Threshold Limit Research Articles

Investigating the carcinogenic and non-carcinogenic health hazards of heavy metal ions in Spinacia oleracea grown in agricultural soil treated with biochar and humic acid.

This study addressed the bioaccumulation and human health risk among the consumption of Spinacia oleracea grown in agricultural soil treated with humic acid (189-2310ppm) and biochars (0.00-5.10%.wt). The biochars came from two local feedstocks of rice-husk (RH) and sugar-beet-pulp (SBP) pyrolyzed at temperatures 300 and 600°C. Total concentrations of Cu, Cd, and Ni found in both the soil and biomass/biochar exceeded global safety thresholds. The bioaccumulation levels of HMs in spinach leaves varied, with Fe reaching the highest concentration at 765.27mgkg-1 and Cd having the lowest concentration at 3.31mgkg-1. Overall, the concentrations of Zn, Cd, Pb, and Ni in spinach leaves exceeded the safety threshold limits, so that its consumption is not recommended. The assessment of hazard quotient (HI) for the HMs indicated potential health hazards for humans (HI > 1) from consuming the edible parts of spinach. The biochar application rates of 4.35%wt and 0.00%.wt resulted in the highest (3.69) and lowest (3.15) HI values, respectively. The cumulative carcinogenic risk (TCR) ranged from 0.0085 to 0.0119, exceeding the cancer risk threshold. Introducing 5.10%wt biomass/biochar resulted in a 36% rise in TCR compared to the control. The utilization of humic acid alongside HMs-polluted biochars results in elevated levels of HMs bioaccumulation exceeding the allowable thresholds in crops (with a maximum increase of 49% at 2000ppm humic acid in comparison to 189ppm). Consequently, this raised the HI by 46% and the TCR by 22%. This study demonstrated that the utilization of HMs-polluted biochars could potentially pose supplementary health hazards. Moreover, it is evident that the utilization of HMs-polluted biochars in treating metal-contaminated soil does not effectively stabilize or reduce pollution.

A comprehensive evaluation of the contamination scenario and water quality in the gas fields of north-east region, Bangladesh

Gas fields generate a significant volume of produced water, disposed in the vicinity of gas fields in Bangladesh after processing. It may have a variety of effects on ecology and the environment. This study was conducted to assess the contamination scenario and quality of produced and discharged water from gas fields in northeastern Bangladesh. The physicochemical analyses for this study were performed using standard procedures. Based on the outcomes of the analyzed samples, the current research employs a variety of indexing and statistical approaches to investigate the overall status of the studied water. The physiochemical analysis revealed high electrical conductivity (EC), total dissolved solid (TDS), salinity, and Na contents in both produced and discharged water. No severe cases have been identified, certain metals, such as Fe, Ni, and Cd, have been detected at levels high enough to impact specific index values in some cases. The results of the weighted contamination index (WCI) indicated mild to considerable pollution in the gas field region. The average score of potential ecological risk (PER) reflects minimal ecological risk. The heavy metal toxicity load (HTML) reveals negligible metal pollution in the studied water. The agricultural risk indices displayed increased sodium concentrations and EC, resulting in salinity and sodium risks. The magnesium absorption ratio is within the allowable range. In addition, the average heavy metal pollution index (HMPI) value demonstrates that the produced and discharged water is unsuitable for drinking. The entropy-based water quality index (EWQI) is below the threshold limit (<100) for all samples, indicating satisfactory water quality. This study is an early effort to evaluate the quality of wastewater produced and discharged from gas fields in Bangladesh. The findings of this research will provide valuable insights for future researchers and regulators in effectively managing and mitigating pollution from wastewater.

