Heavy metals in soils along unpaved roads in south west Cameroon: Contamination levels and health risks

Soils enriched with heavy metals from vehicular emission present a significant exposure route of heavy metals to individuals using unpaved roads. This study assessed the extent of Cd, Cr, Co, Cu, Ni, Pb and Zn contamination of soils along unpaved roads in Cameroon, and the health risks presented by incidental ingestion and dermal contact with the soils using metal contamination factor (CF) pollution load index, hazard quotients (HQ) and chronic hazard index (CHI). CF values obtained (0.9–12.2) indicate moderate to high contamination levels. HQ values for Cr, Cd and Pb exceeded the reference doses. Moderate health hazard exists for road users in the areas with intense anthropogenic activities and high average daily traffic (ADT) volume according to CHI values (1–4) obtained. The economy and quality of life in cities with unpaved roads could be threatened by health challenges resulting from long-term exposure to heavy metal derived from high ADT volumes.     

Health risk assessment of heavy metals in Cyprinus carpio (Cyprinidae) from the upper Mekong River

The purposes of this research are to quantify the concentration of heavy metals (Zn, Cu, As, Pb, Cd, and Hg) in the water and fish tissues of common carp (Cyprinus carpio) in the upper Mekong River and to thereby elucidate the potential dietary health risks from fish consumption of local residents. Surface water and fish tissues (gill, muscle, liver, and intestine) from four representative sample areas (influence by a cascade of four dams) along the river were analyzed for heavy metal concentrations. Results revealed that the levels of heavy metals in fish were tissue-dependent. The highest Cu and As levels were found in the liver; the highest Zn and Pb levels occurred in the intestine, and the highest Hg level was found in the muscle. The total target hazard quotient (THQ) value for residents is > 1 for long-term fish consumption, and local residents are, therefore, exposed to a significant health risk. Results from the current study provide an overall understanding of the spatial and tissue distribution of heavy metals in water and fish body along the upper Mekong River under the influence of cascade dams and highlight the potential health risk of As for the local residents of long-term fish consumption.

     

Heavy metal accumulation in edible fish species from Rawal Lake Reservoir, Pakistan

The aim of the present study was to describe the accumulation of trace metals in the liver, kidney, gills, muscles, and skin of four edible fish species (Tor putitora, Cirrhinus mrigala, Labeo calbasu, and Channa punctatus) of Rawal Lake Reservoir, Pakistan. The fish samples were collected in the pre-monsoon (May 2008) and post-monsoon (October 2007) seasons and were analyzed for heavy metals by using an atomic absorption spectrometer. Kidney and liver showed relatively high concentrations of heavy metals. The accumulation of metals in the different organs of the fish (skin, muscles, and gills) in post-monsoon was higher than in pre-monsoon. In pre-monsoon, the metals followed the trend Zn > Pb > Fe > Cr > Ni > Mn > Co > Cu > Cd > Li, while in the post-monsoon season, the trend was Fe > Pb > Cr > Ni > Zn > Cu > Co > Mn > Cd > Li. The concentrations of Ni, Cr, and Pb in the muscle of all fish species were higher than the WHO guideline values of heavy metals in fishes for human consumption except in T. putitora. Cu level was nearly equal to the WHO maximum levels in C. mrigala and L. calbasu, while it was lower in T. putitora and C. punctatus. It is strongly advocated that risk assessment studies should be conducted and there is an urgent need for water quality restoration and management of Rawal Lake Reservoir.     

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd?>?Zn?>?Cu?>?Pb for fishpond 1 and Zn?>?Cd?>?Cu?>?Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one.     

Evaluating levels and health risk of heavy metals in exposed workers from surgical instrument manufacturing industries of Sialkot,Pakistan

