Permissible Levels Research Articles

Hybrid modeling of piezoresistive pavement using finite element method and artificial neural network

This study aims to establish a hybrid method combining the finite element method (FEM), the mechanical–electrical model, and a back-propagation artificial neural network (BP), to simulate the piezoresistive pavement. First, the tire-pavement FEM model with piezoresistive units was established considering the viscoelasticity of the pavement materials. Subsequently, the mechanical responses of the piezoresistive units under various tire and environmental loads were converted into electrical resistance outputs via the mechanical–electrical model. Finally, BP was trained using simulated data to address challenges associated with the back-calculation of tire loads. Results indicate that the electrical resistance of the piezoresistive unit in complete contact with the tire illustrates an overall rising trend as tire load increases, which is attributed to changes in contact stress. However, the adjacent piezoresistive units display an opposite trend, which can be used to determine the lateral position of the tires. Additionally, electrical resistance shows a non-linear decrease with increasing temperature. The single-hidden-layer BP with 13 neurons was validated to demonstrate higher accuracy compared to multi-hidden-layer BP. Moreover, the Genetic algorithm-optimized single-hidden-layer BP (GA-S-BP) shows further improved performance, achieving an MSE of 1.91 and an MAPE of 8.5%, and a low probability of underestimating tire loads. The GA-S-BP designed in this study can effectively predict tire loads within permissible levels to realize the function of piezoresistive pavement.

Preliminary assessment of heavy metal contamination in children's cereal bars: implications for consumer safety on the Polish market.

The primary objective of this study is to evaluate the content of heavy metals, including cadmium, lead, zinc, arsenic, copper and nickel, in cereal bars intended for consumption by children and adolescents. The study also aims to identify factors that differentiate the content of these products. The study material comprised 50 cereal bars, which were consumed by a population group of children and adolescents. The determination of zinc, arsenic, copper and nickel was accomplished through the utilisation of optical emission spectrometry with inductively coupled plasma excitation on a spectrometer, while cadmium and lead were ascertained by atomic absorption spectrometry with electrothermal atomization (ET-AAS) on an atomic absorption spectrometer. In the heavy metal analysis of the cereal bars, lead was not detected in contents above the limit of quantification (LOQ) of 0.10mg/kg. However, three samples exceeded the maximum permissible levels of cadmium, with contents of 0.046mg/kg in two cases and 0.043mg/kg in one case, while the minimum determined cadmium content was 0.011mg/kg. The arsenic content of the samples oscillated between 0.56 and 4.16mg/kg. Although there are no established standards for nickel, zinc and copper, their contents are of potential health significance in the context of chronic exposure, requiring detailed assessment. The results of the statistical analysis showed significant differences in copper and zinc depending on product composition (p ≤ 0.0001), suggesting higher contents of these metals in oatmeal-dominant products, possibly due to specific raw material sources or variation in the production process. The homogeneity of nickel, cadmium and arsenic contents regardless of product composition was confirmed by the absence of significant statistical differences (p > 0.05). The analysis of geographical variation showed that products of Polish origin were characterised by higher copper and cadmium contents compared to products from Germany, suggesting a potential influence of local environmental and technological conditions. Hazard quotient (HQ and HI) calculations for the analysed scenarios showed that the limits were exceeded, especially for products with a predominance of oatmeal and Polish production, highlighting the need for further research into the sources of these contaminants and their health implications.

Activity hours: Assessing liveability during heatwaves

As climate change increases the frequency and severity of heatwaves, understanding their impact on the well-being, health, and permissible activities of building occupants becomes crucial. Existing work focuses primarily on the thermal comfort of an average individual, neglecting both the impact of extreme heat on liveability and variability in resilience of different population groups. To address these gaps, we introduce the Activity hours (Ah) metric, which quantifies the liveability of indoor environments during heatwaves while taking into account air temperature, humidity, occupant age, permissible activity levels, and duration of exposure. We also present the Heatalyzer tool that allows the computation of Ah for different geographies, building archetypes, and heatwave durations. Through a case study of residential housing in London, we compare Ah with established thermal comfort metrics, highlighting Ah’s ability to quantify heatwave impacts on occupant liveability for different building types and demographic groups. Our results are made widely accessible through the Heatalyzer dashboard, an intuitive website that enables London residents to evaluate their exposure to heat-related risks.

