Search

Due to their toxicity, lack of bioaccumulation and biodegradability, and ease of binding to sediments, heavy metals are considered the main pollutants of rivers. It is, therefore, necessary to control and monitor these pollutants. The present study analyzed the Krzna River, which flows in southeastern Poland and has an outlet to the Bug River. Over much of its length, the Bug River forms Poland's border with Belarus, while its origin is in Ukraine. The main purpose of the conducted research was a qualitative and quantitative analysis of selected heavy metals, i.e., Ni, Pb, Zn, Cd, and Cu, in bottom sediments and surface waters of the Krzna River. The secondary objectives were to evaluate the level of contamination of the studied matrices and identify the sources of pollution. Eighty samples of water and bottom sediments from the Krzna River were collected for the analysis. Due to the varying distribution of metals under the influence of changes in temperature, precipitation, and humidity, the samples were collected in May and August 2023. The average cadmium content in the sediments studied was the same in both May and August, at 0.6 mg/kg. In contrast, the nickel content of the sediments ranged from 4.6 to 6.1 mg/kg in May and from 4.8 to 6.8 in August. Only nickel and cadmium of the five heavy metals tested were present in amounts exceeding the geochemical background value. Analysis of the results indicates that only a minimal amount of heavy metals remain dissolved in the surface waters, and the remainder contaminates the sediments. The average concentrations of metals in the studied bottom sediments and surface waters were as follows: zinc > lead > nickel > copper > cadmium. The content of metals in the studied sediments was not high, but at the same time, their presence above the geochemical background indicates anthropogenic human activity. Any changes in hydrodynamic conditions and various environmental factors may result in the re-release of heavy metals contained in sediments into surface waters. [ABSTRACT FROM AUTHOR]

This study aims to identify the influential parameters and heavy metals in water and assess the water quality classification at the Alpine glacial lakes and rivers in three districts of Pakistan. For this purpose, nine water quality parameters (Cd, Cr, Pb, Ni, Fe, As, and TDS) in mg/L, pH, Ec µS/Cm are used to compute the Water Quality Index (WQI). The Boruta approach was utilized for the identification of influential parameters associated with the water quality classes. Moreover, we employed supervised machine learning models, including a decision tree, the k-nearest neighbor method, a neural network model (multi-layer perception), a support vector machine, and a random forest, to predict and validate the water quality class. The performance of all algorithms is assessed by an accuracy metric. The accuracy rates for the validation set were observed to be 83% for the decision tree model, 75% for the K-nearest neighbor method, 83% for the neural network, 88% for the support vector machine, and 88% for the random forest model. Water quality assessments for observed locations specify significant insights, revealing that 49% of the locations exhibit low water quality. According to the current study, the government should address problems with water quality in Pakistan’s impacted areas by implementing suitable measures designed water monitoring systems and innovative technologies.

River contamination remains a significant public health problem worldwide, including in Indonesia. In the community, rivers are water resources for many purposes. However, indiscriminate use of antibiotics in the veterinary and medical sectors, the community habit of throwing waste into the river, the inadequate removal of human medicine compounds in WWTP, and poor industrial waste management will induce the spread of pathogenic bacteria and antibiotic resistance between the environment and humans/animals. This review aims to analyse the various factors that influence the emergence of pathogenic Escherichia coli and antimicrobial resistance bacteria (ARB) in the aquatic environment, especially in Indonesia. In conclusion, pathogenic E. coli can adjust its physiological or metabolic conditions to survive in aquatic environments and was found resistant to antibiotics. Meanwhile, this study also describes the potency of the aquatic environment in Indonesia as a vector for the spread of pathogenic E. coli and the growth of ARBs, factors involved in the evolution and spread of antibiotic resistance in aquatic environments, and possible ways to curtail microbial risk to public health and the emergence and spread of antimicrobial resistance in the aquatic environment in Indonesia. HIGHLIGHTS Various rivers in Indonesia have the potential to become a reservoir of E. coli pathogens.; Various rivers in Indonesia are efficient vectors for the spread of antimicrobial resistance bacteria.; The antibiotic resistance can spread in the environment.; Pathogenic E. coli can adjust to survive in aquatic environments.; E. coli pathogens can facilitate the transfer of resistance genes between bacteria.;

Batanghari River is the primary source of water for the people of Jambi. Batanghari River’s condition nowadays is worrying because its color is no longer clear. This research focused on determining the content of heavy metals in the Batanghari River's water and sediment. The conducted analysis is an ICP-MS analysis to determine the level of heavy metal (Cu, Cr, Co, Cd, Hg), and an enrichment factor calculation is conducted to determine the source of pollution. The enrichment factor value from the Batanghari River sediment sample declined with the following sequence Cd>Hg>Cu>Cr>Co, in 10 pinpoint locations. These indicate a high degree of anthropogenic activities along the Batanghari River which become the source of heavy metals entering the Batanghari River. The average concentration of heavy metals in the Batanghari River showed that the metal concentrations of Cd, Cu, and Hg are higher than the quality standards that have been set, whereas the metal concentrations of Cr and Co are still by the quality standards that have been set in PP 22 the year 2021.