The study aimed to monitor heavy metal (chromium, Cr; cadmium, Cd; nickel, Ni; copper, Cu; lead, Pb; iron, Fe; manganese, Mn; and zinc, Zn) footprints in biological matrices (urine, whole blood, saliva, and hair), as well as in indoor industrial dust samples, and their toxic effects on oxidative stress and health risks in exposed workers. Overall, blood, urine, and saliva samples exhibited significantly higher concentrations of toxic metals in exposed workers (Cr; blood 16.30 μg/L, urine 58.15 μg/L, saliva 5.28 μg/L) than the control samples (Cr; blood 5.48 μg/L, urine 4.47 μg/L, saliva 2.46 μg/L). Indoor industrial dust samples also reported to have elevated heavy metal concentrations, as an example, Cr quantified with concentration of 299 mg/kg of dust, i.e., more than twice the level of Cr in household dust (136 mg/kg). Superoxide dismutase (SOD) level presented significant positive correlation (p?≤?0.01) with Cr, Zn, and Cd (Cr?>?Zn?>?Cd) which is an indication of heavy metal’s associated raised oxidative stress in exposed workers. Elevated average daily intake (ADI) of heavy metals resulted in cumulative hazard quotient (HQ) range of 2.97–18.88 in workers of different surgical units; this is an alarming situation of health risk implications. Principal component analysis-multiple linear regression (PCA-MLR)-based pie charts represent that polishing and cutting sections exhibited highest metal inputs to the biological and environmental matrices than other sources. Heavy metal concentrations in biological matrices and dust samples showed a significant positive correlation between Cr in dust, urine, and saliva samples. Current study will help to generate comprehensive base line data of heavy metal status in biomatrices and dust from scientifically ignored industrial sector. Our findings can play vital role for health departments and industrial environmental management system (EMS) authorities in policy making and implementation.     

Bioaccumulation and human health risk assessment of chromium and nickel in paddy rice grown in serpentine soils

The natural abundance of Cr and Ni in serpentine soils is well-known, but the food safety of rice grown in these hazardous paddy soils is poorly understood. The study evaluated the bioaccumulation of chromium (Cr) and nickel (Ni) in rice (Oryza sativa) grown in serpentine-derived paddy soils in the Philippines. Surface soil (0–20 cm) samples were collected and characterized across three (i.e., Masinloc, Candelaria, and Sta. Cruz) paddy areas in Luzon Island, Philippines. At least 3 to 4 whole rice plants at mature stage were uprooted manually in each sampling point where the soil samples were collected. The total Cr and Ni concentrations in rice (i.e., roots, shoots, and grains) and soil, soil physicochemical properties, bioaccumulation factor (BAF), translocation factor (TF), and the hazard quotients (HQ) were determined. Results revealed that Cr and Ni in rice were accumulated mostly in the roots. Although paddy soils had elevated total Cr and Ni concentrations, the BAF and soil-to-root TF values for Cr and Ni were < 1. In terms of human health risks, results further revealed low risk for both male and female Filipino adults as HQ values for Cr and Ni were < 1. While it is safe to consume rice grown in the area in terms of Cr and Ni dietary intake, more studies are necessary to understand the dynamics and bioavailability of these heavy metals in other crops and drinking water from tube wells in these areas in order to provide a more holistic human health-based assessments and to ensure consumer safety in serpentine areas. In addition, a more reliable data on Cr and Ni speciation in serpentine soils and crops is critically important. Further studies are also needed to understand the contribution of bioavailable heavy metals in improving the soil health to achieve food safety.

     

Chemical content and source apportionment of 36 heavy metal analysis and health risk assessment in aerosol of Beijing

The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 μg/m³, with a median of 133.97 μg/m³. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m³). The gross α and β concentration levels in aerosols were (1.84?±?1.59) mBg/m³ and (1.15?±?0.85) mBg/m³, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.

     

Heavy metals in water, sediment and tissues of Leuciscus cephalus from a stream in southwestern Turkey

Concentrations of heavy metals (Cd, Cr, Cu, Pb and Zn) were measured in water, bottom sediment and tissues (muscle and gills) of Leuciscus cephalus from the Dipsiz stream in the Yatagan basin (southwestern Turkey), the site of a thermal power plant. Results for levels in water were compared with national and international water quality guidelines, as well as literature values were reported for streams and rivers. Comparisons were made of metal concentrations in water and sediment with those in the muscle and gills of L. cephalus caught from the Dipsiz stream. We found that there was metal accumulation in the gills compared to the muscle. Concentrations of Cd, Pb, Zn and Cr in the gills were higher than that in the muscle; however, Cu levels were higher in muscle than that in gills. Concentrations of heavy metals in L. cephalus muscle were below the legal limits for human consumption, although Cr, Pb and Zn levels in the gills were above the limits in the fish taken from the Dipsiz stream. On the other hand, no correlation was found between metal concentrations in water and sediment or between metal concentrations in water and muscle and gills of L. cephalus. A positive correlation was found between concentrations of Cu and Zn in the sediment and in fish tissue, whereas there was no relationship between other metal concentrations in the sediment and water, and muscle and gills of L. cephalus. As with water, Pb and Cd concentrations in particular were higher in sediment than that in background levels. The results show that the pollutants from the thermal power plant may be a source of these elements.     