A Decentralized Approach to Parking Space Management With Fine-Grained Permission Level Using Blockchain Technology

A Decentralized Approach to Parking Space Management With Fine-Grained Permission Level Using Blockchain Technology

Assessment of Water Quality and Heavy Metal Contamination in River Water and Fish Species from the Bangshi River, Tangail, Bangladesh

The Bangshi River flows through the industrial regions of Dhaka and Tangail, polluted by various wastes, including industrial effluents. This study assessed water quality and heavy metal concentrations in the river, focusing on two fish species, Tengra (Mystus nigriceps) and Tara baim (Macrognathus aral). Fish samples were taken from one station during the wet season, whereas water samples were taken from three stations throughout the dry season (June to August 2022) and wet season (February to May 2022). The parameters analyzed included water temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), total dissolved solids (TDS), electrical conductivity (EC), alkalinity, and the concentrations of heavy metals such as lead (Pb), cadmium (Cd), copper (Cu), and manganese (Mn). Water temperature ranged from 30.5 to 32.3°C during the wet season and 19.91 to 20.5°C in the dry season, remaining within acceptable limits. pH values were within the standard range. However, EC exceeded irrigation standards during the dry season (828 to 903 µS/cm). TDS levels were 83 to 175 ppm in the wet season and 328 to 563 ppm in the dry season, with most dry season samples exceeding fish culture limits. DO values (1.98 to 4.26 ppm) were consistently below recommended levels, while BOD (2.33 to 4.83 ppm) and alkalinity (80.7 to 382.23 ppm) surpassed permissible thresholds, particularly in the dry season. Heavy metals in water were generally within safe limits except for Pb (4.40 to 5.002 ppm). In fish, Pb concentrations exceeded permissible levels (5.35 ppm in Tengra, 4.46 ppm in Tara baim), while Cd, Cu, and Mn were within acceptable thresholds. The elevated Pb levels likely stem from effluents released by glass, textile, and paint industries. These findings highlight potential risks to human health from consuming water and fish from the Bangshi River, underscoring the urgent need for improved pollution control strategies.

Assessment of heavy metals accumulation in food crops irrigated with water of Boumerzoug river (Constantine, North East of Algeria)

<p style="margin-bottom:11px;text-align:justify;"><span style="font-family:"Times New Roman",serif;font-size:12.0pt;line-height:200%;" lang="EN-US">An economy's progress is critically dependent on industrialization. However, it also negatively impacts the ecosystem by releasing dangerous elements like heavy metals into surface aquifers. The purpose of this study was to assess the contamination by heavy metals of edible plants (pepper, watermelon, and lettuce) grown on agricultural land around the Boumerzoug River in Constantine Province, Algeria, and irrigated with river water. Plants were subjected to total quantification of metals (Cu, Cd, Zn, Cr, Pb, and Fe) in four organs (root, stem, leaf, and fruit). Metal concentrations were within acceptable limits, but the Pb and Cd contents were higher than usual levels, indicating a greater potential for health concerns if consumed regularly. The plant organ type affect metal accumulation. The root was the organ that accumulated the most metals, and lettuce was the plant that accumulated the most. The Transfer Factor (TF) was higher for Cd and Cu (> 1). This study recommends continual surveillance of irrigation water and crops to prevent the accumulation of heavy metals beyond permissible levels in the food chain. Thus, to protect both human and animal health in the research area, preventive actions must be taken to limit heavy metal deposition through wastewater irrigation.</span></p>

Temporal Changes in Lead and Cadmium Levels in Amanita muscaria Samples Collected in Poland

