Metal Concentrations In Water Research Articles

Metal/metalloid bioconcentration dynamics in fish and the risk to human health due to water contamination with atmospheric particulate matter from a metallurgical industrial area

Settleable atmospheric particulate matter (SeAPM) containing a mixture of metals, including metallic nanoparticles, has increased throughout the world, and caused environmental and biota contamination. The metal bioconcentration pattern in Nile tilapia (Oreochromis niloticus) was evaluated during a 30-day exposure to 1 g L−1 SeAPM and assessed the human health risk from consuming fish fillets (muscle) based on the estimated daily intake (EDI). SeAPM was collected surrounding an iron ore processing and steel industrial complex in Vitória city (Espírito Santo, Brazil) area. Water samples were collected daily for physicochemical analyses, and every 3 days for multi-elemental analyses. Metal bioconcentrations were determined in the viscera and fillet of fish every 3 days. The elements B, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ag, Cd, Pb, Hg, Ba, Bi, W, Ti, Zr, Y, La, Nb, and Ce were analyzed in SeAPM, water, and fish using inductively coupled plasma mass spectrometry. The metal concentration in SeAPM-contaminated water was higher than in control water. Most metals bioconcentrated preferentially in the fish viscera, except for the Hg and Rb, which bioconcentrated mostly in the fillet. The bioconcentration pattern was Fe > Al > Mn > Pb > V > La > Ce > Y > Ni > Se > As > W > Bi in the viscera; it was higher than the controls throughout the 30-day exposure. Ti, Zr, Nb, Rb, Cd, Hg, B, and Cr showed different bioconcentration patterns. The Zn, Cu, Sr, Sn, Ag, and Ta did not differ from controls. The differences in metal bioconcentration were attributed to diverse metal bioavailability in water and the dissimilar ways fish can cope with each metal, including inefficient excretion mechanisms. The EDI calculation indicated that the consumption of the studied fish is not safe for children, because the concentrations of As, La, Zr, and Hg exceed the World Health Organization's acceptable daily intake for these elements.

Assessment of Physico-Chemical Characteristics and Heavy Metal Content of Mangrove Water and Sediment from Selected Sites, Gulf of Khambhat, Gujarat, India

Due to their function in averting catastrophic weather occurrences like tsunamis and cyclones, mangrove forests are of paramount importance. The current study sought to determine the heavy metal content in water and sediment as well as the physico-chemical quality of mangrove water and sediment. Physico-chemical parameters and edaphic characteristics were studied for different sites i.e. Vadgam, Tada Talav and Kantiajal of the Gulf of Khambhat having mangrove vegetation. Physico-chemical parameters and heavy metals were higher at Kantiajal which is situated in Hansot tehsil of Bharuch district. This might be because it is adjacent to the industrial area of Ankleshwar and Panoli. Some of the physico-chemical parameters studied were turbidity, salinity, dissolved oxygen, COD, sulphate, phosphate, ammonical nitrogen, Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Cobalt (Co) and Lead (Pb) were the metal selected for the study. In order to develop conservation and management plans, a thorough research of the mangrove species in the Gulf of Khambhat, Gujarat, is required. The current study gives the baseline data for these species.

Human health risk assessment of heavy metal concentration in surface water of Sosian river, Eldoret town, Uasin-Gishu County Kenya

Heavy metal pollution in surface waters has become a major worldwide issue as people tend to settle where there is readily available source of water like a river. This research evaluates the causes, concentration and associated health risks of heavy metals in River Sosiani as it passes through the town of Eldoret. Seven water samples were collected and analysed for zinc (Zn), copper (Cu) and lead (Pb. The results disclosed that Pb concentrations were estimated to be in the range of 0.06 mg/l to 0.23 mg/l, higher than the permitted limit by WHO of 0.01 mg/l. Cu and Zn concentration levels were below the permissible limits. The chronic daily intake (CDI) indicated that total hazard quotient of non-cancer risk of Pb was above one and the total HI values for children were greatly elevated compared to those of adults in the studied area. This showed a high risk in exposure to Pb. Health human risk was assessed and the incremental life cancer risk (ILCR) values of Pb for children and adults in all sites were found to be negligible with values below 10−6. However, there is higher cancer and non-cancer risk for children than adults as far as lead metal is concerned. Therefore, measures should be taken in accordance with the standards to prevent potential risk of the river pollution.•Human activities make a significant contribution to heavy metal pollution to surface waters which is a threat to humans.•Water from Sosiani River is not safe for use domestically as far as lead metal levels are concerned.•The results of this study can be used by decision makers to develop measures which can improve the quality of water in the river catchment.