Cameroonian farmers regularly use pesticides in farming to control pests, particularly along the riverbank of the Santchou agricultural area. The aim of this study was to assess the perception of farmers in West Cameroon (Santchou area) regarding the contamination risk in aquatic environments from the use of pesticides. A cross‐sectional study via questionnaires was conducted among 150 selected farmers who cultivated fields along the banks of the Menoua River. Almost all the farmers (90%) used pesticides regularly, particularly herbicides, insecticides, and fungicides to combat pests. The main pesticides used were glyphosate, paraquat, dieldrin, chlorpyrifos‐ethyl, copper oxide, and mancozeb. Farmers who cultivated larger areas of land or who had mixed culture crops tended to use pesticides more often (p < 0.001). The use of river water by farmers was correlated with pesticide use (p = 0.010). Most of the pesticide users (90%) did not use protective equipment when spraying the crops. The farmers' perceptions of the risk of pesticide contamination of the river water (p = 0.002) or fish (p = 0.008) did not influence their actions. A correlation was found among pesticide users who believed that there was a risk of river contamination (45%) or fish contamination (42%) and intensive pesticide application during the rainy season (61%) or non‐respect of the prescribed pesticide application doses (51%; p = 0.002). Farmers who regularly or occasionally consumed fish used pesticides more often than those who did not consume fish from the river. The findings of this study emphasize the need for education of farmers in Santchou to prevent the risk of environmental contamination and health hazards from increased dietary and/or dermal pesticide exposure. Integr Environ Assess Manag 2023;19:1600–1608. © 2023 SETAC Key Points: Pesticides (herbicides, insecticides, and fungicides) are widely used by farmers around the Menoua River (Cameroon); however, excessive use of pesticides cannot be accepted or encouraged because of their potential to harm human health and reduce biodiversity within the environment.There was a discordance between the farmers' perception of environmental and health risks of the pesticides and their attitudes toward self‐protection as well as environmental protection.A small proportion of farmers recognized that the river and fish can be contaminated by pesticides, but many do not share this idea, and others have no idea about contamination of the river and fish by pesticides.The main advisers to the farmers are sellers. These farmers do not adhere strictly to the prescribed dose of pesticides; they usually use river water to mix the pesticides for spraying their crops and neglect protective measures when spraying. [ABSTRACT FROM AUTHOR]

The optimized three-step sequential extraction procedure for the fractionation of micro- and macroelements, was conducted to determine fractional characteristics of PTEs (potentially toxic elements) in surface sediments of rivers in the Vlasina watershed. The sequential extraction results, which enable the evaluation of mobility of the studied elements, have indicated that Zn, Ni, Cu, Cr, and As can be considered slightly mobile, whereas Pb, Mn, Cd, and Co were regarded as possibly mobile elements. Lead was dominantly bounded (specifically adsorbed or co-precipitated) to iron and manganese oxides (up to 80%) and may be released by reduction. Since the content of the exchangeable fraction (F1) is an indicator for anthropogenic impact on the aquatic environment, a low percentage (0–8%) of studied toxic elements in this fraction indicated that these elements have lithogenic origin in most sampling locations in the area of study. Except for Pb, the substantial positive correlations between Al and other elements showed that studied elements came primarily from terrigenous sources. Although the values obtained for the risk assessment code (RAC) indicated a slightly increased mobility of some elements (up to 22.44%), the values of the modified risk assessment code (mRAC), which include toxic effects on the environment, showed there is no danger of pollution by studied elements (all values were < 1%). Our recommendation is to use mRAC instead of RAC in ecochemical studies and assessment of the degree of sediment and soil pollution, because mRAC includes toxic effects of elements. Based on ATI values, river sediments show no toxic to a low toxic degree. Even though obtained results indicate that there was no considerable risk for river water contamination, the ecological risk for Fe and Pb should be monitored in the future. [ABSTRACT FROM AUTHOR]

