Trace Metal Pollution Research Articles

Legacy nitrate and trace metal (Mn, Ni, As, Cd, U) pollution in anaerobic groundwater: Quantifying potential health risk from “the other nitrate problem”

Denitrification in soils and aquifers sustains low nitrate concentrations in many anaerobic groundwaters despite massive inputs of N from agriculture. However, this ecosystem service sometimes comes at the cost of trace metal mobilization and concerns have been raised that denitrification in anaerobic groundwater may lead to trace metal contamination. But it remains unclear, if denitrification must necessarily result in trace metal concentrations that are potentially harmful for humans. For example, formation of iron(oxy)hydroxides after the reaction of nitrate with pyrite may reduce rather than increase the mobility of certain trace metals in aquifers. We quantified the potential health risk resulting from denitrification-associated trace metal pollution (Mn, Ni, As, Cd, U) in anaerobic groundwater with different degrees of nitrate pollution in >800 wells located in Northern Germany. Overall, observed rates of violations of legal quality standards for U, As and Cd are moderate in the study area (<10% of all wells) but elevated for Mn (>50%), which is a common contaminant under the often anaerobic conditions in the study area. However, in groundwater where denitrification had partially proceeded, the risk for drinking water standard violations was higher for Ni, Cd and U (up to a factor of 4 for Ni) as compared to anaerobic groundwater without denitrification, but lower for Mn and As. Especially poorly buffered groundwaters with pH < 5.5 are at risk of Ni and Cd contamination resulting from denitrification, while the opposite is true for Mn and U. Thus, we establish a clear linkage between nitrogen biogeochemistry and trace metal mobility and show how perturbations of groundwater redox and pH conditions by nitrate can further deteriorate groundwater quality. In addition, we find that the combination of oxygen concentrations of lower than 1 mg L−1, and nitrate concentrations above 1 mg L−1 allows for identification of denitrification (as evidenced by excess N2 in groundwater) with 90% accuracy. The methodology developed herein can be used to inform water treatment planning about potential trace metal contamination when drinking water should be produced from anaerobic aquifers beneath agricultural landscapes.

Synthesis of green nano sorbents for simultaneous preconcentration and recovery of heavy metals from water

The wastewater containing Cd, Co, Fe, Cu, Cr, Mn, Ni and Pb ions are as trace metal pollutants. Water pollution caused by increment in industrialization and overpopulation reveals a major threat to human health. Adsorption is recognized as the effective and optimum method to remove water contaminations. The amorphous and porous form of silicon dioxide is silica gel widely used as an adsorbent. It can absorb moisture with traces of the target heavy metal ions. This research elaborates a simplistic, and reliable preconcentration column method highly developed for the determination of Cd2+, Fe3+, Co2+, Cr3+, Cu2+, Mn2+, Pb2+ and Ni2+ ions in model solutions and real water samples by flame atomic absorption spectrometry (FAAS). The proposed operation depends on the retention of the target ions from buffered model solutions on a silica gel filled up a column modified with vanadium(V) oxide sorbent followed by their desorption. SiO2/V2O5 is an efficient adsorbent due to its low cost, eco-friendly and high availability. The adsorbent morphological and interfacial physicochemical characterization was done using scanning electron microscopy, and Fourier transmission infrared spectroscopy, respectively. The 2.92 value achieved for the point of zero charges supports the experimentation for the heavy metal efficient adsorption. Quantitative recoveries were achieved at pH 10 with 50 mg of SiO2/V2O5 mass and adsorption capacity ranged from 28.96 μmol/g (Pb) to 214.86 μmol/g (Fe) with 1114.79 μmol/g in total. Simultaneous preconcentration effect was determined by the interference cations on the sorbent. The LOD varies from 8.42 to 50.56 μg/L and LOQ is achieved from 20.06 to 72.41 μg/L of 15 blank solutions. The developed preconcentration procedure was adequately implemented for the simultaneous analysis of eight metallic ions content in local river samples. The developed vanadium(V) oxide incorporated with silica gel is practicable as an economical and effective adsorbent to eliminate metallic ions from a liquid solution.

