Heavy Metal Concentrations In Sediments Research Articles

Evaluation of Heavy Metal Concentration in Sediments of Rupingazi River, Kenya

Heavy metal concentration (Cu, Zn, Fe, Mn, Ni) was evaluated in sediment samples of Rupingazi river during the wet and dry seasons. In this study, the sediment samples were collected from twenty sampling points along the river. The heavy metal levels were evaluated using Atomic Absorption Spectrphotometer.The obtained data was analyzed using one-way analysis of variance. The range of the concentration of copper was found to be 4.68- 12.69 mg/kg for the wet season and 0.98-24.10mg/kg for the dry season. The mean values of the concentration of iron was found to be 1422-6145.33 mg/kg for the wet season and 1254-5866.67 mg/kg for the dry season. The range of the concentration of Nickel was found to be 0.72- 30.73 mg/kg for the wet season and 2.63-12.48 mg/kg for the dry season. Concentration of manganese was found to be 48.03-411.20 mg/kg for the wet season and 6.15-248.35 mg/kg for the dry season Zinc concentration was found to be 26.29-167.10 mg/kg for the wet season and 4.82-28.39 mg/kg for the dry season. The Zinc, Manganese, Nickel Iron and Copper levels were not beyond the USEPA recommended limits.

Contamination, fraction, and source apportionment of heavy metals in sediment of an industrialized urban river in China

In this study, we conducted an analysis of the heavy metal concentrations, health risk assessment, fraction and source interpretation in surface and core sediments from main stream of the Pearl River and Pearl River Estuary (RRE) area. Results showed that the higher deposited heavy metal concentrations in sediments occur at the Pearl River. The concentrations of heavy metals in surface sediments from the studied locations are in a descending order: Zn > Cr > Cu > Ni > Pb > Cd. Regarding chemical fractions, Cd showed the highest proportion of acid soluble fraction (F1) among all studied heavy metals. The high mobility of Cd poses a significant threat to water bodies and the surrounding environment. The potential ecological risk index (RI) showed the Pearl River sediments exhibited significantly higher values than the estuary sediments. Cd was found to be the primary contributor to potential ecological risk, accounting for 74% of RI. The health risk assessment showed the total hazard index (HI) for child was exceeded 1 mainly driven by Zn, indicating that the child population was at risk of non-carcinogenic effects. Besides, unacceptable carcinogenic risk in both Pearl River and estuary area were observed for children. The positive matrix factorization (PMF) model was used to ascertain sources of six heavy metals and apportion their contributions in sediments. The results showed that the source contributions of natural, industrial, and mixed sources from coal combustion and traffic emissions accounted for 39.81%, 34.10%, 26.10%.

A Microcosm Analysis of Species-Specific Responses of Chironomidae on Heavy Metal Pollution in The Nyanza Gulf of Lake Victoria

The Chironomidae family, known as "non-biting midges" in their adult stage and "bloodworms" in their larval stage, consists of diverse dipteran insects inhabiting various global aquatic environments. Despite extensive global research, data on Chironomidae in the polluted Nyanza Gulf of Lake Victoria, Kenya, is scarce, and molecular identification methods have not been explored. This study aimed to quantify heavy metal concentrations in water, sediment, and insect samples and assess their impact on Chironomid species identified using mitochondrial DNA barcoding of the cytochrome oxidase subunit 1 (COI) gene. Analysis of Variance was used to determine if there were any statistically significant differences in heavy metal concentrations across different sample types or locations along the pollution gradient. Chironomids were collected from Nyanza Gulf, focusing on a pollution gradient. Results showed that concentrations of arsenic (As), lead (Pb), and cadmium (Cd) in insect, water, and sediment samples exceeded standard limits, while mercury (Hg) concentrations were within limits. Significant variations (p ≤ 0.05) in Pb levels were observed in water samples, and heavy metal concentrations in sediment samples varied significantly (p ≤ 0.05), with Pb showing the highest variation (p ≤ 0.0001). Insect samples exhibited significant differences (p ≤ 0.0001) in As and Hg contents. Genetic analysis identified two known species: Chironomus transvaalensis at the heavily polluted Kisumu station and Chironomus pseudothummi at the moderately polluted Kendu Bay and Homa Bay stations. Additionally, a unique Chironomus species was found on Ndere Island, a relatively clean site with restricted human activities. Sequence comparisons indicated proximity to global data but also highlighted the evolutionary significance and uniqueness of the identified species. This study demonstrated the potential use of genetic methods in determining Chironomid species diversity, community structure, and abundance in relation to heavy metal concentration. It suggests that heavy metal pollution may act as a selective pressure, driving the evolution of Chironomid species. The study recommends combining genetic approaches with other pollution sources for a comprehensive understanding of using this species in monitoring pollution

