Mean Concentrations Of Metals Research Articles

Concentration, Distribution, and Potential Aquatic Risk Assessment of Metals in Water from Chott Merouane (Ramsar Site), Algeria.

In this study, 28 surface water samples were collected from eight different sites throughout the Chott Merouane. Samples were detected by atomic absorption spectrometry for Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb, and Zn. The dissolved metal concentrations (mg/L) ranged from 0.05 to 0.90mg/L for Cd, 0.13-6.45mg/L for Co, bDL-2.05mg/L for Cr, 0.03-0.27mg/L for Cu, 0.34-7.41mg/L for Fe, 01.6-4.54mg/L for Ni, 0.15-1.19mg/L for Mn, 0.23-5.88mg/L for Pb, and 0.01-0.28mg/L for Zn. Compared with U.S. EPA standards and other freshwaters worldwide, the most mean concentration of metals in surface water of this salt lake are higher than the guideline levels of aquatic life. This was further corroborated by results from the water quality indices that Chott Merouane is seriously polluted by metals. The values of the metal pollution index indicated that metal pollution level was Cd > Pb > Ni > Fe > Cr > Cu > Mn > Zn, and those metals belong to moderate or high pollution level. The Nemerow pollution index further indicated that Chott Merouane was suffering from serious metal contamination. Based on geostatistics analyses, generally distributions of these metal contents decreased in the order of the North Chott Merouane ≈ the Northwest Chott Merouane > the Eastern part of Chott Merouane > the South Chott Merouane. The quality of water has drastically deteriorated due to the mixed source of anthropogenic inputs. Therefore, necessary conservation and management measures should be taken to improve the water quality of this Ramsar wetland.

Metal solubility and transport at a contaminated landfill site – From the source zone into the groundwater

Risks associated with metal contaminated sites are tightly linked to material leachability and contaminant mobility. In this study, metal solubility and transport were characterized within a glass waste landfill through i) lysimeter-collection of pore water and standardized batch leaching tests, ii) soil profiles extending from the landfill surface, through unsaturated soil underneath, and into the groundwater zone, and iii) groundwater samples upstream, at, and downstream of the landfill. The soil analyzes targeted both pseudo-total and geochemically active concentrations of contaminant metals (As, Cd, Pb, Sb) and basic soil geochemistry (pH, org. C, Fe, Mn). Water samples were analyzed for dissolved, colloid-bound and particulate metals, and speciation modelling of the aqueous phase was conducted. The results revealed a highly contaminated system, with mean metal concentrations in the waste zone between 90 and 250 times the regional background levels. Despite severe contamination of the waste zone and high geochemically active fractions (80–100%) of all contaminant metals as well as elevated concentrations in landfill pore water, the concentrations of Cd and Pb decrease abruptly at the transition between landfill and underlying natural soil and no indication of groundwater contamination was found. The efficient cation retention is likely due to the high pH. However, the sorption of As and Sb is weaker at such high pH, which explains their higher mobility from the pore water zone into groundwater. The field soil:solution partitioning (Kd) displayed a high spatial variability within the waste zone (the highest Kd variability was seen for Pb, ranging from 140 to 2,900,000 l kg−1), despite little variability in basic geochemical variables, which we suggest is due to waste material heterogeneity.

CAN INDUSTRIALIZATION AFFECT HEAVY METALS BIOCONCENTRATION IN DATE PALM TREE FARMS IN THE SULTANATE OF OMAN?

Purpose Industrialization is leading to gradual accumulation of heavy metals in the date palm fruits and ecosystem. This paper aims at estimating the bioaccumulation of heavy metals in soils, fruits (dates) near the industrial area of Al-Rusail in the Sultanate of Oman. There were three sites located for sampling and each with three farms except site 3 with one farm; industrial site, cement factory and control farm. The soil, water and date palm fruits were analyzed for heavy metals concentration using inductively coupled plasma optical emission spectrometer. The results of analysis showed that the mean concentration of heavy metals in soil was in the following order: Ni> Zn > Pb > Cd. The concentration of heavy metals in the groundwater was found to be in this order Zn > Ni> Pb> Cd, and Zn> Pb > Ni > Cd in fruits. The statistical interaction of heavy metal mean concentrations indicated cadmium with the highest mean (0.007117mg/kg) in Farm 1 during the month of June at 0-30cm (mg/kg) in soil under Industrial sites. The fruit stages differ statistically with the highest concentration of zinc ranging from 0.190517 mg/Kg of khalal stage of farm 1 to the 0.03127 mg/kg of the control farm. groundwater heavy metal concentration was very low across the farms with the least (Cd at 0.0002434mg/Kg) in control site and not statistically different from other sites' farms.In general, the research indicated an increases in the heavy metal concentrations with closeness to industrial sites.

