Anthropogenic Heavy Metals Research Articles

Anthropogenic activities affect the diverse autotrophic communities of coastal sediments

Coastal sediments are a critical domain for carbon sequestration and are profoundly impacted by human activities. Therefore, it is essential to understand the structure and components of benthic autotrophs that play a crucial role in carbon sequestration processes, as well as the influence of anthropogenic activities on their communities. This study utilized an urban estuary, an industrial sea bay, a maricultural sea region, and two mangrove coastlines within the coastal areas of Guangdong Province, China. The micro-benthos in these environments, including prokaryotes and eukaryotes, were identified through high-throughput sequencing of 16S rRNA and 18S rRNA genes. The findings show that the autotrophic composition was altered by the interactions of anthropogenic heavy metals (Cd and Zn) and micro-eukaryotes (protazoa, metazoa, and parasitic organisms). Industrial pollution reduced the abundance of both prokaryotic and eukaryotic autotrophs. Mangroves induced a substantial transformation in the sediment eukaryotic and prokaryotic composition, increasing the proportion of autotrophs, notably sulfur-oxidizing and iron-oxidizing bacteria and microalgae. This alteration suggests an increase in specific sulfur and iron cycling with simultaneous carbon sequestration within mangrove sediments. These results indicate that anthropogenic activities affect sediment carbon sequestration by altering autotrophic assemblages along coastlines, thereby inducing consequential shifts in overall elemental cycling processes.

Isotopic evidence of autochthonous organic matter acting as a major sink of anthropogenic heavy metals in modern lacustrine sediments

The knowledge of major sources, sinks, and the burial fate of various pollutants added to modern aquatic ecosystems under changing environmental conditions is limited but crucial for our sustainability. In this context, the spatial distributions and causative factors of organic matter (OM) and heavy metal accumulations have been explored in modern lacustrine sediments of a large urbanized and protected wetland (ULB: Upper Lake Bhopal) in Central India. For this purpose, geochemical properties, in particular, stable isotopes (δ13C and δ15N) were measured in the ULB surficial sediments (core depth ∼0–1 cm; n = 19), and additionally collected riverbed sediments (n = 2) and atmospheric free-fall dust samples (n = 3) from the lake periphery. The major and trace element data indicate widespread mafic sediment provenance and nearly dysoxic lacustrine conditions. The riverine supply of soil OM from cropped lands and the lake productivity (algae, largely sustained by nutrients from sewage and agricultural runoff) are the major OM sources to the western and eastern lake portions, respectively. The fractional contribution from autochthonous TOC (∼0.19–0.95, mean ∼0.62) predominates that of allochthonous TOC (∼0.05–0.81, mean ∼0.38). Whereas, atmospheric dust deposition is a primary anthropogenic source of heavy metals (Pb and Zn). The lake productivity rather than soil OM or any mineral sorbent is found responsible for the anthropogenic enrichments of Pb and Zn in the ULB surficial sediments, especially on the eastern ULB portion under high anthropogenic pressure. Therefore, the settled OM (primarily autochthonous) being oxidizable acts as a temporary but major sink of anthropogenic heavy metals in modern lacustrine sediments, which are vulnerable to heavy metal efflux to the water column by sediment diagenesis.

Statistical analysis and water quality modeling towards holistic health assessment of Himalayan and peninsular rivers of India

