Anthropogenic Sources Of Contamination Research Articles

Hydrogeochemical Investigation of Elevated Arsenic Based on Entropy Modeling, in the Aquifers of District Sanghar, Sindh, Pakistan

Arsenic (As) contamination in drinking groundwater is a common environmental problem in Pakistan. Therefore, sixty-one groundwater samples were collected from various groundwater sources in District Sanghar, Sindh province, Pakistan, to understand the geochemical behavior of elevated As in groundwater. Statistical summary showed the cations and anions abundance in decreasing order of Na+ > Ca2+ > Mg2+ > K+, and HCO3− > Cl− > SO42− > NO3−. Arsenic was found with low to high concentration levels ranging from 5 µg to 25 µg/L with a mean value of 12.9 µg/L. A major water type of groundwater samples was mixed with NaCl and CaHCO3 type, interpreting the hydrochemical behavior of rock–water interaction. Principal component analysis (PCA) showed the mixed anthropogenic and natural sources of contamination in the study area. Moreover, rock weathering and exchange of ions controlled the hydrochemistry. Chloro-alkaline indices revealed the dominance of the reverse ion exchange mechanism in the region. The entropy water quality index (EWQI) exposed that 17 samples represent poor water, and 11 samples are not suitable for drinking.

Characterizing copper and zinc content in forested wetland soils of North Carolina, USA

Wetlands are often located in landscape positions where they receive runoff or floodwaters, which may contain toxic trace metals and other pollutants from anthropogenic sources. Over time, this can lead to the accumulation of potentially harmful levels of metals in wetlands soils. To assess the potential risk of Cu and Zn buildup in wetland soils in North Carolina, soil data from 88 wetlands were analyzed. In a subset of 16 wetlands, more intensive sampling was conducted. Samples were analyzed for Mehlich 3 Cu and Zn, and a subset of the samples was analyzed for total Cu and Zn. Overall, Mehlich 3 Cu and Zn were low, with mean values of 0.9mg/kg for Cu and 3.2mg/kg for Zn. Warning levels for Mehlich 3 Zn were only exceeded in three of the 88 sites; elevated Mehlich Cu was not observed. Total Cu and Zn were also low, with only a few sites having elevated levels; however, there was not a strong linear relationship between Mehlich 3 and total metals. Mean levels of Mehlich 3 Cu and Zn in wetlands were much lower than for human-impacted upland soils and background threshold concentrations that might be indicative of disturbance were much lower than warning levels for agricultural soils. The very low mobile Zn and Cu in most of these wetlands indicated that these metals do not pose a risk to the biota in most North Carolina wetlands, but wetlands with a direct and significant anthropogenic source of metal contamination could be exceptions.

Identification of Metal Contamination Sources and Evaluation of the Anthropogenic Effects in Soils near Traffic-Related Facilities.

Traffic-related facilities typically have much lower metal emissions than other sources; however, they can be numerous and widespread as well. Subdividing pollution sources is necessary to assess soil contamination characteristics and identify sources according to the contamination cause. Anthropogenic contamination by metals was quantitatively determined using contamination factor (Cf) and evaluated using multivariate analysis. More than half of the concentrations for Zn, Pb, and Cu in soils were higher than that in the natural background (NB). Cf of metals was, in decreasing order, Zn > Pb = Cu > Ni = As. Zn, Pb, and Cu were identified as anthropogenic contaminants in correlation analysis. Principal component analysis showed that the two main contamination causes were coarse particles from the maintenance or crushing activities of vehicles and nonexhaust/exhaust emissions. Clusters were classified according to those two anthropogenic and lithogenic causes and included Group I (Zn, Pb, and Cu in garages, auto repair shops, and auto salvage yards), Group II (Zn, Pb, and Cu in parking lots, driving schools, and roadsides), and Group III (As and Ni with high lithogenic properties). Anthropogenic input and sources of soil contamination by metals in traffic-related facilities were appropriately estimated through the combination of Cf and multivariate analysis.