Co-occurrence of polycyclic aromatic hydrocarbons and heavy metals in various environmental matrices of a chronic petroleum polluted region in Iran; Pollution characterization, and assessment of ecological and human health risks

Oil spills from pipeline accidents can result in long-lasting health effect in the people living in a ‎polluted region‎. In this study, the level of the 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs‎) and heavy metals (HMs) have been ‎analyzed in environmental matrices of a region with frequent oil ‎pipeline accidents in Iran‎.‎ The results showed that the mean ‎concentration of ΣPAHs and ΣHMs decreased from the upstream to the downstream and also the levels were ‎higher in the wet season than those in the dry season. The average concentration of HMs in sediments was higher than that in other ‎environments. The 3-ring and 4-ring PAHs were dominant in all of the studied matrices with the average values of 32.61 % and 45.85 %, respectively. The ecological risks of PAHs and HMs were medium and high in all matrices, respectively. In wet season, the total cancer risk (TCR) related to PAHs in agricultural soil was greater than 10−4, whereas it’s very close to the threshold for HMs in water. This study offers a reference for assessing the long-term impact of oil spills in contaminated environmental matrices. The results are crucial for developing effective strategies to mitigate oil pollution ‎impacts and protect environmental and public health.

Heavy metals concentration in sediment and their bioaccumulation in several organisms in Benoa Bay and Lembongan Island, Bali, Indonesia

Abstract. Putri PYA, Rastina, Prartono T, Ismet MS. 2024. Heavy metals concentration in sediment and their bioaccumulation in several organisms in Benoa Bay and Lembongan Island, Bali, Indonesia. Biodiversitas 25: 3230-3238. Human activities could be responsible for introducing heavy metals into coastal areas, and it can contaminate coastal waters such as the tourism area of Benoa Bay and coastal ecosystems of Lembongan Island, Bali, Indonesia. This study aimed to assess the extent of heavy metals on the sediment of those area and their accumulation rate in several marine organisms, including macro-algae (Ulva sp.), seagrass (Thalassia hemprichii), and sea urchin (Diadema sp.). Samples of surface sediments and marine organisms were collected at six stations for both areas and the presence of five heavy metals (Fe, Pb, Cd, Cu, and Cr) was determined using the AAS method. The concentration those metals varied significantly across the six stations. The geo-accumulation index showed that the sediment has been contaminated by Pb and Cd. The ecological risk of heavy metals contamination in Benoa Bay was apparently higher compared to that in Lembongan Island. Marine organisms in Benoa Bay also significantly accumulated heavy metals than those observed in Lembongan Island. Bioconcentration factor (BCF) shows that Cd, Cr, and Pb were the most accumulated heavy metals in marine organisms (BCF>1). It, therefore, suggest that future studies of the bioavailability of heavy metals and exploration the varying capacities of marine organisms are required. Such important information can be used to predict the accumulation of heavy metals in human bodies, and the possibly daily consumption of marine organisms caught from Benoa Bay and Lembongan Island waters.

Contaminant and Assessment of Heavy Metals in Maninjau Lake, West Sumatera, Indonesia