Water occurs naturally in a variety of forms. Liquid water is present in rivers, lakes, the ground, the sea, and precipitation. The primary objective of water quality monitoring is to ascertain whether the water quality being observed is appropriate for its designated purposes. An investigation was undertaken to assess the concentration levels of various water quality parameters, including total hardness, electric conductivity, temperature, Ca, Cl, K, Mg, Na, SO4, and HCO3. The research assessed the physicochemical parameters of ten (10) rivers, including the following: Brahmaputra (Arunachal Pradesh); Barak (Assam); Godavari (Maharastra); Brahmani (Odisha); Sabarmati (Gujarat); Tapi (Gujarat); Mahi (Gujarat); and Ganga (Uttar Pradesh). Water samples were obtained from the aforementioned rivers spanning the years 2013 to 2020. Descriptive Analysis, one-way ANOVA, Covariance, and Correlation were utilized to examine the impact of the rate of change on the interrelationships among the parameters. At the current level, the Narmada River cannot meet the daily demands that arise during and after the monsoon. The primary sources of pollution were inputs from households, businesses, and agriculture. The Gang River portions have been poisoned by sewerages, untreated industrial discharges, and chemical surges from agricultural fields. The basin is still being impacted by a number of anthropogenic pressures associated with an expanding human population, such as changes in land use, elevated water pollution, increased water demand, river channelization, and the Brahmanputra River's regulating flow. Anthropogenic heavy metals Cu, Cd, Cr, Pb, and Ni have not been shown to exhibit seasonal changes; however, geogenic heavy metals Mn, Fe, Mg, and Ca have been recorded to undergo seasonal oscillations in the Barak River and Still. The alkaline impacts of the Godavari water sample on the river are shown by the physical-chemical analysis of the samples. The amount of dissolved oxygen has decreased at various sites when pollutants are added to the water. A rise in BOD and turbidity levels is a result of the introduction of contaminants at different sites. The tests of TDS and F-coli showed an increase in value because of the sewage and burial procedures. Reduced flows below the dam and sudden increases resulted in a significant loss of organisms due to water discharge for hydropower generation. The Krishna River lost several of its characteristic characteristics as a result of dams being built both upstream and downstream. The Brahmani River's summertime dissolved oxygen (DO) levels are found to vary from 6.16 to 7.81 mg/L. The Brahman River's water quality index varied from 36.7 to 44.1, which is considered excellent water quality. Huge public awareness, strong implementing environmental policy decisions are some of the potential solutions to increase the health conditions of the Himalayan and Peninsular rivers of India. India's Himalayan and Peninsular rivers' health is measured via water quality modeling. This study evaluates river health using physiochemical and biological parameters. This study examines Himalayan and Peninsular India's water resource management, environmental preservation, and public health.

Anthropogenic Heavy Metal Pollution in Nuweibaa, Gulf of Aqaba, Egypt: A Threat to Marine Environment and Water Quality

Anthropogenic Heavy Metal Pollution in Nuweibaa, Gulf of Aqaba, Egypt: A Threat to Marine Environment and Water Quality

A nationwide investigation on the characteristics and health risk of trace elements in surface water across China

Rapid urbanization accelerates the release of anthropogenic heavy metals from local to wider water systems, posing a serious threat to aquatic ecosystems and public health. The characteristics of trace elements were investigated to evaluate the environmental status of surface water in 40 cities of China. The concentrations of 22 elements in surface water ranged from 7.00 × 10−4 to 4.37 × 105 μg/L. The water quality can be classified as “excellent” except Songhuajiang. The levels of As, Cd, Cr, Pb, and Hg are all within the limits permitted by national drinking water quality standards. An obvious regional distribution characteristic was observed, with concentrations of Zn, Mn, Ni, Cu, Co, U, and Cr higher in surface water collected in the north than in the south, while the trends for Cd, Tl, and As are opposite. Notably, Tl shows significant geographical divergences, with the level of surface water collected from the south nine times higher than that from the north. The regional distribution of the mineral, industrial, or agricultural activity might be responsible for the south-to-north difference of these elements. The hazard index (HI) and total cancer risk (TCR) through oral or dermal contact with water-related heavy metals were further calculated. The average HI was 0.54 in the north and 0.29 in the south for adults, while HI for children was relatively higher. The value was 1.01 and 0.55 in the north and south, respectively. TCR in the north is 2.58 × 10−4 and mainly contributed by Cr (88.1 %), while TCR in the south is 4.48 × 10−5 and mainly contributed by As (98.4 %). The research results can provide essential data for effective water resources management and human health protection in China.