Assessing the impacts of zeolite on water quality, growth performance, heavy metal content and health condition of farmed tilapia (Oreochromis niloticus)

The rapid expansion and intensification of tilapia (Oreochromis niloticus) aquaculture in Bangladesh results in an increasing tendency of administering more pharmaceuticals in fish health management. Hence, with the aim of investigating the effects of zeolite (a water and sediment treatment compound) on water quality, growth performance, hematology, gut microbial content, and heavy metal content of Oreochromis niloticus, an experiment was performed for 126 days in six experimental earthen ponds (each pond size is one decimal). The stocking density was 300 fry/decimal. Zeolite was applied directly into the water in treatment ponds at a rate of 200 g/decimal during pond preparation and 100 g/decimal/15 days intervals during the culture period as recommended by the manufacturing company. The results indicated that zeolite had a significant effect (p < 0.05) on all growth indices assessed in all three experimental stages (0–42 days, 43–84 days, 85–126 days) in treatment ponds compared to control ones, except condition factor (CF) at the first stage. Hematological results implied that the application of zeolite in treatment pond water had no significant effect on the red blood cell (RBC) and white blood cell (WBC) of experimental fish blood compared to the control. However, a significant effect on the blood glucose level and total viable count (TVC) of the experimental fish gut was observed due to the addition of zeolite in the treatment ponds. Zeolite supplementation in treatment pond water significantly reduced the concentrations of different heavy metals in pond sediment, water and fish flesh compared to the control. Therefore, zeolite could be recommended for administration in aquaculture. Further research is required to find out whether a higher or lower dose of zeolite improves the water quality, growth performance and health condition, and decreases the heavy metal content of fish or not.

Evaluation of metal pollution related to human health risk in freshwater snail Viviparus contectus (Millet, 1813) as a potential bioindicator species in Lake Habitat (Turkey).

Freshwater mollusks are employed as bioindicators for the assessment of water quality in biomonitoring studies since the water quality of natural resources is crucial for humans. The freshwater snail species known as Viviparus contectus (Viviparidae: Gastropoda) is one that people eat. Here, the levels of heavy metals (Cd, Cr, Pb, As, Zn, and Cu) in water and V. contectus samples were determined. An Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES, Spectro Arcos, vertical plasma) was used for the analysing the heavy metal concentrations in water and freshwater snail samples. The results of the current investigation demonstrated that freshwater snails accumulated metals in their water and soft tissues in the following orders: Pb > Cr = Zn = Cu = Cd = As and Zn > Cu > Pb > Cd > As = Cr. Autumn was the time of year when higher amounts of heavy metals (As, Cr, Cu, Zn, and Hg) were found. Pb content in the freshwater snail samples was strongly impacted by seasonal fluctuations (P 0.05). For adults, the EDI (estimated daily intake) values were lower than the TDI (tolerable daily intake) values, and the HI (hazard index) values were below 1. Freshwater snail samples had Zn and Pb levels that were over the FAO/WHO, Turkish Food Codex, JECFA, and EC limit values. Except for Pb, the water study shows mean metal concentrations below the USEPA, Turkish Pollution Control Regulation, and World Health Organisation maximum allowed levels. Aquatic ecosystems were negatively impacted by anthropogenic activities overall, and this study can provide a helpful data set for investigations on metallic contamination in water bodies and biomonitoring in freshwater ecosystems.