Metal and metalloids concentration in Galapagos fish liver and gonad tissues

The Galapagos Islands are one of the best-preserved archipelagos in the world. We sampled individuals of six demersal and three pelagic species. The metal concentration of liver and gonad tissues were analyzed by Inductively Coupled Plasma Optical Spectrometry. Findings suggest none of the pelagic species showed metallic concentrations that could pose a risk to their health or reproductive capacity.S. violacea and P. clemensi Zn levels were higher in liver than in gonads, indicating that these species could be in their reproduction period. Zn risk toxicity for the study species is negligible. High concentrations of Cd were found in the liver of C. princeps, C. affinis and P. albomaculatus which could cause morphological and physiological alterations. We hypothesize that the high metal concentrations found in the demersal species could come from the volcanism of the islands, since no major sources of anthropogenic metal contamination can be found in the archipelago.

Stable isotope fractionation of thallium as novel evidence for its geochemical transfer during lead‑zinc smelting activities

Thallium (Tl) is a highly toxic trace metal. Lead (Pb)‑zinc (Zn) smelting, which is a pillar industry in various countries, is regarded as one of the dominant anthropogenic sources of Tl contamination in the environment. In this study, thallium isotope data have been evaluated for raw material and a set of industrial wastes produced at different stages of Pb-Zn smelting in a representative large facility located by the North River, South China, in order to capture Tl isotope signatures of such typical anthropogenic origin for laying the foundation of tracking Tl pollution. Large variations in Tl isotopic compositions of raw Pb-Zn ores and solid smelting wastes produced along the process chain were observed. The ε205Tl values of raw Pb-Zn ores and return fines are −0.87 ± 0.26 and −1.0 ± 0.17, respectively, contrasted by increasingly more negative values for electrostatic precipitator dust (ε205Tl = −2.03 ± 0.14), lime neutralizing slag (ε205Tl = −2.36 ± 0.18), and acid sludge (ε205Tl = −4.62 ± 0.76). The heaviest ε205Tl (1.12 ± 0.51) was found in clinker. These results show that isotopic fractionation occurs during the smelting processes. Obviously, the lighter Tl isotope is enriched in the vapor phase (−3.75 ε205Tl units). Further XPS and STEM-EDS analyses show that Tl isotope fractionation conforms to the Rayleigh fractionation model, and adsorption of 205Tl onto hematite (Fe2O3) may play an important role in the enrichment of the heavier Tl isotope. The findings demonstrate that Tl isotope analysis is a robust tool to aid our understanding of Tl behavior in smelting processes and to provide a basis for source apportionment of Tl contaminations.

Occurrence, spatial distribution and ecological risk assessment of trace elements in surface sediments of rivers and coastal areas of the East Coast of Bangladesh, North-East Bay of Bengal

Coastal and estuarine ecosystems provide habitats for many organisms. Recently, the estuaries and coastal areas of the East Coast of Bangladesh have become heavily contaminated due to dumping of untreated wastewater into the rivers from a number of different industries. The current study analyzes potentially toxic elements contamination in surface sediments of the Karnaphuli, Sangu, Bakkhali and Naf Rivers, Kutubdia and Moheshkhali Channel, and St. Martin's Island, and assesses the consequent ecological risks. The pollution load index (PLI), geoaccumulation index (Igeo) and potential ecological risk (PER) indices show that the contaminated sediments have negative effects on the aquatic environments. The PLI values ranged between 0.45 and 1.67, which suggests the severity of trace-element contamination. The mean Igeo values showed the sediments range from uncontaminated to heavily contaminated state. The Enrichment Factor (EF) values suggested that the sediments were contaminated by anthropogenic sources, and PER values demonstrate that sites at Sangu, Naf and St Martin's Island are less contaminated compared to sites at Karnaphuli, Bakkhali, Kutubdia and Moheshkhali. Overall, results showed that Karnaphuli river is the most contaminated and St Martin's Island is the least based on the spatial distribution of PLI, Cd, PER and ∑TUs of trace metals in surface sediments. Comparing with the neighboring countries, the concentrations of Cd and Pb were found to be higher while Cr is lower in the East Coast of Bangladesh than the estuarine and coastal waters of the Bay of Bengal rim countries. The present study reveals that the lack of water quality guidelines in Bangladesh for the coastal, estuarine and marine water escalated the dumping of untreated wastewater. Immediate measures need to be taken to address the ecological risks so that an effective management program can be undertaken. A systematic approach for collecting pollutant data and use of isotopes to trace anthropogenic sources of contamination is recommended for pollutants like toxic metals, pesticides and other contaminants in sediment and aquatic products in the entire coastal waters of the Bay of Bengal.