ICP-MS multi-element analysis for determining the origin by multivariate analysis of red pepper flakes from three different regions of Turkey

The concentrations of eleven elements in thirty traditional red pepper flake (Capsicum annuum L.) samples from three regions of Turkey were analysed by inductively coupled plasma mass spectrometry (ICP-MS). Samples were digested in a microwave system. The decreasing sequence of the mean metal concentrations (mg kg−1) in all the samples is as follows:Fe(109)>Al(89.3)>Mn(9.46)>Zn(7.44)>Cu(5.48)>Ni(4.38)>Cr(1.05)>V(0.52)>Pb (0.27)>As(0.18)>Cd(0.15). All the metal pairs showed positive correlations (except for Cu-Al, Zn-Al and Cu-Mn pairs). Multivariate statistical analysis including principal component analysis (PCA) and cluster analysis (CA) was applied to the data to evaluate the analytical results. Thirty red pepper flake samples were classified into three groups by PCA (eigenvalues higher than >1.00). The first PC loads heavily on V, Pb, Zn, Cu, Cr, and Cd. The second PC was primarily loaded by Fe and Al. The third PC correlated very strongly with Ni, As, and Mn. Cluster analysis resulted in the sorting into similar groups. The results show that PCA and CA are useful tools for the regional differentiation of red pepper flakes and for the identification of heavy metal sources. The accuracy of the results was confirmed by analysis of 1573a Tomato Leaves certified reference material.

Environmental Geochemistry of Igarra Marble Mining District, Southwestern Nigeria

The determination of the impacts of marble mining on the environment in Igarra was carried out via the analysis of soil and water samples as geological medium. Seven soil samples, ten water samples and five rock samples were collected. The samples collected were subjected to petro-graphic and geochemical analysis. The mean concentration of metals in soil from Ekpeshi were Cd (3.254 mg/kg), Co (786.554 mg/kg), Cu (12.911 mg/kg), Ni (18.942 mg/kg), Pb (5.5 mg/kg), and Zn (28.457 mg/kg) while the concentrations of the water samples collected from streams, taps and wells were Cd (0.116 mg/kg), Co (15.225 mg/kg), Cu (0.542 mg/kg), Ni (0.276 mg/kg), Pb (0.486 mg/kg), and Zn (0.742 mg/kg). Lead (Pb) showed high concentration of (0.486 mg/kg), Ni (0.276 mg/kg) and Cd (0.116 mg/kg) as against acceptable limits of 0.01mg/l, 0.02 mg/l (NIS) and 0.07 mg/l (WHO) 0.003 mg/l respectively, while in soil it showed high concentration of Cd (3.254 mg/kg) compared to the acceptable limit of 0.8 mg/kg set by the Dutch Standard limit for soil. Lead, Nickel and Cadmium are found to be in high concentration in both surface and underground water, and this calls for treating water in the study area before it’s used as drinking water via drilling water boreholes by the mining and processing companies operating in the area as a form of corporate social responsibility. Also, the provisions in the mining act should holistically be implemented to safe life and health of the populace of the immediately surroundings.