Lead and Cadmium Levels in Water, Surficial Sediments, and Edible Biota of Urban Rivers in Dar es Salaam, Tanzania, During Two Seasons

This study evaluated levels and seasonal patterns of lead (Pb) and cadmium (Cd) in sediment, water, and mudskippers (Periophthalmus argentilineatus) from urban rivers in Dar es Salaam, Tanzania. The samples were seasonally collected from 15 locations, treated as appropriate, and analyzed instrumentally. The study intended to establish contamination levels, identify hotspots, and assess ecological and human health risks. The results indicated that Cd concentrations were lower than Pb in all the sample matrices. In water samples, Pb levels (0.7 to 24.0 mg/L, n = 30, mean = 7.2 ± 6.5) were higher than both the World Health Organization (WHO) and the Tanzanian Bureau of Standards limits, whereas Cd was below the detection limit. In sediment samples, both the Pb concentrations (9.0 to 159.3 mg/kg, n = 30, mean = 44.7 ± 36.6) and the Cd concentrations (0.03 to 0.82 mg/kg, n = 30, mean = 0.24 ± 0.14) exceeded sediment quality guidelines for the protection of aquatic life. The mudskipper samples contained levels below the Food and Agriculture Organization (FAO) and WHO maximum permissible limits. This indicated that they were safe for human consumption. Metal concentrations in water and sediments were lower during the dry season than in the wet season, probably owing to contaminated runoff from land-use practices during the wet season, whereas the mudskipper samples showed the opposite pattern. Determination of the potential contamination index (PCI) in samples enabled the identification of two hotspots that may need intervention. Evaluation of chronic daily intake (CDI), hazard quotient (HQ), and hazard index (HI) implied minimal health risks. Contamination of the rivers by these toxic metals, be it in low concentrations, is an issue of concern.

Bioaccumulation of Metals in Some Fish Species from the Romanian Danube River: A Review

The Danube is the second-largest river in Europe and has been subject to pollution in the past. Additionally, in the last few years, the rapid pace of industrialization and urbanization has led to the inevitable pollution of this aquatic ecosystem by certain metals (essential and non-essential elements). This issue is considered the central problem of pollution in the Danube and is gaining increasing attention. Fish is a good source of proteins, polyunsaturated fatty acids (especially omega-3 fatty acids), essential vitamins, and minerals. Fish are often exposed to metals present in their aquatic environment through direct contact with contaminated water or by consuming organisms that have accumulated metals in their tissues; therefore, the elevated concentrations of metals in water and sediments are reflected in the fish flesh. In this context, the safety of fish and fishery products for human consumption is a public health concern. In the last two decades, more and more reports have shown that Danube River fish are contaminated with metals, causing great concern among consumers. The negative perception continues, although recent scientific studies show that metal levels in the edible parts of the fish are below acceptable limits. The objective of this study was to put together a multitude of scientific research studies that investigate the levels of some metals in various tissues of some fish species with high economic value in the Romanian market, as well as the levels of metals in the water and sediments. The collected data were then utilized to assess the potential health risks posed to humans.

Emergent (branched bur-reed—Sparganium erectum L.) and submergent (river water-crowfoot—Ranunculus fluitans Wimm., 1841) aquatic plants as metal biosorbents under varying water pH conditions in laboratory conditions

