Mean Concentrations Of Heavy Metals Research Articles

Heavy metal concentration in the agricultural soils under the different climatic regions: a case study of Iran

Contamination of agricultural soils with heavy metals is a growing global concern with an increase in anthropogenic activities. Despite local studies conducted, no accurate and comprehensive results about agricultural soils of Iran entirely and regarding the climate have been observed regarding heavy metal concentration. Therefore, the present study is aimed at determining a reliable heavy metal concentration in agricultural soils and evaluate the effect of climate on the average concentrations. To provide harmonized and comparable data, 711 soil surface samples were randomly taken from all of the agricultural soils of Iran during 2016–2018. Also, to evaluate the effect of climate, samples were divided into three parts according to major climates of studied area. Results revealed that the average concentration of Cd, Cr, Co, Cu, Mn, Ni, Pb, Zn, and V in agricultural soils was 0.31, 101, 27.9, 37.2, 702, 68.0, 28.2, 73.0, and 101 mg/kg, respectively. The concentration of Cr, Ni, Co, V, and Pb in, respectively, 28.4, 11.3, 8.72, 1.60, and 1.34% of soil samples was higher than the national standard in contrast to the concentration of the other element, which was lower. There were no significant differences between the average concentrations of heavy metals in agricultural soils with respect of climate, indicating the minimum effects of soil forming factors on soil heavy metals. Comparing the mean concentration of heavy metals in three major climatic zones of the country, it seems that geochemistry is the key factor controlling the concentration of metals in agricultural soils of Iran.

Natural radionuclides, heavy metals and health risk assessment in surface water of Nkalagu river dam with statistical analysis

The concentrations of natural radionuclides (40K, 238U and 232Th), heavy metals (Pb, Ni, Cu, Cr and Cd) and associated health risk in surface water of Nkalagu river dam have been investigated in this study. Gamma-ray spectrometry and atomic absorption spectroscopy were used to analyze the levels of radionuclides and heavy metals, respectively. The mean activity concentrations of the radionuclides were found to be 120.45±6.51 Bq.l − 1 for 40K, 5.49±0.70 Bq.l − 1 for 238U and 0.14±0.01 Bq.l − 1 for 232Th. The mean concentrations of the heavy metals decreased in this order Pb > Ni > Cr > Cu > Cd. The mean concentrations of both radionuclides and heavy metals, except for Cu, exceeded the World Health Organization permissible levels for drinking water. The radiological annual effective dose to the age groups, 0–1 yr, 1–2 yr, 2–7 yr, 7–12 yr, 12–17 yr and >17 yr, revealed a higher value in infants (0–1 yr) than the other age groups. This indicates that infants are the most vulnerable group to radiation hazard. The average daily dose and hazard quotient showed that the metals, Pb and Cd, are the major threat to adults and children. The hazard index revealed children are more liable to non-cancer effects through oral intake.

Effects of heavy metal pollution on hepatosomatic ındex and vital organ histology in Alburnus mossulensis from Karasu River

In this study, histological effects of water pollution to freshwater cyprinid, Alburnus mossulensis, was investigated. Water, sediment, and fish samples were taken from four stations in Karasu River (Erzurum, Turkey) between June and September in 2015? 2016. In water and sediment samples, the concentrations of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, and Pb were detected. Histopathological changes in gill, liver, and kidney tissues were determined by degree of tissue change (DTC), and hepatosomatic index (HSI) was calculated. The mean concentrations of heavy metals in water and sediment samples were lower at station 4. The trend of some metal contents found in the fish was in increasing order of Zn < Cu < Cr < Pb. The observations on histopathology included cellular degeneration, congestion, dilatation, vacuolization, edema, vasodilatation, hyperplasia, hypertrophy, infiltration, melanomacrophage aggregates, glomerulopathy, fibrosis, and necrosis. It was observed that the DTC and HSI values in fish varied significantly from station to station. The results showed that the higher severity of histopathological alterations in the fish tissues was strongly correlated with agricultural and domestic activities in the area.