Preliminary Assessment of Trace Metal Pollution and Their Bioaccumulation in Mollusks Inhabiting the Intertidal Sediments of the Atlantic Coast of Accra, Ghana.

The present study investigated the trace metal levels in sediments, enrichment in sediments, and its bioaccumulation in mollusks collected from the intertidal sediments of the coast of Accra, Ghana, which is influenced by anthropogenic activities. The metals (Fe, Mn, Cu, Cr, and Zn) were analyzed in sediments. The metals (Mn, Cu, Cr, and Zn) were analyzed in the soft tissue of the mollusks collected from the different coastal areas. The results indicate that although Accra is the capital city and the coast receives tons of anthropogenic wastes, trace metal levels were low and there was no enrichment for the metals analyzed except Cu which showed minor to moderate enrichment in the coastal sediments. There was bioaccumulation of the trace metals in the soft tissue of the mollusks, and the results suggest that the mollusks studied, the gastropods (Agaronia razetoi) and the bivalves (Tivela tripla), can be used for biomonitoring.

Remediation for trace metals in polluted soils by turfgrass assisted with chemical reagents

Trace metal pollution in soils is one of the universal environmental problems in the world. Phytoremediation is a green, safe, ecological, and economic method to achieve continuous reduction of soil pollutants. Turfgrass is a plant with great landscape value and has considerable biomass when used for remediation of trace metal contaminated soil. However, its remediation ability needs to be improved in future application. The combined application of turfgrass, citric acid (CA) and auxin (gibberellin, GA3) were applied in the phytoremediation of an artificial nutritive soil derived from sludge, and a field scale orthogonal experiment (L9) was conducted to understand the interaction effect and obtain the optimum phytoremediation. Experimental results showed that the types and cultural patterns of turfgrass mainly determined plant height, root length and trace metal concentration in turfgrass, however CA treatment was prone to increase the aboveground biomass and the concentrations of most trace metals in turfgrasses, especially the concentration of Ni in turfgrass. GA3 spraying significantly increased the concentration of Cd in turfgrass. The culture patterns of turfgrass played 42.4% influence on acid-extractable Cd, while CA applying had 53.8% influence on the acid-extractable Ni. The annual phytoextraction amount of trace metals based on five mowing a year were proposed to assess the remediation ability of treatments, which of the combination treatment (T3, intercropping Zoysia matrella and Lolium perenne, and applying 400 mg kg−1 CA and 30 mg kg−1 GA3) were 1.6–2.1 times higher CK group. This research provides technical reference for intercropping turfgrass for remediation of trace metals in sludge-derived nutritive soil.

Eco-toxic risk assessment and source distribution of trace metals in surface sediments of the coastal and in four rivers estuary of Sarawak

BackgroundTrace metals pollution in the coastal and estuarine sediment could harm water quality and aquatic organisms, leading to potential long-term health risks on the environment and humans. Thus, the purpose of this study was to conduct an assessment of selected trace metals in surface sediments of the coastal and in four rivers estuary in the Sarawak State of Malaysia to investigate their distribution, environmental risk, and potential source distribution.ResultsAverage concentrations of trace metals in sediment increased in the following order: Cd ˂ As ˂ Co ˂ Cu ˂ Ni ˂ Cr ˂ Zn ˂ Mn ˂ Mg ˂ Fe. The enrichment, contamination, and geo-accumulation index results showed that surface sediments were polluted with Zn and Mg. In contrast, the other metals (i.e., As, Fe, Mn, Ni, Cr, Cu, Co, and Cd) indicated background concentration to minor contamination. Generally, the pollution load index values showed that almost all the sampling sites were unpolluted with the selected trace metals. Sediment quality guidelines (SQGs) and risk indexes were employed to assess the ecotoxicological risk of trace metal contamination in the sediments. The results proved that studied trace metals are not likely to have a deleterious impact on bottom-dwelling organisms. Still, a further accumulation of trace metals such as Zn, Ni, and Cr with time may adversely affect bottom-dwelling organisms. The risk index results showed a low ecological risk to the study sites. The correlation analysis and principal component analysis indicated that nine studied trace metals have strong interrelationships, suggesting common pollution sources or similar geochemical characteristics.ConclusionsThe study highlights the need to make tremendous efforts to monitor and control trace metal pollution in the coastal and estuarine areas.