Purpose: Water is an important fundamental resource to support human, animal and plant life. Global reports highlight widespread contamination of water sources due to various human activities. The high level of anthropogenic activity in the Lake Maninjau area, both in agriculture, animal husbandry and settlements, has an impact on decreasing the quality of the lake as indicated by the quality of the sediment and lake water. The research aims to evaluate heavy metal concentrations in sediments and heavy metal processing strategies. Theoretical Framework: Lake Maninjau is one of the lakes in Indonesia that experiences pollution. Recently, this lake has become one of the priority lakes to reduce high levels of pollution (Ministry of the Environment, 2011). The source of Lake Maninjau pollution comes from floating net cages, agriculture, settlements and livestock. This is shown by the accumulation of heavy metals in waters and sediments which is important information for the survival of fish, humans, plants, microorganisms and other aquatic ecosystems (Wibowo et al. , 2022a). Method: The five distinct sample locations were chosen to represent various activities within the Maninjau Lake region, as outlined in Figure 1 and Table 1. Sediment was taken at the surface at a depth of 0-10 cm. samples were processed and analyzed at the P3IN soil science laboratory, Andalas University, as well as assessing sediment quality through Geoaccumulation (Igeo), enrichment factor (EF), pollutant load index (PLI), contamination factor (CF), and potential ecological risk (PER) in five location of Lake Maninjau. Results and Discussion: The results of the research showed that Cu concentrations varied from 0.195 mg/kg to 0.290 mg/kg, with a moderate average of 0.246 mg/kg. Pb metal ranges between 0.325 mg/kg-0.412 mg/kg, with an average of 0.356 mg/kg. Cd metal 0.301 mg/kg- 0.365 mg/kg. The Igeo values for the metals Cr, Cd, Pb, and Cu at the five locations show Igeo < 0, meaning they are not contaminated with heavy metals. The Potential Ecological Risk Index (PER) ranges from 14.8303-19.0094, which shows the low potential ecological risk related to heavy metal pollution Research Implications: It is hoped that this research can help stakeholders in managing the Maninjau Lake ecosystem against potential heavy metal contamination that threatens the lake ecosystem Originality/Value: The use of combination or hybrid technologies to treat heavy metals from wastewater is an effective solution, but it is important to carefully consider and mitigate potential negative impacts on the environment and human health.

Ecotoxicity of trace metal enrichment and the degrees of contaminated sediment and water from Riparian communities in Rivers State, Nigeria

This study assessed trace metal enrichment and contamination levels in Tema, Sangama, and Degema communities in Rivers State, Nigeria. Samples were collected monthly from October 2021 to April 2022. Trace metals such as Pb, Cu, Fe, Cd, Zn, and As were analysed using an Atomic Absorption Spectrophotometer (AAS). The contamination factor, degree of contamination and enrichment factor for trace metals were used to evaluate the impact of pollution levels. There was a descending order of heavy metal concentrations in water at the three stations: Fe > Cu > Zn > Cd > Pb. Sediment heavy metal concentrations were descending from Fe > Zn > Cu > Pb > Cd at the same stations. Heavy metal levels were consistently higher at Sangama. The result revealed that compared to Pb and Zn, Cd contamination was moderate to considerable. Fe contamination was relatively low, but Cu contamination was moderate to high. Water and sediment were contaminated to varying degrees. The contamination levels of Pb, Zn, and Cu were low to moderate. Sangama, Tema, and Degema all had varying degrees of contamination, with some areas having higher contamination levels. This study recommends the need for effective environmental management practices in these coastal marine wetlands.

Characterization of heavy metal contamination in wetland sediments of Bosten lake and evaluation of potential ecological risk, China

In November 2023, twenty-two sediment samples were collected from the Bosten Lake wetland in Xinjiang to determine the concentrations of eight heavy metals: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). This data was used to assess heavy metal contamination and potential ecological risks in the sediments using the Pollution Load Index (PLI) and the Potential Ecological Risk Index (RI). Additionally, multivariate statistical analysis and Positive Matrix Factorization (PMF) were employed to elucidate potential sources and their contributions to contamination. The following are the main conclusions: (1) average concentrations of Zn, Cd, Cr, Pb, and Hg in the sediments surpassed Xinjiang soil background levels by factors of 1.01, 3.58, 1.32, 1.94, and 1.53, respectively. (2) Sediments demonstrated severe pollution with Cd, slight pollution with Zn, Cr, Pb, and Hg, while Cu and Ni indicated mild pollution and As showed non-polluted levels. The overall PLI average (1.01) suggested slight contamination. (3) The descending order of average single ecological risk values were Cd, Hg, Pb, Cu, Ni, Cr, As, and Zn, with a comprehensive RI averaging at 184.07, signaling a moderate ecological risk. (4) Source apportionment revealed that Zn, Cu, Pb, and Ni were influenced by transportation and household waste emissions, while Cr and As were dictated by natural background levels. Hg predominately originated from fossil fuel combustion and Cd from agricultural activities. (5) Mixed sources accounted for the following percentage contributions to sediment heavy metal content: transportation and domestic waste (30.41%), natural background (25.88%), fossil fuel combustion (22.40%), and agricultural activities (21.31%). With anthropogenic inputs exceeding those of natural origins, it is imperative to prioritize the management of Cd, Hg, and Pb as primary pollutants within the region.