Baseline Study of Heavy Metal Pollution in a Tropical River in a Developing Country

Massive load of toxic heavy metals is discharged by human activities, as well as by natural actions, give rise to metal contamination in water body. Sg. Sembilang is one of the rivers that is receiving effluent from various sources such as landfill, industrial, residential, and agricultural runoff. In this study, the concentration of heavy metals in nine stations along the Sg. Sembilang was collected for one year period to evaluate their levels of pollution. Ten heavy metals were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). The mean concentrations of Fe, Mn, Zn, Al, and Cu were 3.01, 0.68, 0.29, 0.007, and 0.027 mg/L respectively, were below the National Water Quality Standards of Malaysia (NWQS), with the exception of Cd, Cr, Pb, Mg, and Ni. Calculated HPI based on the mean concentration of heavy metals, was found to be 6.05, that is below the critical pollution index value of 100. With respect to sampling locations, station J03 registered the highest value of 7.989. This is probably due to the location of J03 which is very near to the effluent discharge point. The analysis indicates the present scenario of water quality of Sg. Sembilang due to the effect of effluent from the landfill material, and waste water from industry, agricultural runoff and residential area. Required steps should be taken to conserve this river from pollution, and also to lessen the environmental risk.

Heavy metals in soil of an urban industrial zone in a metropolis: risk assessment and source apportionment

The risk of heavy metal pollution in industrial zones has received great awareness, but few studies have focused on urban industrial zone of metropolises. In order to explore the pollution characteristic, ecological risks, human health risks, and sources apportionment of heavy metals (HMs), the concentrations of 9 HMs (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) in 48 soil sites of a typical urban industrial zone in Shanghai, China were investigated. The mean concentrations of HMs except As (8.09 μg/g) were higher than the background value of corresponding HMs in Shanghai, with Mn (717.60 μg/g) having the highest concentration. The geo-accumulation index showed that Mn had the most severe pollution. The potential ecological risk index indicated that most HMs were at lower risk, but Hg posed a relatively high risk in many sites. In addition, the entire study area may cause potential ecological risks, especially in the northern and the southeastern areas. In light of the results regarding health risk assessment for children and adults, HMs were negligible of non-carcinogenic risk in humans. As for carcinogenic risk, all HMs had “no significant” cancer risk, except for Cr and Ni at the “acceptable” levels. The results of source apportionment analysis using the positive matrix factorization model indicated that heavy metal pollution was mainly caused by (1) metal manufacturing, (2) machinery manufacturing, (3) pesticides and fertilizers, and (4) manufacture and metallic materials. Our results provide the underlying insights needed to guide soil pollution management and remediation of urban industrial areas in metropolises.

Determination of Heavy Metals in &lt;i&gt;Hoplobatrachus occipitalis&lt;/i&gt; (Crowned Bullfrogs) and Water from Some Reservoirs in Kadawa Irrigation Project Kano, Nigeria

This study was carried out to evaluate the concentrations of heavy metals (Cd, Cu, Mn, Pb, and Zn) in water and crowned bullfrog (Hoplobatrachus occipitalis) organs/parts (muscle, liver, leg, lung and trunk) from Kadawa irrigation project, Kano State, Nigeria. Atomic Absorption Spectroscopy was carried out using Atomic Absorption Spectrometer (AAS) Buck Scientific VGP-210 model (2008). The mean concentration of heavy metals in water samples were 0.11 mg/L, 0.18 mg/L, 0.26 mg/L, and 3.65 mg/L for Cu, Mn, Pb and Zn respectively. The sequence of metal accumulation in all the organs was Zn &gt; Pb &gt; Mn &gt; Cu. The highest concentration of Zn (77.38 mg/kg), Pb (1.81 mg/kg) and Mn (0.68 mg/kg) were found in the lung while Cu (0.07 mg/kg) was deposited more in the liver. Cadmium was notdetected in all the samples analysed. Zinc and lead were the most accumulated metals in all the organs/parts with the range of 77.38 mg/kg - 18.10 mg/kg and 1.81 mg/kg - 0.13 mg/kg respectively. The highest accumulation of metals was found in the lung and liver. The organ/parts accumulation pattern was: lung &gt; liver &gt; trunk &gt; muscle &gt; leg for Zn, Pb and Mn, while liver &gt; lung &gt; trunk &gt; muscle &gt; leg was for Cu. Lung and liver have the highest bioaccumulation of heavy metals while the leg and muscle bioaccumulated the least heavy metals. Hence the water, liver and lung of H. occipitallis are unsafe for consumption, and therefore posed a threat to public health. Farmers should be trained on proper usage of agrochemical.Keywords: Heavy Metals, Crowned Bullfrog, Hoplobatrachus occipitalis, Kadawa, Bioaccumulation

