Seasonal variation of heavy metals in water, sediment, and highly consumed cultured fish (Labeo rohita and Labeo bata) and potential health risk assessment in aquaculture pond of the coal city, Dhanbad (India)

Speciation characteristics, ecological risk assessment, and source apportionment of heavy metals in the surface sediments of the Gomishan wetland

Metal contamination is one of the worldwide environmental issues. The main aim of this study was to evaluate the concentration, probable environmental risk, and source of investigated elements (Al, As, Co, Cr, Cu, Fe, Mn, Ni, and Zn) in sediments and water of the Gomishan wetland. Sediment contamination indices revealed sediments were solely polluted by As. The potential ecological risk index (RI), toxic risk index (TRI), and chemical speciation assessments indicated no major ecological hazards for investigated metals. Correlation analysis and principal component analysis (PCA) indicated that all studied metals in the Gomishan wetland sediments derived from natural sources. HPI, and HEI indices showed that the water quality in terms of hazardous components was inappropriate for aquatic life.

Sources and toxicological effects of metal and metalloids on human health through fish consumption in mineral-rich city, Ranchi, India

Ranchi is the administrative capital of Jharkhand and is located in the southern part of the Chhotanagpur Plateau. It is rich in forest and mineral resources and hence is suitable for the establishment of many large- and small-scale industries. The estimated population of Ranchi for the year 2023 is 3.54 million. These demographic characteristics make the capital more vulnerable to environmental degradation. Also, previous water quality research focused on river, water, and oceans separately; however, little or no work has been carried out on the comparison of metal or metalloid analysis in rivers, waterfalls, and lakes. Hence, the present study aims to assess the pollution status of mineral-rich and industrial hub city, Ranchi, through analysis of metals or metalloids in abiotic (water and sediment) and biotic (fish and human) components. The water, sediment, and fish (Labeo rohita and Catla catla) samples were collected from Subarnarekha river, Jumar river, Dassam fall, Getalsud dam, Hundru fall, Jonha fall, Kanke dam, and Sita fall. Samples were collected following standard methods and analyzed in inductively coupled plasma mass spectrometry (ICP-MS). Among three aquatic systems (rivers, dams, and falls), dams were highly polluted with metals or metalloids, which may be due to effluent discharge from different industries. Additionally, the high population in the city also contributed to metals or metalloids pollution. The reason may be the direct sewage disposal and agricultural and surface runoff in the water systems. It was observed that most of the aquatic systems in Ranchi were severely polluted with metals or metalloids. The fish also accumulated these metals or metalloids in their body and can be life-threatening to the human population consuming them. The THQ (above 1) and HI (2.95) values for As showed that children are more vulnerable to health risk through consumption of contaminated fish. Hence, proper planning and management are needed to overcome the metals or metalloids pollution in Ranchi.

Ecological pollution and health risk monitoring assessment of polycyclic aromatic hydrocarbons and heavy metals in surface water, southeastern Nigeria

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are predominant pollutants linked with anthropogenic activities across a host of environmental mediums. The level of pollution, ecological and health risk were assessed in surface water from Ekulu in Enugu metropolis, Nigeria for 17 PAHs and selected HMs (As, Cd, Cr, Cu, Pb, Ni, Zn) components. PAHs and HMs were determined using a gas chromatography-flame ionization detector (GC-FID) and atomic adsorption spectrophotometer (AAS). The total PAHs in station A (3.17mg/l), B (1.51mg/l), and C (1.83mg/l) were due to high molecular weight (HMW) PAHs than low molecular weight (HMW) PAHs. HMs contents were within USEPA and WHO minimum contamination levels (MCL) except Cr and Pb. The molecular diagnostics of PAHs showed that incomplete combustion of carbonaceous compounds was dominant, while petrogenic was insignificant across all samples. The ecological indices of PAHs and HMs varied from medium to high pollution due to anthropogenic activities that pose a threat to the ecosystem. The non-carcinogenic models showed that hazard index (HI) ranged from PAHs (0.027 - 0.083) and HMs (0.0067 - 0.087) which is less than unity implying no adverse health issues. The lifetime cancer risk (LCR) for PAHs (4.21×10-4 - 9.61×10-4) and HMs (1.72×10-5 - 3.98×10-5) suggested significant cancer risk is possible over some time for a population of 1 in 10,000 and 100,000 for both PAHs and HMs exposure for 70 years. Therefore, there is an urgent need for proper pollution control and mitigation plan to preserve both age groups from being continuously exposed to anthropogenic activities in the Ekulu River and further study should be carried out to monitor the available toxicants.