Health Risk Assessment of Heavy Metals and Microbial Quality of Local Tomato (<i>Solanum lycopersicum</i>) of Ouagadougou, Burkina Faso

Tomato fruit enormously consumed in Burkina Faso is a source of health risk due to its quality. The plant of tomato cultivated in most the industrially polluted area as Ouagadougou, accumulates significant quantities of heavy metals and microorganisms and could be dangerous for consumption. The present study was conducted to investigate heavy metal and microbial contamination in soils wastewater and vegetables (tomato fruit) and to evaluate the possible health risks associated with the consumption of vegetables. Total concentrations of As, Cd, Cr, Cu, Hg, Ni, Se and Zn were determined using atomic absorption spectrophotometry. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial quality was analyzed for the presence of foodborne pathogens. The pH involved from 6.50 ± 0.1 to 9.40 ± 0.12 respectively for Boulmiougou and Kossodo. The mean metal concentrations indicated that soils were strongly polluted followed by wastewater and vegetable. The range of the mean values (in mg · kg-1) exhibited by As, Cd, Cr, Cu, Hg, Ni, Se and Zn in tomato fruit was 17.80 ± 0.32, 2.71 ± 0.02, 11.57 ± 0.2, 203.41 ± 1.20, 15.13 ± 0.30, 53.18 ± 0.20, 38.56 ± 0.10, 109.13 ± 0.25 concerning samples of Boulmiougou and 3.47 ± 0.15, 2.78 ± 0.01, 22.11 ± 0.1, 242.85 ± 2.10, 14.86 ± 0.10, 132.19 ± 1.50, 33.23 ± 0.15, 146.43 ± 1.12 for Kossodo. Microbial count was below to acceptable limits for vegetable, but underlined the presence of spoiler and foodborne pathogens. However, the daily intake of metals (DIM) and the health risk index (HRI) values were found to be under to the prescribed maximum tolerable.

Speciation the heavy metals; Fe, Mn, Cu, Zn, Ni, Cd and Pb in the Sediment of Lake Burullus (Ramsar site), Egypt

This study was carried out to investigate the speciation and distribution of the heavy metals; Fe, Mn, Cu, Zn, Ni, Cd and Pb in the sediments of Lake Burullus, Egypt. The mean metal concentrations of the sediments followed the order of Fe >Mn> Zn > Cu > Ni >Pb> Cd. The evaluated contamination with these metals was revealed moderate to strong ecological risk. According to applying index of the potential ecological risk index (RI), risk assessment code (RAC) and modified risk assessment code (mRAC); the risk levels showed the following order Cd = Pb>Mn> Ni > Zn > Cu > Fe. Considering the metals speciation, high levels were found in the residual fraction for Fe, Cu, Zn and Ni; while were in Fe-Mn hydroxide fraction for Cd and Pb, and in carbonate fraction for Mn. All metals showed enrichment during summer at stations of the southeastern parts of the lake due to the heavy discharge of contaminants from shakhloba, kotichener and Hoksa drains. Therefore, monitoring of contaminants discharge and determination of heavy metal and other pollutants in the water and sediments and its fractionation at Lake Burullus should be introduced for future and management strategies.

Monitoring of seasonal variation of some trace metals concentration in surface water collected from the coastal area of Bangladesh

This study was conducted to determine the seasonal variation of Cr, Ni, Cu, Zn, As, Cd and Pb concentrations in water from four coastal sites of Bangladesh. The mean concentrations of trace metals in the water samples in the range of each elements were Cr (2.6−15.3), Ni (5.1−77.5), Cu (10.2−510), Zn (5.0-1390), As (2.1−13.3), Cd (0.006−0.09), Pb (0.4−109 μg/l) in summer and Cr (3.6−43.7), Ni (10.8−42.4), Cu (7.3−45.2), Zn (18.0-73.9), As (4.0−19.7), Cd (0.025−0.087), Pb (2.8−34.8 μg/l) in winter. The mean concentrations of the metals in water followed a decreasing order of Zn > Cu > Pb > Ni > Cr > As > Cd in the summer and Zn > Ni > Cr > Cu >Pb > As > Cd in the winter. The water of Cox’s Bazar hatchery site showed the highest levels of Zn (1390), Cu (510) and Pb (109 μg/l) in summer while As (19.7 μg/l) showed highest in Cox’s Bazar Bakkhali estuary in the winter samples. The elevated level of Ni (77.5 μg/L) in the summer and Cr (43.7 μg/l) in the winter water samples were also found in the Sundarbans site. The mean concentrations of all estimated trace metals were higher in the winter than in the summer season. It was both in the Chittagong port and Meghna estuary. For the Meghna estuary, the highest concentration of Zn (36.0 μg/l) was observed in the water sample of winter season. Some trace metals exceeded the international quality guidelines. Suspended solid, temperature, rainfall, anthropogenic inputs and geomorphologic setup are influenced by seasonal vagaries which alter the variation of metal distribution.
 J. Biodivers. Conserv. Bioresour. Manag. 2018, 4(2): 67-80