Characteristics and correlation analysis of heavy metal distribution in China's freshwater aquaculture pond sediments

The concentration of heavy metals (HMs) in aquaculture pond sediments significantly affects aquatic food safety and environmental quality. The contamination characteristics, drivers and potential sources of HMs in typical bulk freshwater aquaculture pond sediments in major provinces of China were systematically investigated using a variety of methods and models. Specifically, 130 surface sediment samples were collected from the study area, and the geoaccumulation index (Igeo) and potential ecological risk index (RI) were used to jointly evaluate the characteristics of the HMs. Spearman's correlation and redundancy analysis revealed the main drivers of the HMs. Additionally, the positive matrix factorization (PMF) model and absolute principal component score-multiple linear regression (APCS-MLR) model were used to identify the sources of HMs. The results revealed that the pond sediments were safe for fish culture in most of the study areas. Aquafeed protein content is an important driver of HM concentrations in sediments. The total organic carbon (TOC) content, percentage of clay particles, and pH of the aquaculture pond sediments determined the sediment HMs enrichment abilities as 13.6 %, 52 %, and 9.8 %, respectively. Cd, a significantly enriched pollutant, posed a greater ecological risk than the other five HMs (Cr, Cu, Zn, As, and Pb). Three sources of HMs were identified, including agricultural activity (e.g., aquafeeds, pesticides, and fertilizers), industrial production, and natural sources, with contributions of 44.29 %, 36.66 %, and 19.05 %, respectively. This study provides a scientific basis for minimizing the input and accumulation of HMs in freshwater aquaculture pond sediments, and this can provide insights into the prevention and control of the ecological risks posed by HMs.

HEAVY METALS ASSESSMENT AND ASSOCIATED POTENTIAL HEALTH RISK OF BUILDING SEDIMENT DEPOSITION IN OKPARE CREEK, NIGERIA

Heavy metals concentrations in sediments may pose significant threats to human health and well-being of the general ecosystem. Therefore, it's crucial to conduct a thoughtful assessment of sediment characteristics with regards to heavy metal concentration as a raw material for building in the studied area. Twenty sediment samples were collected (five each fromlocalities) and analysed using atomic absorption spectrophotometer (AAS). The highest concentrations of Zn, Cu, Cd, Cr, Pb, V, Fe and Ni were 6.33, 2.65, 0.45, 1,201, 0.38, 0.00, 1026.39 and 0.65 mg/kg respectively in each of the four localities. The results exceeded both recommended limit and other scientist report of similar environment. Also, the health risk impacts computed were all higher than limits. These high values may be attributed tothe nature of the area geological formation, application of fertilizer to the farmlands and petroleum exploration and production activities. Cd stood out as the main culprit for potential ecological risks. The average contamination level, as indicated by I-geo values ranging from 0.28 to 0.79 mg/kg, raisedconcerns, especially at locality 1. Across the board, I-geo values remained generally low (< 2). Cd and Pb, with an I-geo value of about 1, significantly impacted sediment pollution. Average EF values were from 0.02 to 5.76 which revealed that human activities heavily influenced the sediment, marking them as significantly enriched with observed heavy metals. In particular, Cd played a major role in the sediment's enrichment, indicating a high level of environmental impact.

Analysis of four heavy metal concentrations in sediments from the Jiaozhou Bay, China by visible and near infrared spectroscopy (225–975 nm)

As an important component ofbiogeochemical cyclein coastal ecosystems, sediments are the sink of heavy metals. Therefore, distribution and dynamics of heavy metals in sediments could assess ecological quality and predict ecological risks. In the new era, rapid and green technology are highly needed, especially that could determine multi-parameters simultaneously. Here, we explored a new method to rapidly determine concentrations of heavy metals in sediments by visible and near infrared reflectance spectroscopy (VIRS).We sampled sediments in the Jiaozhou Bay, China, collected their reflectance spectra, and measured concentrations of four heavy metals (As, Cr, Cu, and Zn). Heavy metal models were established and evaluated using substances highly correlated with heavy metals. This study provides an effective reference for rapid analysis of As, Cr, Cu, and Zn simultaneously in sediments, at least in the Jiaozhou Bay, and for ecological environment protection and resource development of the Jiaozhou Bay.

