Atomic Absorption Spectrometer Research Articles

Implications of Heavy Metal Accumulation in Fish Feed, Water, Sediment, and Different Fish Species in a Polyculture System.

Heavy metal bioaccumulation in organisms is primarily a result of dietary uptake. The current study examines the concentrations of heavy metals (Pb, Cd, Cr, and Cu) in fish feed, water, sediment, and three fish species (Catla catla, Labeo rohita, and Cyprinus carpio) from different feeding zones in a polyculture pond system. Furthermore, associated human health risks were also evaluated. The fish samples (n = 25 for each species) were collected from 10 different fish ponds in the Kohat district, Pakistan. Heavy metals were determined using an atomic absorption spectrometer. Results revealed higher concentrations of heavy metals in sediment, followed by water. However, the concentration of heavy metals in fish feed was lower than the standard limits. In the case of fish, the bottom feeder (C. carpio) notably exhibited higher (P < 0.05) levels of heavy metals than the column feeder (L. rohita) and surface feeder (C. catla) fish. Moreover, in the liver of all fish species, the bioaccumulation of heavy metals was higher, followed by the gills. Principal component analysis (PCA) demonstrated a strong correlation of heavy metals in C. carpio gills, flesh, feed, and pond water, while the heavy metals in the liver correlated with the detected metals in sediment. The human health risk analysis shows that bottom feeder fish had higher estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) values (> 1). Consequently, the exposed population may experience adverse health effects. The findings of this study suggest that the bottom feeder (C. carpio) bioaccumulates a higher concentration of heavy metals than column (L. rohita) and surface feeder (C. catla) in the polyculture system.

Assessment of potential health risks associated with heavy metal concentrations in leafy vegetables in Kerman, Iran

ABSTRACT Despite the growing awareness of the nutritional benefits of leafy vegetables, there is a lack of information about the presence of heavy metals and the associated risks in these products. This study aimed to investigate the concentration of heavy metals in leafy vegetables in Kerman City. The research also assessed the intake of heavy metals and the associated drisks for children and adults who consume these vegetables. The study followed the recommended methods by the US Environmental Protection Agency (USEPA) to evaluate both carcinogenic and non-carcinogenic diseases. A total of 400 leafy vegetable samples, including parsley, coriander, Persian leek, and basil, were randomly collected from agricultural farms in the outskirts of Kerman City. The samples were analysed using a graphite furnace atomic absorption spectrometer to measure the concentrations of lead (Pb), cadmium (Cd), iron (Fe), and copper(Cu). The results revealed that the levels of heavy metals in leafy vegetable samples exceeded the recommended standards set by international organisations such as FAO/WHO, European countries, and Iran. The total target hazard quotient (THQ) for non-carcinogenic diseases resulting from the consumption of leafy vegetables was higher than one for both children and adults in all studied areas, indicating a potential risk of non-carcinogenic diseases associated with the consumption of these vegetables. Furthermore, the average Incremental Lifetime Cancer Risk (ILCR) resulting from exposure to agricultural soil through leafy vegetable consumption exceeded the hazardous and unacceptable range of 104− × 10−6 in both children and adults. This suggests the possibility of carcinogenic diseases caused by Pb and Cd through the consumption of leafy vegetables in all studied areas, with a higher overall risk observed in children compared to adults. In conclusion, while leafy vegetables are widely recognised for their nutritional benefits, our study underscores a critical gap in understanding the presence of heavy metals and the associated risks in these products. The findings reveal that the concentrations of heavy metals in leafy vegetables from Kerman City exceed international standards, posing potential health risks, particularly in children. Further research and regulatory actions are warranted to address this pressing issue and ensure the safety of our food supply.

