Accumulation Of Heavy Metals In Sediments Research Articles

Heavy Metal Accumulation in Sediments of a Non-Perennial River in South India: Implications for Ecology and Human Health – A Multi-Index and Statistical Assessment

ABSTRACT The present study assessed the heavy metal pollution in sediment samples collected from the Noyyal River basin (river and lake sediments) during the monsoon and summer seasons. The geo-accumulation index (Igeo) categorizes metals as extremely polluted during monsoon and heavily contaminated to extremely contaminated during summer. The enrichment factor (EF) of metals Mn during monsoon and Cd during summer indicates extremely severe enrichment (EF > 50) and Mo exhibited very high contamination (CF > 6) throughout the basin during monsoon. The average risk index of heavy metal in the basin followed the order Cd (164.15) > Ni (14.82) > Co (4.84) > Cr (2.55) > Cu (1.89) > Zn (1.38) > Mn (0.40) during monsoon and Cd (153.07) > Ni (7.96) > Cu (5.13) > Co (4.63) > Cr (1.89) > Zn (1.21) > Mn (0.3) during summer showing that the PERI of each element was minimal except for Cd. Adverse health-related effects are confirmed by the cumulative total hazard index (THI) for children with HQ ingestion and HI values >1 in all sample locations over both seasons. Principal component and cluster analysis show metals accumulate in sediments mainly through industrial wastewater discharge and also experience significant natural source weathering through rainfall runoff. This research emphasizes the need for enhanced wastewater treatment facilities in metropolitan areas situated along the Noyyal River to potentially reduce the release of heavy metals from both domestic and industrial sources.

The Effects of Cobalt Mining on Water Quality and the Dispersion of Contaminants in the Environment

Cobalt mining, essential for various technological advancements including battery production and electronics, has raised significant environmental concerns due to its potential impact on water quality and the release of contaminants into the surrounding ecosystems. This study aims to assess the repercussions of cobalt mining activities on water bodies and the fate of associated contaminants within the environment.Through a comprehensive literature review and field investigations, this research examines the mechanisms by which cobalt extraction processes, including open-pit mining and leaching techniques, contribute to water contamination. The study evaluates the release of heavy metals such as cobalt, nickel, copper, and arsenic, along with the formation of acid mine drainage (AMD), resulting from sulfide mineral exposure during mining operations. Furthermore, this investigation delves into the persistence and behavior of contaminants released during cobalt mining. It explores the long-term implications of heavy metal accumulation in sediments, soils, and biota, emphasizing the potential for biomagnification and ecological disruption within aquatic ecosystems.Human health concerns related to waterborne contaminants originating from cobalt mining activities are also addressed in this study, highlighting the risks associated with the consumption of contaminated water by local communities.The research findings underscore the necessity for robust environmental regulations, sustainable mining practices, effective waste management strategies, and remediation efforts to mitigate the adverse impacts of cobalt mining on water quality and environmental health. Furthermore, the study emphasizes the importance of continued monitoring and research to better understand the full extent of the problem and develop targeted solutions to safeguard water resources and ecosystems affected by cobalt mining. Keywords: Cobalt mining, Water contamination, Heavy metals, Acid mine drainage (AMD), Environmental impacts, Water quality degradation, Contaminants in mining, Aquatic ecosystems

Ecological risk assessment of heavy metals in riverine sediments of rural area driven by urbanization.

Rural revitalization denotes the gathering of large populations in rural areas and the subsequent gradual urbanization. Rural environments have been deteriorated by heavy metals (HMs) over the last few years. Without the existence of large-scale industries, the accumulation of HMs in sediments due to population aggregation in rural environments needs to be scientifically confirmed. Therefore, in this study we first understand the sediment pollution in rural environments in China and across the globe, and subsequently investigate HMs in sediments in rural micro water. The study area, Sichuan Province, China, was divided into two areas, namely, sparsely populated areas (SPA) and densely populated areas (DPA). Eight typical HMs (As, Zn, Ni, Hg, Cd, Cr, Cu, and Pb) were selected to target in riverine sediments, and the content and spatial distribution characteristics were analyzed. The results indicate that As, Hg, Cd, and Pb concentrations in sediments were higher than background values (BVs), with high concentration sample sites located in the DPA. In addition, the geo-accumulation index (Igeo), pollution load index (PLI) and potential ecological risk index (RI) were used to quantitatively evaluate the pollution characteristics of HMs in sediments, revealing that the sediments exhibited high As and Hg pollution in the DPA (PLI = 1.09). In general, mild (RI = 48.76) and moderate (RI = 154.92) HM pollution was observed in the sediments of the SPA and DPA, respectively, based on the high PLI (> 1.0) and RI (> 150) values. Correlation analysis and principal component analysis (PCA) indicate that the Cd in the sediment generally originated from geogenic sources, while the other elements (Zn, As, Cu, Cr, Hg, Ni and Pb) were primarily linked to anthropogenic sources. Finally, the results demonstrate that population aggregation will lead to the enrichment of HMs.