Elemental analysis of soils along the South African National Road (N3) - a combined approach including statistics, pollution indicators, and geographic information system (GIS).

The South African National Road (N3) in the KwaZulu-Natal province is one of the major transportation routes from the Durban harbor. In this study, metal concentrations in Bidens pilosa L., which grows alongside the N3, and soil were determined using inductively coupled plasma - optical emission spectrometry to evaluate the impact of soil quality on the uptake. Furthermore, the distribution of Pb and Cd was mapped using the geographic information system (GIS) approach to identify the potential benefits of spatial data applications in soil studies. Plant concentrations of toxic metals, especially Pb, were high and were linked to high soil concentrations. The target hazard quotients indicated a low risk of adverse effects due to Cd exposure and increased risk due to As and Pb exposure. The carcinogenic risk was high for As and Cd exposure at all sites and Pb at 40% of the sites. Soil quality indicators (geoaccumulation indices and enrichment factors) showed soils to be moderate to heavily contaminated. Principal component analysis indicated different anthropogenic sources of contamination, including vehicular emissions and a combination of industrial, agricultural, and social impacts. Kriging interpolation depicted the spatial diffusion of Cd and Pb concentrations throughout the study area with different hot-spot areas of metal contamination for these two metals. The study demonstrated that the plants growing along national roads are not suitable for human consumption.

Groundwater antibiotic pollution and its relationship with dissolved organic matter: Identification and environmental implications

The occurrence of veterinary antibiotics and hydro-chemical parameters in eleven natural springs in a livestock production area is evaluated, jointly with the characterization of their DOM fingerprint by Orbitrap HRMS. Tetracycline and sulfonamide antibiotics were ubiquitous in all sites, and they were detected at low ng L−1 concentrations, except for doxycycline, that was present at μg L−1 in one location. DOM analysis revealed that most molecular formulas were CHO compounds (49 %–68 %), with a remarkable percentage containing nitrogen and sulphur (16 %–23 % and 11 %–24 %, respectively). Major DOM components were phenolic and highly unsaturated compounds (~90 %), typical for soil-derived organic matter, while approximately 11 % were unsaturated aliphatic, suggesting that springs may be susceptible to anthropogenic contamination sources. Comparing the DOM fingerprint among sites, the spring showing the most different profile was the one with surface water interaction and characterized by having lower CHO and higher CHOS formulas and aliphatic compounds. Correlations between antibiotics and DOM showed that tetracyclines positively correlate with unsaturated oxygen-rich substances, while sulfonamides relate with aliphatic and unsaturated oxygen-poor compounds. This indicates that the fate of different antibiotics will be controlled by the type of DOM present in groundwater.

Characterization, geostatistical modeling and health risk assessment of potentially toxic elements in groundwater resources of northeastern Iran

Study regionNortheastern Iran. Study focusIn northeastern Iran, water needed for municipal and agricultural activities mainly comes from groundwater resources. However, it is subject to substantial anthropogenic and geogenic contamination. We characterize the sources of groundwater contamination by employing an integrated approach that can be applied to the identification of large-scale contamination sources in other regions. An existing dataset of georeferenced water quality parameters from 676 locations in northeast of Iran was analyzed to investigate the geochemical properties of groundwater. Gridding of the parameters graphically illustrates the areas affected by high concentrations of As, Cl−, Cr, Fe, Mg2+, Na+, NO3−, Se, and SO42-. We then identified potential anthropogenic and geogenic contamination sources by employing random forest (RF) regression modeling. New hydrological insights for the regionRandom forest (RF) models show that the major ions, As, Cr, Fe, and Se content of groundwater are mainly determined by geology in the study area. Modeling also links groundwater NO3− contamination with sewage discharge into aquifers as well as the application of nitrogenous and animal-waste fertilizers. Areas of high salinity result from evaporate deposits and irrigation return flow. Medium to high non-carcinogenic health risk is found in areas with high concentrations of geogenic As and Cr in groundwater. Our approach can be applied elsewhere to analyze regional groundwater quality and associated health risks as well as identify potential sources of contamination.

