Mean Lead Concentration Research Articles

Monitoring and Assessment of Toxicological Risks of Poultry Meat Contaminated with Heavy Metals.

This study aimed to investigate the heavy metal contamination in poultry meat of Kotli Sattian, Rawalpindi. The meat samples from ten sites were analyzed for lead, cadmium, chromium, copper, arsenic, nickel, zinc, iron, sodium, and calcium. The possible health risks of these metals were also observed. Mean lead, cadmium, chromium, arsenic, and nickel concentrations were higher than the permissible limits of the World Health Organization (WHO). Metals in meat samples showed the trend of Fe > Na > Zn > Ni > Ca > As > Cr > Pb > Cu > Cd. All the studied metals except lead were statistically significant (P ≤ 0.05). The hazard quotient (HQ) values of all the metals were below one, except iron. Iron showed chronic health risks in both adults (1.63) and children (3.64). Moreover, the cumulative hazard index (HI) of the metals indicated that meat consumption can pose a significant chronic toxic risk in both adults and children as the HI value was 2.06 for adults and 4.61 for children, which is greater than one. The carcinogenic risk (CR) of arsenic in meat for adults and children exceeded the acceptable range, making it a metal of concern. This means that the consumption of small concentrations of metal through meat may be the source of severe toxicological consequences. It can be concluded that meat is contaminated with metals; therefore, appropriate precautions should be taken to minimize this contamination.

Presence and concentration of lead in keys and keyring items.

Environmental lead is a persistent hazard that disproportionately affects children. Keys are known sources of lead exposure in children, but little is known about the specific lead content or frequency of lead in keys. We identified differences in lead concentration and frequency across items with different physical characteristics. This study tested a convenience sample of keys and keychain objects using an X-ray Fluorescence (XRF) analyzer. The mean lead concentration across 362 objects tested was 1722 ppm (SD 3657 ppm; range 95.5-44 400 ppm). Lead was present in the majority (64%) of objects tested. Door keys had the highest concentration of lead (mean 2646 ppm; SD 3701 ppm). Door keys had significantly more lead than both vehicle keys (p<0.0001) and electronic fobs (p=0.0004). Gold-coloured keys contained significantly more lead than silver-coloured keys (p<0.0001). Copied keys were significantly more likely to contain detectable levels of lead compared with original keys (p<0.0001); however, this relationship was not significant when controlling for key type. There was a positive association between key age and lead concentration (p=0.009). Keys were less likely to contain lead if they were silver-coloured; car keys or electronic fobs; and newer. However, several categories of keys with less lead contained high lead levels, and the majority of items tested (64%) contained more lead than limits on lead in keys that were implemented in Minnesota after data collection (90 ppm). The levels of lead identified highlight the need for public education and potential additional regulatory guidelines for keys.

Investigating the Spatial Patterns of Heavy Metals in Topsoil and Asthma in the Western Salt Lake Valley, Utah

Mining activities, particularly in large excavations like the Bingham Canyon Copper Mine in Utah, have been increasingly linked to respiratory conditions due to heavy-metal-enriched waste and dust. Operating continuously since 1906, the Bingham Canyon Copper Mine contributes 4.4% of the Salt Lake Valley PM2.5 pollution. However, the extent of its contributions to larger-sized particulate matter (PM10) dust, soil and water contamination, and human health impacts is largely unknown. Aerosol optical depth data from Sentinel-2 imagery revealed discernible dust clouds downwind of the mine and smelter on non-prevailing-wind days, suggesting potential heavy metal dispersion from this fugitive dust and subsequent deposition to nearby surface soils. Our analysis of topsoils from across the western Salt Lake Valley found mean arsenic, copper, lead, and zinc concentrations to be well above global background concentrations. Also, the minimum values for arsenic and maximum values for lead were well above the US EPA regional screening levels for residential soils. Thus, arsenic is the metal of greatest concern for impacts on human health. Elevated concentrations of all metals were most notable near the mine, smelter, and tailings pond. Our study linked these elevated heavy metal levels to regional asthma outcomes through cluster analysis and distance-related comparison tests. Significant clusters of high asthma rates were observed in regions with elevated topsoil heavy metal concentrations, impacting both low- and high-income neighborhoods. The findings of this preliminary study suggest that the mine, smelter, and recent construction activities, especially on lands reclaimed from former tailings ponds, could be contributing to atmospheric dust containing high levels of heavy metals and exacerbating asthma outcomes for residents. However, the methods used in the study with aggregated health outcome data cannot determine causal links between the heavy metal contents of soil and health outcomes; they can only point to potential links and a need for further investigation. Such further investigation should involve individual-level data and control for potential confounding factors, such as socioeconomic status, access to healthcare, and lifestyle factors, to isolate the effect of metal exposures on asthma outcomes. This study focused on atmospheric deposition as a source of heavy metal enrichment of topsoil. However, future research is also essential to assess levels of heavy metals in subsoil parent materials and local surface and groundwaters to be able to assess the links between the sources or methods of soil contamination and health outcomes.

