Trends In Metal Concentrations Research Articles

Assessment of Metal Concentration and Bioaccumulation Factor in Surface Water and Fishes Sampled From Four Creeks in the Bonny River Estuary, Niger Delta Region of Nigeria

The indiscriminate disposal of industrial and urban waste has added to the concerns of global water pollution. Anthropogenic activities and activities of oil companies (oil spills) have also contributed to the pollution of the aquatic ecosystem in the Niger Delta region of Nigeria. This study was therefore designed to evaluate the concentration of Iron, Nickel, Lead, Cadmium and Chromium in our surface waters and our marine life. Samples of surface water were collected into 50 cl sterile plastic bottles and labelled accordingly. Twenty medium-sized tilapia fishes from about a one-kilometre radius of each site were caught and also labelled accordingly. Water and fishes from each site were then kept in a cooler, iced and immediately transported to the laboratories for analysis for heavy metals after these fishes were homogenised using a blender. Atomic absorption spectrophotometer was used for the metal analysis. Standards were prepared using tracecert of each of the above-mentioned metals. The results of these study sites (Akpajo, Okujagu, Woji and Elelenwo) had high concentrations of metals. Fishes from all these sites also had high concentration of these metals. The trend of metal concentration in the surface water as follows: Okujagu–Pb>Cr> Cd>Fe = Ni, Akpajo–Cd>Fe>Pb>Cr>Ni, Elelenwo–Pb>Cr>Fe>Cd>Ni, Woji–Cr>Cd>Pb>Fe>Ni. Results obtained also revealed the trend of metal concentration in fish muscles as follows: Okujagu–Pb>Cr> Cd>Fe = Ni, Akpajo– Cd>Fe>Pb>Cr>Ni, Elelenwo–Pb>Cr>Fe>Cd>Ni and Woji–Cr>Cd>Pb>Fe>Ni. Fishes and surface water sampled from these four creeks in the Bonny estuary in the Niger Delta region of Nigeria had high concentrations of iron, nickel, cadmium, chromium and lead in relation to their concentration in surface water. The results of this study revealed that metal concentration in surface water had some relative effect on their concentration in the fishes. This, therefore, means consumption of these fishes may lead to the accumulation of these metals in man to a toxic concentration. This may be one of the reasons for the increase in some heavy metal-related health issues (diabetes, renal diseases) in this region.

Arsenic geochemical species modeling, prediction, and bioavailability in groundwaters of the Oban Massif, southeastern Nigeria

To ascertain the distribution patterns, source identification, chemical speciation, and bioavailability of arsenic in basement aquifers, 64 groundwater samples were analyzed using hydrochemical and geochemical modeling. It was determined that important ion geochemistry, hydrogeochemical facies, and basic hydrogeochemical parameters are interdependent. Arsenic (As) concentrations varied from 0.001 mg/l to 0.03 mg/l, with a mean of 0.007 mg/l. The results of 4.68% of samples were higher than the allowable level of 0.01 mg/l, i.e., groundwater arsenic levels are not dangerous. Significant ion concentrations decreased from dry to rainy seasons suggesting that ionic concentrations generated by silicate weathering in aquifers became diluted. Abundance trends in metal concentration during the dry and rainy seasons were Fe > Mn > Zn > Ni > Cu > As > Pb > Cd and Fe > Zn > Mn > Ni > Pb > Cu > As > Cd, respectively. Of the two hydrochemical facies discovered, the predominant one was the main alkaline-earth-bicarbonate facies [Ca-(Mg)-HCO3] typical of basement terrains, suggesting the fundamental stage of groundwater evolution. Plots of ionic ratios, metal loads, and principal component analyses showed that ionic concentrations are controlled by geology. Geochemical modeling revealed the presence of aqueous arsenic species, which are the less dangerous arsenates at unsaturated levels and do not currently pose a concern.

Modelling of soil environmental quality and early warning of integrated ecological risk

The knowledge of dynamic trend in soil heavy metal contamination and associated risk is important for soil pollution prevention, safe utilization and early warning of soil environmental quality and ecological risk. In this study, a modified integrated risk index (NIRI) was adopted to evaluate ecological risk in agricultural soil in Wenzhou with 70 samples, which is located in the southeast of China. In addition, two scenarios with different metal fluxes (optimistic and default scenario) were constructed to predict future dynamic trend of metal concentrations. Results showed the agricultural soil was mainly contaminated by Cd and Pb. The NIRI indicated moderate to considerable risk in most sites and Cd posed the greatest contribution to NIRI value. Besides, higher risk was determined in paddy soil than that in vegetable. Scenario simulation results revealed general declining trend in optimistic scenario while increasing trend in default scenario for metal concentration. However, exceedance varied with prediction period, soil types and metals. Ecological risk probability showed similar trend with metal concentration, indicating significant shift to higher risk level in default scenario while insignificant decrease in optimistic scenario. The proposed scenario simulation results provide reference to support soil quality improvement and risk management.