Health and ecological risk assessment of heavy metals in water and sediments within a data scarce urban catchment in Tanzania – A case of Ngerengere River, Morogoro Municipality

Low-, middle- and high-income countries, exhibit indications of risks associated with water quality. The study investigated heavy metal concentrations in surface water and sediments within the Ngerengere River and its tributaries (Kikundi, Bigwa, and Morogoro) drain within in the Morogoro Municipality of Tanzania, an Urban Catchment Area (UCA) with limited available data mainly because of inadequate monitoring and reporting capabilities. Analysis of health and ecological risks associated with heavy metal pollution was also carried out using health risk assessments models, pollution indices, and multivariate analysis techniques. Between the dry and wet seasons of 2023, water and sediment samples from (13) sampling stations strategically established along the Ngerengere river and its tributaries were analyzed for six heavy metals (Pb, Cr, Ni, Cd, Cu and Zn) using the Atomic Absorption Spectrophotometer Model Perking Elmer 850 Graphite Furnace and Perking Elmer AS 800 Auto-sampler coupled with a computer interface for operational, displaying and reading the results. The calculated degree of water contamination (Cd) values in river water in both dry and wet seasons ranged from 0 to 6.803 indicating low and high degrees of contamination respectively. Heavy metal concentration in sediment decreases in the order of Zn>Ni>Cr>Cu>Cd>Pb. The non-cancer risk index (HI) via ingestion and dermal pathways in dry and wet seasons for both children and adult groups was <1 hence no non-cancer risk, However, cumulative dermal and ingestion exposure in both children and adults indicated potential cancer risk in dry and wet season. The analysis of ecological risks associated with heavy metal enrichment in the sediment indicated high enrichment of sediments with Cd, Ni and Zn. Conclusively, in wet months, risk indices tend to be low, while in dry months, they typically remain high.

Preliminary Study of pH, EC, TDS, and Heavy Metals Analysis of Oxbow’s Sediments in Bandung Region

The Oxbow Lake is a vital part of river and it usually used for household, agricultural, and fisheries needs. The oxbow lake faces pollution risks from human activities. This study aims to assess the quality of water and sediment by pH, EC, and TDS of water and sediment as well as heavy metal content in sediment. The results show that the environmental conditions of the oxbow lakes around the Upper Citarum River are generally good because they fall within the safe limits for hygiene and sanitation standards, except for Babakan Patrol Oxbow Lake and Sapan Oxbow Lake. Unfortunately, the heavy metal levels in samples O1-2, O4-2, and O7-1 exceed sediment quality guidelines. These measurements indicate evidence of anthropogenic influence on sediment samples.

Neurological risks arising from the bioaccumulation of heavy metal contaminants: A focus on mercury.

This study investigated the concentrations of heavy metals in the water sources of the upstream region of the Huangpu River, the Yangtze River Estuary, and various areas in Shanghai, as well as the heavy metal concentrations in the blood of Shanghai residents. It aimed to analyze the heavy metal elements absorbed by the human body and the resulting pathological effects. The results revealed that surface water primarily contains five heavy metals: copper (Cu), lead (Pb), zinc (Zn), arsenic (As), and mercury (Hg), while water sediments primarily contain seven heavy metals: Cu, cadmium (Cd), Pb, chromium (Cr), Zn, As, and Hg. The main heavy metals present in the human body are Pb, Hg, As, and Cd. By reviewing previous articles, it was found that heavy metal concentrations in human blood are higher than those in surface water, suggesting uncertainties in the heavy metal content of surface water and its tendency to settle at the bottom. Furthermore, a comparison of heavy metal content in sediments revealed that Hg is the most readily absorbed heavy metal by the human body and is also a toxic environmental pollutant. Within the cell, Hg is highly toxic to mitochondria and may cause oxidative stress and neurodegenerative disease. This study concludes that water sediments serve as the major source of pollution in the human body and pose significant health risks, thereby necessitating the implementation of effective preventive measures.