An application of waste algae biochar in aquaculture water to remove co-existed cadmium and PAHs and the corresponding mechanism

Water quality in aquaculture farms is highly related to the quality of aquaculture products and the connected environment. Cadmium (Cd²⁺) and polycyclic aromatic hydrocarbons (PAHs) are two of the most common pollutants in the aquaculture water, while biochar derived from waste algae (Enteromorpha prolifera), namely BE, was applied in farms ponds to improve water quality. Firstly, the adverse environmental impact of BE was minor, while the concentrations of the heavy metal (Cd²⁺ in the present study) and PAHs (FLU, PHE, FLT and PYR) were removed with efficiencies of 49%, 88%, 90%, 91% and 88%, respectively. The ecological risk values (RQs) were reduced subsequently with a rate of 58 ± 11%. After dosing BE, the ecological risk values in all the studied ponds were lower than 1, indicating no ecological risk in the corresponding aquaculture environment. The sorption capacities (q_m) of BE were 15, 12, 6.3, 0.41, 0.29 and 0.56 mg·g^-1 for Cd²⁺, FLU, PHE, FLT, PYR and BaP, respectively. The sorption capacities were acceptable compared with those derived from other types of biomass. The removal mechanisms were partition (PAHs), complexation (Cd²⁺), π-π interaction (Cd²⁺ and PAHs), precipitation (Cd²⁺) and ion-exchange (Cd²⁺). Practically and theoretically, the algae biochar is applicable in the aquaculture environment, where Cd²⁺ and PAHs co-exist.

Bioaccumulation of heavy metals in the different tissues of Mackerel scad, Decapterus macarellus (Cuvier, 1833) collected from Karachi and Gwadar Coasts of Pakistan

Introduction

Among other aquatic animals, fish can also accumulate a large number of toxic metals in their various body organs, which may enter in the human body and cause serious health issues. Therefore, the basic aim of this study was to observe the level of some heavy metals (i.e., Pb, Fe, Cu, Cd, Cr) found in the different tissues of Decapterus macarellus collected from the Karachi and Gwadar coasts of Pakistan.

Methods

About 200 fish samples of five different size groups of Decapterus macarellus were collected from Gwadar and Karachi fish harbors during April to September 2020. Total 10 samples of each size group i.e., S1, S2, S3, S4 & S5 were collected from each coast. Heavy metals were analyzed in fish samples by using the atomic absorption spectrophotometer (AAS).

Results

The overall results revealed that some metals like Cu, Pb, Cd & Cr contents were high in the stomach, while less in the muscles. Whereas, the concentration of Fe was found to be high in the liver, while low in skin of fish. The average values of bioaccumulation of these heavy metals (BAF) were found in decreasing order of Cu > Cd > Fe > Cr > Pb. In this study, except Cd and Cr, all metals were found within the permissible limits. Both sediment and water from the selected site areas were also analyzed to observe their pollution levels in the order of; sediment > water > fish tissues.

Conclusion

Thus, it was concluded that the Karachi environment was much more polluted than the Gwadar environment because it is in an industrial unit and a busy sea site for trade. Moreover, consuming muscles from this species is safe for human health except for iron toxicity, but the use of the liver is not beneficial for all selected metals. Thus, the present work will also be helpful to monitor these toxic metals in a food chain and maintain a healthy life, and reduce all kinds of health risks associated with them.

Current Status of Ponds in India: A Framework for Restoration, Policies and Circular Economy

Healthy pond ecosystems are critical for achieving several sustainable development goals (SDG) through numerous ecosystem services (e.g., flood control, nutrient retention, and carbon sequestration). However, the socio-economic and ecological value of ponds is often underestimated compared to the larger water bodies. Ponds are highly vulnerable to mounting land-use pressures (e.g., urban expansion, and agriculture intensification) and environmental changes, leading to degradation and loss of the pond ecosystem. The narrow utilitarian use-based conservation fails to recognize the multiple anthropogenic pressures and provides narrow solutions which are inefficient to regenerate the degraded pond ecosystem. In this paper, we holistically examined the legal challenges (policies) and key anthropogenic and environmental pressures responsible for pond degradation in India. The country is strongly dedicated to attaining SDG and circular economy (CE) through aquatic ecosystem conservation and restoration. Considerable efforts are required at the administration level to recognize the contribution of pond ecosystem services in attaining global environmental goals and targets. Worldwide restoration strategies were reviewed, and a framework for pond restoration and conservation was proposed, which includes policies and incentives, technologies such as environmental-DNA (e-DNA), life cycle assessment (LCA), and other ecohydrological measures. Nature-based solutions (NBS) offer a sustainable and cost-effective approach to restoring the pond's natural processes. Furthermore, linkage between the pond ecosystem and the CE was assessed to encourage a regenerative system for biodiversity conservation. This study informs the need for extensive actions and legislative reforms to restore and conserve the pond ecosystems.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13157-022-01624-9.