Tissue and parasite accumulation of heavy metals in the giant rat (<i>Cricetomys gambianus</i>) as bioindicators of heavy metal pollution

Heavy metal concentrations in tissues and cestode parasite of the African giant rat collected from staff quarters of the University of Benin, Benin City, Nigeria were determined using Atomic Absorption Spectrophotometry (AAS). Possible human health risk associated with consumption of contaminated rats was also determined using appropriate human intake models. The cestode isolated from the rat was identified as Inermicapsifer guineensis with total infection rate of 100%. The mean concentrations of heavy metals (mg/kg) in liver tissues of the giant rat ranged from 1.82 to 3.98 (Pb), 0.22 to 0.54 (Cd), 22.14 to 45.53 (Zn), 1.87 to 3.37 (Cu) and 1.25 to 3.15 (Co); in heart tissues ranged from 1.39 to 2.01 (Pb), 0.27 to 0.32 (Cd), 23.93 to 53.97 (Zn), 2.17 to 4.66 (Cu) and 1.45 to 2.27 (Co); in kidney tissues ranged from 0.75 to 1.67 (Pb), 0.41 to 0.93 (Cd), 22.77 to 42.14 (Zn), 1.82 to 1.90 (Cu) and 2.05 to 3.08 (Co); in muscle tissues ranged from 1.02 to 1.77 (Pb), 0.24 to 0.31 (Cd), 22.60 to 45.52 (Zn), 1.73 to 2.13 (Cu) and 1.04 to 1.82 (Co) and in parasite tissues ranged from 0.002 to 0.005 (Pb), 0 to 0.001(Cd), 1.19 to 2.63 (Cu) and 0.001 to 0.003 (Co). Mean total concentrations of individual heavy metals in the tissues and parasite of the rat decreased in the order zinc > copper > cobalt > lead > cadmium. Considering the mean concentrations of accumulated heavy metals, the heart and liver were found to be key target organs for heavy metal accumulation. Highly significant positive correlations was observed between heavy metal concentrations in tissues and the parasite (p<0.05, r=0.998), however, bioaccumulation values indicated much higher concentrating capacity of heavy metals in the rat organs than the cestode parasite. Heavy metals are potential risk sources of contamination in the African giant rat ( Cricetomys gambianus ) and should therefore be priority for management in order to control human health risk through ingestion pathway exposures. Keywords: Heavy metals, African giant rat, Parasite, Organs, Risk

Metal concentrations in waters, sediments and biota of the far south-east coast of New South Wales, Australia, with an emphasis on Sn, Cu and Zn used as marine antifoulant agents.

Tin, Cu, Zn, Cd, Pb, Ag and Hg concentrations were measured in waters, sediments and three ubiquitous sedentary molluscs: the oyster, Saccostrea glomerata, a rocky intertidal gastropod, Austrocochlea porcata, and a sediment-dwelling gastropod, Batillaria australis, at 12 locations along the far south coast of NSW, Australia, from Batemans Bay to Twofold Bay during 2009. Metal concentrations in water for Sn, Cd, Ag and Hg were below detection limits (< 0.005 μg/L). Measurable water metal concentrations were Cu: 0.01-0.08 μg/L, Zn: 0.005-0.11 μg/L and Pb: 0.005-0.06 μg/L. Mean metal concentration in sediments were Sn < 0.01-2 μg/g, Cu < 0.01-605 μg/g, Zn 23-765 μg/g, Cd < 0.01-0.5 μg/g, Pb < 0.01-0.3 μg/g, Ag < 0.01-0.9 μg/g and Hg < 0.01-2.3 μg/g. Several locations exceeded the Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand (Australian and New Zealand guidelines for fresh and marine water quality 2000) low and high interim sediment quality guidelines' levels for Cu, Zn, Cd and Hg. Some sites had measurable Sn concentrations, but these were all well below the levels of tributyltin known to cause harm to marine animals. Elevated metal concentrations are likely to be from the use of antifoulants on boats, historical mining activities and agriculture in the catchments of estuaries. All molluscs had no measurable concentrations of Sn (< 0.01 μg/g) and low mean Ag (< 0.01-1.5 μg/g) and Hg (< 0.01-0.5 μg/g) concentrations. Mean Cu (24-1516 μg/g), Zn (45-4644 μg/g), Cd (0.05-5μg/g) and Pb (0.05-1.1 μg/g) in oysters were close to background concentrations. Oysters have Cd and Pb concentrations well below the Australian Food Standards Code (2002).] There were no significant correlations between metal concentrations in sediments and in organisms within locations, and no relationship with levels of boating activity and suspected antifouling contamination. Although not pristine, the low levels of metal contamination in sediments and molluscs in comparison with known metal-contaminated areas indicate that this region is not grossly contaminated with metals and suitable for the development of mariculture.].