Spatiotemporal Changes in Trace Metal Bioavailability in the Sediment Pore water of a Constructed Wetland Using Passive Pore water Samplers.

Sediments in aquatic systems often act as a major sink for contaminants. Diffusive gradient in thin films (DGTs) and in situ equilibrium dialysis samplers (peepers) are two major in situ pore water sampling devices that overcome the problems associated with conventional pore water sampling methods. In the present study, DGTs and peepers were used to study the spatial and seasonal effects (cool months, October-February; warm months, May-September) on metal bioavailability in the H-02 constructed wetland and the sink versus source role of the sediments by calculating the metal resupply capacity. Data showed similar seasonal trends in metal concentrations using passive samplers, peepers, and DGTs. Pooled Cu and Zn concentrations measured using DGTs were lower in warm months (1.67 ± 1.50 and 2.62 ± 0.68 μg L-1 , respectively, p < 0.001) versus in cool months (2.12 ± 0.65 and 5.58 ± 1.33 μg L-1 , respectively, p < 0.001; mean ± 95% confidence interval). Sulfate (SO4 2- ) concentrations were significantly (p = 0.0139) lower in warm months (averaged at 0.22 ± 0.05 mg L-1 ) compared to in cool months (0.16 ± 0.05 mg L-1 ). The increase in SO4 2- concentration is an indicator of the lower activity of sulfate-reducing bacteria, which need SO4 2- during anaerobic respiration, in which SO4 2- is reduced to sulfide (S2- ) that forms insoluble salts with Cu and Zn, which could partially explain the higher bioavailability of these metals in the cool season. Metal resupply capacity of the sediments was mostly <0.2 for Cu and Zn. Taken together, the H0-2 wetland sediments mostly acted as a sink to both Cu and Zn over the course of the present study. Environ Toxicol Chem 2023;42:2726-2736. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Ecological Risk Assessment and Source Contributions of Heavy Metals in the Sediment of the Chan Thnal Reservoir, Kampong Speu, Cambodia

Metal contamination from farming, inadequate wastewater treatment, and poor disposal of municipal garbage are major threats to public health. This research aimed to (1) assess the extent of heavy metal contamination in sediment samples, (2) describe the distribution of heavy metals by locating likely pollution sources using a positive matrix factorization (PMF) model, and (3) quantify the potential ecological consequences associated with these metals at six different places around the Chan Thnal Reservoir. The findings indicated steady degradation and suggested moderate to high metal contamination. Fe &gt; Zn &gt; Cr &gt; Cu &gt; Pb &gt; Co &gt; As &gt; Mn &gt; Cd was the trend of metal concentrations in the sediment. Various soil pollution indices showed that most of the studied sediment samples were clean, moderately clean, or slightly contaminated. However, Co and Cd reached high-risk conditions posing a severe problem to the local population living in and around the Chan Thnal Reservoir. Principal component analysis (PCA) was used to estimate primary factors in PMF analysis. It was found that the contamination of As, Cu, Zn, Cd, and Pb originated from agricultural and traffic vehicle sources; however, Zn, Fe, Mn, Cr, and Cu were derived from natural sources (e.g., atmospheric deposition and compost amendment). Furthermore, Fe, Cd, Mn, Co, Pb, and Cr were generated from urban and industrial sources (metal coatings, plastic burning, wastewater irrigation, and sewage sludge). Accordingly, this research improves our knowledge of the prevalence of heavy metal pollution in agroecosystems, which may be used to foresee and mitigate the risks of heavy metal exposure to humans and other organisms.

