Distribution and Pollution Assessment of Critical Nutrients and Heavy Metals in the Sediments of Loktak Lake, a Ramsar Site in the Indo‐Myanmar Hotspot Region of Manipur Valley (India)

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.

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

The biogeochemical cycle of mercury will be influenced by climate change, particularly at higher latitudes. Investigations of historical mercury accumulation in lake sediments inform future predictions as to how climate change might affect mercury biogeochemistry; however, in regions with a paucity of data, such as the thermokarst-rich Arctic Coastal Plain of Alaska (ACP), the trajectory of mercury accumulation in lake sediments is particularly uncertain. Sediment cores from three thermokarst lakes on the ACP were analyzed to understand changes in, and drivers of, Hg accumulation over the past ~ 100 years. Mercury accumulation in two of the three lakes was variable and high over the past century (91.96 and 78.6 µg/m2/year), and largely controlled by sedimentation rate. Mercury accumulation in the third lake was lower (14.2 µg/m2/year), more temporally uniform, and was more strongly related to sediment Hg concentration than sedimentation rate. Sediment mercury concentrations were quantitatively related to measures of sediment composition and VRS-inferred chlorophyll a, and sedimentation rates were related to various catchment characteristics. These results were compared to data from 37 previously studied Arctic and Alaskan lakes. Results from the meta-analysis indicate that thermokarst lakes have significantly higher and more variable Hg accumulation rates than non-thermokarst lakes, suggesting that certain properties (e.g., thermal erosion, thaw slumping, low hydraulic conductivity) likely make lakes prone to high and variable Hg accumulation rates. Differences and high variability in Hg accumulation among high latitude lakes highlight the complexity of predicting future climate-related change impacts on mercury cycling in these environments.

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.

Depth-related dynamics of physicochemical characteristics and heavy metal accumulation in mangrove sediment and plant: Acanthus ilicifolius as a potential phytoextractor

The presence of heavy metals in rivers in the Niger Delta region has become a source of concern due to its associated health challenges. The present study was conducted to assess the risk of heavy metal accumulation in surface sediments obtained from creeks and dredged tributaries of the River Ethiope, Delta State, South-South, Nigeria. Heavy metals in the sediments were extracted using the three-step sequential extraction method of the European Commission Standard Measurement and Testing Program. The heavy metals; magnesium (Mn), iron (Fe), zinc (Zn), lead (Pb), copper (Cu), cobalt (Co), arsenic (As), chromium (Cr), cadmium (Cd) and barium (Ba) were quantified by employing inductively coupled plasma-mass spectrometry (ICP-MS). Assessment of the extent of sediment contamination was carried out by determining the contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), ecological risk factor (Er), potential ecological risk index (PI) and geo accumulation index (1 geo). Pearson’s correlation coefficient and principal component analysis (PCA) were used to determine the sources and the relationship between pollutants across sediments. The values of heavy metals ranged from 12.5 mg kg–1–116 mg kg–1 and 21.6 mg kg–1–71.1 mg kg–1 in the wet and dry seasons, respectively. The trend of heavy metals for risk index (RI) in this study is Cd &gt; Pb &gt; Cr &gt; Co &gt; Zn &gt; Cu &gt; Mn (wet season) and Cu &gt; Cd &gt; Pb &gt; Zn &gt; Cr &gt; Mn &gt; Co = As (dry season). It showed that heavy metal pollution was a result of Cd for extreme contamination, while moderate to high contamination levels were due to Pb and Cu. The Pearson’s correlation coefficient analysis and PCA displayed strong positive loadings for Mn, Fe, Zn, Pb, Cu and Cd across seasons as a result of high contamination levels in the study sites. The pollution load index revealed that the sediments were polluted by the metals, and the mean and median analyses revealed that the metals datasets were normally distributed, except for Cu with an irregular distribution.

The lake systems of the Qinghai–Tibet Plateau, while serving as vital hubs for socioeconomic development, have become critical zones of heavy metal contamination, posing severe threats to the fragile “Third Pole” ecosystem and regional environmental security. This study investigated the concentration, distribution, sources, and ecological risks of eight heavy metals (As, Cd, Co, Cr, Cu, Ni, Pb, and Zn) in lake sediments and riparian soils of Bangong Co Lake, a remote alpine lake on the Qinghai–Tibet Plateau. Lake sediment and soil samples were collected and tested from various shoreline types, including natural and human-affected areas. The Pollution Load Index (PLI) was applied to assess contamination levels, and source apportionment was performed using principal component analysis (PCA) combined with the Absolute Principal Component Score–Multiple Linear Regression (APCS-MLR) receptor model. Results revealed that heavy metal concentrations were generally higher in soils than in sediments. Compared to regional background values, elevated levels of most heavy metals were observed in human-affected shores, while natural-type soils exhibited higher concentrations of Co, Cr, Ni, and As. In sediments, only Cd and As were notably elevated in human-affected areas. The PLI results indicated that most sampling sites were either uncontaminated or slightly contaminated, with higher pollution levels occurring primarily in human-affected shoreline zones. Source apportionment demonstrated that heavy metals in sediments were predominantly derived from natural sources such as rock weathering, with anthropogenic contributions being relatively limited. In contrast, soils exhibited significant anthropogenic influences, with industrial, transportation, and agricultural activities contributing substantially to Cu (53.27%), Pb (58.64%), Zn (57.98%), Cd (34.09%), and As (39.87%). The research underscores the differential impacts of human activities on heavy metal accumulation in sediments and soils of high-altitude lake systems. It offers valuable baseline data for monitoring and managing heavy metal pollution in ecologically sensitive alpine regions.