Heavy Metal Accumulation in Sediments of Small Retention Reservoirs—Ecological Risk and the Impact of Humic Substances Distribution

Anthropogenic pollutants that accumulate in bottom sediments may pose a serious threat to the aquatic environment and humans. The aim of the study was to determine the ecological risk related to the contamination of sediment with heavy metals and the relationship between the accumulation of heavy metals and various granulometric fractions and humic substances in the bottom sediments of small retention reservoirs located in catchments of varying anthropopressure. The research objects were five small dam reservoirs located in south-eastern Poland. The sediments of the reservoir exposed to the greatest anthropopressure from the catchment area posed a serious threat to aquatic organisms feeding at the bottom. The bottom sediments of the remaining reservoirs showed a low level of potential toxicity (or non-toxicity). The observed relationship between the enrichment of sediments with organic matter (OM) and the increased risk of their ecotoxic impact on aquatic organisms was determined by excessive exposure to heavy metal contamination. The sand content did not appear to have a clear effect on the metal accumulation, although it was associated with enrichment in OM. Due to diverse environmental conditions, it was not possible to unequivocally confirm that the accumulation of heavy metals in the sediments of small retention reservoirs directly depends on the content of organic matter and humic substances, but such relationships were observed in most of the objects.

Heavy Metals in Sediments and Greater Flamingo Tissues from a Protected Saline Wetland in Central Spain

Aquatic ecosystems often act as sinks for agricultural, industrial, and urban wastes. Among potential pollutants, heavy metals can modify major biogeochemical cycles by affecting microorganisms and other biota. This study assessed the distribution and concentration of heavy metals (Cd, Hg, Cu, Pb, and Zn) in Pétrola Lake, a heavily impacted area in central Spain where the greater flamingo Phoenicopterus roseus breeds. This study was designed to determine the concentration and identify the potential sources of heavy metals in Pétrola Lake protected area, including sediments, agricultural soils, and tissues of the greater flamingo. A six-step sequential extraction was performed to fractionate Cu, Pb, and Zn from lake sediments and agricultural soil samples to gain insight into different levels of their bioavailability. Our results showed that Pb and Cd accumulated in lake sediments and agricultural soils, respectively, most likely derived from anthropogenic sources. Multivariate analysis revealed differences between these (Pb and Cd) and the remaining studied elements (Cu, Hg, and Zn), whose concentrations were all below the pollution threshold. Lead pollution in sediments was apparently dominated by organic matter binding, with fractions up to 34.6% in lake sediments. Cadmium slightly accumulated in agricultural soils, possibly associated with the use of fertilizers, but still below the pollution thresholds. In the flamingo samples, low bioaccumulation was observed for all the studied elements. Our study suggests that human activities have an impact on heavy metal accumulation in sediments and soils, despite being below the pollution levels.

The impact assessment of desalination plant discharges on heavy metal pollution in the coastal sediments of the Persian Gulf

In recent decades the development of desalination plants (DPs) for desalination of seawater has increased dramatically, while little attention has been paid to the effects of this activity on the accumulation of heavy metals (HMs) in the sediments of affected ecosystems. The present study was implemented to evaluate (1) heavy metal accumulation in sediments impacted by DPs discharges, (2) spatial and temporal changes of HMs and the contamination degree by different types of pollution indexes (single and integrated indices), and (3) ecological risk assessment of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) in sediments affected by DPs discharges. A total of 288 sediment samples were collected seasonally at 24 stations from November 2019 to October 2020. Analysis of HMs concentrations in sediments near the desalination plant discharge provided evidence of local contamination. Maximum concentration of Cu and Pb elements were found in sediments near the desalination plant discharge point. Hierarchical cluster analysis revealed clear segregation of stations impacted by desalination plant discharges and away from discharges. The values of PLI index in sediments of all sampling stations were < 1, indicating that there was no metal pollution by this index. The potential ecological risk index (PERI) ranged from 5.33 ± 0.51 to 11.81 ± 4.98 in sampling sediments and were classified as “low potential ecological risk”. These results demonstrate that the DPs discharge increased HMs concentrations in the sediments in close proximity to outlets. The necessary and practical regulations and policies regarding the rejection of the DPs discharge and disposal of chemical compounds must be implemented and enforced.