Wastewater treatment from a typical multisystem hospital using chemically modified banana peels: Taguchi parametric optimization and characterization

The study aims to develop an eco-friendly solution for addressing contaminants in hospital wastewater. To achieve this, banana peel, a cost-effective and easily available agricultural waste, was chemically modified using sulfuric acid and sodium hydroxide. The hospital wastewater was analyzed using an Atomic Absorption Spectrometer to identify the presence of heavy metals. The physicochemical properties were measured and compared against the standards set by the World Health Organization (WHO). Scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the chemically modified banana peel. Batch adsorption was conducted with the wastewater using the prepared adsorbent. The effect of contact time, mixing rate, temperature, and adsorbent dosage was examined to know the removal efficiency of the adsorbent. The experimental design incorporates Taguchi OA design to optimize the process. The total heavy metals discovered in the wastewater were As, Cd, Fe, Cu, Ni, Cr, Pb, Mn and Zn. The percentage of Cd, Fe, Cu, Ni, Cr and Pb removed were 79.5%, 87.9%, 56.9%, 89.0%, 88.5% and 93.5%, respectively, at temperature, adsorbent dosage, mixing rate and contact time of 30 °C, 3 g, 700 rpm and 60 min, respectively. The physicochemical properties remain within the acceptable WHO range except the turbidity. At optimum point, the percentage removal of Cd, Fe, Cu, Ni, Cr, Pb and Zn were 64.3%, 80.5%, 51.4%, 82.3%, 72.4%, 86.6% and 72.1%, respectively; while, the conductivity, pH, TDS, and turbidity value were, respectively, 20.57 mS/cm, 6.8, 10.16 mg/l, and 86.31 NTU. Characterization revealed the existence of active functional groups on the adsorbent surface enhancing the hospital wastewater treatment and change in its morphological structure after the treatment was noticed. In conclusion, the modified banana peel was effective for the treatment of hospital wastewater.

Effect of domestic heat processing techniques on the trace metals concentration in imported frozen fish products in Bayelsa State, Nigeria, and health risk assessment

IntroductionTrace metals in fish play different important roles, both for the fish itself and humans who consume them. However, some of these metals are toxic at low concentrations, and are considered as health hazards. In this study, the concentration of six trace metals (Pb, Cd, Ni, Cu, Mn and Zn) were determined in imported frozen fish species available in Bayelsa State, Nigeria. The effect of domestic heat processing techniques (cooking, frying and smoking) on the trace metals concentration, and the potential risk due to consumption of these metals in fish were also evaluated. MethodsFive different species of imported frozen fish species were purchased from wholesale and retail outlets, and were prepared as raw, cooked, fried and smoked samples. A mixture of acids was used for digestion of fish samples, while Flame atomic absorption spectrometer was used for quantification of metals. The hazard index was employed for evaluating the non-carcinogenic risk of metals in fish. ResultsThe average trace metals concentration in the raw fish samples followed the order: Zn > Cu > Cd > Ni > Mn. Pb was undetected in all fish samples. The concentration of the detected trace metals ranged as follows - Cd: 3.45-9.40 mg/kg, Ni: <0.001-13.13 mg/kg, Cu: 6.10-9.95 mg/kg, Mn: <0.001-1.05 mg/kg, and Zn: 14.50-43.65 mg/kg. The Cd concentration in all raw fish species greatly exceeded its permissible limits. The effect of domestic heat processing techniques on trace metals concentration in fish did not follow any regular pattern, and only Cd concentrations exceeded its permissible limit in all heat processed fish samples. The hazard quotient (HQ) values showed that only Cd had HQ values >1 for both child and adult exposure scenarios. ConclusionThe results suggest trace metal contamination of fish samples by Cd, with significant potential non-carcinogenic risk. Since Cd is toxic, continuous screening of imported fish products is necessary, in order to safeguard public health.

Assessment of Heavy Metal Contamination and Health Risk Associated with Cultivated Vegetables along Dhaka-Mymensingh Highway, Bangladesh.