Lime slurry treatment of soils developing on abandoned coal mine spoil: Linking contaminant transport from the micrometer to pedon-scale

Historical and abandoned coal mine spoil continues to generate acid- and metal(loid)-rich porewaters and represents a geographically large and diffuse non-point source of contamination to local watersheds. A potentially inexpensive approach to treat these materials and soils developing on them is through the application of lime slurries, to neutralize acidity and encourage the (co)precipitation of metal(loids) with Fe(III)-(oxy)hydroxides, and potentially other metal-oxides and/or Ca-bearing phases. The efficacy of this approach was evaluated through parallel field application and laboratory-based flow-through column experiments. The field site is Huff Run sub-watershed 25 located in Tuscarawas County, Ohio and was chosen in part because it was previously classified as one of the most highly AMD-impacted sub-watersheds in the region. Two locations with historical spoil were chosen and suction lysimeters were installed at 25 and 75 cm depth to monitor porewater composition on two sides at the base of each pile. Half of each slope received seven lime slurry treatments from June through October of 2017. A suite of aqueous (ICP-OES, IC, and TOC-L) and solid phase geochemical and mineralogical approaches (quantitative SEM-EDS and synchrotron μ-XRF) were used to determine how composition, texture, morphology, and spatial distribution of mineral coatings differ in pre- and post-lime treated soils, and how that impacts the distribution and transport of trace metal(loid)s. Mine spoil porewater at site 1 was slightly less alkaline (pH ranging from 7.04 to 7.37) than at site 2 (ranging from 7.55 to 7.71), and average electrical conductivity values at site 1 (316–405 μS cm−1) were slightly lower than at site 2 (358–464 μS cm−1), although differences between the sites were not significant. Porewater pH and electrical conductivity in all lysimeters decreased over the course of the field season but there was no obvious response to lime treatment at either site or any depth. At site 1, both treatment and depth were significant factors affecting Ca, K, Ni, SO42−, and DOC concentrations while only treatment effects were significant for dissolved Al and Cu (p < 0.05). For all soils, there were no trends in metal concentration observed over time although DOC and SO42− decreased over the field season. Pedon-scale changes in metal porewater concentrations in response to treatment were linked to micrometer-scale changes in mineral surface coatings; specifically, higher concentrations of Ca, Fe, Mn, and Zn were observed in the coatings and no changes were observed in Fe redox speciation, whereas total S decreased likely due to oxidation of S in coal fragments. In contrast to the field experiment, the column experiments exhibited a much greater response in effluent composition with respect to lime treatment. The untreated columns had approximately an order of magnitude more H+ leached over the course of the experiment (p < 0.001) and resulted in greater Ca, Al, Cu, and DIC leached and less Mn, Zn, and SO42−. Soils treated with the lime slurry in the column experiments exhibited larger and thicker secondary Fe-coatings, including the addition of Fe-sulfates. Despite clear trends in the laboratory-based column experiment where the lime-to-soil ratio was higher, the effects were either muted or undetected in the field pilot project, suggesting that a higher application rate of lime in the field is needed to achieve a similar effect. This work provides evidence that a less alkaline lime slurry could be a practical and inexpensive method of treating coal mine spoil-impacted soils and represents an important step in linking laboratory-based remediation studies to implemented field-based studies.

Urban Sustainability at Risk Due to Soil Pollution by Heavy Metals—Case Study: Volos, Greece

The focus of this case study is the meticulous observation of urban soil pollution by heavy metals (HMs), or, alternatively, potentially toxic elements (PTEs). The study took place in the urban center of Volos, Greece. Moreover, 248 soil samples were collected during 2018–2021 (62 samples annually), while 3.65 km2 was, approximately, the study area. The breakdown of total concentrations took place for the interpretation of different soil parameters, also according to mean values and medians of the total concentrations of HMs, the following decreasing order was monitored: Mn &gt; Zn &gt; Cr &gt; Ni &gt; Cu &gt; Pb &gt; Co &gt; Cd. During the 4-year study, an increasing trend of metal concentration was observed (for each year compared to the previous one). Furthermore, the imaginary triangle, which was observed, is bordered by the historic train station, the two city bus and intercity coach stations and the commercial harbor. Statistical analysis was implemented in order to interpret the exceedances of HMs concerning the Directive 86/278/EEC. Principal component analysis (PCA) is an additional technique that was conducted because of the correlations and interdependences between the HMs. A strong correlation was observed between the HMs, but mainly between Cd and Zn, which is probably due to their common origin. During the COVID-19 pandemic, significant changes in metal concentrations were observed in different parts of the city, due to the limited movement of motorized wheeled vehicles, but also due to the long operating hours of the heating systems in the residential area. Further research is needed in the future in order to identify the sources of pollution and to find possible ways to reduce it. All in all, urban soil pollution by HMs is a great conundrum of the environmental aspect of sustainability.

