Mean Heavy Metal Concentrations Research Articles

Analysis of the Concentration of Heavy Metals in Khat Grown in Meru County and the Assessment of Their Associated Health Risks

Contamination of farm produce by toxic heavy metals has become a serious global health concern. These metals can bioaccumulate in plant tissues and are precursors for major public health problems such as cancer and neural impairment. Khat (Catha edulis) also referred to as miraa has the potential to sequester and accumulate both micronutrients and potentially toxic heavy metals in its consumable parts—tender leaves and soft barks of young shoots which are known to possess psychoactive properties when consumed. Therefore, the motivation behind this contribution is to determine the levels of six heavy metals, namely, cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), iron (Fe), and nickel (Ni) in consumable Meru khat samples, compare these levels with the permissible limits of World Health Organization (WHO) in order to predict associated health risks, and to estimate the noncarcinogenic risks of these metals by total health quotient (THQ) and health index (HI) on khat consumers. 1.0 g of dry ground khat samples was digested in 0.05 M HCl and allowed to stand for 5 hours before being analyzed for heavy metals using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The mean heavy metal concentrations (mg/kg) in dry khat samples of six toxic heavy metals were Cd (7.81 ± 1.56), Cr (15.98 ± 2.22), Cu (15.81 ± 2.84), Fe (97.35 ± 32.67), Ni (0.37 ± 0.02), and Pb (32.36 ± 9.95). Based on the results, the mean levels of Pb, Cd, and Cr exceeded WHO permissible limits. In addition, the Pb and Cd THQ values and the HI of the six heavy metals investigated in the khat samples exceeded the threshold value of 1.0. Furthermore, the THQ and HI values showed that Pb and Cd were potentially the major contributors to noncarcinogenic risks on regular khat consumers. This is a matter of concern on the excessive consumption of Meru khat-based products, which over time may cause a toxicological response. Based on the findings of this study, the use of agrochemicals should significantly be minimized in khat farming. Accordingly, the Meru khat farmers should be sensitized on alternative farming practices that do not potentially cause heavy metal contamination in khat.

Risk Assessment of the Impact of Oil Spill on the Heavy Metal Content of Santa Barbara River in Bayelsa State, Nigeria

This study was aimed at assessing both the effect (risk) and impact of a recent oil spill on heavy metal concentration in the Santa Babara River in Bayelsa State, Nigeria. Samples were collected and preserved based on standard methods. The heavy metals of interest were Mercury (Hg), Arsenic (As), Cadmium (Cd), Chromium (Cr) and Copper (Cu) due to their levels of toxicities and presence in water bodies while the five study stations were Worokuma (W), Uwanga (W), Tuweni (T), Shellikiri (S), Inarakiri (I) and Esenfakiri (E). The solar thermos elemental flame atomic absorption spectrometer (AAS), model SE-71096 made in Germany with detection limit of 0.001 mg·kg−1 was used for the heavy metal analysis. The trend of heavy metal abundance was found in this order Cr>Cu>Cd>Pb>Hg=As. All the detectable metals had risk index of greater than 5 but the highest was found in the order, Cd> Pb > Cu > Cr (149, 35, 26 and 12 respectively) which meant extremely high level of pollution. This also indicated the probability of non-carcinogenic effects occurring and increases as HI increases signifying carcinogenic risk via direct ingestion of water. Graphs were used to show trends in both mean heavy metal concentrations and risk assessment indices. Chromium and Pb had moderate contaminations for CF and CDI values, hence regular monitoring of the Santa Barbara River is of essence as most of the inhabitants take this as the only source of potable water as their wells have very high iron content.

Heavy metal exposure risk associated with ingestion of Oreochromis niloticus and Coptodon kottae harvested from a lacustrine ecosystem