Exploring the alteration of environmental radioactivity in terms of compositional elements of heavy minerals in an anthropogenically affected urban river: Radiological and ecological risks assessment

This study explored the alteration of naturally occurring radioactive materials (NORMs: 226Ra (≈238U), 232Th, 40K) in an anthropogenically disrupted urban river-basin (Turag, Bangladesh) in terms of constitutional substances (Sc, Ti, V, Fe, La, Ce, Sm, Eu, Tb, Dy, Ho, Yb, Lu, Hf, Ta, W, Th, U) of heavy-minerals. Average activity concentrations of 226Ra (≈238U), 232Th, and 40K were 41.5 ± 12.9, 72.1 ± 27.1, and 639 ± 100 Bqkg−1, respectively which were relatively higher compared to crustal origin. ∑REEs, Ta, W, Th, and U were ~2 times higher compared to crustal values with Ce and Eu-anomalies. APCS-MLR and PMF receptor models were used to determine the various anthropogenic and/or geogenic sources of NORMs and elements. Layer-wise variations of NORMs and elements were observed to trace the response of sedimentary processes towards the incoming pollution load. Presence of REEs indicates moderate degree of ecological risk to aquatic biota. However, carcinogenic risk (3.84 × 10−4 Sv−1) were significantly higher than threshold limit.

A comprehensive scenario of heavy metals pollution in the rivers of Bangladesh during the last two decades.

For decades, rivers have been used for transporting pollutants loaded with heavy metals (HMs) causing severe pollution in downstream.The current study aimed to review the levels and sources of 10 HMs, viz. As, Pb, Cd, Cr, Fe, Mn, Cu, Co, Ni, and Zn in the surface water of the rivers in Bangladesh. The PRISMA criteria were used to conduct a systematic review of the available literature published between 2001 and 2020, and thus a total of 55 documents were finally selected for review. The mean concentration of each HM exceeding the threshold limits as per World Health Organization (WHO), the United States Environmental Protection Agency (USEPA), and Department of Environment (DoE), Bangladesh standards were higher in the last decade (2011-2020) than in the previous one (2001-2010). Most HM concentrations in water were found above the threshold limits in three divisions (Dhaka, Rajshahi, and Chattogram). The Buriganga River in Dhaka has been the top polluted river in Bangladesh. Among the 10 HMs, six metals (As, Pb, Cd, Cr, Fe, and Mn) exceeded the limit set by WHO, USEPA, and DoE in all three seasons, where mean values of most of the HMs were found to be the highest in the summer season. Statistical analyses identified possible sources of HMs such as natural weathering, electroplating, fertilizers and pesticides, mining and manufacturing, textiles, coal mining and burning, batteries, and paint industries. Strong legislations and regulations, awareness programs, continuous monitoring, and comprehensive research are urgently needed to control riverine HMs pollutionin Bangladesh.

Assessing microbiological and heavy metal pollution in surface waters associated with potential human health risk assessment at fish ingestion exposure

Fish represent a significant source of nutrients but also cause negative health effects due to their bioaccumulation capacity for pollutants. The aim of this study was to examine the transfer of metals from the water of several rivers (Somes, Tisa, Sasar, Lapus, Lăpusel) to fish (Caras sp) tissue (subcutaneous fat, muscles, liver, intestines, kidneys, gills, brain, and eyes) and to identify and assess the carcinogenic and non-carcinogenic health risks of Arsenic (As), Cadmium (Cd), Nickel (Ni), Manganese (Mn), Cooper (Cu), Lead (Pb), Chromium (Cr) and Zinc (Zn) through the ingestion of fish (muscles and subcutaneous fat tissues). The obtained results indicated that a diet consisting of fish is particularly vulnerable, particularly in children compared to adults. The risk assessment results were below the threshold limit, although the fish samples contained heavy metals, with values exceeding the permitted limits of Fe (4.41–1604 mg/kg), Cr (727–4155 µg/kg), Zn (4.72–147 mg/kg), and Ni (333–2194 µg/kg). The studied surface waters are characterized by low and high degrees of pollution with heavy metals, as indicated by the heavy metal pollution index scores (HPI: 12.4–86.4) and the heavy metal evaluation index scores (HEI: 1.06–17.6). The considerable pollution levels are attributed to the high Mn content (0.61–49.7 µg/kg), which exceeded the limit up to fifty times. A consistent set of physico-chemical analysis (pH, electrical conductivity, total hardness, turbidity, chloride, sulphate, nitrate, nitrite, ammonium, Ca, Mg, Na, K) was analysed in water samples as well. Considering the water quality index scores (WQI: 16.0–25.2), the surface waters exhibited good quality. Microbiological results indicated the presence of Listeria monocytogenes and atypical colonies of coagulase-positive staphylococcus in fish. In contrast, the surface waters from which fish samples were collected were positive for Escherichia coli, and coliform bacteria intestinal Enterococci. Based on the study’s results, it is recommended to exercise caution in the case of children related to the consumption of fish and using the waters for drinking purposes. This study provides important data of considerable novelty to the riparian population, researchers, and even policy makers on the quality status and potential levels of contamination of river waters, fish and the bioaccumulation of heavy metals in fish that may cause adverse effects on human health if consumed, and similarly the heavy metal pollution degree of waters and the non-carcinogenic risk of heavy metals through ingestion and skin absorption of water in children and adults (the study area is a significant source of fisheries).