A laboratory experiment was performed to find out the potential bioaccumulation of metals (Al, Cu, Cd, Ni, Pb, Fe, Mn) in aquatic plants acting as natural biosorbents in the environment depending on the variation of water pH. Two plants were selected for the study: branched bur-reed—Sparganium erectum L., as a representative of emergent plants; and river water-crowfoot—Ranunculus fluitans Wimm., 1841, as a representative of submergent plants. The bioaccumulation of metals in plants relative to water (BCFW) was determined, and the metal pollution index (MPI) was calculated. The metal content in water and plants before the experiment was arranged in the following series of increasing values: Cd = Ni < Cu < Pb < Mn < Al < Fe (water) and Cd < Cu < Ni < Pb < Al < Fe < Mn (in both plants). The lowest concentration of cadmium was found in water both at the end and beginning of the experiment. In turn, aluminum level increased, and its concentration was the highest in both acidic and alkaline water. This suggests that aluminum is definitely more available to the organisms living in it under such conditions, and in higher concentrations may be a limiting factor for them. Bioaccumulation of metals (BCFW) in neutral and alkaline environments was higher in branched bur-reed, and in acidic conditions in river water-crowfoot. This may provide a basis for using specific plant species to selectively accumulate metals depending on the range of water pH. This is also supported by the MPI values, which indicate that they have a very high and often the highest impact on metal pollution levels. The observed variability of metals bioaccumulation against the condition of hydromacrophytes makes it possible to consider these plants as biosorbents used in constructed biological treatment plants, which, depending on the species placed there, can selectively absorb particular trace elements. The plants used in the experiment are common hydromacrophytes of Europe, so they can be used in the construction of artificial wetlands across the continent. The apparent diversity of metal accumulation in relation to hydromacrophytes indicates that this type of site can be inhabited by specific species, which can significantly improve the purification of natural or anthropogenic water reservoirs, i.e., those that are intended to perform a filtering function.

Detection of heavy metal contamination in Batlama Stream (Turkiye) and the potential toxicity profile

In this study, heavy metal pollution in Batlama stream flowing into the Black Sea from Giresun (Turkiye) province and the toxicity induced by this pollution were investigated by Allium test. Heavy metal concentrations in stream water were analyzed by using ICP-MS. Germination percentage, weight gain, root length, micronucleus (MN), mitotic index (MI), chromosomal abnormalities (CAs), proline, chlorophyll, malondialdehyde (MDA), antioxidant enzyme activities were used as indicators of physiological, cytogenetic and biochemical toxicity. In addition, Comet assay was performed for detecting DNA fragmentation. Anatomical changes caused by heavy metals in the root meristem cells were observed under the microscope. A. cepa bulbs are divided into two groups as control and treatment. The bulbs in the control group were germinated with tap water and the bulbs in the treatment group were germinated with stream water. As a result, heavy metals such as Al, Ti and Co and radioactive heavy metals such as Rb, Sr, Sb and Ba were detected in the stream water above the acceptable parametric values. Heavy metals in the water caused a decrease in germination, root elongation, weight gain, MI and chlorophyll values, and an increase in MDA, proline, SOD, CAT, MN and CAs values. Comet assays indicated the presence of severe DNA damage. In addition, heavy metals in stream water caused different types of CAs and anatomical damage in root meristem cells. As a result, it was determined that there is intense heavy metal pollution in the stream water and this pollution promotes multi-dimensional toxicity in A. cepa, which is an indicator organism. For this reason, the first priority should be to prevent pollution of water resources in order to prevent heavy metal-induced toxicity in water.

Modeling transport and fate of metals for risk assessment in the Parauapebas river

Excessive concentrations of metals in surface waters may impose risks to both human health and biota. Several processes, such as advection, dispersion, and sorption, determine the transport and fate of these elements in rivers. This study models the transport and fate of 19 metals across 107 km of the Parauapebas river, in the state of Pará, Brazil. The main goal is to evaluate the risk associated with threshold exceedances in the river until the city of Parauapebas, where the river is a source of drinking water. The Hec-Ras software is used to simulate river flow during dry and rainy seasons, and the results are integrated into the SihQual model. This tool incorporates a module for metal changes, considering the dissolved/particulate dynamics, and other relevant processes. The model's accuracy is evaluated using simulated and observed data at 10 monitoring points. The modeled results fall within a 20% range of the observed data variation, particularly for concentration intervals that pose concern for human health and ecological safety. The results indicate iron, manganese, and aluminum as the main substances of concern for surface water quality. Although the risks for the adult health indicated by sampling measurements from 2017 are low, simulated scenarios of increased metal levels indicate higher risks of threshold exceedances. The study implies that reducing metal contents in water for human consumption near Parauapebas city is necessary. Point sources have a larger impact on water quality during the dry season, while diffuse contributions have a larger impact on metal concentrations during the rainy season, especially in deforested areas. The modeling framework can guide pollution control and remediation efforts for stakeholders in the public or industrial sectors.