From sediments to soils: changes in pore water metal bioavailability

The use of sediments as soils is an area of interest for Beneficial Use of dredged sediments. In this study the impact of the transition from sediments to soils is researched by looking at the seasonal and long year (10 year) change in pore water metal chemistry of sediments which are considered clean (class A) according to the Dutch soil directive. This study is based on a combination of geohydrological, geochemical and ecotoxicological risk models and validated against measured pore water concentrations for metals over an dry/wet period. The pore water metal concentrations are compared against standards and expressed as at Risk Characterization Ratio’s (RCR) values. The RCR values are high (> 1) during the first 3 years after the application of sediments as soil, especially at the end of the summer. The multi substances Potentially Affected Fraction (ms-PAF) shows a similar trend as the RCR values, although it takes 5 years before the combined calculated potential ecotoxicity is below the legal 40% threshold level. Translated to land use, it is advised to restrict land use for farming on soils where these clean (class A) sediments are applied for a five-year transition period.Article HighlightsBeneficial Use of sediments should take into account the different conditions when used as soils.Use of sediments as soils lead to a predicable seasonal and multiple year trend in metal concentrations in pore water.The predicted results in metal pore water concentrations are translated into an advice for temporal land use.

Quantifying and characterising metal concentrations in Derwent Estuary sediments using portable X-ray fluorescence spectrometry

The Derwent Estuary is highly enriched in potentially toxic elements, such as Zn, Pb, Cu, As, Hg and Cd, owing to inputs from historical industrial activity adjacent to the river, predominantly prior to strict environmental protections introduced in the 1970s. Contaminants are now buried at shallow depths within the sediment profile, in one or two highly concentrated layers decreasing in concentration away from an electrolytic zinc refinery, regarded as the main source of the contaminants. Enriched metals (Zn, Pb, Cu, Cd and As) in the estuary were estimated from data collected from 37 sediment cores using a portable X-ray fluorescence spectrometer that was validated against inductively coupled plasma mass spectrometer analyses. The thickness of the metal and metalloid enriched layers ranges from 32.5 to 107.5 cm, with an average thickness of 63 cm. Sedimentation rates based on this layer and the time since the start of zinc processing are approximately 0.46 cm/year. Sedimentation rates based on the thickness since maximum metal and metalloid concentrations are between 0.17 and 1.64 cm/year. Based on these sedimentation rates, the average time it will take for surface sediments to return to background metal and metalloid concentrations, if left undisturbed, is approximately 123 years. KEY POINTS Metal contaminant concentrations in Derwent Estuary sediments have two clear peaks in concentrations at depth, where estuary sediments have been enriched at varying rates over the last 97 years. The contaminated layer varies in thickness throughout the estuary, but has an average thickness of 63 cm, a maximum thickness of 107.5 cm and a minimum thickness of 32.5 cm, from surface sediments to the bottom of contamination. All surface sediments were enriched in metals or metalloids, but the overall trend in metal concentrations is decreasing from a major enrichment peak to moderate concentrations at the sediment–water interface. The time required for surface sediments to return to acceptable concentrations as defined by the ISQG is estimated to be on average 123 ± 88 years for the whole estuary with different parts of the estuary returning to background at different times.

ТЕНДЕНЦИИ ИЗМЕНЧИВОСТИ ХИМИЧЕСКОГО СОСТАВА И КАЧЕСТВА ВОДЫ ПРИТОКОВ НИЖНЕЙ ВОЛГИ С УЧЕТОМ АНТРОПОГЕННОГО ВОЗДЕЙСТВИЯ И КЛИМАТИЧЕСКИХ ИЗМЕНЕНИЙ

The regional features of transformation in the chemical composition of water in the Lower Volga tributaries and its main trends under anthropogenic impact and climatic variations are presented. Most trends for the principle ions (sulfates, carbonates, calcium and magnesium ions) are increasing, which may be a consequence of ongoing climate change. Moderate decreasing trends prevail in the concentrations of nutrients and organic substances in water. It was found that the trends in metal concentrations are multidirectional. All revealed statistically significant trends for iron and copper compounds are decreasing, and those for manganese are increasing. Based on the analysis of the identified trends in the chemical composition, the river ecosystems of the Lower Volga tributaries are classified into two categories: stable (“healthy”) and transformed (“transitioning”).