Water quality and health risk assessment of trace elements in surface water at Punjnad Headworks, Punjab, Pakistan

Pollution of the aquatic ecosystem due to different trace elements has become a global concern which has raised health-related issues for both aquatic and human life. Industrial and agricultural water run-off drained into the rivers and deposit trace elements in water, sediments and planktons. This study was designed to calculate the burden of trace elements such as aluminium (Al), arsenic (As), barium (Ba), and lead (Pb) in the river water of Punjnad Headworks, Bahawalpur, Punjab, Pakistan. Samples were collected from surface water, bed sediments and planktons during autumn, winter and spring seasons (September 2018 to May 2019). The results showed that the concentration of Pb was highest in surface water (453.87 mg L^-1), while that of Al was highest in sediments (370.24 µg g^-1) and plankton (315.05 µg g^-1). A significant difference was found in metal concentrations among surface water, bed sediments and plankton at different sampling stations during various seasons. Importantly, the Exp_ing (0.71, 1.23^-3, 0.34, 0.02 for Pb, As, Al, and Ba, respectively) and Exp_derm (7.09^-8, 1.23¹⁰, 3.42^-8, and 2.48^-9 for Pb, As, Al, and Ba, respectively) for trace elements were below 1.0 suggesting non-significant adverse effects of trace elements on human health. This study provided better understanding of various pollutants and their concentrations in water sources at the studied location.

Consumption of metal-contaminated shellfish from the Cuddalore coast in Southeastern India poses a hazard to public health

Seasonal distribution of four metals (Cd, Cu, Pb, and Zn) in eight shellfish species collected from the heavily contaminated Cuddalore coast in Tamil Nadu, Southern India, were analyzed. Metal concentrations in all shellfish species were determined using atomic absorption spectrometry. All metals were present in all seasons in most of the species, however, with a few exceptions. Overall, the metal concentration was in the descending order: Zn > Cu > Pb > Cd. Metals might have emerged from both natural and anthropogenic sources as per multivariate statistical analysis. Bioaccumulation factor results showed that cadmium was more bioaccumulated and beyond the threshold limit. Hazard index (HI) values revealed that consuming shellfish from Cuddalore coast can pose hazards to human health, with all HI values beyond threshold limit across all seasons - premonsoon (1.33), monsoon (1.73), postmonsoon (2.55), and summer (2.64). It is evident that consumption of shellfish across all seasons may have adverse health impacts to the people.

Analyses of the health status, risk assessment and recovery response of the nutritionally important catfish Clarias batrachus reared in coal mine effluent-fed pond water: a biochemical, haematological and histopathological investigation

The present field study evaluates the health status of the catfish Clarias batrachus reared in coal mine effluent (CME)-fed pond water at Rajrappa mining complex using biochemical, haematological and histopathological parameters. Simultaneously, risk assessment along with recovery response of the CME intoxicated fish following their treatment with CME-free freshwater was also studied. The CME-fed pond water fish revealed significant decrease in biomolecules concentrations and considerable increase in activities of several enzymes along with metallothionein level as compared to control. The impaired regulation of metabolic function was also revealed by blood parameters showing significant decrease in haemoglobin content (8.78 ± 0.344 g/100 mL) and red blood cells count (1.77 ± 0.12 × 106 mm3) while substantial elevation in white blood cells (187.13 ± 9.78 × 103 mm3). The histopathological study also confirmed the changes including hypertrophy of club cells of skin, swelling of secondary lamella of gills, extensive fibrosis in liver and glomerular shrinkage with increased Bowman's space in kidney. Potential health risk assessments based on estimated daily intake and target hazard quotient indicated health risks associated with the consumption of such fishes. The CME-contaminated fish when transferred to CME-free freshwater exhibited decreased metal content accompanied by eventual recovery response as evident by retrieval in biochemical and haematological parameters. Withdrawal study also revealed restoration in the activity of different marker enzymes in fish tissues including blood as well as recovery in their cellular architecture. The results of the present study validate the depuration process as an effective practice for detoxification of fish contaminated with effluent.

Metal Accumulation and DNA Damage in Oreochromis niloticus and Clarias gariepinus After Chronic Exposure to Discharges of the Batts Drain: Potential Risk to Human Health

The present work showed the impact of long-term exposure to the Batts drain's discharges on O. niloticus and C. gariepinus fish species. The accumulation level of Cu, Zn, Fe, Cd, Pb and Al in five vital tissues was markedly elevated near the Batts drain (site2) compared to the samples from the reference site (site 1). At the same site, C. gariepinus displayed the highest accumulation capacities when compared to O. niloticus. Based on the metal pollution index, livers and kidneys, followed by gills, showed the maximum overall metal load. The degree of DNA damage (assessed by comet and diphenylamine assays) was relative to the accumulated metals in tissues with species and site specification. The values of the hazard index for human consumption showed that the studied metals were within safe values at normal consumption rates. While harmful health consequences were observed at the habitual consumption level at site 2.

