Assessing the potential ecological risk of Co, Cr, Cu, Fe and Zn in the sediments of Hooghly-Matla estuarine system, India

Pollution indices and correlation of heavy metals contamination in the groundwater around brick kilns in Jammu and Kashmir, India

The present investigation focuses on assessing the water quality of groundwater surrounding brick kilns in the Jammu district of Jammu and Kashmir (J&K). At 43 different brick kiln sites in both north and south regions of Jammu, concentrations of heavy metals were measured using established techniques. The elements zinc, copper, iron, lead, cadmium, nickel, and manganese were analyzed utilizing an Atomic Absorption Spectrophotometer (AAS). The pollution load index value was consistently below unity across all sites, suggesting an absence of pollution and making the water suitable for consumption. The average concentrations, listed in ascending order, were found to be 0.38 mg/L for copper, 0.31 mg/L for zinc, 0.01 mg/L for iron, and 0.09 mg/L for manganese. Notably, concentrations of lead, cadmium, and nickel were found below the detectable levels. Evaluation of contamination factors revealed the sequence Cu > Fe > Zn > Mn, while the geo accumulation index followed the sequence Cu > Fe > Mn > Zn. Comparison of these findings with the established standards of World Health Organization and Bureau of Indian Standards indicated that the recorded ranges were within permissible limits. The study's outcomes suggest that heavy metal emissions from brick kilns may not significantly impact the quality of groundwater. Elevated copper levels found near brick kilns were likely to result from plumbing materials in the study area. Iron and manganese in groundwater seems to have geo-genic origin and not emission-related. This research represents a foundational step in examining groundwater contamination by heavy metals specifically in the neighborhood of brick kilns in Jammu district. It contributes to the establishment of a comprehensive database and serves as a reference point for future studies. Additionally, the study recommends regular monitoring of groundwater to ensure the maintenance of drinking water quality.

Microplastics contamination in two species of gobies and their estuarine habitat of Indian Sundarbans

Sundarbans, a Ramsar site of India is contaminated with heterogeneous microplastic wastes. Boddart's goggle eye mudskipper and Rubicundus eelgoby, were common gobies of Sundarbans estuary which accumulated microplastics during their normal biological activities. We estimated the abundance of microplastics in water, sediment; skin, gills, bucco-opercular cavity and gastrointestinal tract of these two goby fishes. Microplastic load estimated in gobies were 0.84 and 2.62 particles per fish species with a dominance of transparent, fibrous microplastics with 100-300 μm in length. ATR-FTIR and Raman spectroscopy revealed polyethylene as prevalent polymer. Surface degradations and adsorption of contaminants on microplastic surface were investigated by SEM-EDX analysis. Presence of hazardous polymers influenced high polymer hazard index and potential ecological risk index which indicated acute environmental threat to Sundarbans estuary and its resident organisms. Current study will provide a new information base on the abundance of microplastics and its ecological hazard in this biosphere reserve.

Will different land uses affect heavy metal pollution in soils of roadside trees? An empirical study from Shanghai

Heavy metal pollution in roadside soil may harm humans, animals, plants, and local ecosystems. This study aimed to explore the sources and potential ecological risks of heavy metals in soils of roadside trees under different land uses, using soil samples collected from 136 roads across 16 administrative districts in Shanghai. The contents, pollution characteristics, potential ecological risks, and sources of seven heavy metals were analyzed, including Cr, Ni, Cd, Pb, As, Cu, and Zn. Results showed that (1) land use patterns affected the heavy metal contents, with industrial and construction areas showing higher contents while agricultural and forestry areas lower; (2) the ranking of heavy metal pollution levels was Cd > As > Pb > Cu > Ni > Cr > Zn. Cd exhibited the highest potential ecological risk, falling within the moderate to considerable potential ecological risk interval; (3) the sources of Cu, Zn, Cr, Ni, Cd, and Pb were associated with traffic emissions, whereas As had independent other sources and Pb in industrial and construction areas was also influenced by industrial emissions. These results provide valuable references on the control of heavy metal pollutants and the management of land uses in megacities.