Risk evaluation and remedial measures for heavy metal contamination in lagoonal sediments of the Negombo Lagoon, Sri Lanka after the X-Press Pearl maritime disaster

Negombo Lagoon is a vital ecological and socio-economic resource in Sri Lanka that has become susceptible to anthropogenic heavy metal contamination. Therefore, short-core sediment samples from the Negombo Lagoon were analyzed to quantify heavy metal contaminants including both metals (Cr, Ni, Co, Cu, Cd, and Pb) and metalloid As; assess their ecological risk; identify critically polluted regions; and to investigate temporal variation in heavy metal concentration. According to the results, Ni is the most abundant heavy metal in lagoonal sediments. Ni, As, and Cr have severely contaminated the sediments as confirmed by their higher geo-accumulation indices (Igeo) and contamination factors (CF). The degree of contamination (Cdeg) indicated an exceedingly high overall heavy metal contamination, and the pollution load index (PLI) exhibited a prominent site quality decline. Individual potential ecological risk factor (Er) values revealed that Ni, As, and Cd pose a substantial ecological risk. Similarly, the potential ecological risk index (PERI) displayed that heavy metal contamination is a significant peril to this ecosystem. Spatial distributions of the heavy metals are governed mainly by the sediment grain size and freshwater influx. Ni concentration in lagoonal sediments has remarkably increased during the last six years (2016–2022) predominantly due to anthropogenic Ni sources, including the recent X-Press Pearl ship accident. In light of the severe heavy metal contamination in lagoonal sediments, the current study recommends a phytoremediation approach for the Negombo Lagoon.

Geranium robertianum L. tolerates various soil types burdened with heavy metals.

Many heavy metals (HMs) are essential micronutrients for the growth and development of plants. However, human activities such as mining, smelting, waste disposal, and industrial processes have led to toxic levels of HMs in soil. Fortunately, many plant species have developed incredible adaptive mechanisms to survive and thrive in such harsh environments. As a widespread and ruderal species, Geranium robertianum L. inhabits versatile soil types, both polluted and unpolluted. Considering the ubiquity of G. robertianum, the study aimed to determine whether geographically distant populations can tolerate HMs. We collected soil and plant samples from serpentine, an anthropogenic heavy metal contaminated, and a non-metalliferous site to study the physiological state of G. robertianum. HMs in soil and plants were determined using flame atomic absorption spectrometry. Spectrophotometric methods were used to measure the total content of chlorophylls a and b, total phenolics, phenolic acids, flavonoids, and proline. Principal component analysis (PCA) was used to investigate the potential correlation between HMs concentrations gathered from various soil types and plant samples and biochemical data acquired for plant material. A statistically significant difference was observed for all localities regarding secondary metabolite parameters. A positive correlation between Ni and Zn in soil and Ni and Zn in plant matter was observed (p<0.0005) indicating higher absorption. Regardless of high concentrations of heavy metals in investigated soils, G. robertianum displayed resilience and was capable of thriving. These results may be ascribed to several protective mechanisms that allow G. robertianum to express normal growth and development and act as a pioneer species.

Heavy metal characterization of land-based waste dumped at three ocean dumping sites in the Republic of Korea

From 1991 to 2021, 16 categories of land-based waste, totaling 131,400,000 m3, were dumped at three sites in Korea. The concentration of heavy metals varied by waste type, with organic sludge showing higher levels than liquid waste. While wastewater treatment sludge was the most commonly discarded waste, the quantity and types of waste disposed of varied by site. Before the 2015 ban on ocean dumping, 62,330 tons of heavy metals were introduced, including zinc, copper, chromium, lead, arsenic, cadmium, and mercury in descending order of frequency. In each heavy metal category, the portion of land-based waste varied by dumping site. Compared to heavy metals from atmospheric deposition, anthropogenic heavy metal input from dumping was up to 141 times higher for copper. This study serves as a reference for estimating the impact of pollutants from dumped waste.