Study of trace metal contamination and ecological risk assessment in the sediments of a tropical river estuary, Southwestern India

The present study aims to assess the extent of trace metal pollution in the sediments of Sita-Swarna estuary, west coast of India, and investigate their possible ecological risk on the aquatic environment. The sediment cores were analyzed for sand, silt, clay, organic carbon, and trace metals (Al, Fe, Mn, As, Cd, Co, Zn, Pb, Ni, Cr, and Cu) at 2-cm intervals. The study revealed that sediments have deposited in relatively violent to very violent hydrodynamic energy conditions. Factor analysis indicated that the metal distribution is mainly controlled by Fe–Mn oxyhydroxides and organic carbon. Further, the geochemical approach, pollution indices, and statistical evaluation revealed moderate pollution in the catchment. From an ecotoxicological perspective, the estimated risk index (RI) value was found to less than 150, indicating low risk for aquatic life. Thus, this baseline study would help to adopt strategies in pollution control and protect the fragile marine environment.

Metal and metalloid bioaccumulation in three centipedes (Chilopoda)

Three centipede species (Clinopodes flavidus, Cryptops anomalans and Eupolybothrus transsylvanicus) were used as bioindicators of trace metal and metalloid pollution in Belgrade, Serbia. The concentrations of 13 elements (the metals Mn, Co, Ni, Cu, Zn, Rb, Sr, Cd, Tl, Pb and U and metalloids As, Se) in whole animals and soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). Differences in the concentrations of some elements in the analyzed species were observed, both in response to the sites and between species. In most cases, the trace element concentrations were higher in centipedes from a polluted site (an industrial area near a busy street with heavy traffic) but C. anomalans and E. transsylvanicus had higher Mn concentrations at an unpolluted site (a deciduous woodland on Mt. Avala). C. flavidus was a good bioindicator for detecting differences between Zn, Se and Cd. C. flavidus and C. anomalans were more efficient in accumulating Zn than E. transsylvanicus. It appears that C. anomalans poorly accumulated Cd, unlike C. flavidus and E. transsylvanicus, which accumulated Cd according to the high bioaccumulation factor (BAF) values. We conclude that the centipedes C. flavidus, C. anomalans and E. transsylvanicus can be used as suitable bioindicators of trace element exposure. Their ability to accumulate trace elements was different and depends on their physiology and lifestyle as well as the route of exposure.

Impacts of Trace Metals Pollution of Water, Food Crops, and Ambient Air on Population Health in Zambia and the DR Congo.

Zambia and the DR Congo are situated in the central African Copperbelt, which is part of the Lufilian geological structure arc stretching over from Kolwezi in Katanga Province in the DRC to Luanshya in Copperbelt Province in Zambia. The area has large copper-cobalt deposits of which the extraction causes severe ecosystem damage due to pollution of water, food crops, and the ambient air negatively impacting population health. Contamination of drinking water for domestic use and foods (cereals, roots and tubers, vegetables, and fruits) was determined by assessing the contents of trace metals including Mn, Ni, Pb, Zn, Co, As, U, Cd, and Cu and through a questionnaire for environmental damage. Food samples were analyzed by inductively coupled argon plasma/optical emission spectroscopy (ICP-OES), while water and urine samples were analyzed by inductively coupled argon plasma mass spectrometry (ICP-MS). Concentrations of Ni, Pb, and Cd were higher in almost all food crops, although Cu was more in samples of Cucurbita maxima and Amaranthus hybridus. Mean contents (μg/L) of Mn, Zn, Cd, Pb, and U were, respectively, 5,454.6, 2552.2, 138.7, 39.7, 2361.1, and 21.4 in the DRC and 108.9, 543.3, 0.3, 0.2, 1.5, and 0.5 in Zambia, being significantly higher and always far above World Health Organization maximum limits in the DRC. Urine samples taken only from the DRC contained trace metals with children's samples being more contaminated than adult ones. Our results conclusively echo the most critical challenges of toxic pollutants causing numerous health issues among the population. Given an outcry among households adjacent to mines about land degradation and food spoilage, and health problems over years, joint efforts are needed from public and private sectors for stringent mining exploitation monitoring for sustainable governance to protect the environment and ensure food and nutrition safety, and population well-being in Zambia and the DR Congo.