Groundwater resources and quality in Syria

The resources of groundwater and its pollution in Syria are identified, and pathways of contaminants to groundwater are described. Then, suggestions for improvement of groundwater quality in Syria are evaluated. Syria is located in a region where water scarcity is dominant. About 87% of all water in Syria is mainly used for irrigation, with almost 60% of this water taken from groundwater resources. The rest is used for domestic and industrial purposes, which account for 9% and 4%, respectively. Due to over-pumping and the increase in the number of unsustainable wells observed in recent decades, groundwater is quantitatively deteriorating. In general, sources of groundwater contamination fall into two main categories: natural and anthropogenic sources. Important sources of natural groundwater pollution include climate effects. About 43% of groundwater has a high concentration of SO4 and/or NaCl. This is specifically dominant in the eastern region of Syria due to the harsh environment where precipitation is relatively low, and evaporation is high. One of the major sources of anthropogenic groundwater contamination is civil war. Most of the damaged regions are located on permeable rocks, which increases the probability of groundwater contamination due to chemical weapons (CW) used. It is vital to manage and control groundwater resources well. With the increase in water contamination and with the absence of poor water management, access to drinking water will be more of a problem than it is now.

An Assessment of Ambient Water Quality and Challenges with Access to Water and Sanitation Services for Individuals Experiencing Homelessness in Riverine Encampments.

Individuals experiencing unsheltered homelessness face significant barriers to accessing water, sanitation, and hygiene services, but the risks associated with this lack of access and barriers to service provision have been largely understudied. We analyzed water samples upstream and downstream of three homeless encampments in the San Diego River watershed and interviewed service providers from public and nonprofit sectors to assess local perceptions about challenges and potential solutions for water and sanitation service provision in this context. Water upstream from encampments contained detectable levels of caffeine and sucralose. Escherichia coli concentrations downstream of the encampments were significantly greater than concentrations upstream, but there was no significant change in the concentrations of other pollutants, including caffeine and sucralose. The HF183 marker of Bacteroides was only detected in one sample upstream of an encampment and was not detected downstream. Overall, there was insufficient evidence to suggest that the encampments studied here were responsible for contributing pollution to the river. Nevertheless, the presence of caffeine, sucralose, and HF183 indicated that there are anthropogenic sources of contamination in the river during dry weather and potential risks associated with the use of this water by encampment residents. Interviews with service providers revealed perceptions that the provision of water and sanitation services for this population would be prohibitively expensive. Interviewees also reported perceptions that most riverbank residents avoided contact with service providers, which may present challenges for the provision of water and sanitation service unless trust is first built between service providers and residents of riverine encampments.

Comprehensive assessment of heavy metal risk in soil-crop systems along the Yangtze River in Nanjing, Southeast China.

Conventional assessment of soil environmental quality commonly focuses on soil heavy metals (HMs), neglecting the HMs in agricultural products. To response this shortcoming, a comprehensive assessment combining both soil environmental quality and agricultural product security for evaluating soil HM impact is urgently required. This comprehensive assessment incorporates not only the HM contents in soil and agricultural product but also soil environmental quality standards, soil elemental background values, and safety standards for HMs in agricultural products. In this study, it was applied to evaluate the potential risk of HMs in soil-crop systems (i.e., soil-vegetable, soil-maize, soil-rice, and soil-wheat systems) along the Yangtze River in Nanjing, Jiangsu Province, Southeast China. Furthermore, 114Cd/110Cd isotope ratio analysis was used to identify the specific contamination sources. The mean concentrations of Cd, As, Hg, Pb, Cu, Zn, and Cr in the surface soils (0-20cm) were 0.26, 11.07, 0.09, 32.63, 38.57, and 107.92mgkg-1, respectively, exceeding the corresponding soil background values. Fertilizer and atmospheric deposition were the major anthropogenic sources of HM contamination in crop-growing soils. In addition to the crop type, soil pH and organic matter also influenced the transfer of HMs from soils to the edible parts of crops. Results of comprehensive assessment revealed that approximately 11.1% of paired soil-crop sites were multi-contaminated by HMs, among which paddy soils had the highest potential risk of HMs followed by maize soils, vegetable soils, and wheat soils. To evaluate the potential risk of HMs in arable land, this study provides a novel, scientific and reliable approach via integrating soil environmental quality and agricultural product security.