Risk assessment of Cr, As, and Sb to aquatic communities at the water-sediment interface in the lower Yellow River, China, integrated with the Diffusive Gradients in Thin‐films technique

The dynamic concentrations of labile metals/metalloids, measured by the Diffusive Gradients in Thin-films (DGT) technique, can be used for evaluating the toxicity risk of heavy metals to aquatic organisms in sediments. In this study, the different potential risks of the three sediment compartments, overlying water (W), sediment- water interface (SWI) and sediment (S) were independently assessed by studying the concentrations of Cr, As, and Sb in the sediment and water from the lower Yellow River. Total concentrations of these elements and bioavailable concentrations, using DGTs, were explored and probabilistic risk assessment (PRA) based on a Monte Carlo model was performed. The results show that the total heavy metal concentrations in sediment and overlying water were spatially variable due to influences of natural geography and sediment distribution. The trace elements mean concentrations using DGT were 1.68, 1.69 and 0.73 μg·L−1 for Cr, 0.61, 0.51 and 0.39 μg·L−1 for As, and 0.78, 1.16, and 0.41 μg·L−1 for Sb in W, SWI and S, respectively. Among them, the DGT-labile concentration of As displayed a large spatial variability, indicating a close association with anthropogenic activities. The risk quotient (RQ) categories for single heavy metal toxicity demonstrated to be moderate risk for Cr and almost no risk for As and Sb. The combined biotoxicity probability assessment of the three heavy metals showed that they would cause almost no harmful effects to benthic organisms in the whole ecosystem of the Yellow River.

Health risk assessment of heavy metals in wild fish and seasonal variation and source identification of heavy metals in sediments: a case study of typical urban river in Xi'an, China.

In order to determine the status of heavy metal pollution in river sediments and wild fish in Xi'an, concentrations of heavy metals (Cr, Ni, Cu, Zn, As, and Pb) were collected and analyzed in sediments and wild fish during dry season (October-November 2020) and wet season (June-July 2021). This study aimed to investigate the spatial and temporal variations of heavy metals in urban rivers of Xi'an, China. Their distribution characteristics and sources as well their pollution levels and health risks were assessed. The findings revealed that influenced by human activities, the heavy metal content in sediments (mg·kg-1 dry weight) in wet season was ranked as follows: Cr (73.09) > Zn (63.73) > Pb (40.31) > Ni (31.52) > Cu (24.86) > As (6.83); in the dry season: Zn (94.07) > Cr (69.59) > Cu (34.24) > Ni (33.60) > Pb (32.87) > As (7.60). Moreover, 32 fish samples from six species indicated an average metal content trend (mg·kg-1 wet weight) of Zn (8.70) > Cr (0.57) > Pb (0.28) > Ni (0.27) > Cu (0.24) > As (0.05). The potential ecological risk indices for sediment heavy metal concentrations in both seasons were well below the thresholds, which indicates that the aquatic environment is in safe level. The analysis of the potential ecological risk of sediment heavy metal concentrations indicates that the aquatic environment is safe for the time being. Based on the estimated daily intake (EDI), target risk quotient (THQ), total target risk quotient (TTHQ), cancer risk (CR), total cancer risk (TCR), and the permissible safety limits set by the agencies, the consumption of the fish examined is safe for human health. However, the presence of Cr and As in wild fish should still be a concern for human health, especially for children. The cumulative effect of heavy metals and the bioconcentration factor (BCF) suggest that sediment and heavy metals in fish are closely related, with higher concentrations in fish living in the bottom layer of the water column than in other water layers, and increasing with increasing predator levels. Correlation analysis and PMF modeling identified and determined four comparable categories of potential sources, namely, (1) atmospheric deposition and traffic sources, (2) agricultural sources, (3) industrial sources, and (4) natural sources.

Assessing the Seasonal Variability of Water Quality and Heavy Metals Concentration in Sediment, Water, and Fish Muscles of Korotoa River in Bangladesh

Assessing the Seasonal Variability of Water Quality and Heavy Metals Concentration in Sediment, Water, and Fish Muscles of Korotoa River in Bangladesh

Predictions of heavy metal concentrations by physiochemical water quality parameters in coastal areas of Yangtze river estuary