In recent years, an increasing popularity of consuming Amanita muscaria has been observed in Poland, aimed at reducing various medical symptoms. However, there is a lack of data regarding the impact of variations in the content of toxic elements, such as cadmium (Cd) and lead (Pb), in Amanita muscaria collected during late summer and mid-fall. The aim of this study was to determine the concentrations of Pb and Cd in Amanita muscaria samples collected at different times of the year, compare the concentrations of these elements in samples with and without cap skin, and compare the obtained values to permissible limits in dietary supplements. A total of 44 Amanita muscaria samples were collected during three different harvesting periods (August, September, and October 2023) from Puszcza Biała, located approximately 80 km from Warsaw. The mushrooms were subjected to mineralization using concentrated nitric acid and hydrogen peroxide, followed by the determination of Pb and Cd concentrations using an atomic absorption spectrometer. Significant statistical differences were found in the Pb concentrations of samples collected in three different seasons (η2 = 0.67, p < 0.001), with the concentration increasing progressively, reaching its highest value in October. Similarly, the Cd concentration also increased in the later collections, although the effect of time was weaker (η2 = 0.13, p = 0.03). No significant differences were observed in Pb and Cd concentrations between samples with and without cap skin. The average Cd concentrations in mushrooms were significantly higher than the permissible levels in dietary supplements; they were four times higher in August (p < 0.001), six times higher in September (p < 0.001), and nine times higher in October (p < 0.001). The Pb concentration in the October samples was close to the permissible limit but did not exceed it in a statistically significant manner (p = 0.85). Due to the high Cd concentrations and potentially hazardous levels of Pb, the consumption of Amanita muscaria carries a significant risk of toxicity, which may lead to serious health hazards, particularly in the context of prolonged exposure.

Evaluating Water Quality and Organo-Pesticide Contamination in Oreochromis niloticus (Nile Tilapia) in Wawan Rafi and Dambo Dam, Kazaure, Jigawa State:

The study investigated the presence of freshwater pollutants and their effects on Oreochromis niloticus(nile tilapia) in the Wawan Rafi and Dambo Dams of Kazaure, Jigawa State. The water samples were found to be within the World Health Organization's permissible guideline for temperature and dissolved oxygen levels. The mean value of temperature, dissolved oxygen (DO), and conductivity (EC) ranged between 23.13±0.8 and 28.25±0.7, 6.5-8.5mg/l, 7.347±0.3, 145.6±16 and 158.3±6.1. The mean turbidity obtained from all stations was far higher than the 5 NTU (Nephelometric turbidity unit) value recommended by the WHO, indicating that the water samples were more turbid than needed. Total dissolved solids content (TDS) levels in the water samples were above the WHO's recommended level, but TSS's mean values fell below the WHO's recommended limits of 450-2000mg/L. Mean hemoglobin levels varied between 6.230 g/dL and 7.570 g/dL, with low levels likely due to heavy metals altering hemoglobin's properties. The study found that Oreochromis niloticus had mean red blood cells (RBC) ranging from 1.180x1012/mL to 1.45x1012/mL, and mean white blood cells (WBC) ranging from 153.100 x 109/mL to 167.67 x 109/mL. The mean corpuscular hemoglobin concentration was unaffected by blood volume and the number of blood cells. The data suggests that Oreochromis niloticus has a unique cellular structure and composition. Heavy metals in water can significantly impact the life and lifespan of aquatic organisms, including fish and aquatic invertebrates. The average mean value of Lead (Pb) in the water sample falls above the World Health Organization (WHO) recommended level of 0.01mg/l in all stations. Chromium levels are higher than the WHO permitted chromium level of 0.05mg/L, which can affect fish organs like gills and liver. Zn levels are lower than the WHO permissible level of 3 mg/L. The fish concentration of heavy metals analyzed in both Wawan Rafi and Dambo Dam had a highest value of Pb (mg/L) 0.1550±0.0, Cr (mg/L) 0.14205±0.0, Zn (mg/L) 1.7750±0.0, Cu (mg/L) 0.5400±0.,Cd (mg/L) 0.07850±0.0, and Ni (mg/L) 0.0475±0.0which are within permissible limit except for Pb, which is slightly higher than the recommended level. Various organo-pesticide were also detected in fish and water samples of both Wawan Rafi and Dambo Dam of which long-term exposure may lead to bioaccumulation in food chains, posing a threat to human health through dietary exposure. Recommendations include proper waste treatment, strict enactment of government policies on pesticide use, waste disposal, and proper sanitation around water sources. Further studies should focus on oxidative stress enzymes on Oreochromis niloticus in the study area.