Rivers,as the kind of freshwater resources throughout the world, play a key role in the lives of living things. Heavy metal contamination of river water is primarily attributed to human activities, and there is anincreasing need to conduct risk assessments to characterise the nature and magnitude ofrisks to humans and ecological receptors from these contaminants.The PG990 nuclear absorption spectrophotometer measured concentrations of heavy metals. Trace metals (Cd, Pb, Ni, Zn) in Babolrood river from the Babol region of North Iran were analysed to assess pollution using the Hazard Quotients (HQ), Hazard Index (HI) and the Incremental Lifetime Cancer Risk (ILCR).The Environmental Protection Agency (EPA) model was applied to calculate human health risk (HHR). Heavy metal concentration varied considerably Cd (0.004 to 89.287 µg/L), Ni (0.89–49.78 µg/L), Pb (3.4–181.75 µg/L) and Ni (0.0–243.3 µg/L). The oral Hazard quotients (HQ) values for Pb were ranged from 1.04–7.83 µg/L, therefore indicated in all sampled stations HQ values above 1 for children group. In contrast, the oral and dermal HQ values for both groups were less than 1 for Zn and Ni in all sampling stations. The Hazard Index (HI) values demonstrate that total HI values were above 1 for children group in water samples of all stations. Generally, total HI values for children were much higher than that of adults among Babolrood River. The Excess Lifetime Cancer Risk (ELCR) values for Cd and Pb in all sample stations for children were higher than the EPA risk assessment guideline limit (10−6-10−4). [ABSTRACT FROM AUTHOR]

Abstract The objective of this study was to evaluate the levels of environmental contamination in a protected area in the Brazilian Amazon. For this, two areas were chosen along the Mearim River: the reference area (A1) and the potentially contaminated area (A2), where water samples were collected, for physicochemical and microbiological analyses, as well as specimens of Hoplias malabaricus, for the evaluation of biometric data and incidence of branchial lesions. The physicochemical analyzes of the water from both areas showed contamination (low levels of dissolved oxygen, tubidity and high iron concentrations, especially in A2). The microbiological analyzes showed that all water samples showed total coliform values higher than those acceptable by CONAMA and WHO (with higher values in A2), in addition to E. coli values higher than those allowed by legislation in A2. Regarding biometric data, male and female fishes were significantly longer and heavier in A1 during the dry and rain seasons and the gonadosomatic index also showed higher values in A1 than in A2 in both seasons. H. malabaricus showed gill lesions of minimal to moderate pathological importance in A1 and A2, indicating that specimens from both areas of the Mearim River showed biological responses to contamination. The observed changes in the water quality, bimetic parameters and the histological analyzes of the specimens of H. malabaricus directly reflect on the quality and health of the fishes in the Mearim River, and point to the urgent need for prevention and remediation of contamination in these ecosystems.

The contamination of freshwater resource by heavy metals is still a major environmental and human health concern globally. The release of these contaminants into the aquatic environment can lead to the pollution of water resources and generate risks for aquatic living organisms and human health. The sediments can act as reservoir for heavy metals, thereby they are used to assess the pollution status of the rivers. In the present investigation, surface sediments collected from two urban rivers named, N’djili and Lukaya draining through the city of Kinshasa, Democratic Republic of the Congo were characterized for grain size, organic matter (OM) and heavy metals. Additionally, Sediment Quality Guidelines for the protection of aquatic life (SQGs), enrichment factor (EF) and geoaccumulation index (Igeo) were performed to determine the river pollution status. The results highlight high concentrations of heavy metals in sediment samples mainly from N’djili River, reaching the values (mg kg−1) of 180.3 (Cu), 451.5 (Zn), 185.8 (Pb) and 4.1 (Hg). These values exceed the SQGs. Based on EF and Igeo values, the sediments from the two rivers have severe enrichment and polluted with Cu, Zn and Pb, and moderate enrichment of Cr and As. In general, the positive correlation was observed between some heavy metals and OM suggesting that these contaminants could have originated from common sources with a similar transport pathway. Based on the SQGs, EF and Igeo, N’djili River is considered as highly polluted with heavy metals indicating environmental and human health potential risks. The results of this study clearly indicate that the pollution of urban rivers in developing countries can be explained by several anthropogenic activities such as urban runoff, uncontrolled landfills in riverbanks, untreated wastewater from densely populated areas, anarchic commercial and industrial settlements, and heavy road traffic. The approaches used in this study represent a useful tool to assess the river sediment quality of urban river which can be applied to similar environment.

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Louhajang River, Bangladesh, which crosses Tangail as a densely industrialized and urbanized city, supplies water for different purposes. This study reports the levels of pH, electrical conductivity (EC), and some toxic heavy metals in 40 water samples collected during the summer and winter seasons from Louhajang River. The winter season reported higher levels of the examined parameters than the summer season with significant variation (p < 0.05) for all parameters, with the exception of Cd. The metal contents were assessed against local and international standards for drinking, irrigation, and aquatic life purposes where different trends were observed. The heavy metal evaluation index and the ecological risk index reported low to moderate risks. The spatial distribution of metal contents assigned hot spots in some sites along the riverbed. The health risk assessment for three population categories, i.e., adult male, adult female, and children, was examined. Cr and Cd recorded hazard index > 1 in all cases, indicating possible non-cancer risk. The total carcinogenic risk values during both seasons were > 1.0 × 10−6, indicating possible cancer risk. The adopted collection of different approaches (comparison against standard levels of toxicants, statistical analysis, spatial distribution, and health risk assessment) successfully demonstrates a whole picture of the environmental status of Louhajang River, Bangladesh. [ABSTRACT FROM AUTHOR]