Metal-associated human health risk assessment due to consumption of pelagic and benthic ichthyofaunal resources from the highly contaminated Cuddalore coast in Southern India

We present seasonal variation of four metals (Cd, Cu, Pb, and Zn) in nine pelagic and three benthic fish species from the highly polluted Cuddalore coast in Tamil Nadu, India. Metals were assessed using atomic absorption spectrometry and detected in all fish species, in at least one season, except Iniistius cyanifrons where cadmium was not detected throughout. In both benthic and pelagic fish, order of metal concentration was Zn > Cu > Pb > Cd. Multivariate statistical analysis revealed that metals may have originated from both natural and anthropogenic sources. Health risk assessment revealed that consumption of fish from Cuddalore coast does not pose health risk for now; however, hazard index values (pelagic = 0.97; benthic = 0.90) are in borderline. Even a slight increase in metal concentration in fish can prove hazardous for human consumption. Sooner or later, eating fish from Cuddalore coast may pose a considerable health risk to humans if metal pollution is not held at Bay.

Ecosystem impact and dietary exposure of polychlorinated biphenyls (PCBs) and heavy metals in Chinese mitten crabs (Eriocheir sinensis) and their farming areas in Jiangsu, China

This study investigated the presence of 18 dioxin-like and non-dioxin-like polychlorinated biphenyls (dl- and ndl-PCBs), heavy metals (Cd, Hg, Pb, and As) in Chinese mitten crabs (Eriocheir sinensis) and their distribution in Jiangsu, China. Risk assessment and source apportionment were employed for evaluating the eco-toxicological impact and human exposure. It was found that the compositions of PCBs varied spatially, suggesting different sources of pollutants, whilst PCB 28, 105, 114, and 126 were consistently found in all sample types, suggesting a common pollution source remained, and the bio-accumulation process was in effect. The total PCBs in sediment were found much higher than in water, and brown meat had the highest and most diverse PCB congeners among all tissues. The presence of heavy metals was found in all samples in descending order of As>Cd>Pb>Hg and in the order of shell>brown meat>white meat>gill for crabs. The results of risk assessment indicated that the potential carcinogenic and non-carcinogenic risks were within the acceptable range for long-term consumption of the crabs overall. However, the highest toxic equivalent (TEQ), carcinogenic, and non-carcinogenic risks were all recorded in Location C, where dl-PCB 126, 169, and As contributed to the majority of the risks. The ecological risk posed by all HMs was low, but cases of serious point source pollution have been found in the investigated regions, and risks caused by Cd individually should raise concerns. Source apportionment study revealed that the contaminants mostly originated from anthropogenic activities. Natural deposition and transportation played an important role as well.

A study on water quality monitoring of Buddha Nullah, Ludhiana, Punjab (India)

Diverse genotoxic agents, entering the aquatic environment through natural and anthropogenic events, pose serious threats to its biotic components. The present study involves the monitoring of water quality by assessing the genotoxic effects and physico-chemical parameters including heavy metals of 10 surface water samples collected from different locations of Buddha Nullah, a tributary of Sutlej flowing through Ludhiana, Punjab (India). Genotoxicity was evaluated following Allium cepa root chromosomal aberration assay and DNA nicking assay using plasmid (pBR322) whilst the metal (cadmium, chromium, cobalt, copper, lead, nickel and zinc) analysis was conducted using atomic absorption spectrophotometer. All water samples collected from the study area had cobalt and lead content more than the permissible limits (0.04 and 0.01, respectively) recommended by the Bureau of Indian Standards and the World Health Organization. The samples also induced genotoxicity following both bioassays. The water samples collected from Gaunspur (GP), a site approx. 75.53 km upstream of the Sutlej-Buddha Nullah joining point, has shown the maximum genotoxic effect, i.e. 38.62% in terms of per cent total aberrant cells during A. cepa assay and 100% DNA damage during DNA nicking assay. The Pearson correlation indicated that genotoxicity had a significant positive correlation with the content of cobalt (at p ≤ 0.5). During cluster analysis, the samples from 10 sites formed four statistically significant clusters based on the level of pollution that was dependent on two factors like similarity in physico-chemical characteristics and source of pollution at a specific site.