Investigating the relationship of co-exposure to multiple metals with chronic kidney disease: An integrated perspective from epidemiology and adverse outcome pathways

Systematic studies on the associations between co-exposure to multiple metals and chronic kidney disease (CKD), as well as the underlying mechanisms, remain insufficient. This study aimed to provide a comprehensive perspective on the risk of CKD induced by multiple metal co-exposures through the integration of occupational epidemiology and adverse outcome pathway (AOP). The study participants included 401 male mine workers whose blood metal, β2-microglobulin (β2-MG), and cystatin C (Cys-C) levels were measured. Generalized linear models (GLMs), quantile g-computation models (qgcomp), least absolute shrinkage and selection operator (LASSO), and bayesian kernel machine regression (BKMR) were utilized to identify critical nephrotoxic metals. The mean concentrations of lead, cadmium, mercury, arsenic, and manganese were 191.93, 3.92, 4.66, 3.11, 11.35, and 16.33 µg/L, respectively. GLM, LASSO, qgcomp, and BKMR models consistently identified lead, cadmium, mercury, and arsenic as the primary contributors to kidney toxicity. Based on our epidemiological analysis, we used a computational toxicology method to construct a chemical-genetic-phenotype-disease network (CGPDN) from the Comparative Toxicogenomics Database (CTD), DisGeNET, and GeneCard databases, and further linked key events (KEs) related to kidney toxicity from the AOP-Wiki and PubMed databases. Finally, an AOP framework of multiple metals was constructed by integrating the common molecular initiating events (reactive oxygen species) and KEs (MAPK signaling pathway, oxidative stress, mitochondrial dysfunction, DNA damage, inflammation, hypertension, cell death, and kidney toxicity). This is the first AOP network to elucidate the internal association between multiple metal co-exposures and CKD, providing a crucial basis for the risk assessment of multiple metal co-exposures.

Evaluation of Airborne Lead Pollution and Its Association with Children's Urinary Lead Levels

Despite the measures taken by most countries, lead pollution still poses an environmental and health risk to humans, especially children. Therefore, the current study aims to evaluate lead in the air and its impact on children's health. Lead samples from the air and children's urine were collected from three different areas within Kerbala Governorate: the urban city center residential areas, and rural areas as a reference area for comparison. A suspended dust collector was used to collect lead samples, and then the lead concentration was measured using an atomic spectrometer after digesting them with acids. The results of the study showed that the highest concentration of lead was in the center of the urban area (3.150 ?g/m3) and its mean concentration in the air was 1.703 (?g/m3), which is higher than the US Environmental Protection Agency limits, with statistically significant differences between the study areas p &lt; 0.01. The mean concentration of lead in children's urine was 0.622 (?g/dL) with statistically significant differences between the areas p &lt; 0.01. Pearson's correlation coefficient indicated a significant positive correlation between the concentration of lead in the air and children's urine (r = 0.651; p &lt; 0.05). This means that high lead concentrations in children's urine are due to lead air pollution and are an indicator of lead pollution in the environment and warn of potential risks to children's health. Therefore, the study recommends reducing lead emission sources and conducting periodic examinations.

Do lead (Pb) content of lipsticks expose a health risk to children? A risk assessment study.