Assessment of human health risk for surface sediments of Ikpoba River contaminated by heavy metals

Five heavy metals (Cu, Pb, Ni, Cd, Fe) were accessed in surface sediments from Ikpoba River in Benin City, South of Nigeria; an area impacted by soil erosion and the Benin Water Storm project. The heavy metals were analysed using atomic absorption spectrometer. The mean concentrations of heavy metals were 0.543 mg/kg (Pb), 1.289 mg/kg (Ni), 0.001 mg/kg (Cd), 18.90143 mg/kg (Cu) and 1022 mg/kg (Fe) respectively. Human health risk assessment was used to assess the pollution degree of the river sediments. The results indicated that the pollution degree of heavy metals increased in the order Fe>Cu>Ni>Pb>Cd. Human health risk assessment indicated that noncarcinogenic risks all fell below threshold level for both children and adults. The total carcinogenic risk due to Pb and Cd were within the acceptable range for both adults and children. The findings provide a scientific basis for the control of potentially toxic heavy metals concentrations and environmental protection of Ikpoba River.Keywords: Metals; Contamination Risk; River; Sediment

Spatial-seasonal variations and ecological risk of heavy metals in Persian gulf coastal region: case study of Iran.

This study aimed to perform a systematic review to analyse the seasonal concentration and ecological risk assessment of heavy metals (HMs) in seawater and sediment samples collected from the coastline of Jam city in Bushehr, Iran. A total of 96 sediment and seawater samples were collected from 16 sampling stations during the spring, summer, autumn, and winter of 2017. Then, the concentrations of Pb, Ni, Cd, Cr, Cu, Zn, and Fe were determined. Finally, the pollution load index (PLI), ecological risk (Er), and environmental risk (RI) were calculated to assess the HM ecological risk. The results showed that the mean concentrations of HMs were lower than the maximum acceptable concentration by SQG and NOAA. In addition, the PLI assessed a low pollution load level in the region. The ER and RI results also showed that the region was at low risk, and the metal risk was classified as Cd > Cu > Pb > Ni > Zn > Cr. In some samples, the mean concentrations of HM were found to be higher with a statistically significant difference (P˂0.05). The results also showed that sediments were engaging in a moderate Er by Cd. Generally, the rapid growth of urbanization, as well as industrial and human activities, along this coastline and area has increased the pollutants dumped into the seawater and sediments. Thus, it is necessary to take regular monitoring programs and develop better management strategies to minimize the amount of HMs entering into this coastal area.

Ecological and human health risks associated with metals in water from Anka Artisanal Gold Mining Area, Nigeria

Toxic metals are deleterious to the environment. In this study, risks associated with metals in water from Anka area, Nigeria were unraveled. A total of 104 water samples were collected. The concentrations of metals were determined using high performance liquid chromatography–inductively coupled plasma-mass spectrometry (HPLC–ICP-MS), while cations and anions were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Results revealed that the mean concentration of heavy metals in groundwater are Cu: 4.16 mg/l; Zn: 4.23 mg/l; Pb: 0.05 mg/l; Fe: 0.52 mg/l. For surface water, the mean concentration of Cr, Ni, Cu, As, Pb, and Zn is 0.06 mg/l, 6.53 mg/l, 5.92 mg/l, 0.06 mg/l, and 6.45 mg/l, respectively. Average concentrations of Cr, Co, Ni, Cu, Pb, and Zn in mine water are 0.12 mg/l, 2.11 mg/l, 0.66 mg/l, 4.44 mg/l, 2.72 mg/l, and 11.82 mg/l, respectively. Generally, metals in the samples are above recommended drinking water quality standards. Samples were extremely contaminated and released by geogenic and aggravated by mining. The metals pose great ecological risk but do not pose non-carcinogenic health risk while they pose carcinogenic health risk in both through oral and dermal contact with contaminated water. Children are more prone to health risks than adults.

