试样的浸出浓度降低了15.4%;经淋滤后,添加Ca^(2+)的试样滤出液中Cd^(2+)浓度始终低于未添加Ca^(2+)试样.固化后土中弱酸可提取态镉向可还原态镉和残渣态镉转变,添加Ca^(2+)进一步降低弱酸可提取态镉所占比例,减小了Cd^(2+)的迁移能力.

Security Assurance for One-stage Resection of Left Colon Cancer with Acute Obstruction—Thorough and Prompt Enteral Decompression without Contamination

Objective: Thorough, prompt enteral decompression technique without contamination was de- veloped to ensure safety for emergent colon resection and primary anastomosis. Methods: After isolating the mesentery, the “to be resected colon segment” was cut at its lower end, then the proximal cut end was put into a plastic bag which was adhered to one side of the operating table. After releasing the clamp, the content could ?ow into this bag. The operator could squeeze the bowel with two hands by turns, from proximal to farness, and from small bowel to large bowel, until the entire bowel content was fully discharged. Then the upper end of this “to be resected colon segment” was cut, and was removed together with the plastic bag. Results: 31 cases of left colon cancer with acute obstruction were decompressed with this technique. They all recovered smoothly, without anastomosis ?stula. Another 6 cases of hepatic seg- mentectomy with incidental colonectomy were decompressed with this technique and had the same results. This technique was also used in di?erent kinds of acute small intestinal obstruction and gained satisfactory results. Conclusion: This technique could be considered as the preferable choice for intraoperative enteral decompression.

Studies on Contamination of Cytoplasm DNA and Its Control in Plant Chromosone Microdissection

染色体微切割和微克隆已成为复杂基因组研究的有效途径 ,但是操作过程中的核外DNA的污染一直是令人担心的问题。通过研究植物染色体微切割 (微分离 )和微切割的染色体DNA扩增过程中细胞质DNA的污染问题 ,表明目前常用的植物染色体微切割过程中 ,细胞质DNA的污染几乎难以避免 ,并提出了一个改进的降低细胞质DNA污染的方法 ,对如何控制细胞质DNA的污染进行了详细的讨论。

Discussion on Problem of Fermentation Contamination of Heterotrophic Chlorella

The contamination reasons were analyzed form the viewpoints of strain preparation, air system, medium and equipment sterilization and pipeline configura- tion. Moreover, the contamination-preventing measures were defined. We also sum- marized the characteristics of bacteria that contaminated the fermentation, as well as checking methods and remedial measures.

Organic contamination in the Great Wall bay,Antarctica in austral summer

During 1992/1993 austral summer,oil, BHCs,DDTs,PCBs etc.were determined in the sea water, sediments and organisms samples of the Great Wall bay,Antarctica.In surface sea water,the mean concentrations of oil were 0. 26-0. 93 μg/L.DDTs were all lower than the DL of the method,that was<0.04ng/L. BHCs mean concentrations were<0.69-<1.94 ng/L. In other samples,oil,BHCs,DDTs,and PCBs were all relatively higher in patella than that in sediments and seaweed. PAHs could not be detected in all samples. By comparison,the concentrations level of organic contaminants in the Great Wall bay was low yet.

Status of Heavy Metal Contamination in Paddy Soil of Guangxi Province and Effect of Silicon Fertilization on Cd Content in Brown Rice

[Objective] To provide a scientific basis for the management of Cd contamination, the status of Cd contamination in paddy soil of Guangxi Province, as well as the effect of silicon fertilization on Cd content in brown rice, was investigated. [Method] A total of 157 topsoil（0-20 cm） samples were collected from the major rice-growing paddy fields in Guangxi Province. The Cd contents in the topsoil samples were determined. The paddy soil environment quality and potential ecological risk were evaluated by single factor index and potential ecological index methods. In addition, in the Cd-contaminated paddy fields, the effects of different silicon fertilization treatments（no application（CK）, soil application of 750 kg/hm^2 silicon fertilizer（S）, leaf application of 1 500 L/hm^2 0.2% nanometer silicon（L）, soil application of 750 kg/hm^2 silicon fertilizer ＋ leaf application of 1 500 L/hm^2 0.2% nanometer silicon（SL）） on Cd content in brown rice were investigated. [Result] The total Cd contents in the 157 topsoil samples from paddy fields of Guangxi Province ranged from 0.02 to 7.33 mg/kg with an average content of 0.53 mg/kg. The Cd contents in 35.03% of the topsoil samples exceeded the grade II of national soil environment quality standards, and the topsoil samples were dominated by moderate and mild Cd contamination. Different silicon fertilization treatment all significantly reduced the Cd content in brown rice（P〈0.05）. In the treatment III, the Cd content in brown rice was lowest. Compared with that in the CK group, the Cd content in brown rice in the treatment III was reduced by 73.45%, in the treatment II was reduced by 62.07%, and in the treatment I was reduced by 34.48%. [Conclusion] The Cd in paddy fields of Guangxi Province showed a moderate to high ecological risk,and rational application of silicon fertilizer could effectively reduce the Cd content in brown rice.