Lacustrine ecosystems have not been widely assessed for heavy metal contamination and associated health risks; yet, they could be accumulating these contaminants to the detriment of aquatic organisms and communities relying on them for various aspects. The water quality index (WQI) and concentrations of heavy metals including As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, and Zn in water, sediment, Oreochromis niloticus, and in the endemic and endangered Coptodon kottae in Lake Barombi Kotto in Cameroon were determined to evaluate fish heavy metal bioaccumulation, and heavy metal exposure risk posed to communities consuming these fish species. The WQI of the lake was found to be excellent with heavy metal concentrations that were lower than what was obtained in the sediments and fish samples. Mean heavy metal concentrations in sediment ranged from 0.86 ± 0.03 mg/kg for Cd to 560.1 ± 11.15 mg/kg for Fe. In both fish species, Fe, Mn, and Cu had the highest concentrations. Though the heavy metal concentrations in the lake water were low, heavy metal bioconcentration factors for both fish species were very high ranging from 1.6 for Fe to 1568 for Mn. The concentration patterns of heavy metals in the organs of both fish species followed the order bones > gut > muscle. Consumption of these two fish species contributes less than 1.0% of the permissible tolerable daily intake (PTDI) and provisional tolerable weekly intake (PTWI) of these metals with lead (Pb) having the potential to exceed permissible exposure levels when high amounts of these fish are consumed by adults.

Comprehensive spatio-temporal benchmarking of surface water quality of Hindon River, a tributary of river Yamuna, India: Adopting multivariate statistical approach.

The Hindon River is the main tributary of river Yamuna and it is a significant source of surface water, which flows through the major cities of western Uttar Pradesh, India. The indiscriminate development of industries and urbanization along river basin coupled with rapid population growths contribute various amounts of pollutant in the river. Therefore, the present study was conducted to assess the spatial-temporal variability of river water quality (seventeen physicochemical parameters and eight heavy metals) during pre- and post-monsoon seasons for 5years data at 19 sampling sites along the river stretch. Indices associated with water quality and heavy metals were computed to scale the accurate state of risk associated to its use for drinking and irrigation. During the pre- and post-monsoon seasons, only four sites were found having safe water quality index (WQI) values. The mean heavy metal concentrations are found in order of Zn > Fe > Pb > Cu > Cr > Cd > Ni > Mn. Considering the spatial and temporal distribution, the study benchmarked the water quality of Hindon River for priority attention.

A study about radiation dosimetry and heavy metal pollution in the Küçük Menderes Basin, Turkey (Radio-ecological and Heavy Metal Risks)

Agricultural researchers in many countries investigate radiological risks in soil and crops because it concerns human health. In addition, they also study heavy metal pollution in plants in cultivated soil for ecological safety. This study aims to analyze the activity concentrations of radionuclides and heavy metals in soil and corn crops in the Küçük Menderes Basin (Izmir, Turkey) – which is enriched with phosphatic fertilizers. We collected soil and corn samples from the area, and then separately measured concentrations of radionuclides (226Ra, 232Th and 40K) and trace elements (Cd, Cr, Cu, Hg, Ni, Pb and Zn) they contain. Activity concentrations of the radionuclides were acquired by radiometric methods (gamma spectroscopy). Heavy metal amounts were calculated using ICP-MS (inductively coupled plasma-mass-spectrometry). The mean heavy metal concentrations in the soil (Cd, Cr, Cu, Zn, Ni, Pb, Hg) were 0.096, 40.26, 26.51, 72.43, 32.24, 7.05 mg kg-1, 158.28 µg kg-1 and in the corn (Cd, Cr, Cu, Zn, Ni, Pb, Hg) were 0.01, 1.09, 2.05, 22.00, 0.54, 0.24 mg kg-1, 12.15 µg kg-1. The heavy metal concentrations in soil samples were as follows: Hg

Spatial-temporal distribution and pollution indices of heavy metals in the Turnasuyu Stream sediment, Turkey.

The potential contamination levels and human health risk of heavy metals in sediment of the Turnasuyu Stream in Ordu, Turkey, were evaluated comprehensively by taking seasonal samples from three different locations. The order of the mean heavy metals (HMs) concentrations (mg/kg) were as follows: Fe > Al > Mn > Pb > Zn > Cu > Co > Cr > Ni > Cd > As. All HM levels, except Cd and Pb, were in the minimum enrichment range as assessed by the sediment enrichment factor (EF). Similar low contamination levels for all HM, except Pb and Cd, were also observed when the contamination factor (CF) and geo-accumulation index (Igeo) were taken into account. The low risk of the study area has also been confirmed by the ecological risk index (Eri) values. The probable human health risk assessment has been performed, and the lifetime cancer risk (LCR) values for adults were found as negligible with values below 10-6. In addition, the hazard index (HI) and total hazard index (THI) results were both higher in children than in adults. The Pearson correlation coefficient (PCC) revealed the highest correlation between Cd and Pb (0.85). When the ecological indexes and statistical results are evaluated together, it is thought that the presence of HMs in the sediment may be due to lithological reasons as well as anthropogenic activities such as quarrying, municipal, agricultural, and domestic discharges in the region. Mitigation measures should be taken in accordance with the standards within the river basin to prevent the potential risks of pollution.