Assessment of heavy metal contamination within the sediments in some fresh water lakes of Udaipur

Heavy metal concentrations were assessed in sediment samples collected from three lakes of Udaipur, Rajasthan. The aim of the present investigation was to compare the lakes for season wise addition of pollution load. The assessment of heavy metals was done using Contamination factor (CF), Geo accumulation index (Igeo) and Pollution load index (PLI). In summer CF varied from 0.01 to 7.43 i.e low to very high but in winter season all three lakes represented high CF factor. Likewise Igeo index in the sediments for summer ranged between 0.41 to 14.48 mg/kg i.e uncontaminated to moderate to heavy to extreme levels in sediments of lakes and trends were of the order Mn>Zn>Pb>Ni>Cu>Cd. In winter Igeo index ranged between 1.34 to 19.3 mg/kg which is uncontaminated to extreme contamination in bottom sediments and trends were of the order Mn>Zn>Pb>Ni>Cu>Cd. Pollution load index in winter season represented high value i.e more than 1 in both Dudh Talai and Udai Sagar Lake. The proposed study suggested that heavy metal accumulation in sediments during winter was higher than summer season. This has a very significant relevance where the contaminated sediments have one of the most challenging pollution issues owning to the toxicity persistence and bioaccumulation issues of food web.

Heavy metals concentration in mangrove tissues and associated sediments and seawater from the north coast of Persian Gulf, Iran: Ecological and health risk assessment

We evaluated the concentration of copper (Cu), zinc (Zn), mercury (Hg), nickel (Ni), chromium (Cr), vanadium (V), and cobalt (Co) in the mangrove tissues (leaf and root) and adjusted sediments, as well as seawater samples in the north coast of the Persian Gulf from three counties (Mahshahr, Bord Khun, Asaluyeh). Assaluyeh and Mahshahr were selected because of their proximity to the oil and petrochemical industries and Bord Khun was considered for being away from pollution sources. The metal detected in highest concentration in mangrove leaves and roots was Cu (Asaluyeh: 1.507 μg/g and 1.198 μg/g, Bord Khun: 1.812 and 1.756 μg/g, and Mahshahr: 0.880 and 1.617 μg/g, for leaves and roots, respectively). For sediments, Cr (among the metals) had the highest concentration (1.325 μg/g) in Asaluyeh, whereas in Bord Khun and Mahshahr Ni was predominant: 2.542 and 2.237 μg/g, respectively. For seawater, Cu was the most abundant metal and Hg was the one with the lowest concentration. The bio-concentration factor for Zn and Cu revealed that mangroves in the study areas have suitable potential for phytoremediation of these two metals. Translocation factors from the roots to leaves also indicated higher transportability for Zn and Cu through the plant tissues, compared to the other metals. Ecological indexes quantified the contamination of sediments and revealed a low level of heavy metal accumulation in sediments of the north of the Persian Gulf. Human risk hazards appeared low in all the areas under study. Gas and petrochemical activities can be considered as a potential source of the discharge of heavy metals into the aquatic environment.