Cement and oil refining industries as the predominant sources of trace metal pollution in the Red Sea: A systematic study of element concentrations in the Red Sea zooplankton

The Red Sea is exposed to metals from a large variety of natural and anthropogenic sources. In this study, we analyzed 19 common element concentrations in 14 Red Sea zooplankton samples using inductively coupled plasma-optical emission spectrometry (ICP-OES). The average metal or metalloid concentrations of the Red Sea zooplankton were: Ca > Sr > Fe > Al > Zn > As > Cu > Mn > Cr > Mo > Ni > Pb > Cd. The As, Ca, and Cu concentrations significantly increased with increasing latitude, while Cd concentrations decreased (p < 0.01). Our study indicated that anthropogenic activities (i.e., cement factories and oil refining industries) might be the predominant sources of significantly high Cr (1718 mg/kg), Fe (11,274 mg/kg), Mn (57.3 mg/kg), Mo (286 mg/kg), Ni (226 mg/kg), Pb (332 mg/kg), and Zn (17,046 mg/kg) concentrations that recorded in the Central to North Red Sea zooplankton.

Risk assessment of trace metals in Mefou River sediments, West-Africa

This study focuses on risk assessment of Cr, V, Ni, Co, Pb, Cu, and Zn in the Mefou River sediments located at Yaoundé, West-Africa. Sediment samples were collected from five stations in the downstream of the Mefou River, which drains the urban area of Yaoundé between latitudes 3°30′ and 3°58′ North and longitudes 11°20′ and 11°40′ East. The geochemistry data were analyzed statistically and the pollution indices were calculated in order to identify and estimate the sources of metal contamination in the Mefou River sediments. The results obtained show that the average concentrations of trace metals are almost higher than those of the upper continental crust (UCC) and the metal average in the Simbock Lake cores. However, the concentrations of Ni, Cu, Pb, and Zn in sediments located in most urbanized sites are lower than those of the UCC and the average of Simbock Lake sediments. The pollution indices such as enrichment factor (EF), geo-accumulation index (Igeo), and pollution load index (PLI) showed that trace metals were mainly influenced by human sources, except for Pb, Cu, and Zn, which stemmed from natural sources. The sediments of the Mefou River would therefore be affected with low to moderate pollution levels. The low values of potential ecological risk (RI: 22.36–41.53) suggest a low potential ecological risk effect. The multivariate statistical analysis indicates that Ni, Cu, Pb, Co, and Zn have been derived mainly from natural sources, while V and Cr would partially derive from human activities. The results of this research can be a reference for trace metal pollution along an African urbanized river corridor. This can be considered as an act of prevention of urban watercourses in Cameroon and in other parts of the world, especially in major African urban metropolis.

Assessment of trace metal pollution in the bottom sediments of Manzala Lagoon, Egypt

Assessment of trace metal pollution in the bottom sediments of Manzala Lagoon, Egypt

A historical record of trace metal deposition in northeastern Qinghai-Tibetan Plateau for the last two centuries.

Owing to rapid socio-economic development in China, trace metal emissions have increased and lakes even in remote areas have experienced marked changes in the last century. However, there are limited studies revealing long-term trends, anthropogenic fluxes, and spatial characteristics of trace metals in lakes. In this study, we present a geochemical record from Lake Qinghai in the northeastern Qinghai-Tibetan Plateau and reconstruct trace metal pollution history during the last two centuries. The lacustrine sediment core was dated by 137Cs and 210Pb, and sediments deposited prior to the 1850s were selected as the pre-industrial background. Factor analysis and enrichment factor indicated Cr, Cu, and Ni generally originated from natural sources, while Cd, Pb, and Zn have been influenced by human contamination since the mid-1980s. The anthropogenic Cd mainly derived from non-ferrous metal smelting in Gansu Province, and fluxes to Lake Qinghai sharply increased after the mid-1980s. The metal reconstruction is similar to other lake sediment records from China and corresponds well with rapid economic development in China. The spatial pattern of anthropogenic Cd fluxes to lakes is primarily attributed to regional industrial emission, phosphate fertilizers, and manure applied in agriculture.