The practice of using varios methods of sample preparation for the X-ray fluorescence determination of macroelements in geological rocks, soils and sediments

To determine the content of macronutrients in rocks, soils and sediments, three methods of sample preparation were used by the X-ray fluorescence method: pressing powder samples; fusing in gold-platinum crucibles to obtain glass discs; fusing on graphite substrates followed by melting and tablet pressing. A detailed description of each of the methods used is provided. For fusion in gold-platinum crucibles, a ready-made LITHIUM BORATE FLUX (from the company CHEMPHYS) was used, its composition: Li2B4O7 (67%) + LiBO2 (33%) + alloying additive LiBr. For fusion on graphite substrates, powders of lithium tetraborate and metaborate in a ratio of 2:1, dried at 600°C. Random errors of the analysis are estimated: errors of sample preparation and intensity measurement. It is shown that in all cases, the total errors do not exceed the permissible level when conducting mass analyses of the III category. Standard samples of rocks, sediments and soils were used to obtain the grades, The metrological characteristics of X-ray fluorescence analysis techniques using each of the three sample preparation methods are presented. The residual standard deviations of the calibration dependencies are compared. The correctness of the analysis results was verified on three standard samples. The advantages and disadvantages of each sample preparation method are noted. The use of the simplest, cheapest and express method of pressing tablets from the source material is possible only if the content of elements in the analyzed samples does not exceed the limits of the calibration dependencies of this technique. The method of fusion in gold-platinum crucibles requires preliminary information about the chemical composition of the analyzed sample. The method of fusing on graphite substrates (followed by melting and pressing the tablet) is more versatile and has no restrictions on the composition of the fused sample. It is shown that the systematic errors of the method for pressed tablets exceed the errors of the methods using the second and third techniques. The work was performed on the AXIOS Advanced wave dispersive X-ray fluorescence spectrometer (PANalytical B.V., Holland).

Highly sensitive detection of mercury ions in aqueous solutions by laser-induced fluorescence spectroscopy.

Laser-induced fluorescence spectroscopy was used to detect mercury ions in aqueous solutions, in which CH-95 resin was used to chelate the ions to transform the liquid samples into solid ones. The experimental results showed that the fluorescence emission of the chelated solid-state samples excited by a low-power semiconductor laser at the wavelength of 447 nm was significantly enhanced due to the chelating reaction. The fluorescence intensity was proportional to the concentration of mercury ions with a linear correlation coefficient of R2 = 0.994, and the limit of detection was 0.117 ng/L, which was about 10,000 times lower than the permissible level of 1 µg/L for Hg(II) in drinking water. The method greatly improved the sensitivity for the detection of Hg in aqueous solutions.

Polycyclic Aromatic Hydrocarbons in Polish Traditionally and Industrially Smoked Meats as an Element of Monitoring and PAH Reduction Strategies

This work aimed to analyze the PAH content in products smoked in traditional smokehouses with direct and indirect heat sources and in an industrial way as an element of PAH content monitoring in Polish market products. This research material comprised 12 smoked meats (W) and 38 sausages (K), medium or coarsely minced. The content of benzo(a)pyrene and the total content of four marker PAHs was determined by GC-MS. The analysis showed a significantly higher level of PAH contamination in products smoked using traditional methods. The results also indicate that the natural casing is not a barrier against PAH contamination during traditional smoking, and a higher degree of meat fragmentation, together with a small cross-section, increases the PAH content in this technological group. Concentrations of benzo(a)pyrene exceeding the permissible levels were found in the sausages smoked for more than 60 min. As part of the strategies for reducing the PAH content, among others, changing the furnace to an indirect one, shortening the time, lowering the smoking temperature, using artificial casings or removing casings before consumption, drying the product surface before the smoking process, using seasoned and bark-free wood, as well as additional smokehouse equipment, are recommended.

The Effect of the Glucosinolate Sinigrin on Alterations in Molecular Biomarkers of the Myocardium in Swiss Mice.