Bioaccumulation and bioconcentration of metals in Characidae from a Neotropical river basin under anthropic activities

Natural rates of metal mobilization and deposition in terrestrial and aquatic environments have been changed due to anthropic activities, exposing the native biota to dangerous effects related to bioconcentration and bioaccumulation of metals. This study assessed the concentrations of Cr, Ni, Cd, Pb, Cu, Mn, Co, and Zn in the water and riverbed sediment samples from the Verde River basin (VR), and in tissue samples from two native fishes, the Psalidodon paranae, a VR inhabitant, and the Psalidodon aff. fasciatus, a migratory species. Arithmetic mean values of metal concentrations recorded in waters were Cr: 46.16, Ni: 40.29, Cd 43.19, Pb: 57.74, Cu: 63.72, Mn: 98.36, Co: 64.53, Zn: 81.19, while for riverbed sediments were Cr: 11.84, Ni: 10.52, Cd: 7.14, Pb: 15.00, Cu: 22.16, Mn: 334.77, Co: 24.62, Zn: 434.44. For several analyzed samples, metal concentrations found were higher than Brazilian and international limits set for healthy aquatic life and human uses. Analyzed fish tissues also presented metal concentrations higher than Brazilian and international limits set, indicating a high ecological and health risk for the region. Psalidodon paranae showed affinity to bioconcentrate Pb, Zn, and Cd, while Psalidodon. aff. fasciatus tended to bioconcentrate Ni, Zn, and Cr. Multivariate analyses revealed spatial and temporal patterns in the metal contaminations in VR. These patterns were associated with rural and urban activities developed along VR, which practice inadequate soil handling, indiscriminate use of agrochemicals, and the dumping of domestic garbage and untreated and treated sewage into the river. The implementation of public policies for biomonitoring and pollution control by metals in VR is essential to safeguard regional water resources and their biota.

Spatial distribution of heavy metal contamination and uncertainty-based human health risk in the aquatic environment using multivariate statistical method

Heavy metal contamination in the aquatic environment is one of the most serious health issues worldwide. In this study, an evaluation framework is developed to identify the sources and health risk of heavy metals (i.e., As, Hg, Cr, Cu, Zn, Pb, and Cd) contamination in the North Canal of Fengtai District, China, which is based on multiple approaches, including multivariate statistical method, health risk assessment, and uncertainty analysis. Spatial distribution of these heavy metals could exhibit their impact on the aquatic environment. Pearson's correlation analysis shows that a majority of the correlations between different heavy metals are not significant due to the differences in sources of heavy metals. Principal component analysis indicates that there are four principal components to explain 91.381% of the total variance. Moreover, health risk reveals that hazard quotient values are in low levels, ranging from 0.48 to 0.74, relative higher quotient levels could be observed in the northern section. The carcinogenic risk of Cd has exceeded the acceptable level in S1, S3, and S7. Sensitivity analysis ensures the reliability of health risk assessments. Furthermore, some specific recommendations are given to help decision-makers develop more comprehensive strategies for improving water environment quality.

Organochlorine pesticides and heavy metals in the zooplankton, fishes, and shrimps of tropical shallow tidal creeks and the associated human health risk

Studies on organochlorine pesticides (OCPs) and heavy metals (HMs) from tidal creeks are scarce. Sixteen OCPs and seven HMs were measured in the surface water, zooplankton, two fishes (Harpadon nehereus and Pampus argenteus), and one shrimp (Penaeus indicus) collected from three tidal creeks of the Indian Sundarban. The surface water was polluted by hexachlorocyclohexane isomers (ΣHCH: 525-1581 ng l^-1), dichlorodiphenyltrichloroethane congeners (ΣDDT: 188-377 ng l^-1), endosulfan congeners (ΣEND: 687-1474 ng l^-1), and other OCPs (512-1334 ng l^-1). However, the mean HM concentrations in the surface water were <1 μg l^-1. The zooplankton community exhibited bioaccumulation of both OCPs and HMs. Aldrin, Heptachlor, and α-HCH levels in the edible biotas could lead to cancer. Co and Cd levels could lead to non-cancerous risks, and Pb levels could pose a cancerous risk. This study showed that creeks could be potential sites of both OCP and HM pollution.

Food safety in fisheries: Application of One Health approach

Fisheries comprise the fastest growing sector meeting the global protein requirements. Being an affordable enterprise, it is considered a safe source of food and the muscles of healthy fishes are almost sterile. However, a multitude of hazards (biological, chemical, and environmental) can be introduced into aquaculture throughout the production and supply chain. Also, it can originate from unsuitable farming practices, environmental pollution, and socio-cultural habits prevailing in various regions. Hence, with an increasing global population and demands for aquacultural products, assessment and regulation of food safety concerns are becoming significantly evident. Ensuring safe, secure, affordable, and quality food for all in a global context is pragmatically difficult. In this context, it is quite imperative to understand the ecology and dynamics of these hazards throughout the entire production chain in a One Health approach. Here, we discuss the issues and challenges faced in the fisheries sector as a whole and the need for a One Health approach to overcome such hurdles.