Trends in bioaccumulation and metabolite profiles in Mediterranean mussels with sub lethal exposure to mixtures of trace metals

Trace metals are major environmental contaminants, and the accumulation of trace metals could cause changes to the metabolism of marine organisms. In order to understand trends in bioaccumulation and changes in metabolic pathways in marine mussels during short-term and long-term exposure to trace metal mixtures, wild Mediterranean mussels (Mytilus galloprovincialis) were exposed to natural seawater spiked with two sub lethal concentrations of a mixture of copper (Cu), zinc (Zn), and lead (Pb) for 30 days. Mussels were collected every 5 days and trace metal levels in the whole bodies were measured. The gills of mussels collected on day 5 and day 30 were sampled separately. Trace metal levels in whole bodies of these samples were measured and metabolites in the gill tissue extracted, profiled, identified, and compared between groups with different exposure time and trace metal levels. The results showed continuous increase in body burdens of Cu and Pb in mussels throughout the exposure period, while Zn accumulation reached a plateau after day 10 in the whole body and gills. The metabolomics analysis demonstrated that multiple metabolites were down-regulated and multiple metabolic pathways possibly interrupted by exposure to the mixture of trace metals. This study provides extensive knowledge that the effects of Cu, Zn, and Pb exposure on the metabolic pathways have the potential to result in reduced fitness of Mediterranean mussels and demonstrates potential of GC-MS based untargeted metabolomics to be used as a part of trace metal pollution evaluation and ecosystem health monitoring.

Health Risk Assessment, Pore Water Chemistry, and Assessment of Trace Metals Transfer from Two Untreated Sewage Sludge Types to Tomato Crop (Lycopersicon esculentum) at Different Application Levels

The application of untreated sewage sludge to cropland in water-deficient areas is common practice. A study was conducted to investigate the transfer of trace elements from sewage sludge to tomato crop and the potential health risk to humans. Two types of sewage sludge, ISS (I-9 Sector wastewater treatment plant, Islamabad) and WSS (Water and Sanitation Authority wastewater treatment plant, Faisalabad), were applied at 0.5%, 1.0%, and 1.5% w/w and compared with control (without any amendment). The test crop was tomato (Lycopersicon esculentum). Results revealed that the ECe of soil was increased by these treatments with respect to all application levels. The levels of Pb (lead) and Zn (Zinc) solubility in soil were increased about 46- and 28-fold by the application of ISS at 1.5% and 16- and 22-fold by the application of WSS at 1.5%, respectively. The highest shoot biomass was recorded with 0.5% level of WSS, while higher rates (1.0% and 1.5%) of both ISS and WSS showed significant (p &lt; 0.001) decline in shoot biomass production, and the lowest SFW was recorded with the addition of ISS at 1.5% application rate (a significant reduction of 44%) compared to control. The pore water analysis and correlation depicted that dissolved organic carbon (DOC) controlled the release of Zn and Pb. The PLI (value &lt; 1) indicated that the overall pollution of trace metals in the investigated samples was absent, but the Igeo and CF showed the contamination potential for Cd, Cu, and Ni was moderate to strong. DIM and HRI analysis suggested that the tomato was safe for human consumption. The HRI values for all trace metals were below the permissible limit (HRI = 1) described by USEPA-IRIS. It was concluded that a lower rate of both sewage sludge types produces more biomass and less accumulation of trace metals in the test crop.