Effects of hydrologic variability and remedial actions on first flush and metal loading from streams draining the Silverton caldera, 1992–2014

AbstractThis study examined water quality in the upper Animas River watershed, a mined watershed that gained notoriety following the 2015 Gold King mine release of acid mine drainage to downstream communities. Water‐quality data were used to evaluate trends in metal concentrations and loads over a two‐decade period. Selected sites included three sites on tributary streams and one main‐stem site on the Animas River downstream from the tributary confluences. During the study period, metal concentrations and loads varied seasonally and annually because of hydrologic variability and remedial actions designed to ameliorate the effects of acid mine drainage. Water‐quality data were divided into two periods based on the timing of remedial activities in the watershed. The first period includes active water treatment, surface reclamation and installation of bulkheads in adits; the second period includes the decade following these activities. Water‐quality data were used to estimate annual and monthly zinc loads using the Adjusted Maximum Likelihood Method (using LOADEST software) and U.S. Geological Survey streamflow data. This study presents one of the first applications of LOADEST focused on metal loads. Monthly flow‐weighted concentrations were analysed using a Mann‐Kendall trend test to determine the direction, magnitude, and significance of temporal trends in zinc loading in any given month and using t‐test comparisons between the two periods. Zinc loads estimated for the Animas River below the tributaries indicate decreased zinc loading during the rising limb of the hydrograph in the second period, perhaps reflecting a reduction of snowmelt‐derived zinc load following surface reclamation activities. In contrast, base‐flow zinc loading increased at the main‐stem site, perhaps because of the cessation of water treatment in tributary streams. Flow weighting of monthly load estimates yielded increased statistical significance and enabled more nuanced differentiation between the effects of hydrologic variability and remedial activities on zinc loading.

Application of the paleolimnological method to assess metal contaminant distribution (As, Cu, Pb, Zn) in pulp mill stabilization basin sediments, Nova Scotia, Canada.

The paleolimnological method was used to decouple geogenic and anthropogenic metal (loids) contributions in a sediment stabilization basin (Boat Harbour) located in Nova Scotia, Canada. Boat Harbour has been impacted by industrial effluents discharged by a bleached kraft pulp mill (1967 to 2019) and a chlor-alkali plant (1971 to 1992). The former estuary now contains >577,000 m3 of unconsolidated sediment, impacted by inorganic and organic contaminants, including metal[loid]s, polycyclic aromatic hydrocarbons and polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans. Previous studies indicated significant knowledge gaps in our understanding of the spatial, stratigraphic, and temporal variation of sediment contamination. Twenty-five lakebed sediment gravity cores were obtained between 2016 and 2019 to determine spatiotemporal distribution of sediment As, Cu, Pb, and Zn concentrations which consistently exceeded guidelines for aquatic sediments. Results demonstrate there is no distinct spatial trend in metal concentrations despite point source effluent inputs. High and variable concentrations of Cu and Zn in contaminated sediment likely represent a combination of cation capture by highly organic sediment and influence of pulp mill on lakebed sediment chemistry. Elevated Pb in contaminated sediment is the result of atmospheric deposition from combustion of fossil fuels and bioaccumulation in effluent feedstock. Average sedimentation rate (1 cm every 3 years) is high compared to a nearby freshwater lake and is enhanced by increased nutrient loading and more productive water column conditions associated with effluent introduction. Temporal trends indicate significantly higher concentrations of Zn and Cu in top sediment samples consistent with changes in effluent treatment procedures as well as composition of effluent solids. Comparison of geochemistry of effluent influenced sediment and pre-effluent substate sediment at Boat Harbour to freshwater and marine reference was required to understand the degree to which geogenic and anthropogenic sources of metal(loids) have influenced effluent chemistry. This study demonstrates that undisturbed, time transgressive samples from both impacted sites and reference sites combined with non-destructive, rapid, small sample analytical techniques such as X-ray fluorescence, provide an accurate assessment of sediment metal contaminant distribution, data required to guide remediation and environmental effects monitoring and compliance.