The purpose of this research work is to evaluate the degree of eight heavy metals (Fe, Mn, Cu, Zn, Cd, Pb, Cr, and Ni) contamination and health risks of three regularly consumed vegetables (papaya, bottle gourd, and esculent) near one of Bangladesh's busiest roadways, the Dhaka-Mymensingh highway. The heavy metal concentrations in 45 vegetable samples were analyzed using an atomic absorption spectrometer (AAS). These samples were collected from five different sampling sites based on various land use patterns adjacent to the highway. The average concentrations (mg/kg) of Cu, Fe, Mn, Zn, Cr, and Ni were found to be 9.86, 246.8, 16.9, 28.0, 9.02, and 2.02, respectively, for papaya; 14.9, 281.2, 387.6, 49.0, 10.1, and 2.92, respectively, for bottle gourd; and 17.6, 183.4, 107.2, 80.7, 7.98, and 2.34, respectively, for esculent. The mean concentrations of Cr, Zn, and Mn in papaya, bottle gourd, and esculent were higher than the acceptable limit. Correlation analysis revealed a significant positive correlation between Fe-Cu, Zn-Fe, Cu-Fe, and Fe-Zn in papaya; Cu-Zn, Fe-Cr, Zn-Ni, and Cr-Fe in bottle gourd; and Mn-Cr, Mn-Ni, Mn-Fe, and Cr-Ni in esculent, thereby indicating their common anthropogenic sources like agricultural activities, waste from the commercial area, filling station, and vehicular emissions. Health risk assessment through target hazard quotient (THQ) revealed the highest THQ of 9.52 for Cr in bottle gourd, which poses a high non-carcinogenic health risk to the localities upon the intake of these contaminated vegetables. Target cancer risk (TCR) was found to be highest for Cr in papaya (0.013) and bottle gourd (0.014). TCR trends were found for Cr in the following order: bottle gourd > esculent > papaya. This study contributed the greatest concern for both carcinogenic and non-carcinogenic health impacts through ingesting contaminated vegetables.

Assessment of physicochemical, minerals and microbiological qualities of borehole and well water: A case study of Akure Metropolis, Nigeria

Groundwater constitutes a substantial reservoir of fresh water utilized for agricultural irrigation and drinking, emphasizing the critical importance of safeguarding its availability and quality. Contamination of groundwater can arise from chemical, physical, or microbiological sources, each contributing to various health-related issues. In the region of FUTA Southgate, Southwest Nigeria, an assessment was conducted on the physicochemical and microbiological characteristics of groundwater from hand-dug wells and boreholes to ascertain its suitability for human consumption. The analysis indicated that parameters such as BOD, DO TS, TH, and nitrate content were within the acceptable limits set by the World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDQ). However, the presence of heavy metals like Fe, Cu, Cr, Pb, Mn, Cd, and Zn was detected using an atomic absorption spectrometer, revealing a slight level of contamination in both water sources. Furthermore, microbiological examination identified Total Coliform Counts of 382 cfu and 159 cfu in hand-dug wells and boreholes, respectively, indicating fecal contamination. The findings suggest that inadequate sewage systems and improper waste disposal practices contribute to the compromised water quality and elevated nitrate levels in hand-dug wells, rendering the shallow aquifer groundwater unsafe for drinking purposes across all evaluated parameters. Consequently, appropriate treatment and disinfection measures are imperative before utilizing the contaminated borehole and groundwater wells for human consumption or industrial purposes.

СТЕКЛОКЕРАМИЧЕСКИЕ ПОКРЫТИЯ НА ДЕНТАЛЬНЫХ ИМПЛАНТАТАХ С БАРЬЕРНЫМИ СВОЙСТВАМИ

Pateks — the technology of applying a biocompatible glass-ceramic coating based on silicon, carbon and nitrogen on dental implants by PECVD is developed by research and production company Plasmacentre and Pavlov University (St. Petersburg, Russia). Purpose of the research — to evaluate the success of optimization of the surface of doped titanium endosseous dental implants which may be achieved with our glass-ceramic barrier coating technology using physicochemical, cytological and spectrophotometric researches. The main task is to carry out a comparative assessment of the studies’ results between dental implants with and without Pateks glass-ceramic coating (doped with titanium alloy). Materials and methods. Titanium implants (grade 5) from BioMed were used in this research. Some of them were coated with Pateks according to our technology. A human lung fibroblast cells culture was used for the cytological study. Spectrophotometric studies were carried out on atomic absorption spectrophotometer and a atomic absorption spectrometer KVANT-Z.ETA (Russia). Findings. Pateks-coated implants demonstrate advantage in comparison with non-coated ones in certain physicochemical parameters such as decrease of defects’ area in the initial surface of titanium implants which is formed on the previous stages of surface shaping and processing, providing higher surface hydrophilicity, increasing of dielectric characteristics and higher pH value. Pateks coating is safe for fibroblast monolayers and does not inhibit respiratory processes in them. Applying of Pateks glass-ceramic coating with a thickness of 0.5 μm reduces the content of aluminum and vanadium ions in the model medium by almost 2 times and pro- vides a barrier that helps to reduce the negative biological effect of these ions on peri-implant tissues.

