Anthropogenic Sources Of Contamination Research Articles

Application of a microbial and pathogen source tracking toolbox to identify infrastructure problems in stormwater drainage networks: a case study.

Water scarcity and increasing urbanization are forcing municipalities to consider alternative water sources, such as stormwater, to fill in water supply gaps or address hydromodification of receiving urban streams. Mounting evidence suggests that stormwater is often contaminated with human feces, even in stormwater drainage systems separate from sanitary sewers. Pinpointing sources of human contamination in drainage networks is challenging given the diverse sources of fecal pollution that can impact these systems and the non-specificity of traditional fecal indicator bacteria (FIB) for identifying these host sources. As such, we used a toolbox approach that encompassed microbial source tracking (MST), FIB monitoring, and bacterial pathogen monitoring to investigate microbial contamination of stormwater in an urban municipality. We demonstrate that human sewage frequently contaminated stormwater (in >50% of routine samples), based on the presence of the human fecal marker HF183, and often exceeded microbial water quality criteria. Arcobacter butzleri, a pathogen of emerging concern, was also detected in >50% of routine samples, with 75% of these pathogen-positive samples also being positive for the human fecal marker HF183, suggesting human municipal sewage as the likely source for this pathogen. MST and FIB were used to track human fecal pollution in the drainage network to the most likely point source of contamination, for which a sewage cross-connection was identified and confirmed using tracer dyes. These results point to the ubiquitous presence of human sewage in stormwater and also provide municipalities with the tools to identify sources of anthropogenic contamination in storm drainage networks.IMPORTANCEWater scarcity, increased urbanization, and population growth are driving municipalities worldwide to consider stormwater as an alternative water source in urban environments. However, many studies suggest that stormwater is relatively poor in terms of microbial water quality, is frequently contaminated with human sewage, and therefore could represent a potential health risk depending on the type of exposure (e.g., irrigation of community gardens). Traditional monitoring of water quality based on fecal bacteria does not provide any information about the sources of fecal pollution contaminating stormwater (i.e., animals/human feces). Herein, we present a case study that uses fecal bacterial monitoring, microbial source tracking, and bacterial pathogen analysis to identify a cross-connection that contributed to human fecal intrusion into an urban stormwater network. This microbial toolbox approach can be useful for municipalities in identifying infrastructure problems in stormwater drainage networks to reduce risks associated with water reuse.

Groundwater Quality Assessment with Respect to Heavy Metal Content by using Heavy Metal Pollution Index (HPI) of Moradabad District, Uttar Pradesh, India

Heavy metal pollution index (HPI), is a rating method to assess the water quality and to categorize the groundwater pollution with respect to heavy metals content. The aims of the present study are to look over the current status of heavy metals pollution in and around Moradabad city. Heavy metal pollution in water has gained universal consciousness due to its tenacity, accumulation in the food chain and negative effects on ecological as well as human health. Its variation in concentration can cause deterioration of water. The study focuses on examining the content of heavy metal (Zn, Fe, Cd, Mn, Pb, Ni, Cu, and Cr) in the 30 water samples from the surrounding areas of Moradabad city. The concentrations of Cd, Mn, Fe, Cu, Pb, Zn, Ni, and Cr in water samples were recorded in the pre- and post-monsoon season of 2017. The examined samples reveal that the contamination level of heavy metal is in the following sequence Ni>Fe>Pb>Cd>Cr>Cu>Zn>Mn in premonsoon 2017, whereas in postmonsoon season, heavy metals values are shown as Fe>Pb>Ni>Mn>Cr> Cu>Zn>Cd. The HPI average value in pre-monsoon 2017 is 13.07, which recommended that the groundwater quality is good. While in post-monsoon season HPI average values has been 159.26 suggesting that the water quality is poor to inferior. The correlation matrix has been evaluated and shows a positive correlation with the elements. The immense production of industrial solid waste in Moradabad city and its improper disposal in the form of heap piled outside the city area generates leachate. Heavy metal leaching from these disposal points may contaminate the groundwater as well as surface water resources. The study shows that heavy metal concentration has a noticeable rise in water due to different anthropogenic and various natural sources of contamination.