A 2-year study on the spatio-temporal changes in trace metal concentrations in sediment, water and plants within the Walvis Bay Lagoon, Namibia

Most pristine coastal ecosystems are at threat from pollution due to the increasing anthropogenic activities such as mining, recreational activities, and human settlements that discharge waste as effluents. In Namibia, the Walvis Bay Lagoon is regarded as one of the most important wetlands for birds along the Southern African coast and has been designated as wetland of international importance, which makes its protection from pollution very critical. To date, no studies have focused specifically on the potential accumulation of heavy metals in the Walvis Bay Lagoon environment under the current increase in industrial activities around the lagoon. It is therefore imperative to monitor the changes in industrial pollutants such as toxic heavy metals within the Walvis Bay Lagoon, which is critical in evaluating the overall lagoon ecosystem health. Therefore, this study monitored changes in heavy metals (As, Cr, Cd, Ni, Pb and Zn) in sediment, water and Salicornia spp. plants collected from the Walvis Bay Lagoon. The highest concentrations of the heavy metals were found in the sediment in transects located furthest away from the lagoon mouth, though with values below minimum threshold values. For sediment samples, the maximum average concentration recorded was Cr (31.3 mg/kg); Ni (8.03 mg/kg); Pb (27.9 mg/kg); Zn (59.4 mg/kg); As (6.14 mg/kg); whilst for water samples it was As (0.06 gm/L); Cd (0.11 mg/L); Ni (0.68 mg/L) and Pb (1.49 mg/L). It was noted that the stations further away from the lagoon mouth had higher concentrations of most metals, indicating the importance of lagoon recharge and discharge. Sedimentation with clay in areas furthest away from the lagoon mouth could be resulting in higher heavy metal retention within the lagoon and thus periodic monitoring of both heavy metals and clay sedimentation is required. Based on this baseline data, the heavy metal concentrations within the lagoon indicate a healthy lagoon, with no immediate risk posed by the heavy metals. However, this study was only undertaken over two years and more time will be required to monitor the long-term changes in these trace metals to have more policy influencing data, hence continued monitoring is recommended. Monitoring of sediment, water and plants should also be coupled with sampling of organisms like fish, crustaceans and birds, that are found within the lagoon to evaluate any correlations between the source concentrations and that in the organisms.

Determination of heavy metals concentration in some sachet water commonly in Abuja Municipal Council, Nigeria

The aim of the study was undertaken to assess heavy metal concentration in some sachet water commonly consumed in Abuja Municipal Council, Nigeria. This was done by measuring heavy metal concentration using Atomic Absorption Spectrometer at the advance chemistry laboratory, Sheda Science and Technology Complex (SHETSCO), FCT, then estimating carcinogenic and non carcinogenic exposure, contamination factor, degree of contamination and pollution load index. The samples were all obtained randomly within Abuja Metropolis. The carcinogenic and non- carcinogenic exposure are far less than 1. The concentration of the heavy metals in sachet water for Cd, Mn, Pb, Cu and Zn are 0.019 mg/l, 0.173 mg/l, 0.219 mg/l, 1.250 mg/l and 0.0760 mg/l respectively. The value of Cd, Pb exceed the recommend standard of 0.01 set by WHO (2008) while the concentration of Mn, Cu and Zn are below the permissible limit of 0.5 mg/l, 2 mg/l and 5 mg/l. The estimated heavy metal risk resulting from exposure to Cd and the estimated concentration of Pb in this study, was higher than the acceptable limit range provided by WHO. This indicates adverse health effects for people who consume sachet water in Abuja municipal council.