Glucosinolates are chemically stable compounds that exhibit biological activity in the body following hydrolysis catalyzed by the enzyme myrosinase. While existing in vitro and in vivo studies suggest that the hydrolysis products of glucosinolates predominantly exert beneficial effects in both human and animal organisms, some studies have found that the excessive consumption of glucosinolates may lead to toxic and anti-nutritional effects. Given that glucosinolates are primarily ingested in the human diet through dietary supplements and commercially available cruciferous vegetables, we investigated the in vivo effects of the glucosinolate sinigrin on molecular markers in the myocardia of healthy Swiss mice. This study aims to elucidate whether sinigrin induces positive or negative physiological effects in mammals following consumption. The alterations in myocardial parameters were assessed by measuring metabolic, inflammatory, structural, and antioxidant markers. Our findings revealed that subchronic exposure to sinigrin in the myocardia of female mice resulted in a significant increase (p ≤ 0.05) in the levels of the myokine irisin, matrix metalloproteinases (MMP-2, MMP-9), catalase (CAT), and total glutathione (tGSH), alongside a marked decrease (p ≤ 0.05) in the levels of atrial natriuretic peptide (ANP), compared to the control group consisting of both female and male mice. These results suggest that the hydrolysis products of sinigrin may exert a potentially toxic effect on the myocardial tissue of female mice and possess the capability to modulate transcription factors in vivo in a sex-dependent manner. This observation calls for further investigation into the mechanisms regulating the actions of glucosinolate hydrolysis products, their interactions with sex hormones, and the determination of permissible intake levels associated with both beneficial and adverse outcomes.

Modeling of electromagnetic effects of six-phase power lines on pipelines

THE PURPOSE. Development of digital models for calculating induced voltages on a pipeline created by a six-phase power transmission line in normal and emergency operating modes. METHODS. The studies were conducted on a computer model of an electrical network that includes a line of this type. Its formation involved an approach based on the use of phase coordinates. The modeling was carried out using the Fazonord software package, version 5.3.5.3-2024. RESULTS. The following operating modes of a 220 kV multiphase power transmission line were considered: symmetrical and open-phase with loads at the receiving end of 100 + j50 MVA per phase; single-phase, two-phase short circuits, as well as a two-phase ground fault. For comparison, the modes of a two-circuit three-phase power transmission line were modeled. The obtained results allowed us to draw the following conclusions: in a symmetrical load mode, a six-phase line creates induced voltages at certain points of the pipe that are more than three times greater than similar parameters for a three-phase power transmission line; however, the values of induced potentials do not exceed the permissible level of 60 V; in short-circuit modes, the maximum induced voltages in the transmission lines under consideration differ insignificantly; when one phase is disconnected, the induced voltages in a six-phase power transmission line go beyond the permissible limit, and in a three-phase line they do not exceed 60 V. CONCLUSION. The applied approach is distinguished by its universality and can be used to determine modes in networks of various configurations; the developed models can be used in the practice of designing sections of joint passage of promising six-phase power transmission lines and pipelines when developing measures to ensure the safe operation of service personnel.

Impact of Drive Days and No-DriveDays on Atmospheric Carbon Monoxide (CO) concentration

Automobile emissions rise in tandem with population growth. Increases in motorised vehicles lead to high urban traffic congestion, air pollution and health effects such as asthma, cardiorespiratory illness, headaches and cardiorespiratory disorders. The carbon monoxide (CO) released by vehicles acts as a greenhouse gas and is correlated with climate change. The study aims to evaluate and compare CO levels and vehicle counts on Drive Days (DD) and No-Drive Days (NDD) and to analyse the correlation between CO Concentration and vehicle count. The vehicles were counted, and CO concentrations were monitored using a CO meter over a five-year period. The research focused on observing No-Drive Days at Bishop Heber College, where commuters are encouraged to avoid motorised vehicles and to use eco-friendly transport. The number of vehicles has reduced significantly from DDs to NDDs ranging from 36% to 90.3%. On the DD, the CO concentrations were higher than the maximum permissible level signifying the need to take measurements. However, the CO levels have reduced on NDDs with a mean of 1.52 mg/m3 well below the maximum permissible level. The investigation concluded that a decrease in vehicle numbers decreased the atmospheric CO concentration. The organisation and execution of No-Drive Days, as well as participant support greatly influence the level of success and sustainability of such initiatives.