Heavy metal accumulation and potential ecological risk assessment in sediments from the southwestern Konya district (Turkey)

It is aimed to determine the heavy metal concentrations and sources accumulated in the sediments of the creeks in the region as a result of geological factors and to be a reference study before the mining exploration and operation activities to be carried out in and around the study area located in the southwestern Konya district of Turkey. Chemical analyses were carried out on 24 rock samples representing the geological characteristics of the region and 8 stream sediment samples taken from important creeks. Chemical analysis results were evaluated using basic statistical methods and pollution indices. As, Pb, Zn, and Mn concentrations were determined as “unpolluted to moderately polluted” according to the geoaccumulation index. According to the contamination factor, the accumulations for As, Pb, Zn, Mn, Fe, and Al concentrations were determined as a “moderate factor.” It is determined as “low risk” according to the potential ecological risk index. Heavy metals in the region were ranked from the lowest risk to the highest as Ni <Cr <Zn <Mn <Hg <Cu <Pb <Cd <As. The accumulation of heavy metal around the creek deposits is related to the geological processes and climatic events. It is understood that heavy metal deposits in the region are formed due to geological factors, and geological factors have an important role in heavy metal accumulation in the sediments of the creeks.

Ecological and Human Health Risk Assessment of Sediments near to Industrialized Areas along Langat River, Selangor, Malaysia

ABSTRACT Rapid industrialization at Kuala Langat, Selangor have raised environmental and health concerns among the public. Surface sediments from a total of 10 stations, covering the upstream and downstream sites near to plastic recycling factories along Langat River were collected and analyzed for its physicochemical properties, bioavailable heavy metals concentration and pollution degree. Ecological risk assessment of heavy metals was carried out using several pollution indices such as geoaccumulation index (), contamination factor (CF), contamination degree (CD), enrichment factor (EF), pollution load index (PLI) and potential ecological risk index (PERI). For human health risk assessment, non-carcinogenic risk of heavy metals (Cd, Cr, Cu, Pb and Zn) was assessed using hazard quotient (HQ) and hazard index (HI) whereas carcinogenic risk of heavy metals (Cd, Cr and Pb) was assessed using carcinogenic risk index (RI) and total risk (TR). The heavy metal accumulation in sediments in terms of concentration was in the order of Pb > Zn > Cu > Cr > Cd and the mean concentration of the heavy metals were lower than the background value except Pb. The PLI result indicated that the sediment at Langat River was unpolluted but posed low ecological risk by Cr, Cu and Zn, low to moderate ecological risk by Cd, and low to considerable ecological risk by Pb as shown by PERI result. However, non-dietary ingestion of sediment from Langat River showed possible risk of non-carcinogenic effects at certain sites whereas tolerable carcinogenic risk at almost all sites. Organic matter, silt, clay, pH and base saturation showed significant relationship with the heavy metals concentration, indicating the transformation and accumulation factor of heavy metals in river sediment. This study is important to increase the awareness of sediment pollution at Langat River and provide information to the stakeholders in Kuala Langat for future planning and policies to protect the local ecosystem and residents.

The human impacts level and migration of heavy metals in original inshore sediments of Dongying, China

Largely uncontrolled exogenous heavy metals (HMs) are released into the sea which eventually deposit in the original inshore sediments. However, the migration of these HMs was commonly overlooked in previous studies, which makes it hard to determine the fate of these HMs and locate the high-risk HMs pollution areas. Therefore, the original inshore areas in Dongying, China were taken as an example, and eight HMs (As, Cd, Cr, Cu, Hg, Pb and Zn) in sediments and multiple geochemical indexes relevant to the properties of sediments were determined to clarify the level of human impacts on the aggregation of HMs and uncover the migration of HMs from nearshore to offshore. The obtained results suggested relatively low pollution of HMs based on the values of EF and Eri. Due to the intense marine erosion, HMs in the sediments mainly stem from the natural deposition, but are less affected by human activities. Mariculture is widespread but fails to exert its impact on the accumulation of HMs in sediments, mainly due to just the phosphorus, instead of the organic matters, which aggregate effectively. More exogenous HMs are moved from nearshore to offshore so that the offshore rather than nearshore is more susceptible to human activities, confirmed by the higher concentration and EF of HMs in the offshore areas. The migration of HMs may be more related to the altered minerals than the composition of grain size in sediments. The conversion of hydrodynamic conditions induced by runoff reduction may transport more altered minerals along with HMs to a farther area of sea and threaten the broader area of sea.