Lead (Pb) content in lipsticks and potential life-long exposure of which might cause severe effects in consumers are an important concern for public. Thus, studies emphasize that lead exposure has no safe levels. From 10 different brands, in total, 25 solid, gloss and creamy lipsticks are deployed from Turkish markets that are also categorized in two different price ranges. In order to evaluate the blood Pb levels in children, the United States Environmental Protection Agency's 'Exposure Uptake Biokinetic Model' is utilized. To assess the health risk of chronic usage both for children and adults, oral daily systemic exposure levels are calculated with the worst-case scenario and are compared with Maximum Allowable Dose Level for lipsticks. For lifetime risk assessment, exposure is assumed to start by age 7, and four different exposure scenarios have been deployed. The mean lead content of lipsticks shows significant statistical differences between the high- and low-priced lipstick groups. Daily level and total risk for lifetime Pb exposure from deployed lipsticks are below the acceptable risk levels but long-worn usage of products with routine monitoring of metal content is crucial for sensitive and unintended exposure groups.

Heavy Metal Pollution Status in The Main Surface Waters of The N'djili River Basin in Kinshasa, Democratic Republic of Congo: A Review with Application and Evaluation of Pollution Indices Evaluation

The aim of this study was to assess heavy metal pollution in the surface waters of the N'djili river watershed, as well as to determine the main sources of this pollution and their impact on water quality. Five sampling sites were selected in the watershed, representing a variety of urban and industrial influences. In these samples, trace metals such as lead (Pb), cadmium (Cd) and arsenic (As) were measured by atomic absorption spectrometry. The respective mean concentrations of lead (Pb), cadmium (Cd) and arsenic (As) in the surface waters of the N'djili basin are 0.066 mg/L, 0.006 mg/L and 0.310 mg/L. The mean value of the degree of contamination (Dc) in the surface waters of the N'djili basin is greater than 3, indicating heavy contamination of these waters (Lukaya river, Matete river, N'djili river, Ntshuenge river, Ngwele river). The average values of for the trace metal pollution index (HPI) are below the threshold value of 100, so overall, these waters are not very polluted. Nevertheless, particularly high concentrations were observed in the waters of the Matete River, with values exceeding 100, indicating severe localized pollution. Correlation analysis between trace metals and HPI indicates that lead and cadmium are the main contributors to surface water toxicity in the N'djili basin. These results highlight the urgent need to develop targeted strategies to reduce pollution in order to preserve public health and aquatic ecosystems.

Partitioning Human Dietary Exposure to Ammunition-Derived Lead in Meat from Game Animals Between Bullets and Shotgun Pellets

AbstractIn making recommendations for restricting uses of lead shotgun pellets and bullets for hunting, regulatory agencies, including those of EU and UK REACH, estimate human health risks from dietary exposure to lead from both ammunition types separately and attempt to monetise benefits of restriction options. However, available data from diet surveys are rarely sufficient to allow straightforward partitioning of dietary exposure between game killed with lead bullets and shotgun pellets. Because information on game meat consumption was limited, the UK REACH Agency’s draft socioeconomic analysis assigned all health-related economic benefits of lead ammunition restriction to shotgun pellets and none to bullets because a much higher tonnage of shotgun pellets than bullets is used. However, differences between the two ammunition types in exposure pathways make tonnage used an unreliable proxy for dietary exposure. Using primarily data for the UK, we partitioned exposure to lead by estimating tonnages of edible game meat shot with bullets and shotgun pellets separately and the mean lead concentrations in these meats. We estimated that ca.21% of human dietary exposure to ammunition-derived lead in the UK is from bullets and 79% from shotgun pellets. This new partitioning approach could be used to inform cost–benefit analysis in the UK and elsewhere when data from food consumption surveys are lacking.

Water Quality of Roof-Harvested Drinking Water Tanks in a Rural Area near a Gold and Copper Mine: Potential Health Risk from a Layer of Metal-Enriched Water and Sediment

This study investigated the drinking water quality of house water tanks that harvested roof runoff in a rural area surrounding a large copper and gold mine in Central Western New South Wales (NSW). Water was sampled from (1) the tops of water tanks, (2) the bottoms of water tanks, and (3) kitchen taps. Water samples collected from the bottoms of tanks were turbid with suspended sediment. Concentrations of metals (lead, nickel, arsenic and manganese) from bottom-of-tank water samples often exceeded Australian drinking water guidelines. Overall, 37.2% of samples from bottoms of tanks exceeded arsenic guidelines (&lt;10 µg L−1). The mean concentration of lead in water from bottoms of tanks was 695 µg L−1, with 18.6% of these samples exceeding lead guidelines (&lt;10 µg L−1) by &gt;100 times. Our results highlight the risk of contaminated water and sediment at the bottoms of tanks. Further investigation of private household drinking water tanks is recommended for properties in other rural areas, including areas with and without nearby mining activity. We describe a layer of contaminated water and sediment at the bottoms of water tanks, near the water outlet, which is a potential contamination pathway and substantial health risk for house water supplies.