Comparative seasonal assessment of pollution and health risks associated with heavy metals in water, sediment and Fish of Buriganga and Turag River in Dhaka City, Bangladesh

Heavy-metal pollution of surface water, sediment and fish have been seen as a major global problem, with a significant proportion of developing countries like Bangladesh. This study assessed the intensity of alarming six toxic substances (Cr, Zn, Fe, Cu, Pb and Ni) throughout the River water, sediments as well as soft tissues of three widely consumed fishes (Heteropneustes fossilis, Channa punctatus and Channa striata) obtained from two urban streams of the Buriganga and Turag in the Dhaka metropolitan. For evaluating the comparative seasonal variation of heavy-metal concentration, water and sediment samples were collected from five selected sites for two different seasons (viz. 10 from winter seasons and 10 from summer seasons). Finally, a total of 20 water samples, 20 sediment and 12 fish samples were investigated by flame atomic absorption spectroscopy (FAAS) and graphite furnace atomic absorption spectrometer (GFAAS) corrected with the Zeeman effect background correction system. The hierarchy of mean concentration of selected heavy metals in Buriganga water is found to be Fe > Cr > Ni > Zn > Cu > Pb in the winter season whereas during the summer season the order is Fe > Cr > Zn > Ni > Cu > Pb. For the River Turag, the order is Fe > Zn > Cu > Ni > Cr > Pb and Fe > Zn > Ni > Cu > Cr > Pb during winter and summer season, respectively. The level of metals studied surpassed the acceptable level of drinkable water, implying the ineptitude of drinking and cooking water from these Rivers. However, this hierarchy of heavy metals for sediments of Buriganga River changed to Fe > Cr > Ni > Zn > Cu > Pb for the winter season and Fe > Cr > Ni > Cu > Zn > Pb for the summer season. Whereas, for the Turag River, the decreasing trend of metal concentration found in sediment was Fe > Zn > Cr > Ni > Cu > Pb for both seasons. For probable human health hazard implications, contamination factor (CF) and pollution load index (PLI) were studied. The CF values revealed the low-to-moderate pollution of sediment. The PLI value above one shows the degradation of the consistency of the sediments. Fe, Ni, Pb, Cr, Zn and Cu concentrations in fish species were found to be 19.66–45.1, 0.07–12.18, 1.2–10.18, 20.18–187.07, 11.08–68.25, 2.07–10.4 mg/kg, respectively. The metals studied differed considerably among organisms and seasons. Bioconcentration factor (BCF), the daily average consumption of metal (EDI), as well as target threat quotients (THQs) for specific metal indicated that Cr and Pb are harmful in fish muscles and possible risks remain for fish consumers. The obtained concentrations of some metals are higher than the WHO/FAO’s permissible limit, suggesting that the water and fish found in these Rivers are like to be harmful to the human being. This study shows that attention should be given to the risk assessment for heavy metals in these Rivers.

Metals uptake and translocation in salt marsh macrophytes, Porteresia sp. from Bangladesh coastal area

Studies from around the world have suggested salt marshes or coastal wetlands can be used as sites for phytoremediation of metals. However, no investigations have been conducted to assess metal accumulation and translocation capabilities of salt marsh macrophytes from Bangladesh coastal area. The aim of this study was to evaluate the uptake and translocation of eight metals, Fe, Zn, Mn, Cu, Co, Rb, Sr, and Pb in Porteresia sp. from the six salt marsh sites of Bangladesh. The leaf, shoots and root tissues of Porteresia sp. samples were analyzed for metals by using the energy-dispersive X-ray fluorescence (EDXRF). The decreasing trend of metal concentrations was, in roots; Fe > Mn > Pb > Cu > Zn > Sr > Rb > Co, in shoots; Mn >Fe > Cu > Pb > Zn > Sr > Rb > Co, in leaves; Fe > Mn > Cu > Pb > Zn > Rb > Sr > Co. Generally, roots of the Porteresia sp. showed high accumulation of the metals when compared to shoots and leaves suggesting relevant availability in the sediment. Pb was the only metal with concentrations significantly higher in the leaves and shoots than in the root. Except for Pb, bioaccumulation concentration factor (BCF) for all metals was lower than 1 in plant organs indicating poor absorption and bioavailability of metals. Higher value (>1) of BCF for Pb infers the species can potentially be used for Pb phytoremediation. However, the translocation factor (TF) confirmed the diversified mobility of the metals from below-ground part to above-ground parts for all the measured metals in the salt marsh species. Highest mobility was observed for Mn and Pb. But it was hard to find any regular trends among all the metals and all the sites.