Quantitative source apportionment of faecal indicator bacteria from anthropogenic and zoogenic sources of faecal contamination

Recreational bathing waters are complex systems with diverse inputs from multiple anthropogenic and zoogenic sources of faecal contamination. Faecal contamination is a substantial threat to water quality and public health. Here we present a comprehensive strategy to estimate the contribution of faecal indicator bacteria (FIB) from different biological sources on two at-risk beaches in Dublin, Ireland. The daily FIB loading rate was determined for three sources of contamination: a sewage-impacted urban stream, dog and wild bird fouling. This comparative analysis determined that the stream contributed the highest daily levels of FIB, followed by dog fouling. Dog fouling may be a significant source of FIB, contributing approximately 20 % of E. coli under certain conditions, whereas wild bird fouling contributed a negligible proportion of FIB (<3 %). This study demonstrates that source-specific quantitative microbial source apportionment (QMSA) strategies are vital to identify primary public health risks and target interventions to mitigate faecal contamination.

Occurrence, transport and sources of metals and metalloids in the Bangpakong River in the eastern economic corridor area of Thailand

The occurrence of elements in river water is affected by various factors, including mobility, weathering and transport processes and anthropogenic contributions. A total of six water sampling campaigns were conducted from 2021 to 2022 to study the factors affecting the occurrence of twelve elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Se) in the Bangpakong River. The total concentrations of all the elements were within the levels set by the national surface water quality standard. Comparisons of dissolved elemental concentrations in the study area with the global average for dissolved elemental concentrations in pristine rivers indicated contamination with Al, As, Co, Mn, Zn and Se in the river water. Based on the percentage of each element in particulates to the total concentration, Al (80.6 %), Cr (71.9 %), Cu (69.9 %), Fe (95.6 %), Mn (76.6 %), Pb (74.7 %), and Zn (70.6 %) were mainly transported in the particulate phase in both the dry and wet seasons. However, As (65.5 %), Co (60.3 %), and Se (77.6 %) were mainly transported in the dissolved phase in both seasons. The ratios of the dissolved Se concentration in river water to the Se concentration in the Earth's crust indicated significant and high mobility, especially in downstream sites, likely due to Se leaching from alluvial sediments. Seawater intrusion is likely the cause of As and Zn contamination in the dry season. Weathering of rocks and soils likely causes Al, Co, and Mn contamination in the wet season. The anthropogenic sources of contamination include the discharge of Mn and Zn from fertilizers in agriculture and the use of formulated feed in aquaculture. Approximately 52.98, 25.23, 5.68 and 0.63 tons of Fe, Al, Mn and Zn, respectively, are estimated to be transported from the river into the Gulf of Thailand each year.

A Modified Model for Quantitative Heavy Metal Source Apportionment and Pollution Pathway Identification.

Current source apportionment models have successfully identified emission sources and quantified their contributions. However, when being utilized for heavy metal source apportion in soil, their accuracy needs to be improved, regarding migration patterns. Therefore, this work intended to improve the pre-existing principal component analysis and multiple linear regression with distance (PCA-MLRD) model to effectively locate pollution pathways (traffic emissions, irrigation water, atmospheric depositions, etc.) and achieve a more precise quantification. The dataset of soil heavy metals was collected from a typical area in the Chang-Zhu-Tan region, Hunan, China in 2021. The identification of the contribution of soil parent material was accomplished through enrichment factors and crustal reference elements. Meanwhile, the anthropogenic emission was identified with principal component analysis and GeoDetector. GeoDetector was used to accurately point to the pollution source from a spatial differentiation perspective. Subsequently, the pollution pathways linked to the identified sources were determined. Non-metal manufacturing factories were found to be significant anthropogenic sources of local soil contamination, mainly through rivers and atmospheric deposition. Furthermore, the influence of irrigation water on heavy metals showed a more pronounced effect within a distance of 1000 m, became weaker after that, and then gradually disappeared. This model may offer improved technical guidance for practical production and the management of soil heavy metal contamination.

Chemometric Analysis and Human Health Implications of Trace and Heavy/Non-Essential Metals through ingestion of Carbonated and Non-Carbonated Beverages.