Multivariate and health risks analysis of heavy metals in natural water sources around Enugu dumpsite, southeastern Nigeria

The concentrations of heavy metals and health risks associated with the consumption of domestic water sources around a dumpsite in Enugu (southeastern Nigeria) were assessed by atomic absorption spectrophotometry and multivariate analysis. The results showed the dumpsite leachate mean pH value of 4.1, Mn+ of 11.4 µg/l, Fe3+ 4.1 µg/l, Cd+ 0.3, As+ 6.03 µg/l, Pb+ 2.47 µg/l, Ni+ 14.13 µg/l, and Cr3+ 1.48. The groundwater and surface water samples had mean heavy metal values as follows: Mn+ 5.23 and 0.75 µg/l, Fe3+ 1.49 and 0.15 µg/l, Cd+ 0.08 and 0.10 µg/l, As+ 1.90 and 0.15 µg/l, Pb+ 1.01 and 0.35 µg/l, Ni+ 0.37 and 0.05 µg/l, and Cr3+ 0.03 and 0.05 µg/l, respectively. Comparison with maximum permissible limits indicated that the mean heavy metal concentrations of the tested samples were lower than the limits for drinking water, except for Mn+, As+, and Pb + , which were marginal above recommended limits. Principal component analysis results showed two principal components with the first principal component having high loadings of Mn+, Fe3+, As+, Pb+, Ni+, and Cr3+, which are statistically correlated. Probable sources of these contaminants include automobile parts and tools, batteries and electrical appliances and electronics heaped at the dumpsite. Analysis of variance results indicates a significant difference in datasets between and within each and both water sources. Human health risk assessment indices indicated that the water sources are moderate to highly polluted and could pose both non-carcinogenic and carcinogenic threats when consumed untreated, with children being more exposed than adults.

Valuation of the toxicity profile of benthic sediment of Western region in sub-Saharan Africa.

Sediments in water ecology play an important part in affecting the contamination state since they can perform as both pollutants' carriers and bases in an aquatic ecosystem. The sediment samples of River Okhuaihe were examined to reveal its level of pollution. Sediment samples gotten from 4 stations were analyzed for 28 physical and chemical parameters using the standard methods. A high P < 0.01 (significant difference) was detected in nitrate, electrical conductivity, available phosphorus, zinc, lead, chromium, and total hydrocarbon content, while cadmium, manganese, potassium, total nitrogen, and total organic carbon were P < 0.05 (significantly different) across the studied stations. The Duncan multiple range test showed that station 3 was the source of variance for these parameters. All other parameters showed no P > 0.05 (significant difference) across the studied stations. Temporal examination revealed disparities in the arid and rainy periods, for all studied parameters. The mean heavy metal concentrations in the study dwindled in this order: Fe > Zn > Mn > Cd > Cu > Pb > Cr > Ni > V. The principal component analysis results revealed two components that influenced the sediment characteristic of River Okhuaihe, with eigenvalues > 1 accounting for 96.811% of the sum variance. The pollution load index of stations 1, 2, 3, and 4 was 3.54, 2.60, 4.07, and 4.02, respectively, which were greater than the threshold, showing high contamination. This shows that River Okhuaihe is highly polluted with specific sources of organic wastes from farming activities which in turn influence the pH and metal solubility contents of the water body. Therefore, there is a dire need to do regular monitoring of the discharged wastes into the river by water researchers and regulatory bodies to maintain and enhance its natural integrity against unforeseen health issues for the present and future users.