Assessing heavy metal pollution in the surface soils of a region that had undergone three decades of intense industrialization and urbanization

Heavy metals in the surface soils from lands of six different use types in one of the world’s most densely populated regions, which is also a major global manufacturing base, were analyzed to assess the impact of urbanization and industrialization on soil pollution. A total of 227 surface soil samples were collected and analyzed for major heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) by using microwave-assisted acid digestion and inductively coupled plasma–mass spectrometry (ICP-MS). Multivariate analysis combined with enrichment factors showed that surface soils from the region (>7.2?×?10⁴ km²) had mean Cd, Cu, Zn, and As concentrations that were over two times higher than the background values, with Cd, Cu, and Zn clearly contributed by anthropogenic sources. Soil pollution by Pb was more widespread than the other heavy metals, which was contributed mostly by anthropogenic sources. The results also indicate that Mn, Co, Fe, Cr, and Ni in the surface soils were primarily derived from lithogenic sources, while Hg and As contents in the surface soils were controlled by both natural and anthropogenic sources. The pollution level and potential ecological risk of the surface soils both decreased in the order of: urban areas?>?waste disposal/treatment sites?～?industrial areas?>?agricultural lands?～?forest lands?>?water source protection areas. These results indicate the significant need for the development of pollution prevention and reduction strategies to reduce heavy metal pollution for regions undergoing fast industrialization and urbanization.     

Comparative study on the toxic effects of some heavy metals on the Nile Tilapia,Oreochromis niloticus,in the Middle Delta,Egypt

Heavy metals are the most dangerous hazards affecting aquatic biota in Egypt specially the Nile Tilapia, Oreochromis niloticus, which is an important species in commercial fisheries. Some areas were not fully studied to screen the hazards that may affect this economic fish. Therefore, the present study aimed to evaluate the potential hazards of heavy metals on O. niloticus in Al-Gharbiya Governorate in the Middle delta of Egypt. Water and fish samples were collected from Al-Qased canal, Kafr El-Zayaat Nile, El-Maash canal in Al-Gharbiya Governorate plus a reference site which is a fish farm at the Faculty of Agriculture, Damietta University, Damitta Governorate, Egypt. The results showed a significant increase (p?<?0.05) in the lead, zinc, magnesium, manganese, and copper levels while showed a significant decrease (p?<?0.05) in the iron level in the water from all the investigated areas. Cadmium level was significantly high (p < 0.05) in Kafr El-Zayaat Nile and EL-Maash canal only. These metals were also accumulated in the fish livers and gills. Consequently, ALT and AST activities and creatinine level were significantly (p?<?0.05) high in all the investigated areas. Histopathological examination revealed cytoplasmic and nuclear degeneration in the hepatocytes in all the investigated areas. Renal glomeruli and Bowman’s capsule were not completely intact in Al-Qased and El-Maash canals while conspicuous shrinkage of the glomeruli was determined in Kafr El-Zayaat Nile. Furthermore, slight damage in the secondary lamellae was detected in the gill from Al-Qased canal while in the other areas appeared vacuolated or destructed. Finally, spleen sections of fish from different sites showed the absence of melanin pigments and some vacuoles. In conclusion, the Nile Tilapia, Oreochromis niloticus, is affected by the toxic effects of the heavy metals in Al-Gharbiya Governorate in Egypt and this gives an alarm and should be taken into consideration.