Ecological risk assessment and phytomanagement of trace metals in the sediments of mangroves associated with the Ramsar sites of Kerala, southern India

The study investigated trace metal accumulation in the sediments of three major mangrove ecosystems associated with the Ramsar sites of Kerala state, the ecological risks they pose, and the absorption, accumulation, and translocation of metals in five dominant mangrove species, as these systems are heavily impacted by anthropogenic interventions. The trace metal concentrations (mg kg^-1) in the sediment of different mangrove habitats of Kerala ranged from 20 to 295 for Cu, 65 to 350 for Zn, 72 to 151 for Pb, 11 to 210 for Ni, 42 to 228 for Mn, 0 to 6 for Cd,124 to 565 for Cr, and 0 to 2.9 for Ag. An overall enrichment of metals was recorded in sediment, exceeding the prescribed effects range median (ERM) of consensus-based sediment quality guidelines (SQGs) for Cu and Cr concentrations at Munroe Island and Ni at Vypin, indicating a detrimental risk to biota in the sediments. Principal component analysis and a higher geoaccumulation index indicated the contribution of trace metals from industries, agricultural runoff, and urban waste disposal. The ecological risk index suggested that cadmium poses a very high risk to the mangrove ecosystem at Vypin. Furthermore, the bioconcentration factor for various trace metals in Avicennia marina and Lumnitzera racemosa in Ayiramthengu was > 2, suggesting that these species can accumulate trace metals, particularly Cr, Cd, and Pb. Further, our findings suggest that A. marina may be considered as an efficient metal trap for Cd in aerial parts, as indicated by the significant translocation factor (> 1) combined with the bioconcentration factor. Therefore, the study revealed that Munroe island and Vypin had a considerable level of contamination for toxic metals and Avicennia marina could be a promising candidate species for the phytoremediation of these trace metals in the coastal settings of Kerala state.

Differentiating Wild and Apiary Honey by Elemental Profiling: a Case Study from Mangroves of Indian Sundarban

Honey is a natural substance produced by honeybees from the nectar or secretion of flowering plants. Along with the botanical and geographical origin, several environmental factors also play a major role in determining the characteristics of honey. The aim of this study is to determine and compare the elemental concentration of various macro and trace elements in apiary and wild honeys collected from different parts of Indian Sundarbans. The elemental analysis was performed in inductively coupled plasma optical emission spectroscopy preceded by microwave digestion method. The concentrations of 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Se and Zn) were investigated from thirteen locations of Indian Sundarbans. This comparative study shows in wild honey samples, the concentration of K was highest followed by Ca, Mg and Na and Zn was lowest among all. In contrast, in apiary honey samples, Ca had maximum concentration followed by K, Mg and Na and Ag had minimum among all. The elemental concentration in honey from apiary was either equal or higher than their wild counterpart. The results of the factor analysis of PCA algorithm for wild and apiary honey samples were highly variable which implies that the elements are not coming from the same origin. The concentration of element was found to be highly variable across sites and across sources of honey samples.

Distribution and assessment of heavy metals in suspended particles in the Sundarban mangrove river, Bangladesh

The suspended particulate matter (SPM) is an important carrier of heavy metals transportation from land to sea, so it is significant to study the heavy metal pollution in SPM. The distribution and assessment of five heavy metals (Mn, Cr, Ni, Cu, and Pb) in SPM collected from Passur River and its estuary in Sundarban were studied in combination with water temperature, salinity, and turbidity. The results show that the heavy metal content and distribution in SPM are mainly controlled by runoff input, hydrodynamic process and the interaction process of salt and fresh water in estuaries. The quality evaluation results of heavy metals in SPM show that pollution degree is light. Studies on the heavy metals in SPM are of great significance to comprehensively evaluate regional pollution status and carry out early warning.

Geospatial modeling and ecological and human health risk assessments of heavy metals in contaminated mangrove soils

Heavy metal-contaminated wastes can threaten mangrove forests, one of the most biodiverse ecosystems in the world. The study evaluated the geospatial distribution of heavy metals concentrations in soils, the ecological and human health risks, and metal contents in soil fractions and mangrove organisms in the Botafogo estuary, Brazil, one of the most environmentally impacted estuaries in the country. The metal concentrations exceeded by up to 2.6-fold the geochemical background; 91%, 59%, 64%, 31%, and 82% of the soils were contaminated with Cr, Zn, Pb, Cu, and Ni, respectively. Adverse effects to the biota may occur due to Cr, Cu, Ni and Pb exposures. Contents of clay and organic matter were the main factors governing the distribution of metals in soil, contributing to up to 63% of the total variability. However, the geospatial modeling showed that the predictive ability of these variables varied spatially with the metal and location. The ecological and human health risks assessments indicated that the metal concentrations in soils are safe for the environment and human beings. There was a low transfer of metals from the soil to the biota, with values of sediment-biota accumulation factor (SBAF) and biological accumulation coefficients (BAC) lower than 1.0, except for Zn (SBAF = 13.1). The high Zn bioaccumulation by Crassostrea rhizophorae may be associated with the concentrations of Zn in the bioavailable fractions.