Abstract Contamination of fresh water bodies by human enteric viruses from wastewater discharge is a well-established phenomenon. Here we propose a model of viral contamination of rivers based on acute gastroenteritis epidemiology and assess how well it can simulate in situ experimental monitoring. Noroviruses, rotaviruses, enteroviruses, adenoviruses and hepatitis A viruses were quantified by molecular methods after water concentration. Water flows were obtained from the Hydro databank and wastewater treatment plant (WWTP) data. Acute gastroenteritis cases based on medical prescriptions were recorded by the French public health agency. We estimated the total number of daily viral acute gastroenteritis cases and modeled virus shedding and fate in WWTPs and rivers. Simulated virus concentrations were compared to the weighted sum of measured concentrations. Seasonal variations in viral acute gastroenteritis were predicted from vomiting occurrence. All viruses except hepatitis A virus were widely detected in wastewaters and river, in concentrations reaching 10+6 genome copies·L−1 for adenoviruses in the Artière River. We were able to predict virus load in raw wastewater and in the Artière River. Estimated weighting coefficients showed the high impact of noroviruses GII. This model can thus serve to compare water treatment, discharge and reuse scenarios. Graphical abstract Unlabelled Image Highlights • An estimate of enteric virus input in river from emesis revealed by drug prescription. • Seasonal variations in viral shedding and river contamination are well simulated. • Simulations emphasize viruses with a higher medical prescription-to-shedding ratio. • Norovirus GII followed by rotavirus and adenovirus explained most simulated trends. • Simulations show the strong impact of wastewater by-pass and withdrawal for reuse. [ABSTRACT FROM AUTHOR]

Abstract The Mediterranean Sea is affected by one of the most significant plastic pollution worldwide. This review critically evaluates the most recent literature on the presence of microplastics in sediments, suggested to be long term sinks and have a high potential to accumulate this kind of marine debris. A picture of microplastic levels in coastal environments is given, evidencing information gaps and considering also estuary, lagoons and areas influenced by the contribution of rivers. A wide range of contamination levels has been found, with the highest in lagoon and estuary environments. The lack of homogeneity in the methods of study and the need to harmonize the latter and the expression of the results in addition to the need to obtain data on the contributions of the main tributaries of the Mediterranean and on lagoons, are other important considerations taken. Highlights • Sediments are long term sinks with the potential to accumulate microplastics. • The literature analysis evidence shot spots, cleanest areas and information gaps. • Wide ranges of microplastic levels have been found, higher in lagoons and estuaries. • The need of a harmonization of methods and expression of results is emerged. • Lack of microplastic data on the tributaries of Mediterranean and on lagoons. [ABSTRACT FROM AUTHOR]

A careful reading of Bonnail et al. (2019)’s work points out some issues in the description of the Ganges River, e.g., describing it in a way that gives impression to the readers unfamiliar with the Indian rivers that it flows by the national capital New Delhi, after reading “it receives inputs from highly populated cities of India, including New Delhi and …”. However, as a matter of fact, it is not the Ganges, but the Yamuna River, a tributary of the Ganges, that passes through the National Capital Region of Delhi. Moreover, authors identify the studied river as the Ganges, whereas it is one of the distributaries of the Ganges called Hooghly (anglicized version of its local name Hugli). They have referred to the seasonality of the studied river; however, the flow of the studied (Hooghly) river is controlled by a barrage on the Ganges River. Moreover, Hooghly River receives input from its own tributaries; viz., Mayurakshi and Damodar, flowing through highly mineralized and coaliferous areas of Jharkhand state of India. Bonnail et al. (2019) have attributed the contamination of the river sediments to anthropogenic activities alone, by not evaluating likely natural sources. A correction factor for the underestimated total organic carbon (TOC) content obtained using Walkley-Black method should have been applied before using TOC values for factor analysis to overcome the underestimation issue with this method. This work intends to serve as a compendium, rather than a critique, to otherwise commendable work by Bonnail et al. (2019).

Copyright of Revista Luna Azul is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mining has become one of the main causes of increased heavy metal loading of river systems throughout the world. There is however an evident gap between assessments of soil contamination and metal release at the mined sites and estimates of river pollution. The present work focuses on Zaamar Goldfield, which is one of the largest placer gold mines in the world, located along the Tuul River, Mongolia, which ultimately drains into Lake Baikal, Russia. It combines field observations in the river basin with soil erosion modelling and aims at quantifying the contribution from natural erosion of metal-rich soil to observed increases in mass flows of metals along the Tuul River. Results show that the sediment delivery from the mining area to the Tuul River is considerably higher than the possible contribution from natural soil erosion. This is primarily due to excessive mining-related water use creating turbid wastewaters, disturbed filtering functions of deposition areas (natural sediment traps) close to the river and disturbances from infrastructures such as roads. Furthermore, relative to background levels, soils within Zaamar Goldfield contained elevated concentrations of As, Sr, Mn,V, Ni, Cu and Cr. The enhanced soil loss caused by mining-related activities can also explain observed, considerable increases in mass flows of metals in the Tuul River. The present example from Tuul River may provide useful new insights regarding the erosion and geomorphic evolution of mined areas, as well as the associated delivery of metals into stream networks. [ABSTRACT FROM AUTHOR]