Due to the degradation-resistant and strong toxicity, heavy metals pose a serious threat to the safety of water environment and aquatic ecology. Rapid acquisition and prediction of heavy metal concentrations are of paramount importance for water resource management and environmental preservation. In this study, heavy metal concentrations (Cr, Ni, Cu, Pb, Zn, Cd) and physicochemical parameters of water quality including Temperature (Temp), pH, Oxygen redox potential (ORP), Dissolved oxygen (DO), Electrical conductivity (EC), Electrical resistivity (RES), Total dissolved solids (TDS), Salinity (SAL), Cyanobacteria (BGA-PE), and turbidity (NTU) were measured at seven stations in the Yangtze river estuary. Principal Component Analysis (PCA) and Spearman correlation analysis were employed to analyze the main factors and sources of heavy metals. Results of PCA revealed that the main sources of Cr, Ni, Zn, and Cd were steel industry wastewater, domestic and industrial sewage, whereas shipping and vessel emissions were typically considered sources of Pb and Cu. Spearman correlation analysis identified Temp, pH, ORP, EC, RES, TDS, and SAL as the key physicochemical parameters of water quality, exhibiting the strongest correlation with heavy metal concentrations in sediment and water samples. Based on these results, multiple linear regression as well as non-linear models (SVM and RF) were constructed for predicting heavy metal concentrations. The results showed that the results of the nonlinear model were more suitable for predicting the concentrations of most heavy metals than the linear model, with average R values of the SVM test set and RF test set being 0.83 and 0.90. The RF model showed better applicability for simulating the concentration of heavy metals along the Yangtze river estuary. It was demonstrated that non-linear research methods provided efficient and accurate predictions of heavy metal concentrations in a simple and rapid manner, thereby offering decision-making support for watershed managers.

Assessment of some heavy metal content in sediments of a mangrove swamp, niger delta, nigeria using applicable ecological risk indices

Sediments can act as pollutant sinks and a source of pollution in aquatic environments. The surface sediments of the Isaka–Bundu tidal swamp, Niger Delta was assessed for heavy metal content using standard methods and assessment indices. The study was carried out in three stations between January and June 2022. Five heavy metals (lead, copper, cadmium, nickel and zinc) were evaluated while eight assessment indices (Contamination Factor - CF, degree of contamination - DC, Ecological Risk - Er, Potential Ecological Risk - PERI, Pollution Load Index - PLI, Enrichment Factor - EF, Geo-accumulation Index - Igeo and Quantification of Contamination -QoC) were applied. Results showed that cadmium and copper exceeded permissible limits while lead, zinc and nickel were within limits. Stations 1 and 3 recorded significantly higher values indicating anthropogenic influence. The dominant anthropogenic activities observed in the area include maritime and dockyard activities and artisanal crude oil refinery. The assessment indices showed that the sediments were at various levels of heavy metal pollution mainly influenced by copper and cadmium viz: CF: Cu (considerable degree) and Cd (very high degree), DC (very high degree), Er: Cd (high ecological risk) and Cu (very high ecological risk), PERI (significant high ecological risk), PLI (very high level pollution), EF: Pb, Zn, Cu (Station 1) and all Cd (extremely high enrichment), Igeo: Cd (extremely polluted) and QoC: Cu and Cd (anthropogenic source). The sediments were highly polluted with toxic metals, which is detrimental to humans and aquatic biota.Keywords: Heavy metal; Indices; Mangrove; Niger Delta; Sediment.

Assessment of heavy metal concentrations in water and sediments at Motor Park and new bridge areas, lower River Benue, Ibi, Taraba, Nigeria

Heavy metals concentration in water and sediment was investigated at the Motor Park Area and New Bridge Site of lower River Benue, Ibi, Taraba State. The heavy metals levels were examined using atomic absorption spectrophotometer (AAS) Buck Scientific model 210 VGP using spectrophotometry techniques. The highest mean concentration of Zn recorded in the sediment at the Motor Park Area was 0.55 mg/kg while the lowest value of 0.004 mg/kg was recorded for Cr at the Motor Park Area. The highest mean concentration of Mn recorded in the water was 0.375 mg/l at New Bridge Site while the lowest value of 0.00 mg/l was recorded for Cu. Values for Cu, Cd, Cr. Cu were generally low throughout the study period. There was no significant difference (p>0.005) in Zn concentrations in sediment at the sampled locations (Motor Park Area and New Bridge Site) throughout the study periods. However, Cr, Cd and Pb show variations (p<0.005) at the sampled locations. The concentration of Mn (0.375 mg/l) was not significantly different (p>0.05) from Mn (0.325 mg/l) in water between the two location, Pb value (0.343 mg/l) of water in December at the New Bridge Site exceeded the WHO recommended safe limit. However, all other metals were within the WHO and FMENV safe limit for portable drinking water. Since Pb value (0.343 mg/l) exceeded the WHO and FMENV safe limit for December. It shows that there is need for continuous monitoring of Lower River Benue waters at Ibi, Taraba State.