Heavy Metal Concentrations In Samples Research Articles

Ecotoxicological risk assessment of metalloid contamination in the sediment and benthic fauna of a tropical lotic freshwater ecosystem in Southern Nigeria

The increasing exposure of freshwater bodies to pollutants and the bioaccumulation of heavy metals in body parts of aquatic organisms has raised concerns on the ecotoxicological and human health risk. This study evaluated the potential ecological and human health risk of heavy metal pollution in sediment and benthic fauna (Caridina africana) of the Osse River, Edo State, Nigeria. Using requisite equipment, samples of water sediment and C. africana were collected at designated stations from September 2015 to February 2017. Heavy metal concentrations in samples were determined using atomic absorption spectrophotometer. Result showed heavy metal contamination with concentration profiles of Fe > Zn > Mn > Cu > Ni > Pb > Cr > Cd > V in sediments and Fe > Zn > Mn > Cu > Ni > Cr > Pb > Cd > V in C. africana. The potential ecological risk index (PERI) values classified stations 1, 2 and 4 as of low ecological risk (PERI ≤ 150), while station 3 (PERI ≤ 300) was classified as of moderate ecological risk. Human health risk assessment for heavy metals in C. africana indicated significant non-carcinogenic health risk (HI > 1), and high carcinogenic risk to human health. The consumption of the contaminated C. africana, which is harvested in commercial quantities, portends health risk to the general public. There is need for urgent action in the abatement and regulation of identified anthropogenic activities responsible for the release of these heavy metals into the Osse River.

Unveiling the impact and mechanisms of Cd-driven ecological assembly and coexistence of bacterial communities in coastal sediments of Yellow Sea

The microbial community assembly processes and underlying mechanisms in response to heavy metal accumulation in coastal sediments remain underexplored. In this study, the heavy metal concentration in samples were found below the marine sediment quality standards. Through partial Mantel tests and linear regression analysis, Cd was identified as the major influencing factor, displaying strongest correlation with the bacterial community in the sediments. The class Desulfuromonadia was identified as a biomarker which showed enrichment in the sediments with high Cd content. Additionally, the results of null model and the neutral community model demonstrated the prominent role of stochastic processes in the assembly of bacterial community. However, with the increase in Cd concentration, the influence of selection processes intensified, resulting in a decline in species migration rate and subsequent reduction in ecological niche width. Furthermore, the intensified competition and an increase in keystone species among bacterial populations further enhanced the stability of the microbial co-occurrence network in response to high Cd concentration. This study offers an insight into the effects of heavy metal on microbial assembly and coexistence, which are conducive to marine ecosystem management and conservation.

Distribution of heavy metal and pollution assessment in environmental samples along the coastal area of Ras Tanura

ABSTRACT The present work deals with establishing the contents and pollution of heavy metals in samples collected from Ras Tanura along the Arabian Gulf. Using Plasma Atomic Emission Spectrometer ICPE-9820, the concentrations of metals have been measured. For soil samples the range values of metals concentrations (mg/kg) were: Cd (0.87–107), Co (0.32–0.72), Cr (0.27–4.61), Ni (0.01–3.92), Pb (0.18–3.26), Zn (0.23–3.46) and Zr (0.07–0.99). While in marine sediment samples, the range values of concentrations (mg/kg) were: 0.48–0.64 for Co, 1.28–4.21 for Cr, 21.8–80.4 for Cd, 1.28–2.62 for Ni, 1.46–2.09 for Pb, 0.42–1.32 for Zn and 0.59–0.82 for Zr. The contamination factor of metals in marine sediments was also calculated. The heavy metal concentrations in samples were within the acceptable standards set by the US Environmental Protection Agency.

Study of the Transition Pattern of Heavy Metal Absorption in a Rice-Related Matrix

Exposure to heavy metals, including arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg), is a major health hazard. The toxic effects of these heavy metals can exist in a latent state. These metals may accumulate through persistent exposure, causing adverse effects after several years to decades. Heavy metals are found in rice, the main staple food in East Asia. We studied the ecological effects of heavy metals on rice plant roots, straws, and seeds, and the soil and water used for rice cultivation. Food-grade rice grains were also analyzed. The toxicity level of As changed with the chemical form; therefore, species separation analysis of As was conducted. The concentrations of Pb, Cd, and As were analyzed by inductively coupled plasma – mass spectrometry (ICP-MS). The Pb concentration was the highest in soil (59.32 × 102 μg/kg), whereas Cd and As concentrations were the highest in rice roots at 52.36 and 20.65 × 102 μg/kg, respectively. In all samples, Hg was below the detection limit of the employed instrumentation. None of the heavy metal concentrations in the samples exceeded the Korean safety guideline levels. The heavy metal concentrations in the rice samples were the highest near the soil and decreased with distance, particularly As. The concentration of inorganic As was analyzed by high-performance liquid chromatography coupled with ICP-MS. The separation of As species in rice, consumed as food, showed the concentration of inorganic As was 69.51 μg/kg, which is below the Korean safety guideline levels.