Spatial distribution, fractions and risk assessment of five heavy metals in the sediments of Jialing River: a tributary of the Yangtze

Jialing River is one of the largest tributaries of the Yangtze River and the tributary with the most extensive drainage area among all the tributaries. In recent years, it has suffered severe heavy metal pollution. To study the spatial distribution, sediment fractions, sources and risks posed by Cd, Hg, Cu, Pb and Zn downstream of the Jialing River, 10 sampling sites were selected along the river, we collected surface sediments (0–5 cm), and we measured total concentrations of these five typical heavy metals. The results showed that in the study region, heavy metal pollution was more serious in the downstream areas than in the upstream region. Cd and Hg were found to be the most serious pollutants in the study region, at 2- to fivefold and 2- to fourfold higher than background values, respectively. We found significant correlations between the individual metals, indicating that their sources were similar. A high correlation coefficient was observed between sediments and riverbank soils, indicating that heavy metal accumulation in sediments was primarily the result of erosion. Potential ecological risk assessment ranked the severity of pollution for these metals as Cd > Hg > Cu > Pb > Zn. The average contribution rates of Cd and Hg were 49.42% and 43.41%, respectively, with 40% of the sites reaching a considerable ecological risk level. The concentrations of Cd, Zn and Pb present in the exchangeable (F1) and reducing (F2) fraction were > 50% of total concentration. This finding indicated a strong potential for release into the aquatic ecosystem. Special attention should be paid attention to discharges of Cd and Hg, and strategies should be developed to prevent further Cd and Hg pollution in the downstream reaches of the Jialing River.

Statistical modeling the effect of sediment physicochemical properties on the concentration of heavy metal (case study: Musa Creek, SW Iran)

Heavy metal accumulation in sediments is important even at low levels due to their irresolvable character and harmful effects. Therefore, contamination of creeks, especially their sediments, is highly important for scientific communities. This study investigates the relationship between heavy metal accumulation and some physicochemical parameters of sediments (pH, EC, calcium carbonate, texture, specific gravity, density, porosity and percentage of organic matter) in a stretch of Musa Creek beaches. The results showed that the studied sediments are extremely salty and have slight variations in terms of pH. Although there are mostly clay-sized sediments in the studied area, their mineralogical composition contains calcite with smaller amounts of dolomite, aragonite and halite minerals. The correlation between each of the parameters and heavy metal concentration was modeled using OLS regression. Cr, Ni, Zn and Pb concentrations are positively correlated with each other and inversely correlated with Cd. The accumulation of heavy metals is directly related to parameters such as EC, organic matter, clay and silt, specific gravity and porosity; it is negatively related to calcium carbonate, sand and density parameters. Owing to slight variations, the pH parameter lacks any significant correlation with heavy metal concentrations.

A Study of Heavy Metal Accumulation in Sediments at Phuket Bay, Saphan Hin, Phuket Province

A Study of Heavy Metal Accumulation in Sediments at Phuket Bay, Saphan Hin, Phuket Province

Spatial patterns of heavy metal accumulation in sediments and macrophytes of Bellandur wetland, Bangalore

Heavy metals are one among the toxic chemicals and accumulation in sediments and plants has been posing serious health impacts. Wetlands aid as kidneys of the landscape and help in remediation through uptake of nutrients, heavy metals and other contaminants. The analyses of macrophytes and sediment samples help in evaluating pollution status in aquatic environment. In this study concentration of six heavy metals (Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb) and Zinc (Zn)) were assessed in sediment and dominant macrophyte samples collected from Bellandur Lake, largest Lake of Bangalore, India. Sediment samples reveal of heavy metals in the inlet regions and shore samples. The accumulation of metals in sediments were in the order of Zn > Cu > Cr > Pb > Ni > Cd. All metals exceeded the critical limits of metals in the sediment. Concentration of different metals in the macrophyte samples ranked as: Cr > Cu > Zn > Pb > Ni > Cd. Chromium and Copper were found to be more than critical range. Typha angustata had the higher accumulation of all metals except chromium.

Kinetics and Equilibrium Studies of Cu(II) Ions Adsorption from Aqueous Solutions and Kalpani River on TP260H, SK112H and DMSCH