Speciation study of copper, lead, chromium, cadmium and nickel in waters from fish pond and stream of Oke-Osun Farm Settlement, Osogbo, South Western, Nigeria

An author was omitted in this version, an erratum can be found in Volume 20 (3) 2018: https://dx.doi.org/10.4314/ijs.v20i3.22 Speciation of copper, lead, chromium and nickel in waters from a fish pond and stream of a farm settlement in Osogbo, Southwestern Nigeria, was investigated. Wet digestion was used for the extraction of Pb, Cr, Cd, Cu and Ni prior to the determination of their concentrations by Atomic Absorption Spectrophotometry (AAS). Packed Amberlite XAD-A16 resin column was used for the pre-concentration and separation of the various species of metals in water samples. The total mean concentration of heavy metals in the pond and stream were: Cu, 0.317 ± 0.005 and 0.218 ± 0.031; Pb, 0.026 ± 0.001 and 0.032 ± 0.009; Cr, 0.043 ± 0.002 and 0.050 ± 0.003; Cd, 0.004 ± 0.001 and 0.010 ± 0.005 and Ni 0.233 ± 0.001 and 0.233± 0.003 mg/L, respectively. Speciation analysis showed that the concentrations (mg/L) of all the metal species were in the order: Cu > Ni > Cr > Pb > Cd in both the fish pond and stream. There was a significant difference between the mean concentrations of metals in water samples from fish pond and stream (P ≤ 0.05) which strongly suggested that the metals might not have come from the same source. Cluster analysis of metals in the pond and stream samples revealed that the metals could have originated from agricultural runoff, activities on the surrounding farmlands, and vehicular emission, on one hand, and leaching from underlying bedrocks on the other hand. Keyword : Speciation analysis, fish pond, water, metals, farm settlement, Osogbo

HEAVY METALS CONTAMINATIONASSESSMENT FOR SOME IMPORTED AND LOCAL VEGETABLES

The objective of this study, to was measure concentrations of some heavy metals in various imported and locally produced vegetable crops, including root crops (Turnips ''Brassica rapa'' and Carrots ''Daucus carrota''), stem crops (Potatoes ''Solanum tuberosum'' and Onion ''Allium sativa''), leaves (Lettuce ''Lactuca sativa''), and fruits (Tomatoes ''Lycopersicon esculentum'').These crops were collected from Baghdad central whole sales. X-ray fluorescence spectrometry technique was applied to measure heavy metal concentrations. In the imported vegetables, heavy metal mean concentrations were arranged in the following increasing order: Fe&gt;Zn&gt; Cu&gt;Ni&gt;Co&gt;Cd&gt;Cr&gt;Pb, whereas higher levels of Cr, Fe, Cu, Zn, Cd and Pb (1.2075, 165.995, 37.2275, 43.775, 6.0375, 1.48)mgkg-1, respectively, were found within the locally produced vegetables. High level of Co 3.09625 mgkg-1 was also detected in onion, while, increased concentrations of Ni 7.8675mgkg-1 were found in lettuce collected from local market. Overall significant differences in the heavy metals concentration between imported and locally produced vegetables were observed. The daily intake of four main heavy metals (Cd, Cu, Zn and Pb) had been estimated which revealed highly consumption of Cd (310 and 372 µg per day) for imported and locally vegetables respectively. This study suggests raising the concern of the society and Iraqi government to this problem and to take in consideration its impact on general health and environment.