Heavy metal levels and human health risk implications associated with fish consumption from the lower Omo river (Lotic) and Omo delta lake (Lentic), Ethiopia.

This study is the first to determine the levels of heavy metals in commercially important fish species, namely Lates niloticus and Oreochromis niloticus and the potential human health risks associated with their consumption. A total of 120 fish samples were collected from the lower Omo river and Omo delta, with 60 samples from each water source. The fish tissue samples (liver and muscle) were analyzed using a flame atomic absorption spectrometer for nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn). The human health risk assessment tools used were the target hazard quotient (THQ), the hazard index (HI), and the target cancer risk (TCR). The mean levels of heavy metals detected in the liver and muscle of L. niloticus from the lower Omo river generally occurred in the order Fe > Zn > Pb> Cu > Mn> Cr > Co > Ni and Pb > Cu > Mn > Co > Ni, respectively. The mean levels of metals in the muscle and liver tissues of O. niloticus were in the order Fe > Pb > Zn > Mn > Cu > Cr > Co > Ni and Pb > Zn > Mn > Fe > Cu > Co > Ni, respectively. Similarly, the mean levels of heavy metals detected in the liver and muscle of L. niloticus from Omo delta occurred in the order Fe > Zn > Pb > Cu > Mn > Cr > Co > Ni and Fe > Pb > Zn > Mn > Cu > Co > Cr > Ni, respectively. The mean levels in the muscle and liver tissues of O. niloticus from the Omo delta were in the order Fe > Pb > Zn > Mn > Cu > Cr > Co > Ni and Pb > Fe > Zn > Mn > Co > Cu > Ni, respectively. The study revealed that the THQ values were below 1, indicating that consumption of L. niloticus and O. niloticus from the studied sites does not pose a potential non-carcinogenic health risk. Although the TCR values for Pb in this study were within the tolerable range, it's mean concentration in the muscle and liver tissues of both fish species from the two water bodies exceeded the permissible limit established by FAO/WHO. This is a warning sign for early intervention, and it emphasizes the need for regular monitoring of freshwater fish. Therefore, it is imperative to investigate the pollution levels and human health risks of heavy metals in fish tissues from lower Omo river and Omo delta for environmental and public health concerns.

Iron Heterogeneity in Soil and its Relation to its Uptake by Water Leaf (Talinum Triangulaire L.)

This study investigated the relationship between iron (Fe) heterogeneity in soil and Fe uptake by water leaf (Talinum triangulaire). A greenhouse pot experiment was conducted with water leaf grown under three treatments; control (0mg/kg Fe added), homogeneous (1000mg/kg Fe added), and heterogeneous (simulated realistic heterogeneity) for six weeks after initial establishment in the nursery for four weeks). At harvest, plant samples were cut, washed, dried, milled into powder and analyzed for iron concentrations using the Atomic Absorption Spectrometer (AAS) Thermos Fisher Scientific Model 3000 ICE after acid digest by Nitric acid (HNO3). The mean root Fe concentrations of the control, homogeneous and heterogeneous treatments were 1263 ±154mg/kg, 1504 ±178mg/kg and 1393mg/kg ±140mg/kg respectively. The mean shoot Fe concentrations of the control, homogeneous and heterogeneous treatments were 904 ±174u mg/kg, 1401±117 mg/kg and 1045 ±95 mg/kg respectively. There was no statistically significant difference (p &gt;0.005) in shoot and root Fe concentration between treatments. However, the homogeneous treatment was 0.19 times higher than the control and 0.07 times higher than the heterogeneous treatment.  Iron level in the roots was 0.35 times high as the control and 0.25 times higher than the heterogeneous treatment. The Concentration factors for the control, homogeneous, and heterogeneous treatments were 0.1118, 0.1498 and 0.1258 respectively. The similarity in concentration factor between treatments showed that it is an accumulator of Fe and has the affinity for Fe irrespective of the varied soil concentrations. These findings indicate that water leaf possesses mechanisms enabling efficient Fe acquisition from variable soil conditions. Overall, the study provides initial evidence that water leaf is resilient to variability in soil Fe distribution, holding implications for its improved cultivation. However, further research on the specific genes and processes governing iron mobilization and uptake in water leaf is recommended.