HEAVY METAL CONCENTRATIONS IN FISH (Albula vulpes) OF BENIN RIVER IN RELATION TO HUMAN HEALTH

Health risk assessment of heavy metal contamination in humans through consumption of Albula vulpes from Benin River, in Koko Town (Southern Nigeria) was studied. Assessment of heavy metal concentrations was conducted in the liver, kidney and muscles of the fishes using Atomic Absorption Spectrophotometer. Mean heavy metal concentrations for Zn, Cd, Pb, Mn, As and Ni in A. vulpes were 0.69, 0.20, 0.04, 0.16, 0.13 and 0.23mg/kg for liver, 0.29, 0.08, 0.02, 0.06, 0.05 and 0.09mg/kg for muscle, 0.61, 0.18, 0.03, 0.14, 0.11 and 0.20mg/kg for kidney respectively. Target hazard quotients (THQs) for Cd, Pb, As, Ni, Mn and Zn were 0.0010, 0.0007, 0.0214, 0.0006, 0.0001 and 0.0001. The highest THQ value was for Arsenic (0.0214). The least THQ value was for Mn (0.0001). The total THQ (TTHQ) was 0.0239 and this was less than 1, suggesting that the consumption of A. vulpes is unlikely to cause any adverse health effects to consumers.

Heavy Metal Contamination Status and Risk Assessment in Surface Sediments of Köyceğiz Lagoon Estuary System (KLES) (South-West Anatolia)

This study reports the presence of heavy metals (Cr, Ni, Cu, Cd, Pb) in the sediment and water column in the Köyceğiz Lagoon Estuary System (KLES) (South-West Anatolia). The mean heavy metal concentrations (µg L-1) in the water were found as Cr: 3.72-8.36, Ni: 6.51-9.48, Cu: 1.29-11.88, Cd: ND-0.08, Pb: ND-0.34. The heavy metal concentrations in water samples were found to be below the internationally acceptable limits. The mean heavy metal concentrations (mg kg-1) in the sediment were found as Cr: 1.75-4.25, Ni: 5.24-12.69, Cu: 0.25-0.51, Cd: &amp;lt;0.01, Pb: 0.04-0.13. As a result of the analyses conducted concerning contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI), monomial potential ecological risk index (ER), and total potential ecological risk index (RI) for heavy metals in the sediment, it was deduced that there was not any pollution and moderate or high ecological risks.

Heavy Metal Concentrations of Soil, Rock, and Coal Gangue in the Geological Profile of a Large Open-Pit Coal Mine in China

Risk assessment related to heavy metals in mining areas is crucial to ensuring the sustainable development of regional ecosystems and protecting human health. However, almost all research on the impact of mining activities on environmental quality entails field monitoring of surface soils or soil profiles. Here, to compare the variety of heavy metal concentrations in the geological profile, 39 samples (including soil, rock, and coal gangue) were collected and analyzed from hundreds of meters underground in the Pingshuo coal mine (Anjialing coal mine, Antaibao coal mine, and Donglutian coal mine), which is the largest open-pit coal mine in China. The mean heavy metal concentrations of Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni in soils were 0.15 mg/kg, 0.02 mg/kg, 13.70 mg/kg, 27.12 mg/kg, 70.89 mg/kg, 26.10 mg/kg, 79.88 mg/kg, and 37.68 mg/kg, respectively; most of these metals were more concentrated in the soil samples than in the rock and coal gangue samples. A potential ecological risk assessment indicated that As, Pb, Cr, Cu, Zn, and Ni in all samples showed low risk, while the ecological risk degrees of Cd and Hg were higher and contributed most to the total risk index (RI). The highest E_r^i value (92.94) for Cd was found in rock samples, contributing to approximately 55.18% of the to tal RI. For Hg, four rock sampling sites had the highest E_r^i values (427.70, 270.78, 198.96, and 188.70), contributing approximately 68.36–88.07% of the total RI. Ranked after soil (0.15 mg/kg), limestone and shale showed high mean Cd concentrations (both 0.13 mg/kg). The highest mean concentration was found in coal gangue samples (0.1 mg/kg). Compared with the other types of samples, the mean concentrations of Cr, Cu, and Ni in soils, limestone, and mudstone were relatively higher. At different sites, heavy metal concentrations varied greatly at different depths, owing to diverse sample types and rock types. Correlations between heavy metals and soil nutrients indicated that N and P were closely correlated with heavy metals. Comparing the proportions of different heavy metals in various types of samples showed that heavy metals in soils were extremely similar to those in limestone, mudstone, and shale, implying that soils might indirectly inherit their features from their parent material.