Rivers play essential roles in human civilization, while anthropogenic activities have deteriorated their resilience and functionalities. Combating contamination is one of the priorities for building the river's resilience and providing safe water and habitats for livelihoods, wildlife preservation, and food production. We collected 174 water and sediment samples from the upstream to the estuary of the Pearl River (PR), characterized the heavy metal and antibiotics contamination levels, and analyzed the spatiotemporal distribution by compiling historical datasets extracted from published research papers and governmental documents. We also assessed the feasibility of removing PR water heavy metals and antibiotics using biochars derived from two invasive plants, Bidens pilosa L. and Lantana camara. According to our findings, heavy metals and antibiotics in water and sediment increased towards the downstream region of the Pearl River Delta (PRD). The water and sediment samples obtained from the Dongguan and Shenzhen regions exhibited the most elevated levels of heavy metals, whereas the samples from the Huizhou region demonstrated the highest levels of antibiotics. Compared with previously published PRD sediment heavy metals (1976–2011) and antibiotics contamination data (2006–2017), we found that some heavy metals and all measured antibiotics contents in sediment substantially reduced (80–100%). Cu, Zn, Cr, and As significantly polluted the sediment in PRD. Shenzhen had the highest Index of geo-accumulation (I geo) for Cu, Zn, and Cr, while Zhaoqing had the highest I geo for As. The dominant antibiotics were Ciprofloxacin, Doxycycline, Norfloxacin, Ofloxacin, Oxytetracycline, and Tetracycline. Invasive plant-derived biochars showed high antibiotic removal capacity but failed to reduce most PR water heavy metals since these invasive plants are potential heavy metal hyperaccumulators. The spatial distribution of heavy metal and antibiotics concentration/content in water and sediment samples is primarily affected by anthropogenic activities such as industrialization, aquaculture, pharmaceutical, and agricultural practice. Our study provides insights into the extensive freshwater watersheds' decontamination and green policymaking. [Display omitted] • Pearl River has safe water, while the sediment requires further decontamination. • Higher heavy metal and antibiotic concentrations were found in the PR delta. • PR delta sediment heavy metals and antibiotics have reduced substantially (>80%). • Invasive plant-derived biochar can remove antibiotics but not heavy metals. [ABSTRACT FROM AUTHOR]

Tissue samples from 1,117 fish of 25 species were collected from 1991 through 1996 at 13 locations along the River Elbe. The principal indicator species were perch (Perca fluviatilis) (n=118), chub (Leuciscus cephalus L.) (n=113) and roach (Rutilus rutilus) (n=138). Mercury (Hg) concentrations in muscle and liver were determined by atomic absorption spectrometry. The liver/muscle index in three indicator species from heavily contaminated and lightly contaminated localities were significantly different. In fish from heavily contaminated localities, Hg was deposited preferentially in the liver (the depository for inorganic and organic forms of Hg), while in lightly contaminated areas, it was deposited preferentially in muscle.

Contamination of aquatic ecosystems is considered as one of the main threats to global freshwater biodiversity. Within the European Water Framework Directive (EU-WFD) a particular attention is dedicated to assess ecological risks of surface water contamination and mitigation of chemical pressures on aquatic ecosystems. In this work, we evaluated ecological risks of surface water contamination for fish populations in four EU-WFD rivers through an integrative approach investigating three Lines of Evidence (chemical contamination, biomarker responses as early warning signals of contamination impacting individuals and ecological analyses as an indicator of fish community disturbances). This work illustrates through 4 case studies the complementary role of biomarkers, chemical and ecological analyses which, used in combination, provide fundamental information to understand impacts of chemical pressures that can affect fish population dynamics. We discuss the limitations of this approach and future improvements needed within the EU-WFD to assess ecological risk of river contamination for fish populations. [ABSTRACT FROM AUTHOR]

Choosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species ( Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify primary flow paths involved in the chlordecone (CLD) river contamination and quantify the CLD fluxes to assess CLD pollution levels and duration according to a typical catchment of the banana cropping area in the French Indies (Guadeloupe): the Pérou Catchment (12 km 2 ) characterized by heavy rainfall (5686 mm year −1 ). Three sub-catchments (SC1, SC2 and SC3) were studied during the hydrological year 2009–2010: a pedological survey combined with a spatialized hydrochemical approach was conducted. The average soil concentration is higher in the Pérou Catchment (3400 μg kg −1 ) than in the entire banana cropping area in Guadeloupe (2100 μg kg −1 ). The results showed that CLD stocks in soils vary largely among soil types and farming systems: the weakest stocks are located upstream in SC1 (5 kg ha −1 ), where a majority of the area is non-cultivated; medium stocks are located in Nitisols downstream in SC3 (9 kg ha −1 ); and the greatest stocks are observed in SC2 on Andosols (12 kg ha −1 ) characterized by large farms. The annual water balance and the hydro-chemical analysis revealed that the three sub-catchments exhibited different behaviors. Pérou River contamination was high during low flows, which highlighted that contamination primarily originated from groundwater contributions. The results showed that only a small part of the catchment (SC2), contributing little to the water flow, comprises a major CLD contribution, which is in agreement with the highly contaminated andosol soils observed there. Another significant result considers that at least 50 years would be required to export the totality of the actual CLD soil stocks retained in the topsoil layer. The actual time for soil remediation will however be much longer considering (i) the necessary time for the chlordecone to percolate and be stored in the shallow aquifers and (ii) its travel time to reach the river. [ABSTRACT FROM AUTHOR]

La Paz River in Andean highlands is heavily polluted with urban run-off and further contaminates agricultural lowlands and downstream waters at the Amazon watershed. Agricultural produce at this region is the main source of vegetables for the major Andean cities of La Paz and El Alto. We conducted a 1 year study, to evaluate microbial quality parameters and occurrence of multiple enteropathogenic bacteria ( Enterohemorrhagic E. coli-EHEC, Enteroinvasive E. coli or Shigella-EIEC/ Shigella, Enteroaggregative E. coli-EAEC, Enteropathogenic E. coli-EPEC Enterotoxigenic E. coli-ETEC and Salmonella) and its resistance to 11 antibiotics. Four sampling locations were selected: a fresh mountain water reservoir (un-impacted, site 1) and downstream sites receiving wastewater discharges (impacted, sites 2-4). River water (sites 1-4, N = 48), and soil and vegetable samples (site 3, N = 24) were collected during dry (April-September) and rainy seasons (October-March). Throughout the study, thermotolerant coliform density values at impacted sites greatly exceeded the guidelines for recreational and agricultural water uses. Seasonal differences were found for thermotolerant coliform density during dry season in water samples nearby a populated and hospital compound area. In contrast to the un-impacted site, where none of the tested enteropathogens were found, 100 % of surface water, 83 % of soil and 67 % of vegetable samples at impacted sites, were contaminated with at least one enteropathogen, being ETEC and Salmonella the most frequently found. ETEC isolates displayed different patterns of toxin genes among sites. The occurrence of enteropathogens was associated with the thermotolerant coliform density. At impacted sites, multiple enteropathogens were frequently found during rainy season. Among isolated enteropathogens, 50 % were resistant to at least two antibiotics, with resistance to ampicillin, nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline commonly present. Moreover, some Salmonella isolates were distinguished by their multi-resistance to ≥8 antibiotics, within soil and vegetable samples. Overall, this study demonstrates that La Paz River-an affluent of the Amazon macrobasin-is heavily polluted along the year with a high density of thermotolerant coliforms and is a reservoir of multiple antibiotic resistant enteropathogens, present in river water, soil and vegetables. These data highlight health risk associated with food and waterborne diseases at the region. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), plastic particles <5 mm in diameter, have become an emerging ubiquitous concern for the environment. Rivers are the primary pathways that transport MPs from the land to the ocean; however, standardized methodologies for in-situ sampling in freshwater environments remain undefined. Notably, uncertainties in MP sampling methods lead to errors in estimating MP discharge through rivers. In the present study, the inter-sample variance of plankton net-obtained MP concentrations for two urban rivers in Japan was investigated. Numerical concentrations, expressed in particles·m−3, revealed that variance s 2 was proportional to the mean m of replicated estimates of numerical concentrations. A derived statistical model suggested that river MPs disperse according to purely random processes; that is, Poisson point processes. Accordingly, a method was established to project the "precision," the ratio of the standard error to m , of numerical concentrations based on the number of net sampling repetitions. It was found that the mean of two replicates maintained sufficient precision of <30% for conditions with high concentrations of ≥3 particles·m−3. Projected precisions under different levels of MP concentrations are also presented to help design future field campaigns. [Display omitted] • Variance was proportional to the mean of replicated estimates for concentrations. • Modeled values suggested river microplastics disperse via purely random processes. • The mean of two replicates maintained sufficient precision for high concentrations. [ABSTRACT FROM AUTHOR]

Trace elemental content was analysed in edible tissues of Mytilus galloprovincialis collected in five different sampling areas near the mouth of river Tagus estuary in Lisbon. The concentrations of essential elements (S, K, Ca, Fe, Cu, Zn, As, Br and Sr) were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry, while toxic elements (Cr, Cd, Hg, Se and Pb) were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results show that the essential elements K and S are present at the highest concentrations in all the studied samples reaching 2,920 and 4,520 μg g (fresh weight), respectively. The highest levels of heavy metals found were in two areas close to the city for Pb and Cd, but below the maximum allowed values. [ABSTRACT FROM AUTHOR]