Metal Contamination in Field Grown Rice

[Objective] Detecting the concentration of metals （lead, cadmium and arsenic） in the rice from one test field was to provide a snapshot of the current status of metal contamination in rice, coming up with a scientific basis for further research. [Method] The research divided 15 adjacent fields into five groups. Two samples were randomly selected from each field. Metal contamination was evaluated based on GB standards and the overall pollution score （OPS）. [Result] The percentages of samples with above-standard levels of the three metals are 83.3%, 100% and 36.7%, respectively. The values of OPSs are ranged from five to seven, with Pb＇s pollution index constituting the most percentage between three metals in OPS. [Conclusion] A metal contamination in the grown rice of this test field is observed, in which Pb may be the most important factor, and Cd contents in all of the samples exceed the safety value.

A microsatellite study on outcrossing rates and contamination in an Eucalyptus globulus breeding arboretum

Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in Victoria, south-eastern Australia. The microsatellite loci chosen for this study were highly polymorphic with the mean number of alleles per locus of 14.25. Individual mothers varied in their outcrosssing rate estimate from 15% to 95%, the overall outcrossing level in the arboretum was 47.9% and the contamination rate was 17.6%. The high selfing level was likely to result in marked inbreeding depression in the performance of open-pollinated seed lots. Open-pollinated seeds collected from such arboreta are not advisable because of its low genetic quality, although such arboreta may be useful for the seed production through large-scale manual pollination or collecting seeds only from trees or genotypes within the arboretum that have high outcrossing rates.

Use of piecewise polynomial phase modeling to compensate ionospheric phase contamination in skywave radar systems

Recognition and correction of ionospheric phase path contamination is a vital part of the global radar signal processing sequence. A number of model-based correction algorithms have been developed to deal with the radar performance degradation due to the ionospheric distortion and contamination. This paper addresses a novel parametric estimation and compensation method based on High-order Ambiguity Function (HAF) to solve the problem of phase path contamination of HF skywave radar signals. When signal-to-noise ratio and data sequence available satisfy the predefined conditions, the ionospheric phase path contamination may be modeled by a polynomial phase signal (PPS). As a new parametric tool for analyzing the PPS, HAF is introduced to estimate parameters of the polynomial-phase model and reconstruct the correction signal. Using the reconstructed correction signal, compensation can be performed before coherent integration so that the original echo spectrum can be restored. A piecewise scheme is proposed to track rapid variation of the phase contamination based on HAF method, and it can remove the Doppler spread effect caused by the ionosphere nonstationarity. Simulation and experimental results are given to demonstrate the efficiency of the proposed algorithm.

Contamination of Water for Domestic Use and Human Consumption by Heavy Metals Derived from Mining Activity in Parral, Chihuahua, Mexico

Research was done with the objective of evaluating the quality of water supplied to the potable water system in Hidalgo Del Parral, which comes from two main supply sources： wells from ＂Valle del Verano＂, which provide water to the east side of the city, and the Water Treatment Plant, which receives water from different mines and supplies the west side of the city. When this plant is overcome on its capacity of treatment, a part of the water from the mines is fed directly to the northwest part of the city. The metals lead （Pb）, chromium （Cr）, cadmium （Cd）, zinc （Zn）, and arsenic （As） were analyzed by atomic absorption （AA） technique, based on the United States Environmental Protection Agency （EPA） Method 7000B （Revision 2, February 2007）. The digestion process was done according to the guidelines established in Method NMX-AA-051-SCFI-2001, Analysis of Water-Determination of Metals by Atomic Absorption, developed by the National Standardization Technical Committee for Environmental Protection （Mexico）. The samples were collected from the following points： 13 wells and 2 re-pumping stations of ＂Valle del Verano＂, the inlet and outlet of the Water Treatment Plant, and domestic faucets. The east side of the city, supplied by the wells of ＂Valle del Verano＂, is metal-pollution free. The water that comes from the mines contains high concentrations of As, Zn, Cd and Pb, with levels that can get to 0.12, 32.6, 0.26 and 3.5 mg/L, respectively. This water pollution generated by mining can be concluded from the high levels found in the domestic samples in which, for several points, the concentrations exceed the parameters set by the current guideline. According to the results, it is vital to set a plan of remediation for the water that comes from the mines, because there is a great risk for health in the consumotion of this water.