Spatial and seasonal variation in physicochemical parameters and heavy metals in Awash River, Ethiopia

Awash River, one of the major rivers in Ethiopia which originate from the central highland area, crosses different extended agricultural farms as well as various industries which receives large effluents from different sources. Nineteen physicochemical parameters, as well as heavy metals (Fe, Zn, Cu, Pb, Cr, Cd and Ni), were quantified using atomic absorption spectroscopy in eight different sampling stations of Awash River. There was a significant spatial variation (p < 0.05) in average NO3-N, NH4-N, TN, BOD and COD values in Awash River. There is a strong and positive correlation between (pH and EC, r = 0.805), (WT and BOD, r = 0.774), (NO3-N and NO2-N, r = 0.901), (NO3-N and TN, r = 0.906), (NO3-N and TP, 0.830), (NH4-N and TN, r = 0.876), (NH4-N and COD, r = 0.848), (TN and TP, r = 0.819), (TN and COD, r = 0.941) during dry season and also between (WT and BOD, r = 0.704), (turbidity and NO3-N, r = 0.749), (turbidity and NO2-N, r = 0.722), (NO3-N and NO2-N, r = 0.921), (TP and COD, r = 0.789) during wet season. The results showed that the mean concentrations of metals ranked (high to low) Fe > Cr > Cu > Zn > Pb > Cd > Ni during dry season, whereas the concentration of heavy metals during wet season was in the following order of decreasing magnitude Fe > Cu > Zn > Pb > Cr > Cd > Ni. Buffer zones should be protected in order to control soil and agricultural nutrients from entering to Awash River. Moreover, industries at the upper stream area should be properly and adequately treat the wastewater before discharging to the Modjo as well as Awash River.

Heavy Metals in Heterobranchus Longifilis (Cuvier And Valenciennes, 1840) Cultured in Earthen Ponds in Selected Communities in Warri Metropolis, Nigeria

The concentrations of Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) in Heterobranchus longifilis (Mean total length= 40.52 cm; mean weight=563.25 g) cultured in earthen ponds in Warri, Nigeria, were determined by Atomic Absorption Spectrometric technique in order to provide baseline data and to ascertain the suitability of such fish for consumption. The mean concentrations of metals in H. longifilis, ranged from 0.13 mg/kg for Cd in January to 72.51 mg/kg for Cu in June with significant differences (p&lt;0.05) observed in the mean concentrations of Cu, Pb and Zn in fish between months. The mean concentrations of metals in H.longifilis, ranged from 0.12 mg/kg for Cd at Jeddo to 69.27 mg/kg for Cu at Ubeji with significant differences (p&lt;0.05) observed in the mean concentration of Zn in fish between stations. The bioaccumulation quotient (BQ) values ranged from 0.50 for Cd at Jeddo to 37.24 for Cu at Oboroke while the hazard quotient (HQ) ranged from 0.39 for Zn to 3.43 for Pb. The maximum acceptable risk (MAR) values anged from 0.02 for Pb at Ekpan to 6.29 for Zn at Ubeji while the estimated average daily intake (EADI) of heavy metals ranged from 0.09 mg/person/day for Cd to 36.13 mg/person/day for Cu. It was concluded that Cd, Cu and Pb were the metals that presented a potential risk to the consuming public and that the heavy metal content in earthen ponds should be routinely monitored in order to keep metal levels within safe limits.Keywords: Heavy metals, Hazard quotient, Heterobranchus longifilis

Selected trace elements and metals in groundwater within Permian sediments near Olkusz (Zn-Pb ore mining region, S Poland)