Metal(loid) contamination in water, sediment, epilithic periphyton and fish in three interconnected ecosystems and health risk assessment through intake of fish cooked in Indian style

Samples of water, sediment and epilithic periphyton (EP) were collected from a lake (Dimna, DL), an intermediate canal (IC), and a river (Subarnarekha River, SR) to compare the pollution status of an urban ecosystem, and the concentrations of metal(loid) s were determined. Water characteristics were analysed by the water quality index (WQI). Sediment pollution was assessed using the ecological risk index (ERI). Accumulation of metal(loid) s in EP was determined by using bioaccumulation factor (BAF) and biota-sediment accumulation factor (BSAF). The result showed that the DL was least polluted (WQI = 30.39) and SR (WQI = 90.13) was the most polluted ecosystem. Sediment analysis revealed that Ni, Cr and Cd are the significant pollutants, especially in SR. The THQ value for fish dishes cooked in Indian style was found higher than that of raw fish, suggesting calculations considering the cooking process can provide better results. Health risk assessment shows that people inhabiting DL are vulnerable to Cr and Cu exposure, whereas people inhabiting IC and SR are susceptible to As and Co exposure due to the consumption of cooked fish. Moreover, for a developing country like India, it is important to upgrade the assessment methods and include regular monitoring of interconnecting ecosystems for the safeguard of human and ecological health.

Ecological risk assessment and source apportionment of metals in the surface sediments of river systems in Lake Taihu Basin, China

In this study, the concentrations of Zn, Cr, Ni, Cu, Pb, As, Cd, and Hg in the surface sediments of 94 sites sampled from six water systems in the Lake Taihu Basin in China were measured, and the pollution risks and sources of the metals were identified. The results showed that the mean concentrations of Zn, Cr, Ni, Cu, Pb, As, Cd, and Hg in the riverine surface sediments were 163.6, 102.5, 45.5, 44.7, 37.0, 13.3, 0.5, and 0.1 mg/kg, respectively, higher than the corresponding background values (except for Hg). According to the geoaccumulation index (I_geo), the Pb, Ni, Zn, Cu, and Cd concentrations in the riverine surface sediments were generally at low levels of pollution. Based on a pollution load index (PLI) evaluation, the Pb, Ni, Zn, and Cu concentrations in the riverine surface sediments were generally at moderate levels of pollution. According to the thresholds of potential ecological risk, the Cd and Hg concentrations in the riverine surface sediments exhibited moderate potential ecological risks. Multivariate statistical analysis indicated that the Pb in the riverine surface sediments primarily originated from domestic sewage, agricultural wastewater discharge, and petroleum combustion; the concentrations of Cr, Ni, and Zn were influenced by the electroplating and alloy manufacturing industries; the concentrations of Cu and As mainly originated from pesticide use and industrial wastewater discharge; and those of Cd and Hg primarily stemmed from industrial wastewater discharge. This research provides information regarding metallic contamination and the possible associated ecological risks to benthic organisms in the surface sediments of river systems and is useful for developing sustainable strategies for environmental pollution control and management in the Lake Taihu Basin.

Spatial-seasonal variations and ecological risk of heavy metals in Persian gulf coastal region: case study of Iran

PURPOSE

This study aimed to perform a systematic review to analyse the seasonal concentration and ecological risk assessment of heavy metals (HMs) in seawater and sediment samples collected from the coastline of Jam city in Bushehr, Iran.

METHODS

A total of 96 sediment and seawater samples were collected from 16 sampling stations during the spring, summer, autumn, and winter of 2017. Then, the concentrations of Pb, Ni, Cd, Cr, Cu, Zn, and Fe were determined. Finally, the pollution load index (PLI), ecological risk (Er), and environmental risk (RI) were calculated to assess the HM ecological risk.

RESULTS

The results showed that the mean concentrations of HMs were lower than the maximum acceptable concentration by SQG and NOAA. In addition, the PLI assessed a low pollution load level in the region. The ER and RI results also showed that the region was at low risk, and the metal risk was classified as Cd > Cu > Pb > Ni > Zn > Cr. In some samples, the mean concentrations of HM were found to be higher with a statistically significant difference (P˂0.05). The results also showed that sediments were engaging in a moderate Er by Cd.