GEOTECHNICAL AND MINERALOGICAL CHARACTERISTICS OF LATERITIC SOIL AND LOCUST BEAN (PARKIA BIGLOBOSA) PODS ASH AS CONSTRUCTION SOIL

African locust bean (Parkia Biglobosa) has been in great demand and consequently yielding large amounts of the pods which could be a potential hazard to the environment. Converting the pods to ash that would be utilized as construction material is another way of handling them properly. The effects of the mineralogy of the soil on its geotechnical characteristics when the soil is treated with locust bean pod ash have been given very little attention. Therefore, this study considered the effects of locust bean pod ash (LBPA) and the mineralogy of lateritic soil on some geotechnical properties necessary for it to be used as subgrade or foundation soil. The determination of the chemical constituents of the LBPA was carried out using Atomic Absorption Spectrometer. The lateritic soil was characterized by identifying the clay minerals as well as non-clay minerals present in the soil using the x-ray diffraction technique and preliminary tests were also carried out to properly rate the soil. The soil was treated by applying dosages of LBPA 0 – 25% at intervals of 5% and the percentages were measured by weight of the dry soil. The tests conducted on the prepared soil samples with LBPA were specific gravity, consistency indices, compaction (British Standard Light), California bearing ratio and direct shear box test. The LBPA was found to be an acceptable pozzolanic material for the treatment of the lateritic soil. The lateritic soil was observed to belong to soil groups A-2-6(0) in the AASHTO and poorly graded sand (SP) in USCS ratings. It was also observed that the non-clay minerals present in the soil were quartz, feldspar and mica whereas the clay minerals present were kaolinite, iolite, vermiculite and chlorite which had a significant influence on the geotechnical characteristics of the soil. The specific gravity of the LBPA was relatively low and the additions of LBPA reduced the specific gravity of the soil. The consistency indices also dropped and subsequently increased with the further addition of LBPA. The increase in LBPA contents caused increments in the optimum moisture content while the maximum dry density and shear strength parameters reduced. The strength characteristics like the California Bearing Ratio of the lateritic soil improved by 173.91% at the addition of 5% LBSA content which was determined to be the optimum dosage.

Assessment of Nickel Ion Release from NiTi Orthodontic Archwire After Using Magnetized Water as a Mouth Rinse

Objectives This study was to detect whether the magnetized water (MW), when used as a mouth rinse, can influence the release of Nickel (Ni) ions from NiTi (nickel-titanium) archwires. Material and Methods One hundred fifty (0.016” *0.022”) as received orthodontic NiTi archwires were grouped into three chief groups based on the used mouth rinse into MW, Ortho Kin (control positive) (OK) and distilled water (control negative) (DW) groups. Every group contained intervals of five points (24 h, 1 week, 2 week, 3 week and 4 week). Ten archwires were used for each interval. The release Ni was detected at each interval using an atomic absorption spectrometer. The topographic features of orthodontic archwires were examined with a scanning electron microscope and an atomic force microscope. SPSS Statistics software (V.19) was used for statistical analysis. One-way Analysis of Variance (ANOVA) and post hoc Duncan’s multiple range test were used for data analysis with P ≤ 0.05. Results Significantly less amount of Ni ion released in the MW group was recorded from NiTi archwires in comparison with the OK group for all studied intervals. Conclusion MW may be indicated as a suitable adjunct for further commercially available mouth rinses (as OK) throughout orthodontic therapy.