The extensive mining of Zn-Pb ores in the Olkusz region resulted in significant changes of both water table level and chemical composition of water in all aquifers in the area. This was caused by intensive dewatering of mining excavations and development of a thick aeration zone reaching 150 m in a central part of the area. That created favorable conditions for oxidation of metal sulfides occurring in the ore-bearing dolomites (Middle Triassic) and started the process of forming readily soluble hydroxysulphates which then migrated to lower aquifers, including the Permian. As a result of those processes, various metals and other elements toxic to the water environment appeared in leaks observed in mine galleries. Changes in concentrations of selected elements (Fe, Mn, Zn, Pb, Cu, Ba, Ni, Co, As, Cr, Hg, Tl, Ag, Cd, B) in mine waters over the period of the last nearly 50 years were described. Water samples were collected from exploratory boreholes, piezometers, and wells located in investigated area inflows and seepages occurring in shafts and drifts excavated in Permian conglomerates. Mean concentrations of metals (Pb, Cd, Cr, Hg, Tl) and other toxic elements were surprisingly low; Pb, 3.94 μg/L; Cd, 0.2 μg/L; Cr, up to 2.26 μg/L; Hg, 0.25 μg/L; Tl, 3.59 μg/L; and As, 6.31 μg/L. However, the observed concentrations varied significantly over time, reaching respectively up to 190 μg Pb/L, 60 μg Cd/L, 15.6 μg Cr/L, 2.67 μg Hg/L, 81.3 μg Tl/L, and 155 μg As/L.

Concentrations and Human Health Risk of Heavy Metals in Rivers in Southwest Nigeria.

Background.Rivers are the most vital freshwater resources in the world. In Southwest Nigeria, anthropogenic activity stresses the quantity and quality of water resources.Methods.The present study examined the concentrations and human health risk of five heavy metals (manganese (Mn), arsenic (As), chromium (Cr), cadmium (Cd), and lead (Pb)) in selected rivers in Southwest Nigeria. The determination of heavy metals was carried out by atomic absorption spectrophotometry after digestion with a di-acid mixture 9:4 (v/v) (nitric acid: perchloric acid).Results.All rivers had higher concentrations of the five heavy metals in the dry season except for As in Dandaru (0.012 mg/L) and Asejire (0.016 mg/L). Manganese was observed to have the highest mean concentration among all the five metals in both the rainy and dry seasons across the sampled rivers. Generally, the annual mean concentration of metals followed the order: Mn>Cr>Cd>Pb>As in all the selected rivers.Discussion.The human health risk assessment showed that the hazard index and hazard quotient for ingestion of water for Cd and As in all the sampled rivers were higher than the acceptable limit of 1.0, indicating carcinogenic risk (CR) via direct ingestion of water. The CR via ingestion for As in all of the sampled rivers was above the remedial goal target of 1×10−6. The recorded values for chronic daily intake (CDI) were higher for Cr and Mn in all four sampled rivers.Conclusions.The results of the present study showed that As is a driver for carcinogenic risk through ingestion in all of the sampled rivers compared to other metals.Competing Interests.The authors declare no competing financial interests

Geochemistry of cobalt-rich ferromanganese crusts from the Perth Abyssal Plain (E Indian Ocean)

Geochemistry of cobalt-rich ferromanganese crusts from the as-yet-unexplored Dirck Hartog Ridge (DHR), a linear bathymetric feature of poorly understood origin, located in the centre of the Perth Abyssal Plain (PAP), is described for the first time, based on 3 samples analyzed with XRF, ICP-MS and EPMA. Mean bulk concentrations of Fe and Mn were 20.8 and 18.4 wt%, respectively; individual crust layers, however, proved chemically variable. The mean concentration of metals of the highest economic potential (Cu + Ni + Co) was 0.69 wt%. The mean total rare earth elements (REE) and yttrium (ΣREY) contents in the samples (1908 mg/kg) proved moderate. The crusts showed strong positive Ce anomalies, negative Y anomalies and a low YSN/HoSN ratio (mean 0.56). Observations on the texture and chemical composition of the crust samples studied allowed us to distinguish two major and two subtypes of representative colloform structures built of laminae. The Type I colloform structures showed the Mn/Fe ratio to range from 0.86 to 5.69, the ranges in Type II colloform structures being 0.49–2.47 (Subtype II-1) and 6.91–221.42 (Subtype II-2). The Subtype II-2 colloform structures were enriched in Ni (up to 7.31 wt%). The Co and Cu concentrations showed a high variability, 0.03–1.64 and 0.03–0.22 wt%, respectively. According to the current genetic models and discrimination diagrams, the crusts studied were classified as hydrogenetic, although individual laminae and groups of laminae could be regarded as diagenetic or hydrothermal.

Edible Mushrooms from Niger Delta, Nigeria with Heavy Metal Levels of Public Health Concern: A Human Health Risk Assessment.