Elevated levels of trace metals (TMs) and heavy/non-essential metals (HnMs) in commonly consumed beverages concern the public and regulatory agencies. Thus, frequent monitoring of these metals is critically important. The present study intended to assess TMs and HnMs concentrations and associated health risks in beverages. Ten metals, such as Mn, Co, Cr, Cu, and Zn (TMs) and Ni, Cd, Pb, Al, and As (HnMs), were quantified in different beverage brands categorized into two groups such as non-carbonated and carbonated beverages. Chemometric analysis such as hierarchical cluster analysis (HCA), Pearson's correlation coefficient (PCC), and principal component analysis (PCA) were also performed to demonstrate the possible natural and anthropogenic sources of metal contamination. Among the TMs, the mean concentration of Zn (233.3 ± 3.3-291.7 ± 3.2µg/L) followed by Mn (119.0 ± 2.3-146.4 ± 2.2µg/L) was found highest in both carbonated and non-carbonated beverage samples. In the case of HnMs, the lowest mean concentration of Cd (7.4 ± 0.9-18.6 ± 1.2µg/L) followed by Pb (4.1 ± 0.4-4.5 ± 0.4µg/L) was observed in both types of beverage samples. The tolerable dietary intake (TDI) value for Ni and provisional tolerable monthly intake (PTMI) value for Cd were higher than the value established by the WHO and EFSA. The computed values of the hazard index (HI < 1) and the cumulative cancer risk (CCR) indicated a low risk of exposure.

RADIOACTIVITY OF SURFACE MARINE SEDIMENTS OF THE CHAUN BAY. ANALYSIS OF NATURAL AND ANTHROPOGENIC ENVIRONMENTAL FACTORS

The paper presents data on the spatial distribution of activity concentration of natural (232Th, 226Ra, 40K) and anthropogenic (137Cs) radionuclides in the surface layer of bottom sediments of the Chaun Bay of the East Siberian Sea. The measured activity of 232Th and 226Ra is typical for bottom sediments of the Arctic coastal zone and corresponds to the global level. The level of 137Cs activity in bottom sediments showed the absence of local sources of anthropogenic contamination in Chaun Bay, while the mean 40K activity concentration was 1.8 times higher than the global average. The results of statistical analysis showed that the dynamics of riverine run-off, thermoabrasion and currents, as well as aeolian and sea ice transport of sedimentary matter, are the main factors that determined the differences in the behaviour of the studied radionuclides in the surface bottom sediments of the Chaun Bay.

Anthropogenic contamination sources drive differences in antimicrobial-resistant Escherichia coli in three urban lakes.

Antimicrobial resistance (AMR) is an ever-present threat to the treatment of infectious diseases. However, the potential relevance of this phenomenon in environmental reservoirs still raises many questions. Detection of antimicrobial-resistant bacteria in the environment is a critical aspect for understanding the prevalence of resistance outside of clinical settings, as detection in the environment indicates that resistance is likely already widespread. We isolated antimicrobial-resistant Escherichia coli from three urban waterbodies over a 15-month time series, determined their antimicrobial susceptibilities, investigated their population structure, and identified genetic determinants of resistance. We found that E. coli populations at each site were composed of different dominant phylotypes and showed distinct patterns of antimicrobial and multidrug resistance, despite close geographic proximity. Many strains that were genome-sequenced belonged to sequence types of international concern, particularly the ST131 clonal complex. We found widespread resistance to clinically important antimicrobials such as amoxicillin, cefotaxime, and ciprofloxacin, but found that all strains were susceptible to amikacin and the last-line antimicrobials meropenem and fosfomycin. Resistance was most often due to acquirable antimicrobial resistance genes, while chromosomal mutations in gyrA, parC, and parE conferred resistance to quinolones. Whole-genome analysis of a subset of strains further revealed the diversity of the population of E. coli present, with a wide array of AMR and virulence genes identified, many of which were present on the chromosome, including blaCTX-M. Finally, we determined that environmental persistence, transmission between sites, most likely mediated by wild birds, and transfer of mobile genetic elements likely contributed significantly to the patterns observed.IMPORTANCEA One Health perspective is crucial to understand the extent of antimicrobial resistance (AMR) globally, and investigation of AMR in the environment has been increasing in recent years. However, most studies have focused on waterways that are directly polluted by sewage, industrial manufacturing, or agricultural activities. Therefore, there remains a lack of knowledge about more natural, less overtly impacted environments. Through phenotypic and genotypic investigation of AMR in Escherichia coli, this study adds to our understanding of the extent and patterns of resistance in these types of environments, including over a time series, and showed that complex biotic and abiotic factors contribute to the patterns observed. Our study further emphasizes the importance of incorporating the surveillance of microbes in freshwater environments in order to better comprehend potential risks for both human and animal health and how the environment may serve as a sentinel for potential future clinical infections.