A comprehensive exploration on distribution, risk assessment, and source quantification of heavy metals in the multi-media environment from Shaying River Basin, China

Comprehensively understand the distribution of pollutants in the multi-media environment at basin scale is of major importance to the ecological risk assessment and pollution control. In this study, multi-media contamination characteristics of eight heavy metals in the water, soil, and sediment from the Shaying River Basin of China have been analyzed to probe their ecological risks and potential sources. Results revealed that heavy metal concentrations in pore water were higher than those in surface water. While the mean concentrations of most heavy metals increased follow the order of bankside soil (BS)<water-level-fluctuating zone soil (WLFZS)<sediment. The WLFZ was an important transition zone between the BS and sediment for pollutant exchange. The mean heavy metal concentrations in surface water were all below their corresponding water quality standards except Hg. Whereas the mean concentrations of Cr, Ni, Zn, Cd, and Hg in BS, WLFZS, and sediment exceeded their corresponding background values. The assessment results of pollution and risks indicated that Hg and Cd posed the highest potential risks in each medium. Furthermore, according to the factor analysis and PMF model, six potential sources were identified, in which agricultural, fuel combustion, and industrial sources were the dominant anthropogenic sources, accounting for 23.84%, 17.43%, and 14.25% of the total contribution.

Impacts of water-sediment regulation on spatial-temporal variations of heavy metals in riparian sediments along the middle and lower reaches of the Yellow River

The water-sediment regulation scheme (WSRS) of dams influences the desorption, resuspension, and deposition processes of riparian sediments, which in turn affect the spatial-temporal variations of heavy metals (HMs) in riparian sediments and leads to severe degradation of soil and water quality. However, the difference between the trapping effect of dams and the redistribution effects of the WSRS on HMs in riparian sediments, as well as the consecutively seasonal change of HMs after the WSRS, are rarely reported. To fill this gap, the concentrations of six HMs including Cd, Cr, Cu, Ni, Pb, and Zn in riparian sediments along the Xiaolangdi Dam (XLD) Reservoir and its downstream reach were investigated, and the contamination level and potential ecological risk of HMs were assessed, to differentiate the effects of the XLD and its WSRS on the concentration, contamination level, and potential ecological risks of HMs. The results indicated that the mean HM concentrations in riparian sediments were higher than the background values in the study area and showed significant spatial and temporal variations. However, the regional differences of HM concentrations caused by the trapping effect of the XLD were less than the seasonal differences caused by the redistribution effects of the WSRS. The contamination and ecological risk assessment indicated that riparian sediments in the study area were contaminated by the six HMs, particularly by Cd and Pb, which overall exhibited a high and moderate ecological risk, respectively. The sources for Pb were likely agricultural inputs, while the sources for Cd should be attributed to both industrial and agricultural inputs. Overall, the trapping effect of the XLD led to the accumulation of HMs in riparian sediments along the reservoir area, while the regulation effects of the WSRS resulted in the redistribution of HMs in riparian sediments from the reservoir area to the downstream reach.

Geo-spatial distribution of hydrological nephrotoxic characteristics in Kalawewa and Tissawewa reservoirs in Anuradhapura, Sri Lanka

Reservoirs are one of the major water resources subjected to different forms of pollution due to anthropogenic activities. Heavy metals and water hardness are a particular concern due to their potential toxic effect and bio-accumulate ability. Therefore, the objective of this investigation was to analyze the spatial distribution of selected heavy metals Cadmium (Cd), Lead (Pb), and Arsenic (As)) and total water hardness in Kalawewa and Tissawewa reservoirs, Anuradhapura District in Sri Lanka. Cd, Pb, and As contents of water samples were analyzed using Inductive Coupled Plasma Mass Spectrometry (ICP-MS-Agilent-7800). Total water hardness values were analyzed based on Ca and Mg concentrations of water samples. Spatial distribution patterns of analyzed heavy metals and total water hardness values were interpolated using Inverse Distance Weighted (IDW) and Spatial autocorrelation tool in ArcMap 10.2.2 software. Overall, the mean heavy metal concentrations in two reservoirs complied with World Health Organization agricultural water standards. The mean total water hardness values of the two reservoirs reflect “very hard water”, and the distributions of analyzed heavy metals and water hardness were higher in the center. As long term exposure to nephrotoxic heavy metals adversely affects human health, taking all necessary changes before consumption can be recommended.