Lead exposure from honey: meta-analysis and risk assessment for the Arab region

The Codex Alimentarius Commission has adopted a maximum level for lead in honey (0.1 mg/kg). Despite representing a population of more than half a billion, exposure and risk assessments for lead specific to the Arab region are lacking. The aim of this work was to collect analytical data for lead in honey available in Arab countries and to assess the risk caused by exposure to lead from these samples for local consumers. A regional mean lead concentration in honey, obtained through a meta-analysis of 57 studies, was used in deterministic risk assessments for adults (nephrotoxicity and cardiovascular effects) and young children (developmental neurotoxicity). A regional pooled mean concentration of 0.12 mg/kg [95%CI: 0.07–0.21] (0.13 mg/kg, if non-detects are considered at their highest possible value) was obtained. Margins of exposure of 363 [71–17182] and 865 [168–40909] were calculated for adults, and of 48 [9–2273] for children, indicating potential concern for the latter population subset. These values were produced using GEMS consumption data, and considering the same intake for both children and adults, potentially overestimating the risk for children. Nevertheless, food competent authorities should consider measures to reduce lead concentration in honey available for sale in the region to prevent trade constraints and to better protect vulnerable populations.

Heavy Metal Contamination on Vannamei Shrimp Aquaculture in North Coast of Central Java

The North Coast of Central Java receives consignments of waste containing heavy metal contamination from several sources, resulting in a decrease in water quality on the coast. Heavy metal contamination in water sources, such as Pb, Cd, and Cr that will be used in shrimp farming. The impact of Pb, Cd, and Cr can have several adverse effects, such as health risk, ecological imbalance, reduce shrimp growth and productivity, environment pollution. The research was conducted to analyze heavy metal contamination levels in ponds and vannamei shrimp yields on the northern coast of Central Java. The method involved collecting shrimp, water, and sediment samples at nine different locations (Dampyak; Suradadi; Kedongkelor; Danasari; Nyamplungsari; Pesantren; Depok; Wonokerto; Degayu). Heavy metal data were analyzed with SPSS. The mean lead concentrations were 0.52+0.19 mg.kg-1 in sediment, 0.66+0.11 mg.kg-1 in water, and 0.86+0.18 mg.kg-1 in shrimp. Cadmium levels were measured in soil (0.028+0.03 mg.kg-1), water (0.027+0.021 mg.kg-1), and shrimp (0.011+0.004 mg.kg-1). The mean chromium concentrations were 0.51+0.25 mg.kg-1 in sediment, 0.93+0.40 mg.kg-1 in water, and 0.95+0.11 mg.kg-1 in shrimp. Based on the calculation of the average BAF x &gt; 1.0, vannamei shrimp on the northern coast of Central Java have the capability of becoming bioaccumulation and bioindicators. The consumption of vannamei shrimp for 70 years has a lifetime risk of developing cancer due to the LCR value of x &gt; 10-6 on the northern coast of Central Java.

Assessment of Heavy Metal Concentrations in Food Samples of Oil and Non-Oil Producing Communities in Rivers State, Nigeria