Effect of land use conversion on heavy metals and magnetic minerals on water reservoir riparian soils

Spatial hydrological alterations seem to influence the variability of soil-bound magnetic particles and heavy metals in water reservoir riparian wetlands (RW). To date, applying geochemical analysis with magnetic techniques to assess heavy metal pollution is rarely practiced in RW soils. We studied the magnetic properties and heavy metals, including Cu, Cr, and Zn, of topsoils in RW and the adjacent upland regions (UR, as control) in the Three Gorges Reservoir, China. Potentially elevated low-frequency mass magnetic susceptibility (χLF), anhysteretic remanent magnetization susceptibility (χARM), isothermal remanent magnetism, and all selected heavy metals were found in RW. The grain size of the magnetic minerals was coarser in RW than that in UR. The pollution load index (PLI) of the studied samples was 1.18 ± 0.12 and 1.04 ± 0.21 in RW and UR, respectively. PLI and concentrations of Cu, Cr, and Zn were positively correlated with χLF, χARM, and isothermal remanent magnetism in RW, whereas no clear linkages were observed between PLI and isothermal remanent magnetism in UR. This finding reveals that hydrological alterations increased the magnetic enhancement and heavy metal enrichment in RW. We find that magnetic proxies of soils could trace the concentration of selected anthropogenic heavy metals and their pollution level in RW.

Modeling and identification of affective parameters on cadmium's durability and evaluating cadmium pollution indicators caused by using chemical fertilizers in long term.

Soil contamination by anthropogenic heavy metals has become a global issue. This study aimed to investigate cadmium (Cd) concentration, mobility, and contamination indices of Cd in soils in the Hamadan province, west of Iran. To investigate the concentration of Cd in soil, one hundred soil samples from wheat farms and five samples from control lands were collected. Pollution indexes, including Cd mobility, enrichment factor, geoaccumulation index, contamination index, and availability ratio, were investigated. The structural equation model was also used to evaluate effective parameters on cadmium durability in soil. Results showed that mean values of available phosphorus (P) were 83.65, 129, and 65 (mgkg-1) in three land-use types rainfed, irrigated, and controlled, respectively. The mean values of Cd in different land-use types of rainfed, irrigated, and controlled were 0.15, 0.18, and 0.08 (mgkg-1), respectively. The results indicated that the amount of Cd in both forms (available and total) in ones that received fertilizer, especially P fertilizers, was higher than in the controlled one. Other pollution indexes revealed that the study area had been slightly contaminated due to anthropogenic activities. Lime, clay, lead, and OM were identified as affective parameters on cadmium durability. Finally, the results demonstrated that the mobility rate was high. Cd had a higher potential mobility in soil samples in the rain-fed and irrigated land than in the controlled land, and Cd had a low retention time.

Analysis of Heavy Metal Contents (Cu. Pb And Zn) of Coral Annual Band (Porites Lutea) in the Eastern Part of Bintan Island

This study analyzed the growth rate of massive corals Porites lutea and heavy metal contents in its annual band. The aims of this study were to perceive the age of corals, relation between growth rates and sea surface temperature, rainfall, and duration of sunlight as well as the heavy metal (Cu, Pb and Zn ) extent in their annual band. This study was conducted with radiographic approach to determine the direction and the annual band of corals. Sample preparation methods contained determining the annual growth direction, cutting the samples, and dissolving the coral samples. The prepared samples were analyzed using AAS to calculate their Cu, Pb and Zn concentrations. The results showed that the growth rate of P. lutea coral growth rate was range from 2.78 ± 0.25 to 9.90 ± 1.90 mm/year. The growth rate and sea surface temperature were positively correlated (18.28 %), the rainfall and sunlight duration were correlated negatively 37.82 % and 0.67 % respectively. The highest concentration of Cu and Pb were consecutively found at the stations Kawal, Malang Rapat, and Teluk Bakau, while the highest concentration of Zn were consecutively found in Teluk Bakau, Malang Rapat, and Kawal. Through annual band of coral, from surface to the core part of massive colony coral, we noticed The Cu, Zn and Pb increased variedly with value range of 2.087 ± 0.179 to 2.504 ± 0.117 mg/kg for Cu, 12.304 ± 4.815 to 32.944 ± 5.926 1mg/kg for Zn, and 1.761 ± 0.910 to 9.501 ± 0.483 926 mg/kg. The study may reveals an historical apportionment of anthropogenic heavy metals in the studied area.