Storage and recycling of major and trace element in mangroves

The role of mangroves in sequestering metal and nutrients in sediment has been described in the past, but knowledge gaps still exist on storage capacity and recycling fluxes of elements in plant biomass, notably concerning their magnitude in root uptake and loss by litterfall. This study addresses the storage and transport pathways of 16 elements, classified as macro-nutrients (Ca, Mg, Na, K), micro-nutrients (Fe, Mn, Ni, Co, Cu, Cr, Zn, Mo), and potential toxicants (Al, Cd, Sn, Pb) in the world's largest mangroves, the Sundarbans. Elemental concentrations in plant organs were generally lower than in the sediment. The stock of macro and micro-nutrients in plant biomass varied from 60 to 2717 and 0.003 to 37.7 Mg ha^-1 respectively, with highest values observed for Na and lowest for Cd. The Avicennia species exhibited the maximal accumulation of all elements. Translocation of major elements to different plant organs increased with increasing their concentrations in the sediment. Elemental loss via litterfall indicated that Sundarbans mangrove could act as a source, particularly of Mn, to the Bay of Bengal. Moreover, belowground uptake of the 16 elements showed 2-3 fold higher fluxes than their loss via litterfall. There was a significant retention of some trace elements (notably Mo, Cd, and Sn) in plant biomass, which might allow one to use these mangroves for phytoremediation and restoration purposes. We conclude that mangroves efficiently store and remobilize major and trace elements from the sediments by root uptake and recycle back to sediment surface via litterfall.

Toxic metals distribution, seasonal variations and environmental risk assessment in surficial sediment and mangrove plants (A. marina), Gulf of Kachchh (India)

Toxic metal pollution in the coastal ecosystem is becoming a serious problem, particularly in developing countries as a result of the industrial revolution. In recent years, mangroves are continuously contaminating with toxic metals and receiving global attention due to its toxicity, non-degradability, abundance, subsequent bioaccumulation, and biomagnification through successive trophic levels. This study aims to investigate the toxic metal content and pollution status in mangroves surface sediment and plants. Results showed that toxic metals in sediments were higher than natural background levels indicate anthropogenic sources. Fe, Mn, Sb, Ti found higher in concentration among all toxic metals, and site 9, 15, 18, 19, 21, 31 found the highest total metal load. Contamination indices like enrichment and contamination factor, geo-accumulation index, suggest minimal to extremely high level of contamination, and sediments have found extremely contaminated with Sb and As. Contamination degree and modified contamination degree suggest very high degree of contamination at all sites. Pollution load index indicates significant deterioration of sediment quality. Ecological risk and potential ecological risk index also indicate about 72% of sites come under higher ecological risk. Toxic metal in Avicennia marina was found higher in root than leaf. High bioconcentration factor has observed for Pb, Cu, Mo, Zn. Translocation factor for Cu and Zn at all sites, and As, Ni, Pb, Fe, Sr, Mn at some sites indicate high-efficiency in plants for toxic metal translocation.

Modelling the dynamics of the cancer risk due to potentially toxic elements in agricultural soils, in the upper Crocodile River catchment, North-West province, South Africa

Contaminated agricultural soil with potentially toxic elements (PTEs) poses a threat to food safety and can adversely affect human health. This study evaluates the potential health risk caused by PTEs contamination in cultivated soils and the possible related health effect. Sixty-four (64) soil samples from cultivated soils before crop cultivation and post-crop were harvested and twenty-four (24) soil samples from a natural game reserve park were collected and. The PTEs were analysed using the inductively coupled plasma-mass spectrometry (ICP-MS) for the following elements As, Cd, Cr, Cu, Ni, Pb, Zn, Mn, Al, and Fe. The contamination factor (CF), pollution load index (PLI), hazard quotient (HQ), and hazard index (HI) was calculated to assess the human health risks for the different pathways to the exposed population. A carcinogenic probabilistic risk model based on the mathematical derivation and PTEs transmission pathways is presented. The mean concentrations of the PTEs in the cultivated soil varied in order of Al > Fe > Mn > Cr > Ni > Zn > Cu > Pb > As > Cd. Cr and Ni concentrations in all the cultivated soils were found to be higher than the Canadian guidelines and the Finnish permissible threshold guidelines for agricultural. The CF in the soil indicates extreme contamination suggestion an ecotoxicological effect. The PLI value also suggests that the soils have undergone some form of deterioration, particularly with Cr and Ni. The ingestion seems to be the major pathway followed by dermal to children. The HQ and HI values for the children were > 1 indicating an adverse health effect for the children residing around the cultivated fields. The simulated results indicate that the percentage of the affected humans that may be consuming crop derived from the contaminated soil increases by a factor of 2 as the contamination factor increases. The transmission compartments can be used as an effective measure in which mitigation can be effectively used.