Comprehensive Assessment of Heavy Metal Pollution and Ecological Risk in Lakes of Bangalore, Karnataka, India

The contamination of water and sediment by heavy metals poses significant challenges to freshwater ecosystems, agriculture, and aquaculture. This study focused on assessing heavy metal pollution in Ulsoor and Agara Lakes, prominent freshwater reservoirs in Bengaluru utilized for aquaculture. The presence of heavy metals such as Cd, Cu, Zn, Cr and Pb levels were analyzed in water and sediment samples of both lakes over a period of one year (from August 2021 to July 2022), using an Atomic Absorption Spectrometer. Pollution indices (CF, Igeo, PLI, ERI) were computed for sediment, revealing higher metal concentrations compared to water. Correlation analysis identified strong associations between Zn and Cu, Pb and Zn in water, and Cu and Cd in sediment, suggesting common pollution sources. While sediment showed relative safety based on PLI, Igeo, and ERI, CF indicated an unpolluted to moderately polluted status. In conclusion, this study revealed that most metals in the water exceeded permissible limits, highlighting the need for effective remediation measures.

Determination of Some Heavy Metal Concentrations and Physical/Chemical Properties of Well Water in Babylon Governorate/ Iraq

The presence of One of the most significant is heavy metals in water. risks, which may cause health problems. In this work, we tried to determine the amount of three heavy metals (lead, nickel, and cadmium) in groundwater in different locations in Babylon Governorate The current study aims to estimate the quality of groundwater by evaluating its physical and chemical properties, as well as evaluating lead, nickel, and cadmium (Pb, Cd, Ni) in this water and monitoring the variation in their concentration rates during the seasons of the year. Groundwater samples were collected and analyzed using an atomic absorption spectrometer to determine their lead, nickel and cadmium content and compare their levels with the maximum level of contaminants specified by the World Health Organization. Water samples were collected from 15 wells in different areas (Abu Ghariq, Sinjar, Hilla, Al-Mahawil, Al-Imam, Al-Nile, Jableh, Al-Mashrou, Al-Hashimiya, Al-Qasim, Madhatiya, Al-Taliah, Al-Musayyab, Alexandria and Al-Sada) during the period from September 25, 2022 to July 25, 2023.The concentrations of lead and cadmium were higher than the permissible limits suggested by the World Health Organization. As for nickel it did not exceed the permissible limit. The study can then be concluded that it is contaminated with some heavy metals due to the influence of several activities in the study area. Decreased treatment, regulations and integrated management have led to the deterioration of groundwater quality. Total dissolved salts, turbidity, conductivity, and total hardness in the groundwater of these sites were also studied.

A Univariate Optimization Strategy for Pre-concentration of Cobalt(II) in Various Matrixes by a DLLME before Analysis Using FAAS

A procedure based on dispersive liquid-liquid microextraction (DLLME) for cobalt (Co) quantification in an Iraqi environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied in this work. A case-study approach was chosen to obtain further in-depth information on the Co levels and to evaluate the effectiveness of N-salicylideneaniline (SAN) as a complexing agent for pre-concentration and extraction of Co. An univariate strategy was utilized to achieve the optimum extraction conditions. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 1.04 and 3.47 µg L−1, respectively. The results achieved by the proposed system were compared with those using the microwave digestion/graphite furnace atomic absorption spectrometer (MWD/GF-AAS) for digest samples and also for some water samples (Direct GF-AAS). The proposed procedure was applied for analyzing eleven environmental samples. The detectable Co levels for water samples ranged from 0.72 to 4.30 µg L−1 with a relative standard deviation of 3.7–8.8%, while the concentration for solid samples ranged from 0.17–4.51 µg g−1 (2.4–11.8 RSD %). DLLME/FAAS proposed procedure is effective, simple, and has the benefit of minimizing the organic solvent consumption by a few microliters, which results in little waste.

The levels of mercury (Hg) and arsenic (As) in wild boar’s liver (Sus scrofa) in eleven hunting areas from the Republic of North Macedonia