On the nature of heavy metals in PM10 for an urban desert city in the Middle East: Shiraz, Iran

This study investigated the concentrations of suspended particulate matter £ 10 µm in diameter (PM10) and their heavy metal content, including cadmium, lead, chromium, zinc, nickel, aluminum, and iron, in ambient air in the Middle East: Shiraz, Iran. The Crystal Ball 7.3 software package was used to assess carcinogenic and non-carcinogenic health effects due to heavy metal exposure. The mean concentrations of heavy metals increased in the following order: Fe > Al > Zn > Pb > Cr > Ni > Cd. Meanwhile, the average concentrations of PM10 decreased during the same time frame. When comparing PM10 on various days of the week in Iran, including holidays (Thursday and Friday), two days after holidays (Saturday and Sunday), and other days (Monday, Tuesday and Wednesday), the concentrations were higher two days after the holidays as compared to other days of the week (p < 0.05). The excess lifetime cancer risk (ELCR) for Cr, especially for children was 1.20 × 10−2, which surpassed suggested EPA levels. The non-carcinogenic values of heavy metals for children were significantly higher than those for adults for three pathways. The results indicate that children usually had more exposure to heavy metals associated with PM10 as compared to adults.

Coexistence of diverse heavy metal pollution magnitudes: Health risk assessment of affected cattle and human population in some rural regions, Qena, Egypt.

Objective:The purpose of this study was to measure the mean concentrations of heavy metals including aluminum (Al), arsenic, nickel (Ni), mercury, lead (Pb), and cadmium (Cd) and to assess the health hazards due to the exposure of cattle/human population to a distinct or the mixture of heavy metals through various sources.Materials and methods:A total of 180 samples including water sources, animal feed, and raw cows’ milk from rural regions in Qena, Egypt, were examined using the inductively coupled plasma emission spectrometer (ICP; iCAP 6200).Results:The data highlighted heavy metal pollution with variable concentrations among most of the investigated regions. All concentrations of Al, Ni, and Cd detected in the feeding stuff showed a strong correlation to their respective levels in milk rather than those detected in water (R2= 0.072 vs. 0.039, 0.13 vs. 0.10, and 0.46 vs. 0.014, respectively) (p < 0.05). Anisocytosis and poikilocytosis with a tendency to rouleaux formation were evident, and basophilic stippling was a pathognomic indicator for heavy metal toxicity, especially Pb. Leukopenia and macrocytic anemia were shown in 50% and 65% of examined cattle, respectively. The target hazard quotients values were more than one (>1) for all heavy metals from water intake for both children and adults and Al and Cd in milk for children, and the hazard index values were indicated higher for noncarcinogenic health hazards. The target cancer risk values predispose people in the surveyed villages to higher cancerous risks due to exposures to the mixture of heavy metal through the consumption of water and milk.Conclusion:The bioaccumulation and transmission of heavy metal mixtures from water sources and feeding material have detrimental influences on milk pollution and cattle health which seem to be a serious issue affecting public health in those rural communities.

Chromium, Cadmium, Lead, and Arsenic Concentrations in Water, Vegetables, and Seafood Consumed in a Coastal Area in Northern Vietnam.

Background:Heavy metal contamination and related risks for the environment and human health are matters of increasing concern.Methods:The levels of 4 heavy metals (Cr, Cd, Pb, and As) were evaluated in 2 water types (surface and well), 4 types of seafood (tiger shrimp, stuffed snail, snake-head fish, and catfish), and 27 types of vegetables (12 leafy vegetables, 4 pea plants, 4 tuber vegetables, and 7 herbs) that are commonly consumed in northern coastal communes located in Vietnam. Atomic absorption spectrometry was employed for quantification.Results:The mean concentrations of heavy metals detected in water, seafood, and vegetable samples exceeded the national permitted standards and World Health Organization (WHO) recommendation values by at least 2-fold, 2.5-fold, and 5-fold for surface water, vegetables, and well water, respectively. The concentrations of all 4 heavy metals detected in seafood samples were higher than the standards. The levels of heavy metals decreased with increasing distance between the sample collection point and the pollution source.Conclusions:This is the first report of heavy metal contamination of common sources of food and water in the northern coastal area of Vietnam. Significantly, the concentrations of heavy metals detected in study samples exceeded the regulatory limits. These results underscore the importance of continued monitoring and the development of intervention measures to ensure that the quality of food and water meets established standards and protects the health of the local population.