Heavy Metal Concentrations in Trachurus Mediterraneus and Merlangius Merlangus Captured from Marmara Sea, Turkey and Associated Health Risks.

Rapid industrialization and excessive human population growth may cause deterioration in marine water quality and biodiversity. Heavy metals are one of the most common pollutants in the seas and marine organisms, including demersal and pelagic fish, can accumulate them from the environment. Assessment of the ecological risk of heavy metals from fish has an important role in public health. In this study, some heavy metal (Pb, Cd, As, Cr, Hg, Cu, Zn, and Fe) concentrations were determined in the muscle tissues of two commonly consumed fish species, Trachurus mediterraneus (Mediterranean horse mackerel) and Merlangius merlangus (Whiting), which are the fifth (14,222 tons/year) and sixth (6814 tons/year) highest commercial catches of marine fish species in Turkey, respectively. Heavy metal concentrations of samples collected from four sites (Adalar, İzmit Bay, Yalova, and Tekirdağ) in the Marmara Sea were determined using ICP-MS. Fish samples caught at Yalova station were found to have the highest heavy metal concentrations. According to the World Health Organization (WHO), in terms of the mean values, only As, and Cr were higher than permissible limits in T. mediterraneus, while Pb, Cd, As, and Cr were higher in M. merlangus. Arsenic concentrations were higher than maximum limits in both T. mediterraneus and M. merlangus. The estimated weekly intake (EWI) was calculated to assess the potential health impact. The EWI for arsenic, cadmium, lead, and mercury for some sites was above the provisional tolerable weekly intake.

Determination of heavy metals and health risk assessment of cheese products consumed in Greece

Contamination of dairy products with heavy metals is a major concern on a global scale and human exposure to related food products, especially cheese, is of rising concern. The aim of this study was the determination of several heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn) in 15 cheese samples consumed in Greece, during March 2016. An analytical method was optimized and applied, using microwave digestion followed by atomic absorption spectrometry.The optimized method produced good performance characteristics, including low LODs, good linearity (R2 > 0.997) and high recovery (77–114%). Results revealed the presence of low heavy metal concentrations in samples. Two distinct elemental groups were identified using clustering analysis. The first elemental group (Cu, Mn, Zn, Cd, Pb and Se) presented higher contents in hard and salty cheese types, while the second elemental group consisted of Cr, Fe and Ni and exhibited significantly higher concentrations in soft cheeses (water content > 60%). HMs in cheese samples presented low risk to human health. Estimated Daily Intake (EDI) values for Pb, Hg and Cd revealed a minimum exposure of the population to those heavy metals through cheese product consumption. In all cases, THQ values were <1, suggesting that the cheese products under investigation do not present a potential health risk through their consumption. The daily intake (DI) for Zn in cheese products represented 0.50–14.25% of the Recommended Dietary Allowances (RDA) for adults, while for Cu the DI contributed 0.33–10.67% of the RDA values.

Evaluation of the microbial diversity and heavy metal resistance genes of a microbial community on contaminated environment

Heavy metals are low molecular weight elements which at certain concentrations can cause environmental problems as they accumulate. These metals can be toxic depending on their concentration despite being essential to the metabolism of most organisms. Their accumulation in the environment is mainly due to anthropogenic actions which are difficult to revert. In this context, bacteria have been used to efficiently bioremediate the environment. The aim of this study was to map heavy metal resistant genes from bacterial communities in the Riacho dos Macacos compared to those from Rio Grangeiro, used as the environmental control due to its low heavy metal concentration. The samples were prepared by removing the soil and taking these to a laboratory for DNA extraction and subsequent sequencing using the Illumina Miseq kit. Physico-chemical analysis was also performed to quantify the heavy metal concentration in samples. The data were input in the MG-RAST and analyzed. Various genes associated with copper resistance such as Cu ATPase, multicopper oxidase, czc as well as genes associated with zinc resistance were found, especially from the czc family. In the resistant gene taxonomic analysis, the most common bacterial phyla were Proteobacteria with 49.96% and 59.29%, and Actinobacteria with 23.55 and 12.06% in Riacho dos Macacos and Rio Grangeiro, respectively. Other phyla totaled only 27.63% and 32.12%, respectively.