CONCLUSIONS

Generally, the rapid growth of urbanization, as well as industrial and human activities, along this coastline and area has increased the pollutants dumped into the seawater and sediments. Thus, it is necessary to take regular monitoring programs and develop better management strategies to minimize the amount of HMs entering into this coastal area.

Dynamics of Metal Pollution in Sediment and Macrophytes of Varthur Lake, Bangalore

Eutrophication and metal contamination are the principal pollution problem for almost all inland lakes in world. Phytoremediation is one of the viable solutions for this concern. The present study analysed the concentration and distribution of six metals (cadmium, chromium, copper, nickel, lead and zinc) in sediment and macrophyte samples of Varthur Lake, Bangalore. Higher concentrations of studied metals in sediment were observed at the inlet and north shoreline regions of the lake. Alternanthera philoxeroides and Eichhornia crassipes accumulated higher concentration of metals than other species. Accumulation of metals in the sediment were Cu > Zn > Cr > Ni > Pb > Cd, whereas the order in macrophyte samples was Cu > Zn > Cr > Pb > Ni > Cd. Bioconcentration factor (BCF) and translocation factor (TF) of metals in macrophytes revealed metal pollution could be remediated through phytoextraction and phytostabilization.

Levels and human health risk assessments of heavy metals in fish tissue obtained from the agricultural heritage rice-fish-farming system in China

China began to practice Rice-fish-farming system (RFFS) 1700 years ago. Nowadays, the widely spread of metals could be potential threats to the quality of RFFS fish. In this study, Pb, Cd, Hg, As and Cr as the top five most toxic heavy metals were determined in six species of RFFS fish meat obtained from 7 provinces in south China. The mean concentrations of metals in RFFS fish followed Pb (36.89 μg/kg) > As (33.36 μg/kg) > Cr (18.54 μg/kg) > Hg (16.35 μg/kg) > Cd (2.01 μg/kg), which were mostly lower in comparison with fish from traditional aquaculture systems raised by fish feeds. Grass carp obtained lower metal concentrations compared with other fishes, possibly indicating the importance of feeding habits of RFFS fish. Concentrations of metals in fish and RFFS sediment were in good correlations, and benthic fish obtained high pollution levels, suggesting the accumulation of metals through the direct contact with sediment. Risks assessments coupled with Monte Carlo simulation indicated the potential non-carcinogenic risks and carcinogenic risks decreased following As > Hg > Cr ≈ Pb > Cd, and As > Cr > Cd > Pb, respectively. These results suggested RFFS is still a successful mode of green agriculture.

Elemental distribution in urban sediments of small waterbodies and its implications: a case study from Kolkata, India

The impacts of elemental pollution in sediments of freshwater bodies are of particular concern in rapidly urbanizing cities of the developing world and have been extensively studied in rivers and lakes. The current study is an attempt to highlight the importance of smaller waterbodies, which happen to form a natural network in cities, for assessing the contamination status of sediments. The distribution of elements (Al, Ca, Fe, K, Mg, S, Si, Ti, Ba, Mn, Sr, V, As, Cr, Cu, Ni, Pb and Zn) in sediments of 15 ponds and 6 canals was studied to understand the overall pollution status and the associated ecological risk to aquatic organisms. Geochemical indices revealed Cr, Cu, Pb and Zn to be the principal elements of concern. The mean concentration of Cr, Cu, Pb and Zn was 308, 174, 76.9 and 446 mg kg^-1, respectively. Ecological risk assessment revealed that Cr in 86% sites, Ni in 52% sites, Cu and Zn in 28% sites and Pb in 10% sites were associated with possible ecological toxicity. The findings suggest that multielemental concentration in sediments of ponds and canals could effectively distinguish between pristine and polluted sites and suitably identify the main elements of concern to support cost-efficient waste management solutions customized to both the sites and elements of concern.

An approach to counter sediment toxicity by immobilization of heavy metals using waste fish scale derived biosorbent

The utilization of fish scale-derived biosorbent for immobilization of cadmium and lead in polluted sediment was thoroughly investigated in this study. Fish scale (FS) biomass was chemically and physically treated. The FS biomass treated with acid (0.1 M HCl), alkali (0.1 M NaOH) and hydrothermally, showed minimum removal capacity. While, FS treated hydrothermally along with acid showed the maximum removal efficiency of metal ions. We used different dosages (0%, 2.5%, 5%, 10%, 15%, and 20%) of FS biosorbent in the sediment. Isotherm modelling showed that this biosorbent can hold 89.30 and 92.65 mg/g of Cd and Pb on its surface. This indicated that prepared FS biosorbent has enough potential to adsorb Cd and Pb ions on its surface from the sediment. Compared to the control, sediment treated with 20% FS showed the highest immobilization capacities for Pb (92.9%), and Cd (87.9%). The values of partition coefficient (K_d) increased by 83% for Pb and 78% for Cd, which specified that availability of free ions of Pb and Cd in the aquatic system was successfully decreased. The sediment treated with 20% FS biosorbent showed 70-80% immobilization of Cd and Pb from mobile and exchangeable fractions that ultimately decreased the bioavailability of metal ions to the biota. Inclusively, compared to control, sediment served with 20% FS biosorbent showed higher level of Pb and Cd ions in residual fraction near by 80%. The prepared FS biosorbent had shown its potential in immobilizing the Cd and Pb ions from sediment as a cheap and ecologically feasible method for amendment.