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 469.18μg/m3, with a median of 133.97μg/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 (6ng/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.

Analysis of Heavy Metals in Tea Soil, Tea Leaves and Seagim Dam Water across the Seasons in Kakara District of Taraba State, Nigeria

The levels of heavy metals were assessed in tea soil, tea leaves and Seagim dam water samples collected from Kakara tea estate, Taraba State. The concentration of heavy metals was determined by the use of AAS. The concentration of Ca, Cd, Co, Cu, Fe, K, Mn, Ni, Pb, and Zn in all the soil samples collected across the season ranged from [6.102-11.00],[0.023-0.873],[0.029-0.058],[0.241-0.410],[0.900-1.958],[1.366-20.80],[0.263-0.496],[0.023-0.496],[0.018-0.068]and[0.110-0.275] mg/kg, the concentration of Ca, Cd, Co, Cu, Fe, K, Mn, Ni, Pb, and Zn in all the leaves samples collected across the season ranged from [0.982-3.566],[0.014-0.029],[0.010-0.071],[0.059-0.204],[0.066-0.755],[19.98-38.66],[0.106-0.369], [0.008-0.031], [0.006-0.099] and [0.080-0.199) mg/kg, the concentration of Ca, Cd, Co, Cu, Fe, K, Mn, Ni, Pb, and Zn in all the water samples collected across the season ranged from [9.029-13.74],[0.014-0.151],[0.063-0.114],[0.090-0.204],[1.604-2.069],[3.013-6.711],[0.262-0.429],[0.058-0.112],[0.043-0.113] and [0.128-0.225] mg/dm3 respectively. The result analysis showed that the mean concentration of heavy metal was higher in wet season than in dry season and among the metals analyzed K, Ca and Fe were the most abundance in all the samples. The concentrations of heavy were found to belower than the maximum permissible level.

Evaluation of heavy metal contamination in water, soil and plant around the open landfill site Mogla Bazar in Sylhet, Bangladesh

This study was aimed to determine the heavy metal concentration in water, soil, and plant around an open landfill site in Mogla Bazar, Sylhet, Bangladesh. The concentration of different metals such as iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), lead (Pb), and cadmium (Cd) were analyzed using a Flame Atomic Absorption Spectrophotometer (AAS) with proper digestion method. The mean concentration of heavy metals found in the water samples were in the following order Mn>Fe>Pb>Cu>Zn>Cd. Besides, the trend of trace metals mean concentration order in the soil is Fe>Mn>Pb>Zn>Cu>Cd. Luffaacutangula, Oryza sativa, and Raphanussativus var. longipinnatuswere accumulated a higher concentration of metals which can be associated with adverse health effect in the area. All the metal contents were compared with the established permissible limit provided by WHO/FAO, EU, IS, USEPA and also reported by different authors. The Geo-accumulation index (I-geo) values of metals indicate that the soil was unpolluted to moderately polluted for Pb and Cd in some sampling stations. The mean Heavy metal pollution index (HPI) value was obtained 311.61 which are higher than the critical value 100. It implies that the condition of the surrounding environment is being polluted. The Pearson's correlation matrix was performed to detect the interrelation among the heavy metal contents. There was a significant positive correlation found in water samples rather than soil and plant samples. Additionally, the Transfer Factor (TF) values were decreased as follows: Cu>Zn>Mn>Cd>Fe>Pb. In conclusion, the heavy metal accumulation level in soil, water, and plant is slightly higher than the standard level which implied that it would be dangerous to human and the vicinity of the environment.