Heavy metal concentrations in Chinese folk medicines for treating epilepsy in children in rural China, and their prescription by village doctors: a cross-sectional survey

BackgroundIn areas of rural China inhabited by minority groups, local village doctors often use traditional Chinese folk medicines to treat primary epilepsy in children. However, such folk medicines have been implicated in heavy metal poisoning in children. This study determined the heavy metal concentrations of samples of folk medicines, and examined the attitudes of local doctors regarding their use. MethodsInductively coupled plasma-optical emission spectrometry (ICP-OES) was used to identify toxic heavy metals from 33 samples of folk medicines (28 mixtures and five monomers) from eight counties in western Hunan Province, China, from March 1, 2018 to March 30, 2018. Village doctors in western Hunan Province, China, participated in face-to-face interviews based on a questionnaire focused on knowledge about the heavy metal toxicity of folk medicines. FindingsFour toxic heavy metals—cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As)—were identified in the samples. The mean (SD) concentrations of Cd, Pb, Hg, and As, were 0·513 (0·237), 5·145 (2·404), 0·298 (0·179), and 0·321 (0·106) mg/kg, respectively. Furthermore, Cd was found in 76%, Pb in 68%, Hg in 38%, and As in 24% of the samples. These levels exceeded the Chinese legal limits of 0·3, 5·0, and 0·2 mg/kg, respectively. The highest concentration of lead found in a sample was 65·42 mg/kg. The questionnaire was completed by 112 village doctors, of whom 68% considered folk medicine to be safe for treating epilepsy and 77% believed that some heavy metals, especially lead, were efficacious for treating epilepsy. InterpretationSome folk medicines contain heavy metal concentrations exceeding safe limits. The use of folk medicines by rural village doctors to treat epilepsy might lead to increased heavy metal exposure in children in these rural areas. It is important to focus on this issue given the potential harmful effects on children's health. There is a clear need for multifaceted interventions that target village doctors to improve their knowledge of heavy metal poisoning in children. FundingThis study was supported by the Yale-China Association.

Genetic structuring of the moss Pseudoscleropodium purum sampled at different distances from a pollution source.

In this study, we used amplified fragment length polymorphism analysis to investigate the genetic structure of the terrestrial moss Pseudoscleropodium purum (Hedw.) M. Fleish. naturally exposed to different levels of atmospheric deposition of heavy metals. We also determined the heavy metal concentrations in samples of this moss to evaluate whether there was a relationship between atmospheric pollution and population genetic diversity. A low level of genetic diversity and a limited gene flow among populations were observed which is in accordance to the prevalence of asexual reproduction in this species. In addition, no significant correlation was found between metal content and gene diversity in P. purum, probably because of the common history of the sampled populations and/or to the lack of a drastic reduction of the size of the population; nonetheless, a clear genetic structure was evident in relation to the existing pollution gradient. Thus, based on the results of the principal coordinate analysis and Bayesian analysis of the genotypes, the mixed structure of the second most polluted population would suggest an ongoing differentiation of metal-tolerant genotypes in the most polluted sites of the sampling area.

Monitoring-based discrimination of pathways of traffic-derived pollutants

We conducted a systematic monitoring study of roadside pollution based on surface-based samplers (U-channels) and samplers at different heights (poles). The study aim was to discriminate pathways of traffic-derived pollutants by surface runoff, splash water and airborne transport, and to assess the use of magnetic parameters for efficient monitoring concepts. At two high traffic density roads in southern Germany, we installed vertical poles at 0.5-m and 1.5-m distances from the roadside with samplers at various heights (surface, 0.5 m and 2 m), along with 4-m long U-channels (at the surface and 2.5 cm above it) perpendicular to the road. Clean quartz sand was used as collector material. Mass-specific magnetic susceptibility (χ), heavy metal (HM) and polycyclic aromatic hydrocarbon (PAH) concentrations all showed a significant increase over one year in pole and U-channel collectors. Systematic differences of χ, PAH and HM concentrations in samples at various heights and distances from the road indicate a common pathway of magnetic particles and pollutants and a dominance of splash-water transport. A magnetite-like phase turned out to be responsible for the enhancement of χ. Significant positive correlations between χ and total PAHs as well as HMs suggest that χ can be used as a proxy for traffic-derived PAH and HM pollution. The results of our monitoring studies could be used to provide basic knowledge to support the development of new monitoring approaches for traffic-derived pollution along roadsides.