Activity Concentrations of Cs-137, Sr-90, Am-241, Pu-238, and Pu-239+240 and an Assessment of Pollution Sources Based on Isotopic Ratio Calculations and the HYSPLIT Model in Tundra Landscapes (Subarctic Zone of Russia)

The paper is devoted to the assessment of the content of anthropogenic radionuclides in tundra landscapes of the subarctic zone of Russia. The authors of the article studied the features of accumulation and migration of anthropogenic radionuclides and identified probable sources of their entry into environmental objects. Peat samples were collected on the territory of the Kaninskaya Tundra of the Nenets Autonomous Okrug (Northwest Russia). A total of 46 samples were taken. The following parameters were determined in each peat sample: (1) activity and pollution density of anthropogenic radionuclides; (2) isotopic ratios of anthropogenic radionuclides; (3) activity ratios of each radionuclide for layers 10–20 cm and 0–10 cm. The results of the studies showed that the pollution density of the Nes River basin with the radionuclides Cs-137 and Sr-90 is up to 4.85 × 103 Bq×m−2 and 1.88 × 103 Bq×m−2, respectively, which is 2–5 times higher than the available data for the Kanin tundra, as well as for Russia and the world as a whole. The data obtained for Am-241, Pu-238, and Pu-239+240 showed insignificant activity of these radionuclides and generally correspond to the values for other tundra areas in Russia and the world. It was found that some tundra areas (“peat lowlands”) are characterized by increased radionuclide content due to the process of accumulation and migration along the vertical profile. Calculations of isotope ratios Sr-90/Cs-137, Pu-238/Pu-239+240, Pu-239+240/Cs-137, Am-241/Pu-239+240 and air mass trajectories based on the HYSPLIT model showed that the main sources of anthropogenic radionuclide contamination are global atmospheric fallout and the Chernobyl accident.

Радиационно-гигиеническая оценка воздействия негативных природных факторов, а также последствий деятельности ОАО «Гидрометаллургический завод» на население города Лермонтов

The article presents the results of a radiation-hygienic assessment of the contribution to the total effective radiation dose to the population of the radon-hazardous territory (town of Lermontov, Stavropol Region) of the aerosol-unattached fraction of the radon and thoron decay progeny after inhalation of them. Research on this topic was carried out in the Russian Federation for the first time. The article also assesses the possible contribution of the source of anthropogenic radioactive contamination of the surrounding area – the tailings storage facility of JSC «Hydrometallurgical Plant»

Integrated approach to hydrogeochemical appraisal of groundwater quality concerning arsenic contamination and its suitability analysis for drinking purposes using water quality index

Arsenic (As), contamination in drinking groundwater resources is commonly environmental problem in many developing countries including Pakistan, with significant human health risk reports. In order to examine the groundwater quality concerning As contamination, its geochemical behavior along with physicochemical parameters, 42 samples were collected from community tube wells from District Bahawalpur, Punjab, Pakistan. The results showed the concentration of elevated As, its source of mobilization, and associated public health risk. The As concentration detected in groundwater samples varied from 0.12 to 104 µg/L with an average value of 34.7 µg/L. Among 42 groundwater samples, 27 samples were beyond the permitted limit of 10 µg/L recommended by World Health Organization (WHO), for drinking purposes. Statistical analysis result show that the groundwater cations values are in decreasing order such as: Na+ > Mg2+ > Ca2+ > K+, while anions were HCO3– > SO42– > Cl– > NO3–. Hydrochemical facies result depict that the groundwater samples of the study area, 14 samples belong to CaHCO3 type, 5 samples belong to NaCl type, 20 samples belong to Mixed CaMgCl type, and 3 samples belong to CaCl2 type. It can be accredited due to weathering and recharge mechanism, evaporation processes, and reverse ion exchange. Gibbs diagram shows that rock water interaction controls the hydrochemistry of groundwater resources of the study area. Saturation Index (SI) result indicated the saturation of calcite, dolomite, gypsum, geothite, and hematite mineral due their positive SI values. The principal component analysis (PCA) results possess a total variability of 80.69% signifying the anthropogenic and geogenic source of contamination. The results of the exposure-health-risk-assessment method for measuring As reveal significant potential non-carcinogenic risk (HQ), exceeding the threshold level of (> 1) for children in the study area. Water quality assessment results shows that 24 samples were not suitable for drinking purposes.