Determination of heavy metals in soil used for potato cultivation by atomic absorption spectroscopy in awi Zone, Amhara Region, Ethiopia

The study evaluates heavy metals in soil used for Potato cultivation by Atomic Absorption Spectroscopy in awi Zone, Amhara Region, Ethiopia. In this study, 75 soil samples from three agricultural areas, namely: Guaguasa Shikudad, Fagita Lecoma and Banja districts were collected and analyzed for Lead (Pb), Cadmium (Cd), Nickel (Ni), Copper (Cu) and Zinc (Zn) using Atomic Absorption Spectroscopy. The results obtained revealed that the mean heavy metal concentrations for Pb, Cd, Ni, Cu, and Zn were 75.33–77.00mg/kg, 17.11–18.76mg/kg, 60.26-101.78mg/kg, 125.17-383.39mg/kg and 244.20—287.87mg/kg respectively. In general, the level of metals in soil collected from the sampling sites are found to be decreased in the order of: Cu&gt;Zn&gt;Ni&gt;Pb&gt;Cd. Soil analysis showed that the concentration of Cu, Cd and Ni higher than permissible levels there WHO/FAO thresholds for agricultural soils the soil is polluted by toxic heavy metals (Cu, Cd and Ni). Therefore, the soils studied were harmful for the cultivation of potatoes and other agricultural purposes.

Organochlorine pesticides and heavy metals in the zooplankton, fishes, and shrimps of tropical shallow tidal creeks and the associated human health risk

Studies on organochlorine pesticides (OCPs) and heavy metals (HMs) from tidal creeks are scarce. Sixteen OCPs and seven HMs were measured in the surface water, zooplankton, two fishes (Harpadon nehereus and Pampus argenteus), and one shrimp (Penaeus indicus) collected from three tidal creeks of the Indian Sundarban. The surface water was polluted by hexachlorocyclohexane isomers (ΣHCH: 525–1581 ng l−1), dichlorodiphenyltrichloroethane congeners (ΣDDT: 188–377 ng l−1), endosulfan congeners (ΣEND: 687–1474 ng l−1), and other OCPs (512–1334 ng l−1). However, the mean HM concentrations in the surface water were <1 μg l−1. The zooplankton community exhibited bioaccumulation of both OCPs and HMs. Aldrin, Heptachlor, and α-HCH levels in the edible biotas could lead to cancer. Co and Cd levels could lead to non-cancerous risks, and Pb levels could pose a cancerous risk. This study showed that creeks could be potential sites of both OCP and HM pollution.

Heavy metal concentrations in vegetables cultivated and sold in Machakos Municipality, Kenya

Heavy metal contamination of vegetables is a key aspect of food quality assurance since vegetables form a substantial proportion of the daily human diet. Health risks in urban populations due to exposure to heavy metals are on the increase because of the consumption of vegetables irrigated with wastewater. This study analyzed the concentration of Cd, Cu, Pb, Zn and Cr in spinach and kales grown using contaminated water of the Mitheu urban stream and those sold within Machakos municipality. Vegetable samples were collected once per month for a period of four months starting from June to September 2019. The mean heavy metal concentrations obtained were0.013 – 3.19 mg/kg, 0.468 – 1.706 mg/kg, 0.02 – 0.368 mg/kg, 5.78 – 26.7 mg/kg, and 0.104 – 14.0 mg/kg for Cd, Cu, Pb, Zn and Cr respectively in kale samples from the different sampling sites. The heavy metal mean concentrations in spinach were 0.055 – 0.575 mg/kg, 3.79 – 5.55 mg/kg, 0.098 – 1.49 mg/kg, 8.32 – 20.7 mg/kg and 0.368 – 4.43 mg/kg for Cd, Cu, Pb, Zn and Cr respectively. The mean concentrations of Cd, Pb, Zn and Cr in both spinach and kales in some of the sampling sites were above WHO permissible levels for heavy metals in vegetables for human consumption. However, the mean concentration of Cu was below WHO recommended levels. Consumption of these vegetables therefore poses a health risk to the consumers. There is need to create public awareness on the dangers of consuming contaminated vegetables. Additionally, measures to curb heavy metal pollution in Mitheu stream should be taken by the County Government of Machakos.