     

Organochlorine pesticides,PCBs and heavy metals in tissues of the mullet Liza aurata in lake Ganzirri and Straits of Messina (Sicily,Italy)

The aim of this research was to investigate the presence of organochlorine pesticides, PCBs and heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in fish living in lake Ganzirri and the Straits of Messina, using the mullet Liza aurata as a "biological indicator". Different tissues of Liza aurata, which include the muscle, gill and vertebral column, were taken for analyses. Quantitative determination of the organochlorine compounds was performed by GC-ECD and confirmed with GC-MS. The concentrations of "essential" and "toxic" heavy metals were determined by Atomic Absorption Spectrophotometry. For the mullets of lake Ganzirri, the study showed DDE in three samples of gills and one of muscle, at concentrations below the MRL; no appreciable residues of PCBs (Aroclor 1232 series) were found. The concentrations of Zn and Cu were much higher than those of the "toxic" metals. No traces of organochlorine pesticides and PCBs were found in the individuals from the Straits of Messina. Therefore, these results indicate that these two environments are not at toxicological risk.     

Major, minor and trace element content derived from aquacultural activity of marine sediments (Central Adriatic, Croatia)

Introduction and purpose

Studies examining the environmental impact of marine aquaculture have increased significantly in number during the last few decades. The present paper investigates a region of rapid growth in intensive aquaculture and its influence on the local marine ecosystem.

Discussion

This study was undertaken with the specific aim of assessing the effect of fish farming on marine sediment at a farm near the island of Vrgada in the Central Adriatic. Data obtained regarding major (Si, Al, K, Na, Fe, Ca, Mg), minor (Mn, P, Ti) and trace (As, Au, Ba, Cd, Co, Cr, Cs, Cu, Ga, Hf, Hg, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Se, Sr, Ta, Th, Tl, U, V, Y, Zn, Zr) elements were used to estimate the spatial and temporal distribution of metals in the sediment and their possible relationship with local aquacultural activity.

Results

Although the measured concentrations of heavy metals in sediment below fish cages were notably different and potentially a result of farming activity, the values were generally lower than background concentrations observed in the Central Adriatic. In contrast, concentrations of heavy metals at a reference site unaffected by aquaculture varied from lower levels to values even higher than those observed below the high-production cages. Furthermore, calculated environmental index values indicate that the sediment below the farm is either uncontaminated or suffers from only low levels of contamination.

Conclusion

Such results suggest that the effect of observed fish farm activity on the local marine ecosystem is practically negligible.     

Heavy metal concentrations in Mullus barbatus and Pagellus erythrinus in relation to body size,gender, and seasonality

Marine environments have been subjected to an increase in heavy metal pollution. Investigations were conducted in the bioaccumulation of heavy metals for both a benthic (Mullus barbatus) and a benthopelagic fish species (Pagellus erythrinus). The aim of this study was to examine the concentration levels of four metals in the body tissue of two fish species, in Pagasitikos Gulf in Greece, and to determine if metal concentration levels were affected by season, size, and species. Fish samples were collected monthly from September 2009 to August 2010. Chromium (Cr), Copper (Cu), Zinc (Zn), and Cadmium (Cd) concentrations were measured in muscle, gills, vertebral column, and in the “remaining fish sample.” Statistical analysis pinpointed substantial differences in metal concentration levels between some size classes. Significant differences were observed between two fish species’ tissues concerning Cu, Zn, and Cd concentrations. Cu and Zn concentrations varied amongst red mullet tissues as did Zn and Cd concentrations in common pandora. Ample variations were found seasonally in metal concentration levels; however, nonsignificant statistical differences were found among sexes.     

Heavy metal bioaccumulation in selected medicinal plants collected from Khetri copper mines and comparison with those collected from fertile soil in Haridwar,India

Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6–76.5 mg kg^?1) than those from Haridwar samples (7.40–15.3 mg kg^?1), which is correlated with very high copper levels (763 mg kg^?1) in Khetri soil. Among various heavy metals, Cr (2.60–5.92 mg kg^?1), Cd (1.47–2.97 mg kg^?1) and Pb (3.97–6.63 mg kg^?1) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4–69.3 mg kg^?1), Fe (192–601 mg kg^?1), Zn (24.9–49.9 mg kg^?1) and Se (0.13–0.91 mg kg^?1) and potentially toxic metals like Ni (3.09–9.01 mg kg^?1) and As (0.41–2.09 mg kg^?1) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.     