Spatiotemporal variability of heavy metals and identification of potential source tracers in the surface water of the Lhasa River basin

The Lhasa River basin is the economic and population center of Tibet and has abundant resources. Due to its harsh weather condition, high elevation, and inconvenient accessibility, few studies have focused on heavy metal distributions in this region. In the present study, to investigate the dissolved trace metal pollution and its controlling factors, 57 water samples from the Lhasa River and its tributaries were collected during three water flow regimes in 2016. The data on the dissolved fraction revealed that the Lhasa River basin appeared to have no to low pollution levels. However, the Lhasa River water showed alkaline characteristics which may affect the presence of heavy metal elements in a dissolved fraction. The concentration of heavy metal elements in colloidal or particulate matter therefore needs attention. Multivariate analyses were performed to determine the significant relationship between the data and to identify controlling factors for dissolved heavy metals in the study area. The results suggested that Mn, Cd, Cu, and Zn originated from a natural geological background, whereas Pb originated from mining drainage and As was influenced by geothermal flows. The concentration of dissolved heavy metals in the Meldromarchu tributary was greatly affected by the mining drainage water, while that in the Tölungchu tributary was greatly influenced by the geothermal water sources. This paper provides the first comprehensive analysis of dissolved heavy metal pollution characteristics and the controlling factors of pollution during the three different water flow regimes of the Lhasa River basin.

Bioaccumulation of heavy metals in Channa punctatus (Bloch) in river Ramganga (U.P.), India

Ganga is the largest riverine system of India with a fragile ecosystem. Its prone to anthropogenic disturbances because of its cultural, economic and environmental values. The contamination of river Ganga by heavy metals (HM) is due to biotic (anthropogenic sources) and abiotic (pesticides, fertilizers) sources that poses a devastating health hazard to human, plant and edible fish life. The chemical analysis with the help of atomic absorption spectrometer performed on its water samples demonstrated the accumulation of heavy metals such as Arsenic (As), Lead (Pb), Cadmium (Cd), Iron (Fe), Zinc (Zn). Moreover, the spectrophotometric analysis indicated clearly the accumulation of heavy metals in order of occurrence (Fe > As > Cd > Zn > Pb) in liver and (Zn > Fe > As > Cd > Pb) in kidney of edible fish Channa punctatus. The present study has be used to sensitively monitor the extent of heavy metals pollution in the biotic aqua life of river Ramganga system and its suggested that the bioaccumulation of heavy metal in Channa punctatus has reached above permissible limits for human consumption, indicating potential health risks. Necessary biological steps should be taken to handle such food pollution and prevent the environmental risk and food chain disruption.

Heavy metal speciation, leaching and toxicity status of a tropical rain-fed river Damodar, India

Speciations of metals were assessed in a tropical rain-fed river, flowing through the highly economically important part of the India. The pattern of distribution of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) were evaluated in water and sediment along with mineralogical characterization, changes with different water quality parameters and their respective health hazard to the local population along the Damodar River basin during pre-monsoon and post-monsoon seasons. The outcome of the speciation analysis using MINTEQ indicated that free metal ions, carbonate, chloride and sulfate ions were predominantly in anionic inorganic fractions, while in cationic inorganic fractions metal loads were negligible. Metals loads were higher in sediment phase than in the aqueous phase. The estimated values of I_geo in river sediment during both the seasons showed that most of the metals were found in the I_geo class 0-1 which represents unpolluted to moderately polluted sediment status. The result of partition coefficient indicated the strong retention capability of Cr, Pb, Co and Mn, while Cd, Zn, Cu and Ni have resilient mobility capacity. The mineralogical analysis of sediment samples indicated that in Damodar River, quartz, kaolinite and calcite minerals were dominantly present. The hazard index values of Cd, Co and Cr were > 1 in river water, which suggested potential health risk for the children. A combination of pragmatic, computational and statistical relationship between ionic species and fractions of metals represented a strong persuasion for identifying the alikeness among the different sites of the river.