Sources and spatial variations of heavy metals in offshore sediments of the western Pearl River Estuary

The concentrations of six heavy metals (Cd, Cr, Cu, Pb, Zn, and As) in offshore surface sediments of western Pearl River Estuary were analyzed to investigate their sources and spatial variations using factorial kriging analysis. Three-scale spatial variations in heavy metal concentrations were identified and separated: nugget, local, and regional scale, which indicated sample errors, anthropogenic pollution and natural variation, respectively. Anthropogenic heavy metals varied sharply and heterogeneous at range of 60 km. Maoming Port, Hailing Bay and coastal area northeastern Hainan Island were potential polluted areas of Cd, Cr, Cu, Pb, Zn and As, also the Nandu River, Baoling River and Wanquan River estuaries were potential polluted areas of As. These polluted areas ranged up to 60 km in size and tended to extend with currents. The natural heavy metals varied continuously and relatively homogeneous at range of 180 km, which was dominated by riverine input and paleo-sea-level changes.

The Relationship Between Geological and Environmental Aspects with the Anomalies of Track Elements and Heavy Metal Elements in the Volcanic Area of the Muria Peninsula

The Muria Peninsula is a complex of volcanic activity located in the back arc of Sunda, which includes Kudus, Jepara, and surrounding districts. Volcanic activity on Mount Muria, can be used to study geological conditions, which were closely related to chemical elements. The presence of chemical elements in the river sediments of the Muria Peninsula was also influenced by anthropogenic heavy metal pollutants present in river deposits along the Muria Peninsula. The purpose of this study was to determine the relationship between the geological conditions and the environmental conditions of the Muria Peninsula with the anomaly of track elements and heavy metal elements. The methods used in this research were the pick test method, XRF geochemistry and the results were correlated into a geochemical anomaly map. The results showed that there were trace elements anomalies of Ce and Nd in Jepara area which were influenced by Muria shoshonitic rocks. Anomaly of Cu element was found in Jepara area, anomaly of Mn element was found in Jepara and Demak, and anomaly of Zn element was found in Jepara and Demak. Anomaly of Cu, M,n and Zn elements were high in upstream area and caused by land use of dry agriculture, paddy fields and settlement areas.

An Early Modern anthropogenic heavy metal record of the Helgoland mud area (German Bight, North Sea)

An Early Modern anthropogenic heavy metal record of the Helgoland mud area (German Bight, North Sea)

130 years of heavy metal pollution archived in the shell of the intertidal dog whelk, Nucella lapillus (Gastropoda, Muricidae)

Heavy metals in coastal waters are a great environmental concern in the North Sea since the middle of the 20th century. Regulatory efforts have led to a significant reduction in atmospheric and water-transported heavy metals. Still, high concentrations of these in sediments remain a risk for ecosystems, requiring close monitoring. Here, we investigated the applicability of Nucella lapillus museum collections as a tool for targeted tracking of chronic anthropogenic heavy metal pollution. We analysed the concentration ratios of the common heavy metals Cu, Cd, Pb, and Zn in relation to Ca in N. lapillus shells collected from the Dutch and Belgian intertidal zone over the last 130 years. We found that shell Cu/Ca and Zn/Ca concentration ratios remained remarkably constant, whereas Pb/Ca concentration trends were closely aligned with emissions of leaded petrol in Europe. Our results suggest that N. lapillus provides a suitable Pb pollution archive of the intertidal zone.