The monitors have recently been defined as the organisms in which changes in known characteristics can be measured to assess the extent of the environmental contamination. Among the numerous game species, the wild boar as omnivore is characterized as an exceptionally good biomonitor. The concentrations of one heavy metal (Hg) and one metalloid (As) were measured using cold vapor atomic absorption spectrometer and atomic absorption spectrophotometry in the liver tissue of free-living wild boars. From 11 hunting areas locations that cover the whole territory of North Macedonia in a period of 7 years (2016-2022) a total of 608 wild boar liver samples were harvested during the regular hunting season. The mean concentration of Hg from 11 hunting grounds ranged from 12.7 μg/kg to 68.8 μg/kg, and mean concentration for all was 45.67 μg/kg. The average concentration of As ranged from 22 μg/kg to 55.3 μg/kg, and mean concentration for all was 33.1 μg/kg. For mercury, 6.56% or 40 of the total number of samples (608) exceeded the maximum allowed limits, and for arsenic none of the examined samples exceeded the allowed limit. For both elements a statistically significant difference was determined in relation to the years, with irregular oscillations from year to year. The mean values for mercury and arsenic are encouraging and generally indicate the relatively low contamination in the territory of the Republic of North Macedonia. However, the statistical differences due to the year as a factor suggest there is the need for the further research.

Evaluating arsenic contamination in northwestern Bangladesh: A GIS-Based assessment of groundwater vulnerability and human health impacts

One of the biggest environmental worries in the world today is the risk of arsenic (As) contamination in groundwater. The Atomic Absorption Spectrometer (AAS) was used in this work to assess the As content in groundwater samples from 38 shallow (27 m) tubewells in northwest Bangladesh to determine the existing situation, potential source(s), and likely health risk of As and other important water quality parameters. The range of arsenic concentrations (μgL−1) was troublesome and greater than the WHO recommended level for drinking water, ranging from 0.50 to 164 (mean ± SD: 20.22 ± 36.46). In groundwater, the concentrations of Fe, and Mn vary from 0.04 to 52.75 mgL−1 (mean ± SD: 4.23 ± 9.68), and 0.23 to 3.27 mgL−1 (mean ± SD: 1.10 ± 0.67). The obtained groundwater samples have pH values ranging from 5.9 to 7.1, which indicates a somewhat acidic to neutral character. Major cations have an average abundance that is as follows: Ca2+ > Mg2+ > Na+ > K+, while major anions have an average abundance that is as follows: HCO3− > Cl− > SO42− > NO3−; Ca2+ and HCO3− are the main cation and anion, respectively. The groundwater in the Rajarampur village was deemed unfit for drinking or irrigation based on analyses of water quality performed using the entropy water quality index. The Ca–HCO3 type of water, in which Ca2+ and HCO3− are the main positive ions and negative ions, is suggested by the Piper tri-linear diagram. It was discovered that silicate weathering regulates the hydro-geochemical activities in groundwater using a bi-variate examination of several hydro-chemical variables. Four major clusters were observed for the water sample. According to reductive dissolution processes and principal component analysis, the arsenic in groundwater is geogenic in origin. Arsenic is discharged from sediment to groundwater by reductive dissolution of FeOOH and MnOOH, as shown by the modest connection between As, Fe, and Mn. The United Nations Environmental Protection Agency's (USEPA) suggested value for probable cancer risk assessment was 10−6, however the probable cancer risk assessment found a higher value, indicating that the population in the study region was at high risk for cancer. Remedial measures for arsenic mitigation include removing arsenic from groundwater after it is extracted, searching for alternative aquifers, and implementing various water-supply technologies such as dugwells, deep tubewells, pond-sand filters, and rainwater harvesting systems.

Assessment of Naturally Occurring Radionuclides and Heavy Metals Level and Health Risks in Commonly Consumed African catfish, White Catfish and Nile Tilapia Fish Species from Epe Waterside Region of Lagos, Nigeria

Elevated levels of radionuclides and toxic metals in water can potentially influence the growth of fish during their mature stages, posing a risk of human exposure through the consumption of contaminated fish. This investigation assessed the levels of health risk of naturally occurring radionuclides and heavy metals in commonly consumed African catfish, White catfish and Nile tilapia fish species in the Epe Waterside region of Lagos, Nigeria, using a sodium iodide detector and an atomic absorption spectrometer. The activity concentrations (Bq/kg) of 40K (29.1±21.0-823.5±18.2) were higher than 226Ra (27.1±87.8-202.7±50.3) and 232Th (52.9±7.4-600.2±7.0), with mean values exceeding the permissible limits set by WHO. The mean committed effective dose rate is above the 50 mSv recommended by ICRP. The mean annual intake and cancer risks for people who consume fish on a weekly basis (nutrition statistics for seven, five, three, and one day per week) were relatively high, surpassing the permissible limit of 1.0×10-6 as recommended by WHO. The concentrations of heavy metals (Zn: 0.026-1.344, Cu: 0.008-0.055, and Cd: 0.048-0.250 mg/kg) exhibited mean values that fell within the acceptable limits defined by FAO/WHO, with the exception of Pb, which recorded a higher concentration ranging from 2.51 to 3.39 mg/kg. The fish's natural habitats (lagoon) have been contaminated by toxins, likely originating from industries, waste disposal activities, agrochemicals, rusty pipes, and other fittings. Encouraging the cultivation of fishes in domesticated ponds around the study area can reduce the risk of consuming contaminated fish and other seafood.