Assessment of Pb, Cd, Cr and Ni in Water and Water Hyacinth (Eichhornia crassipes) Plant from Woji Creek, Rivers State, Nigeria

This study evaluates the levels of Pb, Cd, Cr and Ni and the potential ability of water hyacinth (Eichhornia crassipes) plant to bioaccumulate these metals in Woji Creek, Rivers State, Nigeria by collecting water and water hyacinth samples along a 1.3 km stretch of the creek between 2018 and 2019 for analysis. Water samples and plants were collected from five stations across the creek from June to October of both years. The trend of metal concentration in the surface water is Pb &gt; Cr &gt; Ni &gt; Cd in 2018 and Pb &gt; Ni &gt; Cr &gt; Cd in 2019. In 2018, metal concentration in the root are in the order: Cr &gt; Ni &gt; Pb &gt; Cd, while the trend for the shoot is Cr &gt; Pb &gt; Ni &gt; Cd. In 2019, Cd was detected in the roots ranging from 1.009 ± 0.001 to 9.545 ± 0.006, while Pb ranged from 0.298 ± 0.006 mg/kg to 121.006 ± 0.005 mg/kg. There was substantial bioaccumulation of Pb, Ni and Cr in the roots with most plant roots having BCF &gt; 1. In the shoot, BCF was &gt; 1 for Pb and Cr only, while Ni had BCF &lt; 1. The findings from this research also assert that the E. crassipes can be used in the application of rhizofiltration as phytoremediation technique in Woji creek.&#x0D; Keywords: Metal accumulation, phytoremediation, Translocation, Bioconcentration, Woji creek

Evaluating the Variation of Dissolved Metals on a Highway Roadside Using a Generalized Additive Mixed Model (GAMM)

Assessing metal concentrations in roadside soils requires a better understanding of the extent to which they are affected by different environmental factors such as soil texture, depth, pH, runoff concentration, and precipitation. Monthly data of dissolved Cd, Ni, Cr, Pb, Cu, and Zn concentrations in three different roadside soils (sandy loam, gravel (0–32 mm) and a mixture of sandy loam and gravel) were measured during a 2-year lysimeter field study at different depths. The data was used to assess the variation of trace elements and how they were affected by environmental factors. For data interpretation, generalized additive mixed models (GAMMs) were used to explore the complex behavior of metals in heterogeneous soils by detecting linear and nonlinear trends of metal concentrations in the soil solution. As a result, the modeling approach showed that Cd, Ni, Cr, Pb, Cu, and Zn concentrations are functions of different environmental variables, which have either linear or nonlinear behavior. All investigated metals showed that pH could explain their variation. With exception of precipitation, Ni and Cr variations can nearly be explained by the same environmental factors used in this study (time, pH, infiltration volume, roadside soil type, runoff concentrations, and depth). During the study period, we found that Zn variation can be explained by its nonlinear relationship with all the significant studied environmental factors. As the depth increases from the surface to 30 cm of depth, the metal concentration of Cd, Ni, Cr, Pb, and Zn increases. Surprisingly, the roadside soil consisting of gravel has the lowest organic carbon and showed the lowest median concentration of Cd, Ni, Pb, Cu, and Zn at 30 cm. Moreover, the model showed that the surface runoff volume has no effect on the metal variation in the soil solution.

Trace elements in marine organisms of Magdalena Bay, Pacific Coast of Mexico: Bioaccumulation in a pristine environment.

Trace element (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) concentrations were assessed in marine organisms (n = 52) sampled from the Magdalena Bay lagoon complex in Baja California Sur, Mexico, a pristine marine environment. The overall trend of metal concentrations (dry weight) in the organisms was found to be Fe > Zn > Cd > Cu > Mn > Pb > As > Hg > Ni > Cr > Co. Bivalve mollusks (53.83mgkg-1) contained twofold higher levels of metals than the finfishes (20.77mgkg-1). Calculated BioConcentration Factor(BCF) values showed that dissolved Mn is readily bioavailable to the organisms, whereas Biota Sediment Accumulation Factor(BSAF) indicated high values for Zn, Cu and Cd. Cd and As levels were observed to be increasing with the trophic levels. Toxic elements, namely Pb, Cd and As in the studied fish species were found to be higher than the values recommended for human seafood consumption. The study provides a comprehensive baseline report on trace element bioaccumulation in several marine organisms that will aid in developing effective conservation strategies of the highly biodiverse lagoon complex.

A survey of metal concentrations in marine sediment cores in the vicinity of an old mercury-mining area in Karaburun, Aegean Sea.