Low-cost Ozone Measurement Device in the Chappuis Band

Ground level ozone in the atmosphere is an air pollutant. This is formed in the atmosphere through a complex reaction of the chemical substances emitted from the vehicles, plants and many other sources. Its presence close to the earth is harmful to humans, animals, plants and non-living things. Different countries have different permissible level of concentration of ozone in the atmosphere. The Central Pollution Control Board of India has set the permissible limit for ozone concentration at 100 ?g/m3 over 8 hours. Hence, it is very essential to know the concentration of ozone in the atmosphere for healthy living. There are various types of ozone measurement devices. Optical absorption based UVC-type ozone measurement devices are costly and there is necessity to replace ozone scrubbers used in those devices at regular intervals. Mercury lamps used in these optical absorption based ozone measurement devices produce harmful UVC rays. Mercury lamps also have a shorter life period. To overcome these shortcomings, a low cost LED based Ozone measurement device has been developed and concentration of ozone can be measured by this device. In this investigation, Yellow-Green, Diffused Yellow, DIP Yellow, Amber, and Orange LEDs have been used to generate incident light sources from 573 nm to 605 nm wavelengths. In the detector stage, available 565 nm and 580 nm peak sensitivity photodiodes have been used to measure the reduced intensity using the Beer-Lambert Law. It is found that DIP and Diffused yellow LEDs show better results among these LEDs when tested by 565 nm and 580 nm photodiodes. The use of LEDs and Photodiodes makes this system low-cost in comparison to other available ozone-measuring systems.

Synthesis, Characterization, and Docking Studies of 1,4-dien as a Potential Impurity in Bimatoprost Drug.

The origin, synthesis, characterization and docking studies of (Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R,1E,4E)-3-hydroxy-5-phenylpenta-1,4-dien-1-yl)cyclopentyl)-N-ethylhept-5-enamide, an impurity generated in the preparation of an anti-glaucoma agent-Bimatoprost has been described. This impurity was controlled by employing 30% Pd/C, and the impurity level was brought to the permissible level, i.e., 0.03% (ICH guidelines) in the final drug preparation of Bimatoprost. Finally, induced-fit docking calculations were performed to theoretically evaluate the binding efficiencies of these inhibitors in the crystal structure of Prostaglandin F syn-thase (PGFS). There are negligible differences in RMSD and docking scores between the two ligands, which amount to only 0.18 Å and 0.313 kcal/mol, respectively. These findings strongly indicate that both ligands are likely to exhibit similar biological functions and effi-ciencies.

Challenges of cannabidiol determination in emulsified cosmetics and application of solid-phase extraction followed by HPLC-UV-MS/MS.

The recent surge in popularity of cannabidiol-infused products extends beyond food and supplements to the cosmetic industry. Accurate labeling remains a significant concern, as many products fail to meet advertised cannabidiol content and/or contain psychoactive tetrahydrocannabinol above the permissible levels. In this work, we present the use of an HPLC-UV-MS/MS method for the quantification of five major cannabinoids (cannabidiol, cannabidiolic acid, tetrahydrocannabinol, tetrahydrocannabinolic acid, and cannabigerol) in oil-in-water cosmetic emulsions. The sample extraction is based on dispersing the sample in isopropanol, followed by solid-phase extraction using Bond Elut Plexa PAX cartridge. The viability of this method is demonstrated by comparing matrix effects in samples subjected to solid-phase extraction (0‒11% suppression of cannabidiol ionization) to samples extracted without additional purification steps (0‒84% ionization suppression of cannabidiol ionization). The limit of quantification is determined at 0.1 mg/g and the calibration is employed in the range of 0.1‒50 mg/g for cannabidiol and 0.1‒10 mg/g for all other analytes. Finally, 36 real cosmetic samples from the Czech market were analyzed. Of these, 14 indicated the amount of CBD on the label but only five (36%) were accurate, i.e., within 90‒110% of the labeled amount, and a considerable amount of THC (0.16 ± 0.01 mg/g) was found in one sample. These findings contribute to the cumulating evidence that cannabidiol-based consumer products are often mislabeled and highlight the importance of better regulatory compliance.