Assessment of pollution and metal toxicity in the bed sediment of El-Rayan Lakes, Fayoum, Egypt

Sediments are vital components of aquatic ecosystems, which trap and store various essential elements as well as harmful polluting substances. This is why sediment quality assessment is of great importance in measuring the quality, or pollution, of water bodies. In this study, the levels, ecological risk, and toxicity indices of 17 heavy metals (HMs) were evaluated in the sediments of the two lakes: Upper Wadi El-Rayan Lake (UWRL) and Lower Wadi El-Rayan Lake (LWRL). Both are important wetlands in Egypt used as agricultural drainage water reservoirs for Fayoum province. As revealed by the texture of the sediments, the sand represented the major sediment portion of the UWRL, while the mud was dominant in the LWRL. According to ecological risk assessment, the sediments of the two lakes suffer different degrees of metal pollution, mainly Cd, Pb, and Ni. Based on sediment quality guidelines, toxicity indices indicated different potential toxic effects of the studied HMs on benthic-dwelling organisms, but Ni and Ba had the highest potential biological risk. Results also revealed that the area facing the El-Wadi Drain is the most polluted due to its proximity to the water drainage entrance. However, LWRL is generally more polluted than UWRL. This is related to the shrinkage of water volume and lake area; it causes an increase in the concentration of metals in water, and thus an increase in the sedimentation rate of these metals into the bottom.

Metal Transport in the Mixing Zone of an Estuarine River to the Northern Gulf of Mexico

To better understand the pollution potential of metals in estuaries heavily concentrated with petrochemical industries, we measured concentrations of total recoverable metals in the lower Calcasieu River in southwestern Louisiana that flows into the northern Gulf of Mexico. Water samples were collected at six sites along the last 88 km reach of the river monthly between May 2013 and November 2015, during which salinity ranged from 0.02 to 29.5 ppt from upstream to downstream. The samples were analyzed for a series of total recoverable metals, including aluminum (Al), arsenic (As), boron (B), cadmium (Cd), calcium (Ca), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), lithium (Li), magnesium (Mg), manganese (Mn), nickel (Ni), silicon (Si), titanium (Ti), vanadium (V), and zinc (Zn), of which only Al, As, B, Ca, Fe, Li, Mg, Mn, Si, Ti, and Zn had a detection rate higher than 30% over the 31-month study period. In the freshwater portion of the river, Si, Ca, Al, Fe, and Mg showed the highest concentration (8, 5, 4, 2, and 2 mg/L, respectively), while Li, As, Zn, Ti, and B had the lowest concentration (6, 16, 27, 34 and 50 µg/L, respectively). The concentrations of Al and Si declined by more than 30% from the freshwater to the river mouth, but the concentrations of Li and B increased by 61 and 66 times, respectively. None of these metals’ concentrations were found to exceed US EPA standards, but the rapid increase in Li and B concentrations may indicate a potential anthropogenic influence. On average, the Calcasieu River discharged a total of 35,484 tons of the elements each year (or 8059 kg/km2/yr), of which Si, Al, Ca, Fe, and Mg contributed 98%. Three major components of factors were extracted explaining 34, 20, and 13% (cumulative 67%) of the total variation in the metal concentrations. Salinity and pH were the major (&gt;0.3) parameters in component 1 explaining the variability of B and Li; TSS was the major (&gt;0.3) parameter in component 2 explaining the variation of Al, Fe, and Ti concentration; and temperature and DO% were the major (&gt;0.3) parameters in component 3 explaining the variation of Mn concentration. Further studies on riverbed sediment metals and their effect on metal concentrations in surface water can help understand the metal sources and their potential effects on coastal aquatic ecosystems.