Heavy Metal Concentrations in Soil and Green Vegetables (Vigna unguiculata) around Volcanic Mountain of Oldoinyo Lengai, Arusha, Tanzania

The aim of this work was to assess heavy metal concentrations of samples collected from areas around a volcanic mountain in Tanzania. Fifty five soil samples and 10 samples of bean leaves were analysed using Energy Dispersive Xray Fluorescence spectrometry (EDXRF). The concentrations of heavy metals in the samples are presented, statistical analysed and compared with control. The concentration in bean leaves are also compared with the maximum tolerable limits set by FAO/WHO to assess their safety for consumption. The results from this study show that high concentration of elements in both soils and bean leaves samples from Oldoinyo Lengai areas might be associated with frequently eruptions of the volcanic mountain of Oldoinyo Lengai. Hence, farming in Oldoinyo Lengai areas is introducing heavy metals in the food chain.

Multivariate association of regional factors with heavy metal concentrations in moss and natural surface soil sampled across Norway between 1990 and 2010

Assessing effects of air pollution needs the monitoring of atmospheric deposition. At least for enhancing the spatial resolution of measuring deposition by use of technical devices and of deposition modeling, mosses are used complementarily as biomonitors. In Norway, since 1985, nationwide surveys have been carried out every 5 years. This study aimed at investigating statistical relationships between heavy metal concentrations in samples of moss and natural surface soil, collected in spatial dense networks covering Norway, and regional factors. Heavy metal (HM) concentrations in moss samples collected in 1990, 1995, 2000, 2005, and 2010 and in natural surface soil specimens sampled in 1995 and 2005 across Norway were assessed statistically. Classification and regression trees were computed in order to uncover multivariate relationships between HM concentrations in moss and natural surface soil and potential influencing environmental factors that were integrated into the multivariate analyses. Atmospheric deposition of HM could be proved as the strongest predictor for HM concentrations in moss and natural surface soil samples. Land use within a 5-km radius and population density around the sampling sites were identified as further predictors of HM concentrations in moss and natural surface soil. HM monitoring with moss and natural surface soil samples indicates complementarily atmospheric deposition and thus should be carried out as long-term observation.

Environment Parameters Affecting Heavy Metal Concentration in Sand Collected from Children Playground in Seoul Metropolitan Area

The concentrations of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), zinc (Zn), nickel (Ni), and arsenic (As) in sand samples collected from selected children's playground and their correlation with environmental parameters, such as concentration of particulate matter in the atmosphere (<TEX>$PM_{10}$</TEX>), apartment age (> 5 years), clay and organic matter contents in sand samples, were analyzed. The average heavy metal concentration in samples was 0.040 mg <TEX>$kg^{-1}$</TEX> for Cd, 0.200 mg <TEX>$kg^{-1}$</TEX> for Cr, 1.75 mg <TEX>$kg^{-1}$</TEX> for Cu, 15.1 mg <TEX>$kg^{-1}$</TEX> for Ni, 3.42 mg <TEX>$kg^{-1}$</TEX> for Pb, 66.7 mg <TEX>$kg^{-1}$</TEX> for Zn and 0.750 mg <TEX>$kg^{-1}$</TEX> for As, all of which were below the environmental regulatory level established by Korea Ministry of Environment. However, in the consideration of direct and oral exposure by children to playground sand, the risk of the concentration range in the samples might be greatly enhanced. Heavy metal concentration in samples collected from high <TEX>$PM_{10}$</TEX> (> <TEX>$70{\mu}gm^{-3}$</TEX>) area was slightly greater than in samples from low <TEX>$PM_{10}$</TEX> (< <TEX>$70{\mu}gm^{-3}$</TEX>), indicating the contribution of particulate matter in air phase to heavy metal concentration in playground sand samples. The concentrations of both Cd and Pb were the highest in apartments older than 21 years (0.050 mg <TEX>$kg^{-1}$</TEX> and 5.28 mg <TEX>$kg^{-1}$</TEX> for Cd and Pb respectively) and showed positive correlation with apartment age (p<0.01 and p<0.001 for Cd and Pb, respectively). Clay content in playground sands ranged 3.8~11.2% and was positively correlated with heavy metal concentration. Organic matter content was negligible (mostly < 0.1%) and showed poor correlation with heavy metal concentration. In conclusion, concentration of heavy metals in playground sand was found to be predominantly influenced by the apartment age and clay content in sand samples and supplemented by dust deposition of particulate matter (<TEX>$PM_{10}$</TEX>) from atmosphere.