Distribution, source apportionment, and risk analysis of heavy metals in river sediments of the Urmia Lake basin

The anthropogenic heavy metal dissemination in the natural environment through riverine sediments is a major ecological and public health concern around the world. This study gives insight into the source apportionment and potential ecological and health risks of heavy metals in river sediments of the Urmia Lake basin, a natural world heritage located in northwestern Iran. A comprehensive sediment sampling was conducted in seven major rivers feeding the basin during the summer and winter of 2021. Samples were analyzed for zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb), and nickel (Ni) contents and a suite of chemical and physical properties. Subsequently, Pollution Index (PI), Pollution Load Index (PLI), Ecological Risk (ER), Hazard Quotients (HQ), Hazard Index (HI), and Carcinogenic Risk (CR) indices were determined. The mean concentration of heavy metals in all rivers’ sediments exhibited the descending order of Ni > Zn > Pb > Cu > Cd during both summer and winter. Multivariate analysis suggested that Zn was primarily initiated from natural processes, Cd and Pb were affected by human activities, and Cu along Ni were derived from natural and anthropogenic factors. The PI unveiled that most sediment samples were unpolluted to slightly polluted by Zn, Cu, and Pb, and slightly to moderately polluted by Cd. PLI and ER indices demonstrated that the sediment poses non to moderate pollution and low to moderate ecological risk, respectively. Using a human health risk approach, we found that the HI values of all heavy metals and THI were less than one for children and adults implying non-carcinogenic risk in the analyzed sediments. Carcinogenic effects of Cd and Pb at all rivers sediments via ingestion, inhalation, and dermal contact were almost within tolerable risks (1 × 10−6 to 1 × 10−4) for children and adults. PI, PLI, ER, HQ, HI, and CR index values of sediment samples during the summer were higher than those during the winter. This is attributed to the greater heavy metal concentrations and the lower water flow during summer. Our results provide practical information for better management and control of heavy metal pollution in aquatic-sedimentary ecosystems.

A Facilely Synthesized Tourmaline–Biochar Composite for Enhanced Removal of Cr (VI) from Aqueous Solution

Hexavalent chromium (Cr (VI)), an anthropogenic heavy metal pollutant, is harmful to human beings, due to its carcinogenicity. In this study, a tourmaline–biochar composite (TMBC) was synthesized to remove Cr (VI) from an aqueous solution. The effects of different ratios (TM:BC) and pyrolysis temperatures on TMBC adsorption performance were compared. The TMBC samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscope–energy-dispersive spectrometry (SEM-EDS). The kinetics and thermodynamics were analyzed to investigate the sorption mechanism. The results showed that the proper pyrolysis temperature was 650 °C, and the ratio of TM:BC was 1:3. SEM results showed the TM was well attached to the BC which assisted tourmaline dispersion. The adsorption kinetics were well fitted by the pseudo-second-order model, indicating that the sorption was related to chemical absorption. Langmuir adsorption isotherms suggested monolayer adsorption between the Cr (VI) and the TMBC, and the maximum adsorption capacity of the TMBC for Cr (VI) was 43.64 mg/g, which was more than twice the amount for the pristine TM (17.84 mg/g). The automatic polarization of water caused by tourmaline was the unique adsorption property of the TMBC. Therefore, TMBCs can be used as an economic adsorbent in the remediation of heavy metal pollution.

Potential Sources of Heavy Metals in Sediments of an Urban‒Agricultural Watershed and Relationship with Land Use Using a Statistical Approach