Geographic distribution of heavy metals and identification of their sources in soils near large, open-pit coal mines using positive matrix factorization

Mining activities are considered the most important factor causing heavy metal accumulation in surface soil and it is important to understand the spatial distribution and source of heavy metals in typical steppes. In this study, the contents, spatial distribution, and sources of heavy metals were determined using geostatistical analyses, multivariate statistical analyses, and a positive matrix factorization (PMF) model using 152 soil samples collected from a grassland near the Sheng-Li coal base. The results shows that the mean concentration of heavy metals is low and does not threaten the quality of the local soil. However, the concentrations of eight heavy metals (Cu 15.04 mg kg-1, Zn 49.30 mg kg-1, Cd 0.11 mg kg-1, Pb 20.00 mg kg-1, Se 0.12 mg kg-1, Ge 1.45 mg kg-1, As 9.06 mg kg-1, and Sn 2.52 mg kg-1) are higher than their mean background values in soil in Inner Mongolia. High coefficients of variation for the heavy metals, especially Ge (1.03), and As (0.56), indicate that the concentrations of the elements are affected by the presence of the open-pit mines. Multivariate statistical and geo-statistical analyses show that Ge and As are highly correlated (R2 = 0.67, P < 0.01), suggesting that they have the same source. Using geostatistical and PMF models, we identified five potential pollution sources in the study area: 1) Industrial pollution (21.2 %), which includes smelting activity and open-pit coal mines, as suggested by elevated levels of Zn, Cd, Ge, and Cu; 2) Germanium mining (7.6 %), as indicated by higher levels of Ge and As; 3) Natural sources (37.2 %), as indicated by higher levels of Mn and Ni; 4) Coal mining activity (8.5 %), as indicated by higher levels of Sn and Cr; 5) Coal conveyor belts and high vehicular traffic, as indicated by elevated levels of Pb and Se. Taken together, the results of this study indicate that the coal base has a significant effect on the heavy metal concentration in the grassland. Therefore, the identification of the spatial distribution of heavy metals in the area may be key to controlling the pollution in the grassland. The results of this study can help to reduce pollution sources, cut down on pollution transport. So that zonal pollution control and ecological protection in the typical steppe region is achieved.

Human risk associated with potential exposure to heavy metals in a gadoid fish species from selected markets in Benin City, Nigeria

The study ascertained the levels of Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) in the Atlantic cod (Gadus morhua) of mean weight 679 ± 16.05 g, from selected markets in Benin city, Nigeria, by Atomic Absorption Spectrometric technique, in order to ascertain their suitability for human consumption. The mean concentrations of heavy metals in G. morhua ranged from 0.03 mg/kg Cd at New Benin market to 52.85 mg/kg for Zn at Ramat market while there was no significant difference (p>0.05) in the mean concentrations of heavy metals in fish between markets. The estimated daily intake (EDI) values for heavy metals ranged from 0.0032 mg/person/day for Cd to 1.70 mg/person/day for Zn while the estimated annual intake (EAI) values for heavy metals ranged from 1.17 mg/person/year for Cd to 620.5 mg/person/year for Zn. The estimated quantity consumed (EQC) values ranged from 0.000064 mg/meal for Cd to 0.034mg/meal for Zn while the theoretical maximum daily intake (TMDI) was 2414 mg/person/day. The margin of exposure (MOE) values for heavy metals ranged from 0.63 for Cd to 4.19 for Cu while the total toxicity of mixtures (TTM) value was 4.82. The toxic/hazard quotient (TQ) values ranged from 0.24 for Cu to 1.60 for Cd while the total heavy metal load in fish by market, ranged from 41.26 mg/kg at New Benin market to 59.27 mg/kg at Ramat market. The mean concentrations of Cd, Pb and Zn in G. morhua exceeded the thresholds established for heavy metals in fish by CODEX Alimentarius, Commission Regulation and Food and Agriculture Organization of the United Nations (FAO), thus making them the metals of critical ecological concern. The implication is that G. morhuamust be consumed with caution in order to avert health problems associated with excess concentrations of Cd, Pb and Zn.Keywords: heavy metals, Gadus morhua, toxic/hazard quotient, markets, Nigeria

Monitoring of the changes in potential environmental risk of some heavy metals in water and sediments of Burullus Lake, Egypt