Highlights: [•] Prediction of mining impact on groundwater and surface water quality. [•] Mining impact controlled by mixing and sulfate reduction. [•] Predicted diffuse mine drainage into a river corresponds to measurements. [•] Mining impact on river water is expected to quintuple within the next 40years. [ABSTRACT FROM AUTHOR]

Abstract: This study provides evidence on the sources and pathways of trace-metal contamination using isotopic tracers, δ34S of dissolved sulfate and 206Pb/207Pb of suspended particulate matter (SPM), in an urban French river. The trace-metal contamination of the Orge River watershed was correlated with a highly contrasted land-use pattern with mainly forests and agricultural lands upstream and a highly dense urban area (up to 8000inhabitants/km2) downstream in the suburbs of the Parisian megacity. The increase in the sulfate concentrations (0.25–1mmol/l) of the dissolved compartment (<0.45μm) monitored during a hydrological year (2010/2011) correlated with the dissolved sulfate δ34S and δ18O ratios (+2 to +12 and +6 to +13‰, respectively). This result indicated that the runoff and sewage waters are important sources of water in the river, particularly for the highly urbanized sites. The lead enrichment factor in the SPM was observed to increase according to the urbanization gradient (1 to 6), and the associated 206Pb/207Pb ratio indicated that the signature of the lead-bearing particles transformed from a three-endmember system (2001 samples) to a two-endmember one (2010/2011 samples) over the last decade. These results suggest that gasoline-originated lead has disappeared from particulate fluxes since the lead additive prohibition in 2000. The lead-bearing species in the Orge River were also observed to originate mainly from urban activities, and the reactivity of selected urban lead-bearing species is discussed based on microscopic observations. Finally, coupling the δ34S and 206Pb/207Pb ratios provided a powerful indicator of urban influence as a function of both river hydrodynamics and physico-chemical conditions. [Copyright &y& Elsevier]

Mine drainage impacts from a coal waste pile at Smolnica, Poland have been monitored. Groundwater in an unconfined aquifer downgradient from the pile has near-neutral pH, but high concentrations of sulfate (up to 3,827 mg/l), chloride (up to 903 mg/l), and sodium (up to 2,606 mg/l). Concentrations of iron and manganese are elevated only locally, and concentrations of other metals are low. The behavior of sulfate seems to be conservative in the downgradient aquifer, and gypsum may only be precipitating locally. Concentrations of iron and manganese seem to be controlled by the precipitation of ferric oxide and hydroxides and rhodochrosite, respectively. Complete neutralization of mine drainage by carbonates is consistent with high concentrations of calcium (up to 470 mg/l) and magnesium (up to 563 mg/l) and also with high strontium concentrations of up to 3.08 mg/l, observed in groundwater downgradient from the pile. Hydraulic head profiles at two sites within the river bottom sediments indicate upward flow toward the river with large local differences in groundwater recharge. Water chemistry profiles in the river bottom sediments and geochemical modeling suggest conservative behavior of Na, Cl, and SO4 and precipitation of Fe and Mn at the groundwater/river water interface. Mine drainage enters the Bierawka River and causes increasing sulfate concentrations. In contrast, concentrations of sodium and chloride in the Bierawka River decrease downgradient from the pile because water in the river upgradient from the pile is already highly contaminated by these species from the discharge of mining waters. Concentrations of Fe and Mn in the river water are low, as a consequence of the precipitation of Fe and Mn oxide and hydroxides. Direct geochemical modeling was able to reproduce measured concentrations of conservative species (e.g., Na, Cl, and SO4), but errors for metals and Ba were relatively large. In addition, calculated PCO2 values in the river water are very high, suggesting that equilibrium with atmospheric PCO2 and PO2 has not been reached, and at least some reactions should be modeled as kinetic processes. High concentrations of Na, Cl, and SO4 contribute to the contamination of the Odra River, which is joined by the Bierawka River farther downgradient, thus limiting the use of river water for recreation and other purposes. [ABSTRACT FROM AUTHOR]

The foremost feature of a diatom is the species-specific ornamentation of the silicon cell wall, which is preserved and faithfully reproduced through the generations. If exposed to different kinds of stress during reproductive processes, the diatom cell outline and striation pattern can change in different ways, producing teratological forms. These modifications can be slight, leading to difficulties in establishing a threshold between normal and teratological cells, or so marked that it is very difficult to recognize whether an unknown form is teratological or whether it belongs to a new species or variety. Teratological forms appear as an accidental effect of environmental stresses, which can be both physical and chemical. Artificial conditions also often lead to the development of teratological forms. Most frequently, diatoms present abnormal valve outline (lack of symmetry, bent, incised, swollen, or notched profile), unusual raphe system (fragmented, displaced, and bifurcated), abnormal striation pattern (irregular, altered, fragmented, and branched), and unusual raphe channel system (distorted, curved, and occasionally doubled back). In this review we analyzed 222 articles, published from 1890 up to 2008, with the aim to correlate the abnormal diatom cell morphology to environmental alterations, in a perspective which can greatly enhance the evaluation of river environmental quality for biomonitoring purposes. [ABSTRACT FROM AUTHOR]