Distribution of selected heavy metals in skin and muscle of five tropical marine fishes

An investigation was carried out to determine the effect of tissue type, tissue location and size of fish on the heavy metal levels of five species of fish found in the marine environment of the tropical island of Trinidad. The study was conducted with the fish species Lutjanus synagris, Micropogon furnieri, Cynoscion leiarchus, Caranx hippos and Scomberomorus brasiliensis, and focused on the muscle and skin tissues of the fillet of these fish. The metals Fe, Zn, Cu, Ni, Pb, Cd and Cr were analysed by atomic absorption spectrophotometry after acid digestion of the tissues, but only Fe, Zn and Cu were detected. Skin tissue showed elevated levels of metals in comparison with muscle tissue, and significant differences in metal levels with respect to tissue location in skin, and varying effects of size on both muscle and skin metal levels in the different species, were found. These results emphasize the need for careful sampling of tissue in these fish species if reliable data on heavy metal levels are to be generated.     

Potential risk assessment of heavy metals by consuming shellfish collected from Xiamen, China

Concentrations of Hg, Pb, Cd, and Cr in 240 shellfish including oyster, short-necked clam, razor clam, and mud clam collected from six administrative regions in Xiamen of China were measured. The daily intakes of heavy metals through the consumption of shellfish were estimated based on both of the metal concentrations in shellfish and the consuming amounts of shellfish. In addition, the target hazard quotients (THQ) were used to evaluate the potential risk of heavy metals in shellfish on human body. Results showed that the concentrations of heavy metals in shellfish ranged at the following sequence: Cr > Cd > Pb > Hg. The concentrations of Hg and Pb in most samples were below the limits (0.3 mg?kg^?1 for Hg and 0.5 mg?kg^?1 for Pb) of national standard (GB 18406.4-2001) set in China. About 57 % of samples were found to contain more than 0.1 mg?kg^?1 of Cd, in which the highest level was found in oyster from Xiangan with a value of 1.21 mg?kg^?1. The average concentrations of Cd in oyster and mud clam samples were 0.338 and 0.369 mg?kg^?1, respectively, which were significantly higher (p?<?0.05) than those in the samples of short-necked clam and razor clam. The highest concentration of Cr was found to present in short-necked clam from Jimei with a value of 10.4 mg?kg^?1, but a mean value of 1.95 mg?kg^?1 in all the shellfish was observed, and no significant difference was found among the different sampling regions. The calculated daily intakes of Hg, Pb, Cd, and Cr through consuming the shellfish were 0.005, 0.122, 0.137, and 1.20 μg?kg^?1 day^?1, respectively, which accounted for 2.19, 3.42, 13.7, and 40.1 % of the corresponding tolerable limits suggested by the Joint FAO/WHO Expert Committee on Food Additives. The THQ values of the four metals were far below 1 for most samples, except for those of Cd and Cr in the four shellfish species with the mean values of 0.132 and 0.385, respectively. The highest THQ values of Cd were observed in the species of oyster (0.719) and mud clam (0.568). But the high THQ values of Cr observed in all the four species were derived from the applied reference dose (RfD) data of Cr(VI) due to the unavailable RfD value of total Cr. The results indicate that the intakes of heavy metals by consuming shellfish collected from Xiamen of China do not present an appreciable hazard risk on human health, but attention should be paid to consuming those with relatively high THQ values, such as oyster, mud clam, and short-necked clam.     

Determination of Heavy Metals in Indoor Dust From Primary School (Sri Serdang,Malaysia): Estimation of the Health Risks

Heavy metal concentrations (Pb, Cd, and Cu) in classroom indoor dust were measured. The health risk (non-carcinogenic) of these heavy metals in classroom indoor dust to children was assessed based on United States Environmental Protection Agency health risk model. Indoor classroom dust samples were collected from 21 locations including windows, fans, and floors at a primary school in Sri Serdang, Malaysia. Classroom dust samples were processed using aqua regia method and analyzed for Pb, Cd, and Cu concentrations. The highest average heavy metal concentrations were found in windows, followed by floor and fan. Pb concentrations ranged from 34.17 μg/g to 101.87 μg/g, Cd concentrations ranged from 1.73 μg/g to 7.5 μg/g, and Cu concentrations ranged from 20.27 μg/g to 82.13 μg/g. Ventilation and cleaning process were found as the possible factors that contributed to heavy metal concentration in window, floor, and fan. Moreover, the hazard index (HI) and hazard quotient (HQ) values for heavy metals Cd and Cu were less than one. By contrast, the HI and HQ values for Pb (maximum values) were more than one, indicating potential non-carcinogenic risk to children. Long-term persistence of leaded petrol, building materials, interior paint, school located near industrial areas and major roads, as well as vehicle emission are the factors attributed to the presence of heavy metals in classroom dust. Further research under a long-term monitoring plan and actual values in a health risk model is crucial before a final decision on heavy metal exposure and its relationship to young children health risks can be made. Nevertheless, the findings of this study provide crucial evidence to include indoor dust quality in school assessment because the environmental processes and impacts of surrounding school area have health risk implications on young children.     