Modeling distributed metal pollution transport in a mine impacted catchment: Short and long-term effects

A spatially distributed trace metal transport and transformation module was developed and implemented within the hydrological model TOPKAPI-ETH. The new module can be used to better understand, at high spatial and temporal resolution, the transport and reactions of trace metals as they move through a catchment from upland sources to downstream areas and water bodies. The newly developed module takes into consideration solid metal in multiple chemical phases with different reactivity and simulates their mutual transformation over time, which gives the possibility to analyze the fraction of different solid metal phases present in the river suspended sediment. The characteristics and potential of the model are demonstrated by simulating Zinc (Zn) and Cadmium (Cd) dynamics in a headwater catchment of the Xiang River in South China, which has been highly perturbed by mining activities. The developed module is shown to reasonably reproduce the observed dynamics of dissolved and total trace metals flux for 14 months at two monitoring stations. The distributed solute transport model was proved to be capable of explaining the reasons underlying the spatial variability of C-Q relationships that are driven by the combined effect of point and non-point pollution sources, as well as identifying the spatiotemporal hotspots of trace metal pollution. By means of synthetic numerical experiments, a limited impact of slow reactions on dissolved Cd transport from upland to river over short-temporal scales was demonstrated, while for longer scales, e.g. >5 years, this effect becomes more relevant, highlighting potential long-lasting sources of trace metal pollution and their impacts.

Induction of hormesis in plants by urban trace metal pollution

Hormesis is a dose–response phenomenon observed in numerous living organisms, caused by low levels of a large number of stressors, among which metal ions. In cities, metal levels are usually below toxicity limits for most plant species, however, it is of primary importance to understand whether urban metal pollution can threaten plant survival, or, conversely, be beneficial by triggering hormesis. The effects of Cd, Cr and Pb urban concentrations were tested in hydroponics on three annual plants, Cardamine hirsuta L., Poa annua L. and Stellaria media (L.) Vill., commonly growing in cities. Results highlighted for the first time that average urban trace metal concentrations do not hinder plant growth but cause instead hormesis, leading to a considerable increase in plant performance (e.g., two to five-fold higher shoot biomass with Cd and Cr). The present findings, show that city habitats are more suitable for plants than previously assumed, and that what is generally considered to be detrimental to plants, such as trace metals, could instead be exactly the plus factor allowing urban plants to thrive.

The heavy metal pollution in groundwater, surface and spring water in phosphorite mining area of Tebessa (Algeria)

The aim of this study is to measure the trace metal pollution in surface waters, spring waters and groundwater found in the Djebel Onk. The samples were analyzed using the Inductively Coupled Plasma Mass Spectrometry method. The results show that the surface water, spring waters, and groundwater are contaminated by these trace metals, particularly lead, uranium, iron, lithium, selenium, and magnesium. The observed levels reflect the evidence of the bad quality of these waters (surface waters, spring waters, and groundwater), which show a higher hazard quotient measured at 1 in the groundwater. It was concluded that the consumption of these waters without treatment could have negative impacts on human health in general and that of children in particular.

Mineralogy and geochemistry of Tecolutla and Coatzacoalcos beach sediments, SW Gulf of Mexico

Mineralogic and geochemical studies were performed in the Tecolutla and Coatzacoalcos beach sediments, located at the SW Gulf of Mexico. The main concern of this article is to infer the weathering, provenance, and degree in which trace metal pollution affects the beach sediment composition. The chemical index of weathering (CIX) for the Tecolutla and Coatzacoalcos beach sediments indicate a moderate intensity of weathering in the source area. The SiO2/Al2O3 ratio values (>6) in the Tecolutla and Coatzacoalcos sediments suggested a high compositional maturity and recycling. A difference in the Al2O3/TiO2 ratios between the Tecolutla and Coatzacoalcos beach sediments points out that the sediments were derived from intermediate and felsic igneous rocks, respectively. A negative correlation for Al2O3 against TiO2 and P2O5, and trace elements Y, Nb, V, Sc, and Cr for the beach sediments suggests an association of these elements with detrital minerals rather than aluminosilicates. The provenance discrimination based on major element concentrations indicates an intermediate and a felsic provenance for the Tecolutla and Coatzacoalcos sediments. The major and trace element geochemistry of beach sediments are associated with a passive margin setting.The Enrichment factor (EF) and Geo accumulation index (Igeo) values show that the Tecolutla sediments are moderately enriched by Cu (EF ∼ 10–17) and Cr (1< Igeo <2). An enrichment of EF value for Cu in Tecolutla beach sediments may be a response of anthropogenic and natural sources by the weathering of intermediate igneous rocks. The moderately to highly enriched Igeo values of Pb, Zn, and V observed in the Coatzacoalcos beach sediments, indicate that the sediments were influenced by the waste generated by urban activities in the river drainage catchment area.