Simple and effective filtration system for drinking water production from harvested rainwater in rural areas.

Rainwater harvesting (RWH) for drinking water production has been a potential solution to mitigate water scarcity in rural areas. There was limited research focusing on the quality of treated rainwater. This study developed and tested the quality of a drinking water filtration system (DWFS) for treating harvested rainwater to support rural communities. Physiochemical and microbial quality assessments of first flush, pre-filtered and filtered rainwater over 12 months of the experiment were investigated. The findings are: (1) the first flush system used in this study (diameter of 90mm and length of 1m) showed a marked improvement in roof harvested rainwater quality (by about 75%), (2) the quality of the harvested rainwater could meet drinking water guidelines once treated by DWFS, which could eliminate harmful pathogens but bypass other essential constituents at permissible levels (e.g., suspended solids, dissolved compounds, metals and nutrients), and (3) the configured system offered a drinking water production capacity of 60L/h. It should be noted that the configured filter would need adjustments to be adopted in a different region.

Content of heavy metals, macro- and microelements in apple fruits

The research evaluated the content of heavy metals, micro, and macronutrients in fruits of eight apple varieties - Red Del. Superchief, Fujion pbr, Enterprise, Pinova, Orion, Red Del. Mestar, Gemini and Crimson crisp, grown in orchard near Brestnik village, situated at 3.5 km distance from the potential source of pollution (the Holding KCM 2000) near Plovdiv, Bulgaria. Significant varietal differences in the composition of the apple fruit were observed. The highest content of Pb, Cd, Zn, Cu, Fe, Mn, P, Mg and K were found in the variety Red Del. Superchief. Variety Pinova contained Ca and Hg, the variety Orion - Cr and Ni, and the variety Gemini - B, Na and As. However, the content of Cd, Zn, As, Cr and Ni in the fruit of all tested varieties was below the maximum permissible level. The Pb content in the apples of the varieties Enterprise, Pinova and Red Del. Mestar was low and did not exceed the maximum permissible level for heavy metals in food, thus these apple varieties can be included in the daily human diet without any restrictions. Keywords: apples, cultivars, nutrients, toxic elements, fruits

Clarias Gariepinus Parasites as Bioindicator For Assessing Water Quality in Omi Dam, Kogi State, Nigeria

Studies using host-parasite dynamics as bioindicator of effects and accumulators of heavy metals for assessing environmental quality are still scarce, particularly in developing countries. This study aimed at elucidating the possible use of parasites of fish in monitoring and assessing water quality. 102 samples of 18 species of parasites of Clarias gariepinus were analyzed for copper, lead, manganese, iron, zinc and cadmium concentrations. Heavy metal concentrations were determined using atomic absorption spectrophotometer. Physico-chemical parameters were measured on sites using Hanna instrument. The nutrients and non-toxic constituents of water were also determined using methods by (American Public Health Association, 1999). The data obtained were analyzed using analysis of variance and significant differences accepted at p ≤ 0.05. Duncan Multiple range test was used to compare the heavy metal accumulation in the parasites and sample t- test was used to compare the values of physico-chemical parameters, nutrients and non-toxic constituents of the water. The heavy metal concentrations in parasites of C. gariepinus were in the order of Lead>Cadmium>Copper>Iron>Magnese>Zinc. Bioindicating capacity of parasites were in the order Nematodes>Cestodes>Protozoan>Trematodes. All physico-chemical parameters of the water (pH, temperature, salinity, turbidity, electrical conductivity, total dissolved solid) except dissolved oxygen were within the permissible level of the WHO (2011) permissible limits. The water nutrients except fluoride were within the permissible limits of WHO (2011). The non-toxic constituents were within permissible limits except NH4+ in the control study sites and PO43- in both study sites that was not within permissible limits. This study revealed that parasites can be ideal indicators for both effects and accumulation of heavy metals in aquatic environments. Findings from this study demonstrate the need for an ecosystem friendly approach towards sustainable management of dams and rivers. This will curb aquatic pollution which can directly and indirectly affect the structure and composition of fish parasite communities and also lead to a health risk in people consuming aquatic resources contaminated with heavy metals.