Nitrogen and metal pollution in the southern Caspian Sea: a multiple approach to bioassessment

The Caspian Sea hosts areas of high ecological value as well as industrial, leisure, and agricultural activities that dump into the water body different kinds of pollutants. In this complex context, a proper description of the origin and potential sources of pollution is necessary to address management and mitigation actions aimed at preserving the quality of the water resource and the integrity of the ecosystems. Here, we aimed at detecting sources of both nitrogen inputs, by N stable isotope analysis of macroalgae, and metals in macroalgae and sediments in two highly anthropized coastal stretches at the Iranian side of the Caspian Sea. Sampling was done near the mouth of rivers and canals draining agricultural and urbanized areas. In the westernmost waters, facing a port city, low macroalgal δ¹⁵N signatures indicated industrial fertilizers as the principal source of pollution. By contrast, in the central coastal waters, facing touristic areas, the high macroalgal δ¹⁵N indicated N inputs from wastewaters. Here the lowest dissolved oxygen concentrations in waters were associated with excess dissolved inorganic nitrogen. Metal concentrations varied largely in the study areas and were lower in macroalgae than in sediments. Localized peaks of Pb and Zn in sediments were observed in the central coastal sites as probable byproducts of mining activity transported downstream. By contrast, Cr and Ni concentrations were high in all sampling sites, thus potentially representing hazardous elements for marine biota. Overall, macroalgal δ¹⁵N coupled with metal analysis in macroalgae and sediments was useful for identifying the main sources of pollution in these highly anthropized coastal areas. This double approach in comprehensive monitoring programs could thus effectively inform stakeholders on major environmental threats, allowing targeted management measures.

Soil contamination by potentially toxic elements and the associated human health risk in geo- and anthropogenic contaminated soils: A case study from the temperate region (Germany) and the arid region (Egypt)

The aim of this study was to assess the soil contamination caused by potentially toxic elements (Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, V, and Zn) using various indices and the associated risk of human health for adults and children in selected soils from Germany (Calcic Luvisols, Tidalic Fluvisols, Haplic Gleysols, and Eutric Fluvisols) and Egypt (Haplic Calcisols, Sodic Fluvisols, and Eutric Fluvisols). Soil contamination degree has been assessed using indices such as contamination factor (CF), pollution load index (PLI), geo-accumulation index (I_geo), and enrichment factor. We also assessed the health risk for children and for male and female adults. Chromium, Cu, As, Mo, Ni, Se, and Zn in the German Fluvisols had high CF of >6, while in the Egyptian Fluvisols Se, Mo, As, and Al revealed a high CF. The PLI (1.1-5.2) was higher than unity in most soils (except for Tidalic Fluvisols), while the most important contributor was Se, followed by Mo and As in the Egyptian Fluvisols, and by Cr, Cu, and Zn in the German Fluvisols. The median value of hazard index (HI) for children in the studied soils indicated an elevated health risk (higher than one), especially in the German Fluvisols (HI = 4.0-29.0) and in the Egyptian Fluvisols (HI = 2.2-5.2). For adults, median HIs in all soils were lower than unity for both males and females. The key contributor to HI was As in the whole soil profiles, accounting for about 59% of the total HIs in all three person groupings. Our findings show that in the studied multi-element contaminated soils the risk for children's health is higher than for adults; while mainly As (and Al, Cr, Cu, and Fe) contributed significantly to soil-derived health risk.

Selection of priority management of rivers by assessing heavy metal pollution and ecological risk of surface sediments

This study aimed to select rivers of priority management through the assessment of heavy metal pollution of sediments. We investigated the distribution characteristics of heavy metals in surface sediments of the Nakdong River in South Korea and used various pollution indices to assess pollution risk and identify factors influencing pollution. The kriging method was used to determine heavy metal distribution. The pollution load index, potential ecological risk index, mean PEL quotient, and the Canada Council of Ministers of the Environment sediment quality index were used as sediment pollution assessment methods. The toxicity evaluation was performed on sites that appeared to be contaminated, by applying existing methods for assessing sediment pollution level and the national standards for evaluating the pollution level. The toxicity test was performed on Hyalella azteca, and a methodology for assessing sediment pollution level was proposed. Ecotoxicity was assessed at seven sites that were found to have heavy metal contaminants. The results showed that sites N1, N8, T28, and T29 were not toxic, while T8, T19, and T21 were. Thus, this study shows that high heavy metal pollution does not necessarily lead to a toxic environment. To assess sediment pollution, an additional assessment of toxicity should be made, along with assessments of existing sediment pollution. Our results demonstrate that streams showing high sediment pollution levels should be granted priority in management. The efforts should particularly focus on Cu at T8, Cr at T19, and Hg at T21.