The aim of this study was to assess the historical trends of metal concentrations in coastal sediments in the vicinity of an inactive mining area, find background values and contamination levels of metals around the Karaburun peninsula, and then search for other sources of mercury in marine sediment cores using multivariate statistical analysis and report the potential ecological risks from that metal contamination. Surface sediment samples were taken from seven stations. Water depths were less than 20m (coastal area) at stations KB07 and KB08. The depths at stations KB01, KB02, and KB03 were between 20 and 40m, and stations KB05 and KB06 were more than 40m (open area). In surface sediments at depths between 20 and 40m, Mo, Cu, Pb, Zn, Ni, Co, Fe, Cd, Ti, Zr, Sn, As, Y, and Hg levels revealed higher contamination factors (Cf) compared to those of the coastal and open areas. Also, sediment samples were taken for historical records at stations KB01 and KB02 for 2012. Metal concentrations of Cu, Zn, Ni, Co, As, Sb, Cr, Ba, Ti, Al, and Hg in the sediment core samples were significantly higher during the Holocene (~5700 BC to 2000 B.C.) and Medieval Warm periods (~1000 A.D. to 1400 A.D.) and tended to decrease towards the Little Ice Age (2200 B.C. to the birth of Jesus Christ). Background concentration of Hg in sediment was found as 1.67μg/g around the Karaburun peninsula. Average EF values higher than 20 were identified for As, Hg, Sb, and Ca. Ni and Hg levels were found above the PEL values. It was determined that the accumulation effect of Hg coming from the mafic rocks due to erosion in the marine environment was higher than that of Hg coming from the mine. The factor analyses showed an association between Hg, Ni, and Co. This reveals the importance of the contribution of mafic rocks reaching the marine environment by wave erosion. According to the factor analyses, high concentrations of Pb, Zn, Cd, As, Sb, Ba, Ti, and Zr were detected in the lithogenic sources.

Levels of Some Heavy Metals in African Giant Land Snail (&lt;i&gt;Archachatina marginata&lt;/i&gt;) in Major Markets in Abeokuta, South West Nigeria

The level of heavy metals (Pb, Cu, Cd) as bio indicator of metal pollution in Abeokuta by analysing snails samples from major markets in Abeokuta. The level of heavy metals (Pb, Cu, Cd) were determined using Atomic absorption Spectrophotometer. Analysis of the results showed that the concentration of lead ranged from 4.15 mg/kg in Omida market to 7.93mg/kg in Lafenwa market. Similarly, Copper concentration ranged from 0.339mg/kg in Omida market to 0.719 mg/kg in Lafenwa market. The highest concentration of Cadmium was at Lafenwa market with a value of 0.06 mg/kg. Lafenwa market showed the highest concentration of the three metals and the trend of metal concentration was of the order Pb > Cu > Cd. The levels of contamination of the snail samples were lower than the recommended FAO/WHO levels. However, there is need for regular periodic checking of heavy metals level of edible snails available in open market to safe guard the health of the general public.

Effect of Heavy Metal Contamination on the DNA Mutation on Nepenthes Plant from Abandoned Mine

Objective: Heavy metal contamination on water, soil, crops and including to the other living organisms, including their effects on DNA mutation in abandoned mine is highlighted in this study Methodology: In this study, 6 toxic metals, Zn, Pb, Fe, Cd, Cr and Mn in Nepenthes plants at an abandoned copper mine site were investigated. A total of 20 Nepenthes plants were collected from different sites of the abandoned mine. Metal concentration was determined using the Inductively Coupled Plasma/Optical Emission Spectrometry (ICP/OES) technique and electrophoresis gel and Inter Simple Sequence Repeat (ISSR) amplification processes for DNA mutation analysis. The total concentration trend of metal concentrations recorded with Cu (up to 88.797 mg kg–1)>Mn (39.018 mg kg–1)>Zn (30.260 mg kg–1)>Pb (8.206 mg kg–1)>Cd (0.168 mg kg–1). Results: The results also showed that concentration of heavy metals in Nepenthes plants collected from the abandoned mine were much higher than in control plants. However, the concentrations were still under the tolerance limit of heavy metals in plants except for Cu concentration. Besides, the concentration of heavy metals generally is higher in the flowers of the plants. For DNA analysis, based on the image obtained the result showed the DNA bands were located at the same location with the control Nepenthes which indicated there is no mutation occurred for the Nepenthes collected from the abandoned mine. Conclusion: From the result it is suggested that pitcher plant such Nepenthes may act as a potential phytoextraction of heavy metal from contaminated soil or water compounds at the abandoned mine.