A comparative study of trace metals in male and female Caspian kutum (<Emphasis Type="Italic">Rutilus frisii kutum</Emphasis>) from the southern basin of Caspian Sea

This study focuses on the extent of zinc (Zn), copper (Cu), cadmium (Cd), cobalt (Co), manganese (Mn), lead (Pb), mercury (Hg), and arsenic (As) bioaccumulation in edible muscles of Caspian kutum (Rutilus frisii kutum), in both male and female sexes at Noor and Babolsar coastal regions from the southern basin of Caspian Sea. These values were compared with the WHO and the UNFAO safety standards regarding the amount of the abovementioned heavy metals in fish tissues (mg/kg ww). Results showed that the accumulation of these elements (except for Zn) was not significantly different between sexes of male and female in Babolsar coastal regions (P?>?0.05). In the other hand, accumulation of Hg and As at edible muscles of Caspian kutum has significant difference between two sexes of male and female in Noor coastal regions (P?<?0.05), the female had higher concentration than the male. Furthermore, it was not significantly correlated with sex and rivers in length and weight of fish (R ²?<?0.50; P?>?0.05). Based on the results, the concentration of heavy metals in the studied fish tissues proved to be significantly lower than international standards (P?<?0.05), so its consumption is not a threat to the health of consumers.     

Screening Capsicum chinense fruits for heavy metals bioaccumulation

Elevated concentrations of heavy metals in edible plants could expose consumers to excessive levels of potentially hazardous chemicals. Sixty-three accessions (genotypes) of Capsicum chinense Jacq, collected from 8 countries of origin were grown in a silty-loam soil under field conditions. At maturity, fruits were collected and analyzed for seven heavy metals (Cd, Cr, Ni, Pb, Zn, Cu, and Mo) concentrations. The main objectives of this investigation were: 1) to determine the concentrations of seven heavy metals in the soil and monitor their accumulation in mature fruits, 2) to categorize the pepper accessions as low or high heavy metal accumulators, and 3) to determine if heavy metal content of the pepper fruit was lower than the permitted limits. Concentrations and relative proportions of heavy metals in pepper fruits of C. chinense varied among accessions. Fruits of Plant Introduction (PI) 355820 accumulated significant concentrations of Cd (0.47 μ g g^?1dry fruit). PI-260522 accumulated the highest concentration of Pb (2.12 μ g g^?1 dry fruit) among the 63 accessions tested. This accession (PI-260522) contained about twice the Pb limit on a fresh weight basis. Among the 63 accessions analyzed, PI-238051 contained the highest levels of Ni (17.2 μ g g^?1). We concluded that high accumulator genotypes may be useful for phytoremediation, while, low accumulator accessions might be appropriate selections for growing on Cd-, Pb-, or Ni-contaminated soils to prevent potential human exposure to heavy metals and health hazards through the food chain.     

The comparison of three cyprinid species in terms of heavy metals accumulation in some tissues.

In this study, three cyprinids species (Acanthobrama marmid, Cyprinus carpio, and Chondrostoma regium) from Keban Dam Lake, Elazi?, Turkey, were compared in terms of the levels of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), cobalt (Co), cadmium (Cd), and lead (Pb) in muscle, skin, liver, gonad, and gill tissues. The Co, Cr, Cd, Mn, and Pb were not found in detectable levels in any organs and tissues of any species, according to results obtained by an atomic absorption spectrophotometer. Only Fe, Cu, and Zn were detected in all tissues examined. The results obtained from different cyprinid species were compared to each other and to tolerable values for heavy metals provided from the Food and Agriculture Organization (Rome, Italy) to determine whether these fish species have any risk for human consumption.