An assessment of trace metal pollution indicators in soils around oil well clusters

Due to the metallic ion constituents of crude oil, environmental levels of toxic metals are often exacerbated when oil is spilt. Biseni community plays host to numerous oil production companies in Bayelsa state, Nigeria. However, the tendency for this clan to be flooded, particularly owing to its lowland features has continued to negatively impact on the environment. Sometimes, floods are accompanied by spilt residual oil that encroach living areas, thus leading to the contamination of open water bodies, underground water resources, and fish and crop farms. This study surveyed the impact of oil seepages from oil well clusters on the overall soil quality by applying trace metal pollution indicators. Trace metals were analyzed by atomic absorption spectrometry, and concentration ranged from 5893.0-6263.8 mg/kg, 0.03–11.52 mg/kg, 3.15–6.46 mg/kg, 4.46–58.64 mg/kg, 13.61–29.83 mg/kg, 0.23–0.73 mg/kg, 8.32–20.69 mg/kg, and 4.24–9.31 mg/kg for iron, copper, nickel, lead, zinc, cadmium, chromium and cobalt respectively. Concentrations were within target limits stipulated by the Department of Petroleum Resources, Dutch standard limit and World Health Organization. Zinc and chromium showed the strongest correlation (r = 0.92, p < 0.05) in the study area, whilst one-way ANOVA revealed equality (p > 0.05) among the different sampling points. This is evidence that the field area is affected by similar contamination source. Whereas, the micro-pollutant metals depicted significant variability (p < 0.05), probably due to the outlier concentration of iron. Overall, lead was the most contaminating metal, while location BNS2 (0.3m) was the most considerably contaminated area. Enrichment factor revealed the anthropogenic origination of lead. Index of geo-accumulation of lead ranged from moderate to heavy contamination, with lead recording very high contamination factor, and the degree of contamination depicting considerable risk, especially at the top soil. Pollution load index showed most contamination (moderately polluted) at BNS2. Quantification of contamination showed relative contamination for most locations, whereas potential ecological risk index mostly depicted low risk, apart from the exhibition of moderate risk of lead and cadmium at BNS2. Conversely, sum of pollution indices and risk index revealed low contamination and low risk respectively.

Mediterranean fanworm, Sabella spallanzanii (Gmelin, 1791), as a potential biomonitor of trace metal pollution in the marine environment

Levels of trace metals (Cd, Cr, Cu, Fe, Ni, Pb, Mn, and Zn) were measured in soft tissues and external tubes of the Mediterranean fanworm, Sabella spallanzanii (Gmelin, 1791), to evaluate its suitability as a biomonitor of metal pollution. Study was conducted in the coastal area of the eastern Adriatic Sea. Polychaetes were collected from two locations, a site located in a local marina and an unpolluted control site. Results indicate that S. spallanzanii has the capacity to accumulate metals in soft tissues as well as in tubes. The levels of most metals were considerably higher in tubes compared to soft tissues, indicating long-term accumulation of metals in tubes. High levels of several metals (Cu, Zn, Cr, Pb and Fe), found in soft tissues and tubes sampled at the marina site, reflect the elevated contaminant levels in the marina, associated with the use of antifouling agents, paints, petrol additives, and ship maintenance activities. Metal concentrations in tissues and tubes generally decreased with size, indicating the influence of growth and metabolic rates on trace metal uptake. Trace metal levels found in S. spallanzanii tissues were comparable to the levels found in Mytilus galloprovincialis, a species commonly used in biomonitoring studies, in areas exposed to similar levels of anthropogenic stressors. According to the results of the present study, S. spallanzanii has been identified as a suitable biomonitor of metal pollution due to its sedentary nature, widespread distribution, abundance and the ability to accumulate high levels of metals within its tissues and tubes.