Lead concentration in different trophic levels: experimental analysis

This study aimed to experimentally evaluate the capacity of lead (Pb) accumulation and passage at different trophic levels. To do so, the aquatic macrophyte M. linifera, grasshoppers of the T. surinama species, and Theraphosa sp. spiders were collected and subjected to experiments 1, 2, and 3 with 1 g.L-1, 0.1 g.L-1 of Pb, and without lead, respectively. After analyzing the results using a flame atomic absorption spectrometer, the presence of Pb was detected in the analyzed trophic levels. The highest concentration of Pb was found in the aninga root in experiment 2 (219,705.6 mg.Kg-1), and the lowest concentration was found in the leaf of experiment 1 (79.4 mg.Kg-1). The grasshoppers in experiment 1 and 2 did not show traces of Pb, only in their feces, the highest being 201.98 mg.Kg-1 and the lowest being 8.74 mg.Kg-1.Traces of Pb were also found in the spiders, with the highest concentration detected in experiment 1 (7.42 mg.Kg-1). The study revealed an increase in Pb concentration in the experimental food chain across the three trophic levels. T. surinama acted as a lead desconcentrator in the food chain, returning the ingested lead to the environment, creating a cycle in the aquatic environment where lead can be reabsorbed by the plant.

Spatial distribution of Pb and Zn in soils under native vegetation in Southeast Brazil.

Heavy metals can play an important biological role as micronutrients but also as potentially toxic elements (PTEs). Understanding the natural concentrations of PTEs-Pb and Zn included-in soils allows for the identification and monitoring of contaminated areas and their role in environmental risk assessment. In this study, we aim to determine semi-total or natural and available concentrations of Pb and Zn in topsoils (0-20 cm depth) from 337 samples under native vegetation in the State of Minas Gerais, Brazil. Additionally, we sought to interpret the spatial geochemical variability using geostatistical techniques and quality reference values for these elements in soils were established. The semi-total concentrations were determined by flame and graphite furnace atomic absorption after microwave-assisted nitric acid digestion method. The available concentrations were extracted using the Mehlich-I extractor and determined by atomic absorption spectrometer. Spatial variability was modeled using semivariance estimators: Matheron's classic, Cressie and Hawkins' robust, and Cressie median estimators, the last two being less sensitive to extreme values. This allowed the construction of digital maps through kriging of semi-total Pb and Zn contents using the median estimator, as well as other soil properties by the robust estimator. The dominance of acidic pH and low CEC values reflects highly weathered low-fertility soils. Semi-total Pb contents ranged from 2.1 to 278 mg kg-1 (median: 9.35 mg kg-1) whereas semi-total Zn contents ranged from 2.7 to 495 mg kg-1 (median: 7.7 mg kg-1). The available Pb contents ranged from 0.1 to 6.92 mg kg-1 (median: 0.54 mg kg-1) whereas available Zn contents ranged from 0.1 to 78.2 mg kg-1 (median: 0.32 mg kg-1). The highest Pb and Zn concentrations were observed near Januária, in the northern part of the territory, probably on limestone rocks from the Bambuí group. Finally, the QRVs for Pb and Zn in natural soils were lower than their background values from other Brazilian region and below the prevention values suggested by Brazilian environmental regulations.

Characterization of heavy metal-associated bacteria from petroleum-contaminated soil and their resistogram and antibiogram analysis.

The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0mm to 13.0 ± 0.0mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.