Assessment of heavy metals contamination of sediments and surface waters of Bitter lake, Suez Canal, Egypt: Ecological risks and human health

The concentrations of heavy metals in the surface waters and sediments of Bitter Lake were investigated to assess the level, distribution, and source of pollution and the associated ecological and human health risks. The ecological indices of the lake water indicate low contamination degrees by heavy metals. A dermal exposure-based health risk evaluation revealed no carcinogenic or non-carcinogenic impact on human health. The contamination factor (CF) for Cu, Ni, Pb, Mn, Fe, and Zn (CF < 1) indicate low contamination levels, while Cd reaches very high contamination in most sediment sites (CF ranges from 6.2 to 72.4). Furthermore, the potential ecological risk factor (Eri) and modified hazard quotient (mHQ) indicate low ecological risk for all metals except Cd, revealing high to very high-level ecological risk in most sites (Eri ranges from 185 to 2173 and mHQ from 1.8 to 6.3). This emphasizes the urgency of prompt actions to improve the environment in Bitter Lake.

Determination of heavy metal content in water, sediment and some macrophyte species, iron reeds, Bitlis-Türkiye case study

Determination of heavy metal content in water, sediment and some macrophyte species, iron reeds, Bitlis-Türkiye case study

Assessment of heavy metal pollution and quality in lake water and sediment by various index methods and GIS: A case study in Beyşehir Lake, Turkey

Beyşehir Lake, Turkey's largest freshwater lake, is also a “Drinking Water Reserve”. In the study, heavy metal (As, Cr, Cu, Ni, Zn, Pb, Cd, Hg, Fe, Al, Mn) concentrations of seasonal lake water and bottom sediment samples were determined to evaluate the heavy metal pollution. Several index methods were applied, and pollution assessments were made using the obtained analysis results of lake water and sediment samples. The average concentrations of the heavy metals in the lake waters are observed as Fe > Al > Mn > As>Zn > Ni > Pb > Cr > Cu > Hg > Cd. When the lake waters were compared with the TS 266 (2005) and WHO (2017) limit values, it was determined that lake waters are below the limit values in terms of the heavy metals. According to index results, all of the lake samples are suitable for use as drinking water in accordance with the heavy metal pollution index (HPI) value, all of the samples are in the “low pollution” class in accordance with the heavy metal evaluation index (HEI) and degree of contamination (Cd) values. In addition, the water average concentrations of the heavy metals in the lake sediments are observed as Fe > Al > Mn > Cr > Ni > Zn > Cu > As>Pb > Cd > Hg. The contamination factor (CF) and enrichment factor (EF) revealed that sediments were considerably and moderately polluted by As, Cr, Cu, Ni, Cd, Fe and Mn and low polluted and/or unpolluted by other metals. The calculated pollution load index (PLI) and Igeo values indicate that lake sediments do not carry a risk of heavy metal contamination.

Comprehensive Monitoring and Ecological Risk Assessment of Heavy Metals in Soil and Surface Water of Chishui River Basin in Upper Reaches of the Yangtze River

Chishui River is an important ecological security barrier area in the upper reaches of the Yangtze River in China. Therefore, it is of great significance to conduct research on soil and water ecological risks in the Chishui River basin. In this paper, the risk of heavy metals pollution and its control factors was evaluated systematically by using surface water and soil samples from 16 tributaries in the Yunnan section of the Chishui River basin. The method of soil environmental capacity and ecological risk index were studied. The results showed that the average concentration of heavy metals in the surface water of the main stream was in the order of Fe &gt; Mn &gt; Zn &gt; Cu &gt; Pb &gt; Cd &gt; Hg. Except for Hg, all the concentrations of heavy metals were far lower than the Class I water limits in the Environmental Quality Standards for Surface Water (GB3838-2002) issued by the Ministry of Ecology and Environment, PRC. The average concentration of Hg concentration was 0.056 μg·L−1, which was slightly higher than the limit value of Class II. Heavy metals in the surface water were distributed in a point-like manner in the main stream of the Chishui River, which was mainly affected by mining drainage, township sewage, and human production activities. Meanwhile, the environmental capacity study showed that the heavy metals in soil were in the order of Zn &gt; Pb &gt; Cr &gt; Ni &gt; As &gt; Hg &gt; Cu &gt; Cd, and the environmental capacity were significant differences among different soils: purple soil &gt; limestone soil &gt; loess &gt; yellow-brown soil. Soil Cd tended to migrate out of the soil under the control of the occurrence form, vegetation coverage, and human production activities, while Cr, Cu, and Ni tended to accumulate in the soil. The average comprehensive ecological risk index (RI) of heavy metals in all tributaries ranged from 44.86 to 154.15, mainly distributed in medium and low ecological risk. Therefore, it is recommended to dynamically monitor and control these pollution points in the Chishui River basin to prevent the risk of heavy metals from escalating.