BackgroundBurullus Lake has received a great attention because of its environmental and economic importance for connecting with the Mediterranean Sea through El Boughaz opening. Some of the chemical analyses were performed to study the potential environmental risk of Burullus Lake. The present study explores the potentiality of environmental risk of Fe, Mn, Co, Ni, Cr, Cd, Pb, Zn, and Cu for detecting most vulnerable areas to water and sediment pollution at Burullus Lake during different three periods: 2010, 2012, and 2015. The concentrations of DO, BOD, COD, and TDS during three periods 2010, 2012, and 2015 were higher than the WHO limits for the protection of fish and other aquatic life in Burullus lakes.ResultsThe mean concentrations of heavy metals in Burullus bottom sediments in 2010 were arranged in descending order as follows: Fe > Mn > Cr > Zn > Ni > Cu > Pb > Cd, while the descending order in 2012 is Fe > Mn > Zn > Cr > Cu > Ni > Pb > Cd, as well as the descending order in 2015 is Fe > Mn > Zn > Cr > Ni > Pb > Cu > Cd. The Fe is the highest concentration in all years.ConclusionsThe potential ecological risk index (RI) 2010 is S4 > S11 > S7 > S6 > S9 > S5 > S1 > S10 > S8 > S2 > S12 > S3, where RI 2012, S4 > S9 > S6 > S10 > S5 > S8 > S2 > S12 > S3 > S11 > S7 > S1 as well as RI 2015, S4 > S11 > S7 > S6 > S9 > S1 > S2 > S10 > S12 > S8 > S3 > S5.

Determination of heavy metal pollutions in the atmospheric falling dust by multivariate analysis

The purpose of this study was to assess some heavy metal (HM) concentrations in the soil and atmospheric falling dust along the Yazd highway, Yazd Province, Iran. The total concentrations of cadmium (Cd), cobalt (Co), copper (Cu), nickle (Ni), lead (Pb), zinc (Zn), iron (Fe) and manganese (Mn) in the dust and soil samples were measured using atomic absorption spectrophotometry after digestion with acid. The relationship between HMs in the falling dust was determined using correlation coefficients, principal component analysis and cluster analysis. The mean concentrations of HMs in falling dust were higher than those of the nearby soils, except for Fe, Pb and Zn. The highest correlation between HMs in the falling dust and soil was associated with Cd and Fe as well as Cd and Ni with the correlation coefficients of 0.81 and 0.97, respectively. Based on the principle component analysis, cluster analysis and correlation coefficients, two resources were identified for HM concentrations in the falling dust. The measurement of enrichment factor exhibited that the region dust infiltration of metals on Mn (13.46), Zn (8.16) and Cu (5.21) are grouped in the severe enrichment class. Increasing industrialization and human activities lead to enter intensified levels of HMs into atmosphere. So, implementation of environmental standards and improvement of public transportation are necessary to reduce the level of pollutants entering the atmosphere.

Assessment of heavy metal bioaccumulation in food web of the coastal waters of Jiangsu Province, China, based on stable isotope values (δ13C and δ15N).

The coastal waters in Jiangsu Province have always been an important fishery base since ancient time. In recent years, with the development of the industry in coastal cities, heavy metal pollution is becoming serious in Jiangsu Province. However, the bioaccumulation of heavy metals in the coastal food web is still unclear. In this study, we collected samples (including macroalgae, bivalves, cephalopods, gastropods, crustaceans and fish) through fishery resources survey in the coastal waters of Jiangsu in May 2017 and quantified the main ways of the material circulation and energy flows by constructing the food web using stable carbon and nitrogen isotopes. In addition, the bioaccumulation patterns of eight elements (seven heavy metals and 1 metalloid) through the food chains were investigated. The results showed that there were two energy pathways in this offshore ecosystem: the planktonic food-chain and the benthic food-chain, with Scapharca subcrenata and Phalium strigatum as the primary consumers, respectively. The benthic food-chain was the dominant food chain in energy recycling. The mean concentration of heavy metals from high to low in orga-nisms were Zn, Cu, As, Cd, Cr, Pb, Ni and Hg. The highest concentrations of elements were found in bivalves and the lowest ones in fish. The concentration of As in most species, the levels of Cd in bivalves and Oratosquilla oratoria, the Cr in Coilia mystus and the Zn, Cu, Cr in Ostrea denselamellosa exceeded the proposed health advisory levels. Regarding the bioaccumulation, a decrease in the concentration levels of Zn, Cd and Ni were observed along the planktonic food-chain and a significant positive correlation between Hg and trophic position were found across the benthic food-chain. Other elements had no significant change.