Unraveling the riverine antibiotic resistome: The downstream fate of anthropogenic inputs

River networks are one of the main routes by which the public could be exposed to environmental sources of antibiotic resistance, that may be introduced e.g. via treated wastewater. In this study, we applied a comprehensive integrated analysis encompassing mass-flow concepts, chemistry, bacterial plate counts, resistance gene quantification and shotgun metagenomics to track the fate of the resistome (collective antibiotic resistance genes (ARGs) in a microbial community) of treated wastewater in two Swiss rivers at the kilometer scale. The levels of certain ARGs and the class 1 integron integrase gene (intI1) commonly associated with anthropogenic sources of ARGs decreased quickly over short distances (2-2.5 km) downstream of wastewater discharge points. Mass-flow analysis based on conservative tracers suggested this decrease was attributable mainly to dilution but ARG loadings frequently also decreased (e.g., 55.0-98.5 % for ermB and tetW) over the longest studied distances (6.8 and 13.7 km downstream). Metagenomic analysis confirmed that ARG of wastewater-origin did not persist in rivers after 5 ~ 6.8 km downstream distance. sul1 and intI1 levels and loadings were more variable and even increased sharply at 5 ~ 6.8 km downstream distance on one occasion. While input from agriculture and in-situ positive selection pressure for organisms carrying ARGs cannot be excluded, in-system growth of biomass is a more probable explanation. The potential for direct human exposure to the resistome of wastewater-origin thus appeared to typically abate rapidly in the studied rivers. However, the riverine aquatic resistome was also dynamic, as evidenced by the increase of certain gene markers downstream, without obvious sources of anthropogenic contamination. This study provides new insight into drivers of riverine resistomes and pinpoints key monitoring targets indicative of where human sources and exposures are likely to be most acute.

Identifying anthropogenic sources of groundwater contamination by natural background levels and stable isotope application in Pinggu basin, China

The assessment of natural background levels (NBLs) in groundwater is considered as an efficient way to distinguish the geogenic compound from anthropogenic pollution of groundwater—a basic issue in groundwater environmental management. At present, most studies only assess NBLs of single parameters in groundwater. Such method, however, ignored the complex components and interaction in the groundwater, which leads to the inaccuracy of the assessment. In this study, 51 groundwater samples were investigated in November 2018 in Pinggu basin—one of the most important emergency groundwater supply sources of Beijing. Hierarchical cluster analysis (HCA) was used firstly to divide the study area into four zones. By combining single-parameter NBLs assessment and comprehensive NBLs assessment, the possible anthropogenic impact on groundwater quality in different zones could be determined with the use of land use map. For single-parameter NBLs assessment, iterative Grubbs’ test was used to assess NBLs of the data following Gaussian distribution, and the median plus/minus twofold the median of the absolute deviations from the median (median ± 2MAD) method was used to assess NBLs of the data for the non-Gaussian distribution. For comprehensive NBLs assessment, Mahalanobis distances of scatters in scatter plots which express the hydrogeological evolution processes were involved. In addition, δ15N-NO3− and δ18O-NO3− were used to analyze the sources of nitrate in groundwater. The results showed that the groundwater was affected by industrial activities, agricultural activities, urban domestic sewage and landfills. And the groundwater quality in the east of the study area was better than that in the west. Nitrate in the groundwater of study area mainly came from nitrification, and denitrification occurred in the groundwater near the landfills. This study provides a way to assess the NBLs of groundwater quality, and to determine sources and transformation of nitrate in the groundwater, which contributes to the identification of anthropogenic pollution in groundwater.