Mushrooms (US6759049B2, CA2372185A1, DE60108325D1) can be contaminated by heavy metals as described in various patents. This study has determined the potential human health risk associated with the consumption of mushroom in Niger Delta, Nigeria. Concentrations of Pb, Cd, Sn, Cu, Ni, Al and Zn in both wild/cultivated mushroom and background soil/substrate were determined using Atomic Absorption Spectrometer (AAS). Heavy metal pollution was calculated using Bio-Concentration Factor (BCF) and Pollution Load Index (PLI) while human health risk assessment employed Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), Carcinogenic Risk (CR) and Total Cancer Risk (TCR). The mean concentration of metals in mushroom and soil/substrate ranged from 0.021 mg/kg - 29.16 mg/kg and 0.01 mg/kg - 56.11 mg/kg. When compared with standards by WHO, EU, SON, DPR, USEPA and NAFDAC, 100% violation was observed in Ni, Cu, Cd, Zn and partial violation by Pb in the mushroom sample although soil heavy metal concentrations were within safe limits. There was bioconcentration and heavy metal enrichment as PLI ranged from 3.39 - 23.58. Estimated daily intakes were (0.00 - 0.47, 0.00 - 0.51 and 0.00 - 1.17) mg/kg/day and THQ were (0.01 - 0.46, 0.01 - 0.31 and 0.03 - 1.51) for adults, adolescents and children respectively. There was a violation of Permissible Tolerable Daily Intakes (PTDI) set by JECFA. Hazard indices were all >1, another indication of health concern. Nickel showed the highest carcinogenic risk with values of 4.83E-04 - 1.43E-01, 5.31E-04 - 1.00E-01 and 1.20E-03 - 2.29E-01 for adults, adolescents and children respectively. About 80% of TCR ranged from x10-1 - x10-3. Consumption of mushroom in Niger delta-Nigeria may pose significant health risk.

Environmental impact assessment of natural radioactivity and heavy metals in drinking water around Akkuyu Nuclear Power Plant in Mersin Province

The aim of this study was to determine natural radioactive and heavy element concentrations in Mersin drinking water samples before the commissioning of the Akkuyu nuclear power plant and to collect data for possible environmental contaminations in the future. Drinking water samples were taken from the provincial center, districts, and populated villages. The annual effective dose of natural radionuclides and cancer risks were calculated for each person living in the city. Hazard index and cancer risk were calculated, which were caused by heavy elements. Mean gross alpha and beta radioactivity concentrations in drinking water were 0.059 Bq/L and 0.120 Bq/L, respectively. The annual cumulative effective dose for people was 30.83 $\mu $Sv. Average estimated excess cancer risk related to this exposure was 16.9 $\times $ 10$^{-5}$. Mean metal concentrations of Cr, Ni, Zn, Cu, Ba, and Cd in drinking water were 1.33, 4.65, 54.8, 11.1, 26.3, and 0.36 $\mu $g/L, respectively. Pb and As were lower than the detection limits. Mean calculated hazard index depending on heavy metal concentration was 6.8 $\times $ 10$^{-1}$ for drinking water. Cancer risks of heavy metals decreased in the order of Cd $>$ Cr $>$ Ni for the region.

Investigation of the extent of contamination of heavy metals in agricultural soil using statistical analyses and contamination indices

ABSTRACTTo examine the level of contamination of Eshghabad region, Neyshabur, the concentration of heavy metals in soil was measured. For this purpose, 37 samples were taken from surface soil and the total concentration of heavy elements was measured by inductively coupled plasma (ICP). The mean concentration of Pb, Ni, Cu, Zn, and Fe was obtained to be 195, 87.3, 22.8, 274.8, and 2.5%, respectively. Using five valid indicators, the intensity of metal contamination in soil was calculated and compared. Furthermore, using statistical analyses, the relationships between the elements, their origins, and the spatial distribution of metals across various stations were investigated. The results indicated that the mean value of all of the studied metals (except for iron and copper) is greater than the mean concentration of metals in the Earth's crust. The indicators showed very high contamination for lead, while low to medium contamination for other elements of interest in the farming soils of the region. Statistical analyses indicated that there is a relatively similar contamination intensity across all of the studied stations. Considering the quality standards, the soils of this region are threatened by contamination of lead.