Study on moss biomonitoring of atmospheric deposition of minor and trace elements in the region of Polog, North Macedonia

AbstractA study was conducted to investigate air deposition and to explore the natural or anthropogenic sources of contamination with potentially toxic elements (PTEs) in the region of Polog, North Macedonia, using moss samples as biomonitors of air pollution. The distribution of 22 elements was detected in 43 moss samples collected in the region. Multivariate statistical analysis was applied to the available data. Factor analysis identified five association factors, of which four factors, F1 (Cr, Li, V, Co, Fe, Al, Ni, and As), F2 (K, P, and Mg), F4 (Ag and Cu), and F5 (Ba, Sr, and Mn) were related to lithogenic sources and one factor F3 (Hg, Pb, Cd, and Zn) was related to mixed lithogenic and anthropogenic sources. The content of the elements of F1 is higher in the areas on Mount Šar (area without industrial and urban activities), where Precambrian and Paleozoic shales and Paleozoic sandstones predominate, indicating that their origin is mainly a natural phenomenon. The high contents of the elements from F2, F4, and F5 are also related to the lithology of the studied region. Thus, the high contents of elements from F2 are distributed in the western part of the area, where Precambrian and Paleozoic shists and Paleozoic sandstones dominate, and their contents correlate well with the contents of lithogenic elements in the soil samples from the same region. Elements of Factor 4 have higher contents in the southern part of the region, in areas with Paleozoic‐Mesozoic carbonates and Precambrian‐Paleozoic shales, while elements of Factor 5 occur in the regions with shales, Quaternary sedimentary rocks, and Precambrian‐Paleozoic shales, also indicating the lithogenic character of this factor. In addition to the lithogenic origin of the distribution of elements contained in F3 (Hg, Pb, Cd, and Zn), anthropogenic activities also have an influence on the increased content in the northeastern part of the region. This is due to dust emissions from the Silmak ferrosilicon smelter, as well as emissions from industry (steel smelters) and urban activities of the nearby capital Skopje.

Anthropogenic Coal Ash as a Contaminant in a Micro-meteoritic Underwater Search

Chemical composition for spherules recovered from the search area of CNEOS 2014-01-08 in the Pacific Ocean has been recently released. A three-order of magnitude difference from CI-chondrites has been identified for elements beryllium, lanthanum and uranium in five samples. The lack of consensus regarding atmospheric survival and precision of path estimates motivate an examination of possible contaminants. Contents of nickel, beryllium, lanthanum and uranium are examined in the context of a known anthropogenic source of contamination, and found to be consistent with coal ash as suggested from a publicly available coal chemical composition database (COALQUAL). The meteoritic origin is disfavored.

Assessment of soil quality along river Ng'ombe impacted by battery recycling factory at Ubungo in Dar-es-Salaam

Urban soils and streams contaminated with heavy metals have grown ubiquitous around the world throughout the industrialization age, severely reducing the quality and diversity of life. Industrial waste, such as chemical-releasing factories, is one of the primary anthropogenic sources of heavy metal contamination in soil and water bodies. To analyze the impact of industries to heavy metal contamination, the study assessed the soil quality along the heavy metals polluted river Ng'ombe near the battery recycling plant in Dar es Salaam, Tanzania's commercial city. The research looked at three heavy metals (Cu, Pb, and Zn) in a total of eight samples. Soils were found contaminated with both metals i.e., Copper, Lead, and Zinc at 4.68, 4.08 mg/L and, 5.79, respectively. Based on the soil samples taken surrounding the industry, it is possible to establish that the industry contributes significantly to the contamination in the soil and river Ng'ombe stream. Pb contamination was found to be fairly equally distributed across the area (2 to 6 mg/kg), as opposed to Zn (0.8 to 17 mg/kg) and Cu (0.04 to 19 mg/kg), which were shown to vary greatly on soil samples obtained around the area. Different pollution indices including geo-accumulation index, Potential contamination index, Contamination factor, Pollution load index and Modified degree of contamination were also used to investigate the impact of soil contamination, and all of them revealed that industrial discharges were an influence. However; study found the levels to be in permissible limit, but still, it exposes the community to cumulative consequences of metals bioaccumulation.