Distribution of some potentially toxic heavy metals in the soil of Shoubra El Kheima, Egypt

This study aims to detect the effect of industrialization and urbanization on the soil content of some potentially toxic heavy metals. The soil of Shoubra El Kheima was considered one of the most fertile soils in the Nile Delta, Egypt. Forty samples from this soil were texturally categorized and chemically analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The data were treated statistically and by geographic information system technique. The agricultural soils in the study area are mainly classified as clayey soil, whereas urban and industrial soil samples are varied in their classification from clayey to loamy sand. As, Cd and Zn in the soil exceed the maximum permissible limits whereas, Cu, Cr, Ni and Pb are within the permissible limit except for some samples. The obtained data show that the concentrations of Cu, As, Zn, Pb, Ni and Cr increase in the southeastern and southwestern parts of the study area. Urbanization, agricultural practices, and the atmospheric deposition from the different industrial activities are thought to be the main anthropogenic sources of heavy metals contamination in the study area.

Differentiation of natural and anthropogenic contaminant sources using isotopic and microbial signatures in a heavily cultivated coastal area.

Hydrogeochemical and multiple isotope data for groundwater samples were obtained and interpreted to discriminate anthropogenic and natural contaminant sources in a coastal aquifer underlying a heavily cultivated watershed in Hwaseong, South Korea. The local aquifers are vulnerable to contamination, due to high anthropogenic N inputs and the location close to the ocean facilitating seawater intrusion. Thus, to effectively control the groundwater quality in the study area, it is necessary to differentiate between anthropogenic and natural contaminant sources. The concentrations of NO3-N in the groundwater ranged between 0.14 and 45.6mg/L in August 2015 and 0.2-39.6mg/L in March 2016. High concentrations of Cl- (388-1107mg/L) and a high electrical conductivity (1027-2715μS/cm) were observed in the study area, suggesting that the groundwater was affected by seawater intrusion. Furthermore, δ15N-NO3-, δ34S-SO42- values and 87Sr/86Sr of groundwater were determined to reveal the origins of the natural and anthropogenic contaminants and the groundwater mean residence times (MRT) and 87Sr/86Sr ratios were used to assess the hydrogeochemical processes along the flow path in the study area. Young groundwater was affected by an anthropogenic contamination source with contributions of 26-46% adding nitrate to the aquifer, whereas old groundwater was impacted by mixing with seawater with contributions of 10-20% with low concentrations of NO3-N, but elevated concentrations of chloride and sulfate. Recently recharged uncontaminated groundwater showed oxic conditions with a diverse microbial community structure, whereas young groundwater contaminated by anthropogenic sources showed a less diverse microbial community structure. The results of this study suggest that multiple isotopes combined with groundwater MRT and microbial data can be applied to distinguish natural and anthropogenic contaminant sources in a groundwater system.

Ecological effects and causal synthesis of oil sands activity impacts on river ecosystems: water synthesis review

Oil sands development in the lower Athabasca River watershed has raised considerable public and scientific concerns regarding perceived effects on environmental health. To address this issue for tributaries and the mainstem of the Athabasca River in the Athabasca Oil Sands Region, the Water Component of the Joint Oil Sands Monitoring (JOSM) plan produced monitoring assessments for seven integrated themes: atmospheric deposition, tributary water quality, river mainstem water quality, groundwater quality and quantity, water quality and quantity modelling, benthic invertebrate condition, and fish health. Our review integrates and synthesizes the large and diverse datasets assembled in the seven JOSM theme assessments to (i) evaluate possible environmental effects based on known sources and candidate proximal causes and (ii) determine the importance of cause-and-effect pathways related to contaminant, sediment, and nutrient inputs. Although JOSM research identified ecological effects that appear to be associated with contaminant exposure, the source of this exposure is confounded by co-location of, and inability to differentiate between, oil sands operations (principally released by atmospheric emission) and inputs from the natural bitumen outcrops (e.g., erosional material transported by surface and groundwater flows). Nutrient enrichment from treated municipal sewage effluent was the dominant ecological effect observed for the mainstem Athabasca River, associated with increased fish size and changes in invertebrate assemblages, likely because this pollution source is discharged directly into the river. If the direct release of treated oil sands process water occurs in the future, then the potential ecological impact of these direct industry releases will need to be evaluated carefully. The ecological causal assessment method proved to be a useful tool for better understanding how stressor sources relate to ecological effects through candidate proximate causes. Factors that confound our ability to assess the ecological effects of oil sands development focus on our inability to adequately differentiate between contaminants supplied from natural and anthropogenic contaminant sources. Our causal synthesis identifies options for changes in future monitoring to better anticipate and detect degradation in the ecosystem health of the lower Athabasca River and its tributaries.