Aim: To compare heavy metal concentrations in locally consumed vegetables and food crops grown in oil and non-oil-producing communities in Rivers State.&#x0D; Study Design: Descriptive cross-sectional study.&#x0D; Place and Duration of Study: Kegbara Dere and Omerelu communities in Gokana and Ikwerre local government areas, Rivers State, Nigeria between November 2021 and January 2022.&#x0D; Methodology: Heavy metal concentrations (lead (Pb), cadmium (Cd) mercury (Hg), and arsenic (Ars) of vegetables, food crops, and sea animals selected from the local markets and rivers of the two communities were determined. Data entry and analysis were done using IBM Statistical Package for Social Sciences (SPSS)version 21. T-test was used to compare the mean differences in heavy metal concentrations of vegetables and food crops between the two communities.&#x0D; Results: Mean concentrations of Lead (0.70 vs 0.01) Cadmium (0.09 vs 0.00) and Arsenic (0.18 vs0.00) respectively of vegetables grown in the oil-producing community were higher than that of the non-oil-producing community. The difference was not statistically significant (P&gt;0.05). Mean concentrations of Lead (1.48 vs 0.00) Cadmium (0.28 vs 0.00), and Arsenic (0.41 vs 0.00) of the food crops in the oil-producing community were higher than that of the non-oil-producing community. However, only the difference in the lead concentrations was significant (P&lt;0.05) The concentrations of Pb, Cd, and Ars in sea creatures collected from the surface waters of the oil-producing community were above WHO-recommended limits.&#x0D; Conclusion: Food grown in oil-polluted environments has higher heavy metal concentrations compared to non-polluted environments and therefore highlights the need for continued and increased efforts towards complete remediation of the polluted regions of the Niger Delta.

Lead exposure of mainland Australia's top avian predator

Lead (Pb) toxicity, through ingestion of lead ammunition in carcasses, is a threat to scavenging birds worldwide, but has received little attention in Australia. We analyzed lead exposure in the wedge-tailed eagle (Aquila audax), the largest raptor species found in mainland Australia and a facultative scavenger. Eagle carcasses were collected opportunistically throughout south-eastern mainland Australia between 1996 and 2022. Lead concentrations were measured in bone samples from 62 animals via portable X-ray fluorescence (XRF). Lead was detected (concentration >1 ppm) in 84% (n = 52) of the bone samples. The mean lead concentration of birds in which lead was detected was 9.10 ppm (±SE 1.66). Bone lead concentrations were elevated (10–20 ppm) in 12.9% of samples, and severe (>20 ppm) in 4.8% of samples. These proportions are moderately higher than equivalent data for the same species from the island of Tasmania, and are comparable to data from threatened eagle species from other continents. Lead exposure at these levels is likely to have negative impacts on wedge-tailed eagles at the level of the individual and perhaps at a population level. Our results suggest that studies of lead exposure in other Australian avian scavenger species are warranted.

Spatial Distribution, Contamination Assessment and Origin of Soil Heavy Metals in the Danjiangkou Reservoir, China.

Soil heavy metal contamination is crucial due to menacing food safety and mortal health. At present, with the fast advancement of urbanization and industrialization, heavy metals are increasingly released into the soil by anthropogenic activities, and the soil ecosystem contamination around the Danjiangkou Reservoir is directly associated with water quality security of the reservoir. In this paper, using 639 soil samples from the Danjiangkou Reservoir, Henan Province, China, we studied a variety of space distribution characteristics of heavy metals in soil. Geographic information system analysis (GIS), geo-accumulation index (Igeo), contamination factor (CF), principal component analysis (PCA) model, and positive matrix factorization (PMF) model were used together to recognize and quantify the distribution, contamination, and origin of heavy metals. We uncovered an exceptional variety of heavy metal concentrations among the tested soils: the mean arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), manganese (Mn), nickel (Ni), zinc (Zn), lead (Pb) and mercury (Hg) concentrations (14.54, 0.21, 18.69, 81.69, 898.42, 39.37, 79.50, 28.11, 0.04 mg/kg, respectively, in the topsoil (0-20 cm depth)), all exceed their background values. The mean Igeo value and CF values of these trace elements are both in descending order: Cd > Co > Mn > Ni > Pb > Zn > Cr > As > Hg. Cd was the highest contributor to the assessment of heavy metal pollution, with an average Igeo value over three, indicating that the study area is modestly contaminated by Cd. The PCA analysis and PMF model revealed three potential sources, including natural sources (PC1) for Cr, Co, Mn and Ni; agricultural sources (PC2) for Cd, Zn and Hg; and industrial emissions and transportation sources (PC3) for Pb. This study displays a map of heavy metal contamination in the eastern area topsoil of the Danjiangkou Reservoir, showing the most severe pollutant is Cd, which poses a threat to the water quality security of Danjiangkou Reservoir and provides a significant source identification for future contamination control.