An Evaluation of the Presence of Heavy Metals in the Poultry Feeds Marketed in Ijebu Jesa, Osun State

One of the most crucial areas of agriculture is poultry production, with commercial layers and broilers making a significant contribution to supplying the rising need for protein from the growing population through eggs and meats. It's crucial that hens have enough of certain necessary metals like copper (Cu), zinc (Zn), and manganese (Mn) in their meals. We examined the levels of cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), chromium (Cr), and zinc (Zn) in four brands of two commercial feeds (Animal care and Top feeds) that are often used by chicken farmers in Osun state. The meals were bought at Ijebu-Jesa, Osun State, from several retail establishments. Atomic Absorption Spectrometer (AAS) analysis was done after the feeds had been ashed, digested, and examined for metal contamination. The concentration of the key components was consistently lowest in starting feed. The feed had relatively little of the necessary components (copper, zinc, iron, and manganese). Because of this, the projected nutritional values of the feed based on the concentrations of the necessary components were extremely low. This demonstrates that supplements were not provided to the diets as was reasonable to expect. The feed samples, however, had very high levels of lead. Anthropogenic sources of lead contamination in the environment, particularly fossil fuels, may be to blame for this. Adoption of alternative renewable energy sources like biodiesel and bioethanol is highly necessary.

Natural vs. anthropogenic metals for reconstructing the source-to-sink pathway (Naples Bay, eastern Tyrrhenian Sea)

The grain size, nutrients, and metals contents of sediments are important tracers for reconstructing the origin of the contaminants and the pathway of the sediments from the source to the sink. This is particularly important in areas with high geological variability and a high demographic pressure. The origin and distribution of contaminants and nutrients allow us to identify the source-to-sink pathway of the sediments. In particular, the Sarno River is one of the main contributing sources of anthropogenic contaminants due to the outflow from the large surrounding large industrial area. Geochemical and physical parameters of sediments were analyzed along a transect from the coastline to a water depth of 112 m, with the objective of exploring the spatial variability of sediment contamination in the continental shelf of Naples Bay. The latter is characterized by a complex geological area and is subject to river inflow from a highly industrialized area. The data have been analyzed using principal component analysis (PCA), hierarchical correlation analysis (CA), and analysis of variance (ANOVA). To distinguish between a natural and anthropogenic origin of contaminants and to construct the source-to-sink pathway, the relationship between geochemical and physical data and their distribution was examined, and the results were compared with published data collected onshore. Four distinct sectors with different associations of metals, grain size, and total organic carbon have been recognized: I) offshore Vesuvius volcano, the occurrence of coarse-grained sediments, associated with As, Fe, Mn, and low TOC values, suggests a natural origin of the contaminant due to the volcanic nature of the substrate; II) offshore the Sarno River, the presence of Cr, Cd, Cu, Pb and Zn, associated with the high TOC content, suggests an anthropogenic origin for the contaminants; III) offshore Sorrento Peninsula, the presence of As, Fe, Mn, and some gravel made up of pumice and bioclasts indicate a predominance of contaminants of natural origin; and IV) finally, the distal part is not subjected to a primary terrestrial input. Metals contamination of anthropogenic origin and the organic matter in sediments decreased rapidly with distance from the coast highlighting the main deposition area close to the river discharge.

Chemical fractionations and mobilization potentials for some trace metals in reef sediments and corals of Qeshm Island, the Persian Gulf

The bioavailability of trace metals in coral skeletons and sediment samples from Larak and Qeshm Islands in the Persian Gulf was investigated using the sequential extraction technique (SET), bioaccumulation measurement and risk assessment indices. The fractionation results and risk assessment indices indicated that Pb at the Qeshm Station and Cd and Zn at both Stations could have adverse biological effects due to high bioavailability. The bioaccumulation rate of metals in different reef species and at different Stations was not significant. The studied coral reefs showed a high tendency for Pb adsorption, so they could be an efficient bioindicator of Pb contamination. Statistical analysis showed that Pb and Zn were mainly from anthropogenic contamination sources, while the other metals were primarily of natural origin. The results indicated that further studies are needed to make a realistic assessment of the discharge of trace metals to the Persian Gulf.