Higher bioavailability of Cu and Zn in the eastern part of Johore Causeway: Will the pattern remain the same beyond 2030?

The purpose of this paper is to discuss Cu and Zn concentrations in Perna viridis soft tissues from the western and eastern parts of Johore Singapore Causeway. The polluted eastern portion of the Causeway had greater levels of Cu and Zn in different areas of the soft tissues of mussels than the western part. This indicated the eastern section of the semi-enclosed Causeway had higher Cu and Zn bioavailability than the western part. With some reports of high metal levels in the eastern part of the Causeway from 2015 to 2018, it is predicted that there will be a plausible constant source of anthropogenic metal contamination in the eastern part of the Causeway beyond 2030 if anthropogenic activities are not effectively controlled.

ESTUDIO INTEGRAL DE LA CALIDAD DEL AGUA EN EL LITORAL DEL PUERTO SAN CARLOS, BAJA CALIFORNIA SUR, MÉXICO

Physical, chemical and biological parameters were measured in March and November 2014. These water analyses were carried out at 22 sites on the coast of Puerto San Carlos (Magdalena Bay, Baja California Sur, Mexico), with the objective of assessing water quality and identifying possible sources of water pollution and its status according to Mexican regulations. The study area was divided into three zones according to its main activity: (1) thermoelectric power station, (2) fiscal port harbor and (3) San Carlos estuary, adjacent to the to the town of the same name. The measured physical, chemical and biological parameters were temperature, salinity, dissolved oxygen, chlorophyll-a, nutrients, dissolved trace metals, and coliform bacteria. The results showed poor water quality in the three areas studied, in accordance with NOM-001-SEMARNAT-1996 and the ecological criteria for water quality CE-CCA-001/89, in particular regarding phosphate, ammonium, and silicate (unregulated) concentrations, as well as the presence of Escherichia coli . The three zones are considered sources of anthropogenic contamination whose impact is greater in the warmest month and dead tides, probably due to the entry of water contaminated by anthropogenic waste derivatives. According to the sanitary authorities of the state of Baja California Sur, the certification of water quality in Magdalena Bay has been variable: it was not certified in 2014, whilst in the period 2015-2017 it was re-certified. Although this region is an important touristic and fishing site, it is at risk of contamination due to the lack of a wastewater treatment system in the town and the inadequate disposal of raw sewage from the port.

Sources of anthropogenic contamination of soil in the Upper Silesian Agglomeration (southern Poland)

This assessment of the environmental degradation by toxic chemical elements within the Upper Silesian Industrial Agglomeration of Poland encompasses the impact of mining for base metals and coal and non-ferrous metallurgy, as well as the discharge of industrial and municipal sewage causing strong degradation of the natural environment in the area over the years. The content of the following elements: Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, P, Pb, S, Sn, Sr, Ti, V and Zn has been assessed both in the topsoil (0.0–0.3 m) and the subsoil (0.8–1.0 m) of the study area. Concentrations of the elements in the <2 mm soil fraction were analysed using the ICP-OES method after Aqua regia extraction. The soil contamination was assessed based on the enrichment factor ( EF ) and geo-accumulation index ( I geo ). The tests revealed elevated contents of several metals, arsenic and sulphur, exceeding the regional geochemical background levels. Unusually high concentrations of the following elements: As (up to 5,300 mg/kg), Cd (up to 388.8 mg/kg), Cr (up to 1,638 mg/kg), Cu (up to 13,230 mg/kg), Hg (up to 23.44 mg/kg), Mo (up to 93.7 mg/kg), Pb (up to 54,940 mg/kg), Sn (up to 701 mg/kg) and Zn (up to 88,120 mg/kg) were recorded. The highest concentrations of these elements were found in the proximity of smelters and residential areas. The spatial distribution of metals is shown as interpolated data on maps and compared with the locations of mining and industrial sites.