Levels of Toxic and Essential Elements and Associated Factors in the Hair of Japanese Young Children.

There is growing concern regarding the effects of toxic element exposure on the development of children. However, little is known about the level of toxic elements exposure in Japanese children. The purpose of this study was to assess the concentrations of multiple elements (aluminum, cadmium, lead, calcium, copper, iron, magnesium, sodium, zinc) in the hair of 118 Japanese young children and to explore the factors associated with their element levels. The element concentration was analyzed by ICP-MS, and children's food and water intake were assessed by the questionnaire. Results showed that there were no large differences between the level of elements in the hair of Japanese children and those of children in other developed countries. Girls had significantly higher levels of aluminum, copper, and iron (p = 0.000, 0.014, and 0.013, respectively), and boys had a higher level of sodium (p = 0.006). The levels of calcium, iron, magnesium, and sodium in nursery school children were significantly higher than those in kindergarten children (p = 0.024, 0.001, 0.046, and 0.029, respectively). Multiple regression analyses with controlling the confounding variables showed significant negative associations of frequency of yogurt intake with aluminum and lead levels (p = 0.015 and 0.037, respectively). When the children were divided into three groups based on the frequency of yoghurt consumption, viz. L (≤once a week), M (2 or 3 times a week), and H (≥4 to 6 times a week) group, the mean aluminum concentration (µg/g) in the L, M, and H groups was 11.06, 10.13, and 6.85, while the mean lead concentration (µg/g) was 1.76, 1.70, and 0.87, respectively. Our results suggested the validity of hair element concentrations as an exposure measure of essential elements and frequent yogurt intake as a viable measure for protecting children from toxic elements. However, these findings will need to be confirmed in more detailed studies with larger sample sizes in the future.

Potential hepatic-protective effect of Physalis peruviana against lead-induced toxicity in albino rats

&lt;p&gt;Lead toxicity poses a serious threat facing humanity. Research aims to investigate the potential hepato-protective effect of &lt;em&gt;Physalis peruviana&lt;/em&gt; (P.P) fruit against lead toxicity (10 ppm (1/45 LD50)) in male albino rats. Toxicological induction with lead acetate lasted for 28 days followed by treatment with 200, 300, and 500 mg/kg of lyophilized P.P. fruit extract for another 28 days. Superoxide dismutase, malonaldehyde, catalase, and glutathione peroxidase were measured using a spectrophotometer. Lead concentration in liver tissues was assessed using Atomic Absorption Spectroscopy after four and eight weeks, in addition to Aspartate aminotransferase, alanine aminotransferase, and complete blood count were measured. Lead acetate induced a substantial elevation in malonaldehyde levels, and a significant decrease in Superoxide dismutase, catalase, and glutathione peroxidase activities. Treatment with 200, 300, and 500 mg/kg P.P showed an improvement in the activity of the antioxidant enzymes in a dose-dependent manner. Co-administration of P.P. ameliorates the damage caused by lead acetate. &lt;em&gt;Physalis peruviana&lt;/em&gt; solution showed a reduction in the mean lead concentration in a dose-dependent response of 0.26±0.02, 0.21±0.02, and 0.14±0.03 ppm for groups III, IV, and V, respectively. In conclusion, P.P. fruit extract can improve antioxidant activity and exert a beneficial effect in the treatment of Pb-induced hepatotoxicity.&lt;/p&gt;

Water quality assessment of alpine glacial blue water lakes and glacial-fed rivers

The study mainly focuses on heavy metals’ quantification, investigation of physicochemical characteristics, source apportionments, human health risk assessment, and connectivity between the water of alpine glacial lakes and rivers. In this regard, twenty-six water samples are taken from sixteen lakes and two lakes-fed rivers. The physiochemical parameters, particularly heavy metals are quantified using atomic absorption spectrophotometer. The Pearson correlations are used to find out the relationship between various heavy metals and physicochemical parameters. The multivariate methods, Principal component analysis (PCA), and Hierarchal cluster analysis (HCA) are conducted for contamination source apportionment. In the findings of the current analysis, the mean concentration of Lead (Pb 0.51), Cadmium (Cd 0.04), Nickel (Ni 0.06), Chromium (Cr 0.08), Iron (Fe 0.06), and Manganese (Mn 0.09) is the most common heavy metal contaminants found in both lakes and river water. Copper (Cu 0.00) and Arsenic (As 0.001) concentrations are lower in both lakes and rivers. Other tested physicochemical characteristics, such as pH, Hardness, Chemical oxygen demands (COD), total dissolved solids (TDS), dissolved oxygen (DO) chloride (Cl-), sulfate (SO4), nitrate (NO3), and bicarbonates (HCO3) are within the maximum permissible limits of World Health Organization’s (WHO).