Quantitative assessment of exposure of heavy metals in groundwater and soil on human health in Reasi district, Jammu and Kashmir

The assessment of heavy metal contents in environmental sectors is important to estimate the carcinogenic and non-carcinogenic doses and risks for the mankind associated with it. The present work deals with the assessment of the risk exposure related to heavy metal contents in groundwater and soil samples to two different age groups via three different transits, i.e., ingestion, inhalation and dermal. The concentrations of heavy metals (Zn, Cd, Cu, Pb and Cr) were measured in the villages of lower Himalayas of Reasi district by using microwave plasma atomic emission spectrometer. The calculated mean contamination factors of heavy metals in soil samples were as: Zn, 0.73; Cu, 0.70; Pb, 0.74; and Cr, 0.33; which led to pollution load index less than unity. The overall carcinogenic risks have been varied from 6.4E-08 to 5.1E-07 in soil samples and from 7.3E-06 to 1.1E-04 in ground water samples and were found to be well within the range prescribed by USEPA (Screening level ecological risk assessment protocol for hazardous waste combustion facilities, appendix E: toxicity reference values, US Environmental Protection Agency, Washington, D.C., 1999). The mean values of heavy metal contents except lead and chromium in water samples were found to be less than the values prescribed by various agencies. Geo-accumulation Index showed that Pb contribute to the highest contamination (0 < I_geo < 1) among the other heavy metals. Cluster analysis and principal component analysis identified that Zn, Cu, Pb and Cr had a relationship and the presence of these heavy metals could be related to vehicle emissions, traffic sources and industrial sources. The overall mean values of the non-carcinogenic doses and associated hazard risks in soil and water samples calculated for children were found to be higher than the adults which may be due to hand to mouth activities.

Trace metals contamination in different compartments of the Sundarbans mangrove: A review

This review study aimed to decipher distribution of trace metals (Al, As, Cd, Cr, Cu, Hg, Pb, Ni, Mn, V, and Zn) in different compartments and human health risk in the Sundarbans mangrove ecosystems. The literature suggested relatively higher contamination of soils and sediments than fish, crustaceans, and water. Cd, Fe, Ni, and Pb are most likely to accumulate in roots of mangrove trees, while Al, As, Co, Cr, Cu, Mn, and Zn tend to accumulate in the leaves. According to human health risk studies, fish consumption is the main route of trace metals exposure to human. Majority of the studies conducted in the Indian Sundarbans; whereas, in Bangladesh part, there is an evident lack of such kind of studies. Finally, this review highlights the foremost data and research gaps, which will help to refine the risk of trace metals and scarcity of researches in the Sundarbans mangrove ecosystem.

Sediment quality, elemental bioaccumulation and antimicrobial properties of mangroves of Indian Sundarban

Mangroves have wide applications in traditional medicines due to their several therapeutic properties. Potentially toxic elements (PTEs), in mangrove habitats, need serious concern because of their toxicity, bioaccumulation capacity and ecotoxicological risks. In the current study, we aimed to examine sediment quality and bioaccumulation of PTEs in a mangrove-dominated habitat of Sundarban, India, and their relation with antimicrobial property of ten mangrove species of the region. Antimicrobial activity of different solvent fractions of mangrove leaves was assessed against seven microorganisms. The highest antimicrobial activity was detected in ethyl acetate and acetone-extracted fractions of Avicennia alba. Various sediment quality indices revealed progressively deteriorating nature of surface sediment having moderate contamination, however, low ecotoxicological risk. The accumulation factors (AF) for different PTEs indicate a gradual metal bioaccumulation in leaf tissue. Antimicrobial activities indicated both positive and negative correlations with manganese (Mn), copper (Cu), iron (Fe) and zinc (Zn) concentrations of mangrove species. Concentration of Mn showed a significant correlation with almost all the fractions, whereas Cu had correlation with ethyl acetate, acetone and methanol fractions (P < 0.05). The AF of Mn and Cu exhibited correlation with antimicrobial activities of acetone and methanol fractions, whereas Fe and Zn had correlation with hexane and ethyl acetate fractions. Overall, Mn, Fe, Cu and Zn concentrations of Acanthus ilicifolius and Avicennia alba leaves and in the surface sediments demonstrated the strongest association (P < 0.05) with their antimicrobial activity as also depicted in correlation and cluster analysis studies. Thus, this study will help to establish a link between the PTEs in mangrove ecosystem with their bioactivity.