Assessing pollution levels and health effects of heavy metals in sediments around Cayeli copper mine area, Rize, Turkey

Heavy metal concentrations of Mn, Cr, Fe, Ni, Cu, Zn, Cd and Pb in sediment samples collected from 12 stations in the Black Sea coast, Buyukdere and Sabuncular streams around Cayeli copper mine area in Rize, Turkey were measured using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The mean concentrations of Mn, Cr, Fe, Ni, Cu, Zn, Cd and Pb in the sediments have been determined to be 585.10, 22.50, 33,603.95, 7.40, 63.97, 75.50, 0.20 and 7.83 mg kg−1, respectively. The mean heavy metal concentrations examined in sediment samples have been determined as lower than the permissible level for sediment. Assessment of the heavy metals pollution in the sediments was carried out by calculating the enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) indices. It has been found according to the mean EF values in sediment samples that Mn, Cr, Fe, Ni and Pb had no enrichment while Cu, Zn and Cd showed minor enrichment in the field. The mean Igeo and PLI values indicated that sediments in the field were not polluted with all heavy metals examined. PCA showed that the origin of Mn, Cr, Ni and Pb was natural sources and Cu, Zn and Cd were lowly influenced from anthropogenic inputs, and the origin of Fe was also natural sources but was slightly influenced from anthropogenic inputs. Human health risk assessment of the heavy metals was carried out by calculating the hazard quotient (HQ) and the hazard index (HI) for the non-carcinogenic metals and the carcinogenic risk (CR) for the carcinogenic metals through ingestion and dermal contact. The mean HQ, HI and CR values were in safety limits. This indicated that the levels of all heavy metals examined in the sediments did not cause carcinogenic and non-carcinogenic health risks for humans via ingestion and dermal contact.

Effect of heavy metals on toxicogenetic damage of European eels Anguilla anguilla.

Aquatic organisms are exposed to a variety of contaminants such as heavy metals introduced into the environment as a consequence of anthropogenic activities that usually cause genotoxic damage in aquatic organisms. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn, Co, and Mn) on DNA damage of Anguilla anguilla was examined by comet assay at reference site and three different sampling sites of the Orontes River. The relative mean heavy metal concentrations in water column were in the order of Fe>Cr>Pb>Zn>Ni>Cu>Mn>Cd>Co in all the sampling sites. Cr, Cd, and Pb concentrations at all sampling sites were above the values allowed by the EPA (1999, 2016). With these results, negative effects of Cr, Cd, and Pb appeared on ecosystem health. The comet assay showed a higher level of DNA damage in the gill cells in comparison with the liver cells of A. anguilla. The highest level of DNA damage as %T-DNA, tail moment, and tail migration in gill cells were 20.007 ± 1.744 %; 2.899 ± 0.341 μm, and 12.383 ± 01.040 TMi and 20.172 ± 1.944 %, 2.559 ± 0.265 μm, and 10.763 ± 0.910 TMi at Site 2 and Site 3, respectively. The correlations between heavy metals and DNA damage parameters revealed that both Cu and Co in water showed significant negative correlations (p < 0.05) with DNA damage levels. Consequently, this study revealed the genotoxic damage of A. anguilla due to pollution in Orontes River and lead to the better understanding of genotoxicity and heavy metal relationships.

Monitoring of technogenic pollution of soil in the region

The purpose of the study is to conduct monitoring of technogenic pollution of soil in the Samara region. The objectives of the study are to identify the sources of technogenic pollution of soil, to analyze the minimum and maximum concentrations of heavy metal on long-term observation plots and background plots, to assess the average and the maximum values of total petroleum hydrocarbons (TPH) in soil of observed land plots. The allowable concentration levels of heavy metals (manganese, lead, cadmium, copper, nickel and zinc) in the soil of the Samara region are not exceeded. Mean heavy metal concentrations in soil did not exceed the maximum permissible concentration (MPC) and the approximate permissible concentration (APC) and was 0.1-0.6 MPC (APC). The maximum concentration of metals in soil was 0.1-0.9 MPC (APC). However, the obtained results were higher than background concentrations of metals. The mean concentrations of aluminium exceeded the background levels by a factor of 3.4-6.7. The maximum concentrations of aluminium in soil was observed in the area of the Samara metallurgic plant (ZAO ‘Arconik’) and was 9.2 of background.