Cu2+ adsorption on the Amberlite Lewatit MDS TP260 (TP260H), DIAIONTM SK112 (SK112H), DOWEX™ MARATHON™ MSC (DMSCH) were studied in a batch mode, as a function of pH (3-9), agitation time and different initial concentration ranges (25-120 mg/L and 160-240 mg/L) were studied at a constant temperature of 20°C. The sorption of Cu2+ increases with the increase in concentration and pH of the solution. However, the Cu2+ sorption decreases when pH>5 which may not only due to the decrease in the active surface sites because of the formation of Cu(OH)2 but also due to the surface alteration. The data is found to fit both the Freundlich, Dubinin-Radushkevich and Langmuir equations. Cu2+ adsorption followed the pseudo-second order kinetics for all the resins. The Freundlich, Dubinin-Radushkevich and Langmuir constants, calculated from the sorption of Cu2+ on resins were presented and demonstrated the practical utility in the removal of the Cu+2 ions from water, synthetic wastewater and river of kalpani. In water Cu+2 was highest followed by Cd and Ni while Cr, Pb and Zn were not detected in water. Whereas the heavy metal accumulation in sediments was in the order of Cu>Zn>Cr>Ni>Pb>Cd. Cu+2 ions. Sediments and water did not exceed WHO guidelines. Resins used to remove Cu+2 ions may remove other heavy metals as well. Sorption of Cu+2 ions in these resins and intraparticle diffusion was the key rate limiting step.

Flow of heavy metals (Ni and Cu) in the catchment area of a subarctic lake

This paper considers methodological approaches to estimating the flow, balance, and accumulation of heavy metals (HMs) in a lake under conditions of long-term air pollution. Using the example of Chunozero Lake in the Lapland State Biospheric Reserve in Murmansk region, the accumulation of HMs in sediments is estimated for over a 70-year period of activity of a metallurgical mining enterprise (GMK Severonikel). The thickness of polluted sediments in a greater part of the lake water area averages 2 cm, and the average sedimentation rate for the last 20 years is 1 mm/year. Metals accumulated in lake sediments can indicate a danger of pollution in the future, particularly if processes of lake eutrophication develop. Due to the peculiar properties of substance flow to the Chunozero, the running type of water-mass movement, and the elongated form of the lake, only about 3% of HMs that enter the catchment area accumulate in sediments, in contrast to Imandra Lake (which has the largest area), where the accumulation of HMs reaches 55% owing to the fact that they enter mainly in the composition of wastewater and the low velocities of water flow.

Factors contributing to heavy metal accumulation in sediments and in the intertidal mussel Perna perna in the Gulf of Annaba (Algeria)

This paper presents the results of a seasonal survey of heavy metals accumulated in sediments and in the soft parts of the body of the mussel Perna perna at four stations in the Gulf of Annaba (Algeria). Pooled soft tissues from 10 mussels representing the entire range of sizes were digested in nitric acid. Statistical analysis reveals a significant seasonal effect on all the measured metals, the highest values being recorded in winter. With the exception of Cr, the levels for all metals were significantly higher in the east, at the outlet of the Seybouse River, than at all other monitoring stations. The study also shows that north-western waters are subject to a significantly lower degree of heavy metal pollution than elsewhere in the gulf. Levels were nevertheless within the limits of public health standards.The results confirm the usefulness of P. perna as a bioindicator for heavy metal pollution.

Historical records of heavy metal accumulation in sediments and the relationship with agricultural intensification in the Yangtze–Huaihe region, China

The extensive use of fertilizers on farmlands during the past several decades in China has led to a rapid deterioration of environmental water quality in recent years. An agricultural watershed with high-yield grain production and characterized by multipond systems in the Yangtze–Huaihe region of China was selected to establish the historic records of heavy metal pollution by 137Cs-dated sediment cores. The experimental results indicated that the contents of most of the heavy metals investigated, such as Cd, Cr, Cu, Ni, Pb, and Zn, continuously increased in the multipond sediments throughout the past three decades. An inflection point appeared in the 1980s, prior to which all heavy metal contents showed little or no increase with time. Thereafter, the heavy metal contents increased dramatically due to the extensive application of phosphate fertilizers. The mean Cd content in 1980 was 0.13 μg/g which increased rapidly to 0.33 μg/g in 2004, but prior to 1980, the level was only 0.08 μg/g. Similar trends were also found for other heavy metals. The enrichment factor (EF) values indicated that Cd was not only the most anthropogenic metal in the multipond sediments but also aggravated anthropogenic impacts on the watershed environment during the past two decades. The high proportion of chemical reactive forms of Cd (10%–30%) implied a moderately high ecological risk. Our results clearly reveal that the extensive use of fertilizers has resulted in significant heavy metal pollution in this watershed, which threatens the water quality of the watershed and downstream water bodies.