The contamination of riverbeds by solutes derived from the surface flow has recently received increasing attention. Channel morphological features such as bed forms are important characteristics of the stream-subsurface interface and represent one control on the rate of solute delivery from the stream to the bed. Generally, larger bed forms are expected to produce greater rates of stream-subsurface exchange. However, the longitudinal dimension (wavelength) of the bed form is also important, and this effect can produce penetration patterns that may be unexpected from a visual observation of the bed surface. Experimental tests in a recirculating flume demonstrate these effects. Commonly used mathematical models do not consider the bed form geometry explicitly and depend on the availability of calibration data to derive exchange parameters for each stream reach. More detailed models that consider the effect of bed form shape are capable of simulating some of the observed experimental results. However, existing physically based models are shown to be insufficient for some bed form geometries that may occur in real streams. [ABSTRACT FROM AUTHOR]

Only organochlorine (OC) residues were monitored by gas chromatography in water, sediment and shrimp samples collected every month between July 1982 and August 1983 from the rivers of Rio Cobre basin. In samples collected every four months during 1989–1990, and seven times during July 1995–March 1996, OC and OP (organophosphates) residues were monitored. Carbamate and pyrethroid residues were not monitored. The detection of residues in 1982–1983 was 54 to 100% in water and sediment, and 83 to 100% in shrimp samples from various sampling stations in the four rivers. In other years, it ranged from about 40 to 100% in the three types of samples. In 1982–1983, DDE and dieldrin residues were found to be much higher than those of lindane and α- and β-endosulfan in Black River, Rio Pedro, Thomas River and Rio Cobre in the watershed. The ranges of means of each residue in water (μg L-1), sediment (ng g-1) and shrimp (ng g-1) samples, respectively, were: DDE, 0.059–102.0, 3.44–13.97, 0.344–14.57; dieldrin, 0.026–173.6, 1.21–2.75, 0.427–5.59; α-endosulfan, bdl, 1.75–4.00, bdl; β-endosulfan, bdl (below detectable limits), 2.51–9.48, bdl; and lindane, (bdl), 0.110–0.319, 2.90. In 1989–1990 and 1995–1996, residues of six OCs and two OPs were detected quite regularly. DDE, dieldrin and Chlorpyrifos residues were much higher than those of the other insecticides. The range of their means in water (μg L-1), sediment and shrimp (ng g-1), respectively, were: DDE, 1.66–19.76, 0.941–5.84, 1.11–8.32; dieldrin, 0.077–7.22, 0.425–3.31, 0.385–1.59; α-endosulfan, 0.034–1.25, 0.021–1.22, 0.032–3.62; β-endosulfan, 0.665–1.23, 0.008–3.60, 0.005–3.97; endosulfan sulphate, 0.959–1.34, 0.035–3.08, 0.012–1.80; lindane, bdl, 0.005–0.82, 1.19–1.56; chlorpyrifos, 0.702–4.06, 0.005–1.51, 0.156–7.04; and diazinon, bdl, 0–0.150, 0.001–0.006. At the mouth of the river, where it discharges into the sea, the levels of almost all the residues were higher than upstream. [ABSTRACT FROM AUTHOR]

A careful reading of Bonnail et al. (2019)'s work points out some issues in the description of the Ganges River, e.g., describing it in a way that gives impression to the readers unfamiliar with the Indian rivers that it flows by the national capital New Delhi, after reading "it receives inputs from highly populated cities of India, including New Delhi and ...". However, as a matter of fact, it is not the Ganges, but the Yamuna River, a tributary of the Ganges, that passes through the National Capital Region of Delhi. Moreover, authors identify the studied river as the Ganges, whereas it is one of the distributaries of the Ganges called Hooghly (anglicized version of its local name Hugli). They have referred to the seasonality of the studied river; however, the flow of the studied (Hooghly) river is controlled by a barrage on the Ganges River. Moreover, Hooghly River receives input from its own tributaries; viz., Mayurakshi and Damodar, flowing through highly mineralized and coaliferous areas of Jharkhand state of India. Bonnail et al. (2019) have attributed the contamination of the river sediments to anthropogenic activities alone, by not evaluating likely natural sources. A correction factor for the underestimated total organic carbon (TOC) content obtained using Walkley-Black method should have been applied before using TOC values for factor analysis to overcome the underestimation issue with this method. This work intends to serve as a compendium, rather than a critique, to otherwise commendable work by Bonnail et al. (2019). [ABSTRACT FROM AUTHOR]