Heavy metal concentrations in Caspian pond turtle (Mauremys caspica) in Zarivar International Wetland, Kurdistan Province of Iran.

In the present study, the cadmium, lead, and zinc levels in the blood and shell of Caspian pond turtles (Mauremys caspica) were investigated at five stations in Zarivar International Wetland in Kurdistan Province. All specimens were released at their capture locations within 2h of capture. Water samples were collected at each station. Heavy metal concentrations were determined using an atomic absorption spectrometer. The mean cadmium, lead, and zinc concentrations were 0.04, 32.10, and 11.45mg/l in blood samples; 1.82, 16.91, and 89.22mg/l in shell samples; 0.005, 1.30, and 0.07mg/l in water samples, respectively. In this study, the highest metal adsorption was zinc and was observed in shell. According to the results of this study, the shell of the Caspian Pond Turtle can be used to estimate the concentration of heavy metals. Our results suggest that Caspian pond turtle can be used as a biological indicator to estimate heavy metals.

Environmental distribution and risk of exposure of Heavy Metal Pollutants from Lolgorian Artisanal Gold Mining in Kenya.

The aim of the study was to assess the distribution of heavy metals in the environmental compartments from artisanal and small-scale gold mining (ASGM) activities from Lolgorian, Kenya. The investigation was carried out using Inductively-Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Mercury (p > 0.05) (p = 0.755), arsenic (p = 0.182), and lead (p = 0.430) mean concentrations in soil, water, sediments, and ore were not significantly different. The mean mercury, lead, and arsenic concentrations in the water were 0.66mg/L, 0.46mg/L, and 1.25mg/L, respectively. In sediments, the mean values of Cr (66.65mg/kg), Zn (45.62mg/kg), Hg (24.63mg/kg), Pb (22.35mg/kg), Cd (0.90mg/kg), and Mn (613.10mg/kg) were found to be significantly higher. A positive correlation between ore-tailings (r = 0.971109), tailings-sediment (r = 0.9441036), and ore-sediment (r = 0.9441036), was observed indicating the presence of harmful heavy metals in the environment in excess of national and World Health Organization (WHO) recommended threshold, posing a high risk of multiple human exposure pathways.

Assessment of Heavy Metal Concentrations (Cu, Cd, Pb, and Zn) in Wastewater from Gusii Treatment Plant in Kisii County, Kenya

The concentrations of heavy metals were determined from wastewater samples collected from the Gusii wastewater treatment plant, from May to July, 2021. Heavy metal analysis was done using a flame atomic absorption spectrophotometer, model AA 7000 Shimadzu, Japan. The results showed that the concentrations of Zinc and Cadmium were below the detection limit for all the sampling sites. The concentrations of Lead and Copper (Mean ± SE) ranged between 0.34 ± 0.06 mg/L and 0.86 ± 0.08 mg/L and 0.25 ± 0.05 and 0.34 ± 0.01 mg/L respectively. The month of July exhibited a higher mean Cu concentration of 0.35 ± 0.004 mg/L compared to the mean Cu concentration (0.2 ± 0.02 mg/L) of May. Likewise, the mean lead concentration of May (0.60 ± 0.04 mg/L) was higher than the mean (0.53 ± 0.05 mg/L.) of July. The independent sample t-test showed that mean Cu concentration difference was significant between the sampling months (t (34) = 21.58; p &lt; 0.05) while for Pb it was not significant between the sampling months (t (30) = 1.241; p = 0.274). The percentage removals of Copper and Lead were generally low at 12.61 % and 6.27 %, respectively. The continued discharge of effluent into River Riana may lead to accumulation of heavy metals in the environment, which in turn poses health risks to the general public. Therefore, the study recommends that Gusii Water and Sanitation Company continue monitoring and assessing the levels of heavy metals in the treatment plant for its sustainability.