Assessment of long-term effects from cage culture practices on heavy metal accumulation in sediment and fish

Long-term fertilization increases heavy metals accumulation in topsoil but not in deeper layers of red soil sloping farmland.

The main objective of this paper is to evaluate how a choice of different background values may affect assessing the anthropogenic heavy metal pollution in sediments from Tisza River (Serbia). The second objective of this paper is to underline significance of using geochemical background values when establishing quality criteria for sediment. Enrichment factor(EF), geoaccumulation index (I geo), pollution load index(PLI), and potential ecological risk index (PERI)were calculated using different background values. Three geochemical (average metal concentrations in continental crust, average metal concentrations in shale, and average metal concentrations in non-contaminated core sediment samples) and two statistical methods (delineation method and principal component analyses) were used for calculating background values. It can be concluded that obtained information of pollution status can be more dependent on the use of background values than the index/factor chosen. The best option to assess the potential river sediment contamination is to compare obtained concentrations of analyzed elements with concentrations of mineralogically and texturally comparable, uncontaminated core sediment samples. Geochemical background values should be taken into account when establishing quality criteria for soils, sediments, and waters. Due to complexity of the local lithology, it is recommended that environmental monitoring and assessment include selection of an appropriate background values to gain understanding of the geochemistry and potential source of pollution in a given environment.

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.

Metal contamination from upstream river water is a threat to coastal and estuarine ecosystem. The present study was undertaken to unveil sedimentation processes and patterns of heavy metal deposition along the salinity gradient of a tropical estuary and its mangrove ecosystem. Sediment columns from three representative sites of differential salinity, anthropogenic interference, and sediment deposition pattern were sampled and analyzed for grain size distribution and metal concentrations as a function of depth. Sediments were dominantly of silty-medium sand texture. A suite of fluvial and alluvial processes, and marine depositional forcing control the sediment deposition and associated heavy metal loading in this estuary. The depth profile revealed a gradual increase in heavy metal accumulation in recent top layer sediments and smaller fractions (silt + clay), irrespective of tidal regimes. Alluvial processes and long tidal retention favor accumulation of heavy metals. Enrichment factor (0.52-15), geo-accumulation index (1.4-5.8), and average pollution load index (PLI = 2.0) indicated moderate to higher heavy metal contamination status of this estuary. This study showed that alluvial processes acted as dominant drivers for the accumulation of metals in sediments, which prevailed over the influence of marine processes. Longer tidal retention of the water column favored more accumulation of heavy metals. Metal accumulation in the sediments entails a potential risk of bioaccumulation and biomagnification through the food web, and may increasingly impact estuarine ecology, economy, and ultimately human health.

Assessment of heavy metal pollution and human health risk along the Southeast coast of India: A comprehensive ecotoxicological study.

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

Organic arsenical herbicides, which include monosodium methylarsonate (MSMA), have been applied to golf courses and lawns throughout Florida, USA, since the 1950s. These products convert rapidly to inorganic forms of arsenic (As) in soils and are mobilized readily. Leachates have been known to contaminate groundwater and surface waters, although past studies have not examined whether use of these products has led to significant As accumulation in lake sediments. We used paleolimnological methods to document the depositional history and inventories of total As in sediments and porewaters of Little Lake Jackson in Florida, which is adjacent to three golf courses. Six sediment cores, four of which were 210Pb dated, showed porewater total As concentrations as high as 435 μg l−1, and dry-sediment total As concentrations as high as 148 mg kg−1. Approximately 537 kg of total As is present in >19,000 metric tons of sediment (dry mass), and an additional 18 kg of As is dissolved in 10.8 × 104 m3 of porewaters. Total As content in surface sediments (mean = 47.3 mg kg−1) exceeds the consensus-based sedimentary concentration for probable toxicity effects in freshwater benthic fauna. Surface and subsurface waters flow to the lake from topographically higher areas to the west, where golf courses and residential areas are located. Total As concentrations were elevated highly in monitoring wells and in a stream that flows between the golf courses and lake, but As was below detection limits in wells that were located at the distal perimeter of the golf courses. Subsurface and surface waters exit the lake towards topographically lower areas to the east. Nearly all As in sediments remains bound in the solid phase, indicating that As sedimentary profiles largely reflect depositional history. Sedimentary As concentrations are correlated strongly with aluminum and iron, which suggests that As was scavenged from lake waters during the past. Sedimentary As concentrations increased until the 1980s, then declined somewhat to the present time. Dissolved As was scavenged efficiently from the water column when hypolimnetic waters were oxygenated persistently, but after eutrophication led to a seasonally anoxic hypolimnion in the 1980s, apparently less As was co-precipitated, and more was lost to hydrological outflow. Arsenic accumulation in sediments might be common in areas where As derived from organic arsenical herbicide applications is directed by shallow water tables towards adjacent lakes.