Mathematical models to predict soil heavy metal toxicity in the 2012 Olympic site

Heavy metal concentrations in samples collected from the London 2012 Olympic Village were determined using a three-step sequential extraction and a rapid extraction method. Metal toxicity was measured by employing the Microtox® solid phase analysis. Both extraction methods produced comparable results (p = 0.996), but the rapid method produced higher readings. A number of heavy metals were detected using the two extraction methods, including aluminum, arsenic, cadmium, chromium, copper, iron, nickel, lead and zinc; beryllium, molybdenum, niobium and titanium were also found in low concentration ranging between 0.16 and 27.10 mg/kg in the total acid digestion. The total metal levels in all the soil samples were within the UK Soil Guideline Value (SGV) except for lead which ranged between 62.9 and 776.2 mg/kg. The 30 min EC50 of different soil fractions was 2–5.8 g/L. In the absence of any of heavy metals in the SGV, the Dutch Guideline values were referred. Mathematical models for a number of metals were generated based on the changes in EC50 values between each (F1, F2 and F3) soil fractions and the initial toxicity in the non-fractionated samples. The resulting models produced good R2 values (>96%) for predicting the change in toxicity of lead, cadmium, zinc and copper by measuring their changes in concentrations. These models could substantially reduce the time requires to determine the toxicity in the samples; they would be a useful tool in the clean up process where monitoring of metal toxicity is required.

Verbascum sinuatum L. (Scrophulariaceae) (Sığır kuyruğu) Türü Kullanılarak Karadeniz Sahil Şeridinde Taşıtların Sebep Olduğu Ağır Metal Kirliliğinin Araştırılması

In this study, the heavy metal pollution caused by vehicle traffic was investigated in the leaves of Verbascum sinuatum L.(Scrophulariaceae) collected from the Blacksea coast ranging between Samsun, Ordu, Giresun, Trabzon, Rize and Hopa. Sample collection procedure was made in 23 stations in the related route. Heavy metal concentrations in the leaf samples of each station were determined with Perkin Emler Optic Emission Spectrometry (ICP-OES). Heavy metal concentration in samples was showed an order as Lead (Pb) > Zinc (Zn) > Chromium (Cr) > Nickel (Ni) > Copper (Cu) > Cadmium (Cd). The results of this study showed that the heavy metal accumulation in samples increased with an increase in traffic and V. sinuatum used as a biological indicator of this accumulation.

Behaviour of heavy metals in the estuarine area of the Capibaribe River in the Northeast of Brazil

The Capibaribe river estuary extends more than 15 km, mostly within urban areas in the city of Recife, capital of the state of Pernambuco, with a high population density and many heavy industries dealing with metal including platting. For this reason the river receives many different forms of pollution such as wastewater, litter or industrial effluents without treatments as well as sediments derived from the degradation of its borders or from hills erosion located around the city. To study the behaviour of the heavy metal along the Capibaribe river estuary, sixteen sediment samples were collected in different waterlogged areas: eight from the right border of the river and eight from the left, each one in front of the other. Sediment superficial samples were collected with a plastic manual sampler and submitted to granulometric analyse to determine the distribution of the soil fractions, x-ray diffractomety to determine the mineral composition of the clay fraction and lithium metaborate fusion to determine the total metal concentration using ICP-AES method. Eight metallic elements were studied (Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in 16 (sixteen) sediment samples collected. The results indicated that the concentration of total heavy metal along the Capibaribe estuary was influenced by sediment granulometric composition, with a trend to high total heavy metal concentration in samples with high percentage of clay. On the other hand, only the determination of the granulometric composition wasn't sufficient to analyse this behaviour because some points with high percentage of sand presented high concentration of total heavy metals what can be due to other factor like predominat kind of clay mineral, amount of humic substances, hidrodinamic regime among others.

Capsella bursa-pastoris (L.) Medic. as a biomonitor of heavy metals

Capsella bursa-pastoris (L.) Medic. (shepherd's purse) has been tested as a possible biomonitor of heavy metals in the city of Bradford, UK and compared with Poa annua L. (annual meadow-grass), a species with a similar ecology that had previously been studied for biomonitoring potential. Forty-two sites (urban roadside, urban, urban park, suburban and rural) in and around Bradford were investigated. Concentrations of Pb, Cd, Zn and Cu have been determined in soils and in washed and unwashed plant leaves. Differences between the washed and unwashed samples, reflecting airborne and soil entry routes, respectively, varied according to the metal pollutant. There were significant relationships between the heavy metal concentration in samples of surface soil (depth 0–10 cm) and washed leaves, the concentrations being greater with progressively increased urbanisation of the sites. Capsella bursa-pastoris has been found to be a useful biomonitor of the four heavy metals studied, and it may be a particularly useful species since it could monitor short-term changes in pollution in urban areas.