Riparian Bird Occupancy in a Mountain Watershed in the Colorado Mineral Belt Appears Resilient to Climate-Change-Driven Increases in Metals and Rare Earth Elements in Water and Aquatic Macroinvertebrates

Acid rock drainage (ARD) impacts species composition in mountain streams. The potential impact for riparian birds experiencing elevated metal uptake by consumption of benthic invertebrates is concerning but not well studied. We investigated the influence of metal and rare earth element (REE) content in benthic invertebrates on the presence of breeding birds in an ARD-impacted watershed in Colorado, USA, where tree swallows in nest boxes had previously been found to have elevated metal concentrations at some sites. The concentrations of particular REEs in invertebrates were higher than those for cadmium or lead. Avian point counts indicated that most bird species detected were present at most sites, and that tree swallows were rarely found. Occupancy models showed that the availability of shrub or forest habitat was a good predictor for a few habitat-specialists, but metal and REE concentrations in water and invertebrates were not good predictors of avian presence. For other species, neither habitat type nor water quality were important predictors. Overall, this study indicates that the climate-change-driven increases in metals and REEs may not influence the presence of riparian birds in ARD-impacted streams.

Land development and road salt usage drive long-term changes in major-ion chemistry of streamwater in six exurban and suburban watersheds, southeastern Pennsylvania, 1999–2019

In urbanized areas, the “freshwater salinization syndrome” (FSS), which pertains to long-term increases in concentrations of major ions and metals in fresh surface waters, has been attributed to road salt application. In addition to FSS, the water composition changes as an influx of sodium (Na+) in recharge may displace calcium (Ca2+), magnesium (Mg2+), potassium (K+), and trace metals by reverse cation exchange. These changing ion fluxes can result in adverse impacts on groundwater and surface waters used for municipal supplies. Few datasets exist to quantify the FSS on a watershed scale or link its manifestation to potential controlling factors such as changes in urban development, land use/land cover (LULC), or wastewater treatment plant (WWTP) discharges in upstream areas. Here, we use two decades (1999–2019) of monthly streamwater quality data combined with daily streamflow for six exurban and suburban watersheds in southeastern Pennsylvania to examine the relations among Ca2+, Mg2+, K+, Na+, chloride (Cl−), sulfate (SO42-), and alkalinity (HCO3−) concentrations and upstream controlling factors. Flow-normalized annual and baseflow (August ̶ November) concentrations for Ca2+, Mg2+, Na+, and Cl− increased in all six watersheds over the 20-year study, providing evidence of FSS’s impacts on groundwater that sustains streamflow. Additionally, a redundancy analysis using 2019 flow-normalized values identified the following positive associations between solute concentrations and controlling variables: 1) Cl−, Mg2+, and Ca2+ with impervious surface cover (ISC), 2) Na+ and SO42- with ISC and total WWTP discharge volume, and 3) HCO3− with agriculture and total WWTP discharge volume. From a human health perspective, 2019 flow-normalized Na+ concentrations exceeded the U.S. Environmental Protection Agency’s 20 mg L-1 threshold for individuals restricted to a low sodium diet. Furthermore, indices used to evaluate the corrosivity of source waters to drinking water infrastructure and inform municipal water treatment practices, such as the Chloride to Sulfate Mass Ratio and Larson Ratio, increased between two- and seven-fold over the 20-year time. Collectively, the results elucidate the causal factors of the FSS in suburban and exurban watersheds and its potential impacts on human health and drinking water infrastructure.