This study verified pollution levels through evaluation of the Sediment Quality Guidelines (SQGs), pollution load index (PLI), and potential ecological risk index (PERI) by analyzing the concentrations of heavy metals in sediments of an urban‒agricultural watershed in the Yeongsan River basin, South Korea. Statistical analyses were performed to determine the relationships between pollution levels and land use, and potential sources of pollution were identified. For spatial distributions, Pb, Zn, Cu, Cd, and Hg concentrations were highest at mid-upstream, but As, Cr, and Ni concentrations were similar at most sites. The polluted sites, which showed the potential toxicity toward benthic organisms in comparison to SQGs, were most frequently observed at mid-upstream. Moreover, PLI and PERI evaluations also confirmed levels of high anthropogenic pollution and the potential ecological risk at mid-upstream. The mid-upstream sites with high heavy metal pollutions showed high correlations with urban land use, which showed the highest distribution, implying a close relationship with anthropogenic impacts such as high population density and industrial complexes. Statistical analyses also confirmed that high heavy metal concentrations in the mid-upstream were closely related to urban land use. These findings suggest that urban areas are highly likely to cause anthropogenic heavy metal pollution in sediments as point or non-point sources such as domestic sewage and industrial wastewater flow into rivers.

Spatial Distribution of Heavy Metals in Near-Shore Marine Sediments of the Jeddah, Saudi Arabia Region: Enrichment and Associated Risk Indices

Red Sea coastal development has rapidly accelerated in recent decades that has led to a rise in the anthropogenic heavy metal levels in sediments. A total of 80 surficial sediment samples were collected from the shallow waters along the eastern Red Sea coast near Jeddah, Saudi Arabia. These samples were collected from three locations, designated as North, Middle and South of Jeddah, to assess the concentrations of six heavy metals: chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), and lead (Pb). The results showed that the concentrations (mg/kg) of these metals in the studied sediments follow this order: Pb (77.34 ± 150.59) &gt; Mn (36.52 ± 37.72) &gt; Zn (18.02 ± 23.94) &gt; Cr (9.56 ± 5.81) &gt; Cu (9.18 ± 13.67) &gt; Ni (3.68 ± 4.54). The majority of the polluted sediments were recorded in the Middle and South locations. Pollution and enrichment indices such as Geo-accumulation indices (Igeo), Enrichment Factors (Ef), Contamination Factors (Cf), Pollution Load Indices (PLI), Potential Ecological Risk Indices (PERI) and Potential Toxicity Response Indices (RI) were calculated from the measured metals to establish baselines for the region and assess specific metal enrichments by location along the Jeddah coastline. The Igeo values showed that 30% of the Southern location stations are considered moderately to highly polluted. The Ef for all the studied sediments followed this order: Pb (extremely severe enrichment) &gt; Zn &gt; Cu &gt; Cd &gt; Cr (severe enrichment) &gt; Ni (moderate enrichment).

Species-specific bioaccumulation and health risk assessment of heavy metal in seaweeds in tropic coasts of South China Sea

Seaweeds are widely known superfood in coasts where most anthropogenic heavy metal discharges are inputted and stored. The present study analyzed 11 seaweed species and 13 heavy metals to test the hypothesis that the species-specific capacity of heavy metal bioaccumulation had great significance to health risk of human. The seaweeds were collected from tropic coasts of Hainan Island. We comparatively determined the bioaccumulation level of metals in different species. The results revealed that the red algae mainly concentrated V, Se, Mn, Ni, and Ag. The brown algae mainly concentrated Cr, Co, Cu, Cd, As and Fe, while the green algae mainly concentrated Zn and Pb. The cluster analysis, principal component analysis and metal pollution index indicated that Padina crassa, Sargassum thunbergii, Caulerpa racemosa and Asparagopsis taxiformis showed similar metal bioaccumulation behavior. The health risk assessment revealed that the overall hazard index (HI) of seaweeds consumption to adults was less than 1, while the HI of Sargassum oligocystum, Turbinaria ornate, Sargassum polycystum and Sargassum thunbergii consumption to children was greater than 1, suggesting a moderate or high risk to children. Moreover, the exposure amount and the carcinogenic risk parameter indicated that As and Cr were the limiting factor for seaweeds consumption. Overall, our findings here largely supported our hypothesis that the heavy metal bioaccumulation behavior and health risk was highly variable and complex among different species. We thus suggested that the species-specific health risk of heavy metals in seaweeds should be cautiously evaluated in natural environments.