137Cs and isotopic ratios of Pu and U in lichens and mosses from Russian Arctic areas

Knowledge of past anthropogenic sources of radionuclide contamination in Russian Arctic areas is important to assess the radioecological situation of these less-studied regions. Therefore, we investigated the sources of radionuclide contamination in Russian Arctic in the 1990s. Lichen and moss samples were collected from 1993 to 1996 in Kola Peninsula, Franz Josef Land, and few other locations. The activity concentration of 137Cs was determined from the archived samples by gamma spectrometry in 2020. After radiochemical separation of Pu and U isotopes from the lichens and mosses, mass ratios 240Pu/239Pu, 234U/238U, 235U/238U, and 236U/238U were determined by mass spectrometry. 137Cs activity concentrations at the sampling date were found to vary from 3.1 ± 1.4 (Inari, Finnish-Russian border) to 303 ± 7 (Kola Peninsula) Bq/kg. The ranges of isotopic ratios were 0.0592 ± 0.0007 to 0.253 ± 0.082 for 240Pu/239Pu, (4.89 ± 3.91) × 10−5 to (6.86 ± 0.04) × 10−5 for 234U/238U, 0.0072104(21) to 0.007376(41) for 235U/238U, and from below 1 × 10−7 to (2.65 ± 0.19) × 10−6 for 236U/238U, respectively. Based on the measured isotopic ratios and characteristic isotopic ratios of known contamination sources, the main Pu and U sources in the sampled lichens and mosses are global fallout, the Chernobyl accident, and possibly local nuclear activities. These results contribute to further understanding of past nuclear events and resulting nuclear contamination in Russian Arctic terrestrial areas.

Wastewater discharges alter microbial community composition in surface waters of the canadian prairies

Microbial communities are an important component of freshwater biodiversity that is threatened by anthropogenic impacts. Wastewater discharges pose a particular concern by being major sources of anthropogenic contaminants and microorganisms that may influence the composition of natural microbial communities. Nevertheless, the effects of wastewater treatment plant (WWTP) effluents on microbial communities remain largely unexplored. In this study, the effects of wastewater discharges on microbial communities from five different WWTPs in Southern Saskatchewan were investigated using rRNA gene metabarcoding. In parallel, nutrient levels and the presence of environmentally relevant organic pollutants were analyzed. Higher nutrient loads and pollutant concentrations resulted in significant changes in microbial community composition. The greatest changes were observed in Wascana Creek (Regina), which was found to be heavily polluted by wastewater discharges. Several taxa occurred in greater relative abundance in the wastewater-influenced stream segments, indicating anthropogenic pollution and eutrophication, especially taxa belonging to Proteobacteria, Bacteroidota, and Chlorophyta. Strong decreases were measured within the taxa Ciliphora, Diatomea, Dinoflagellata, Nematozoa, Ochrophyta, Protalveolata, and Rotifera. Across all sample types, a significant decline in sulfur bacteria was measured, implying changes in functional biodiversity. In addition, downstream of the Regina WWTP, an increase in cyanotoxins was detected which was correlated with a significant change in cyanobacterial community composition. Overall, these data suggest a causal relationship between anthropogenic pollution and changes in microbial communities, possibly reflecting an impairment of ecosystem health.

Assessment of metal contaminants along the Bay of Bengal — Multivariate pollution indices

The spatial concentration of heavy metals (Mn, Ni, Cu, Co, Zn, Cd, and Pb) was studied in coastal areas (n = 9) including water (n = 27) and sediment (n = 27) in the Palk Bay, India to understand the metal pollution due to prevailing natural and anthropogenic activities. Pollution indices like metal index (MI), geoaccumulation index (Igeo), contamination factor (CF), pollution load index (PLI) and potential ecological risk (PER) were calculated based on the background/reference value. The values of MI index indicated that water was free of metals, whereas Igeo, CF, PLI and PER indicated moderate contamination of sediment in monsoon. Cadmium concentrations were the highest irrespective of the indices (Igeo: 0.04–1.42, Cf: 0.36–0.74, PLI: 0.36–0.74, and PER: 76.89–143.36) indicating moderate pollution. The Principal Component Analysis (PCA) affirmed that Cd was positively correlated with stations indicating anthropogenic sources of Cd contamination.