Reducing exposure levels of immersion washing workers to ortho-phthalaldehyde by improving exhaust systems.

The American Conference of Governmental Industrial Hygienists recommends a threshold limit value-ceiling (TLV-C) of 0.1ppb for occupational exposure to ortho-phthalaldehyde (OPA) used in washing endoscope probes. To adhere to this extremely low exposure limit, this case study aimed to reduce OPA exposure concentrations of workers during immersion washing of an endoscope probe body. This was achieved by attaching a new duct and hood to the existing ceiling exhaust system. The type of hood was determined by calculating and comparing the capture velocity obtained by assuming either an exterior or an enclosing hood. Additionally, the effect on improving the working environment was tested before and after the installation of the hood by measuring the OPA vapor concentration. The calculated capture velocities of the exterior and enclosing hoods were 0.05m/s and 0.19m/s, respectively. Considering the operability, the exterior hood was more appropriate; however, the calculated capture velocity indicated potential inadequacy in meeting the TLV-C requirement, leading to the adoption of the enclosing hood. The OPA vapor concentration in ceiling value measurements taken after the enclosing hood was fitted was reduced to 0.2ppb, that is, 1/10 of the original concentration. Although the environmental concentration after the improvement still exceeded the TLV-C of 0.1ppb, this study's findings indicate that even substances with extremely low occupational exposure limits can be managed with appropriate local exhaust ventilation.

The scale effects of agricultural credits, institutional governance and microfinance sustainability in Sub-Saharan African countries

PurposeThe study examines the synthesized influences of institutional governance and the scale effects of agricultural credits on the sustainability of microfinance institutions (MFIs) in Sub-Saharan Africa.Design/methodology/approachUsing a sample of 840 MFIs (300 independent and 540 networked), the study applied Generalized Method of Moments (GMM) and Lewbel’s estimator.FindingsResults indicate positive effects of financial structure, efficiency and agricultural credit scale on sustainability, with a non-linear U-shaped relationship between agricultural credit size and microfinance sustainability. Depending on institutional governance quality, a threshold is identified where agricultural credit scale significantly enhances the quality of Portfolio at Risk (lnPAR) in independent MFIs and Returns on Assets (lnROA) in networked MFIs.Research limitations/implicationsStudy suggests strengthening governance for transparency and operating within optimal size for enduring sustainable performance. While focused on Sub-Saharan Africa, future research could expand to various economies or introduce additional variables for a comprehensive analysis.Practical implicationsMFIs can achieve sustainability by implementing management guided by better institutional norms, innovative financial transformations better suited to financing agricultural activities and techniques and an organizational structure more aligned with their performance targets.Social implicationsBroader and more reliable access to financial services, particularly in the agricultural sector, can stimulate production and alleviate poverty.Originality/valueThe study’s originality lies in its contribution to the literature by examining the role of institutional governance in microfinance institution performance and evaluating microfinance in a broader Sub-Saharan African context, proposing threshold limits where agricultural microcredit compromises performance.

Estimation of the Hazardous Chemical Leakage Scale Inside Buildings Using CFD

Increased industrialization and aging infrastructure have resulted in leaks of hazardous chemicals, such as CO. Leak modeling is crucial to developing emergency response strategies. Therefore, we simulated the time to criticality (TTC), which is the time to reach the threshold limit for occupational exposure, of a CO leak. The basis of the study is a fire dynamics simulator, a computational fluid dynamics model that was used to investigate the movement of CO in various scenarios, including using different building layouts and areas, temperatures, and leak diameters. Multiple regression analysis was performed to obtain regression equations for the TTC as a function of the independent variables. Ultimately, we found that the type of dispersion varies with respect to the temperature-dependent density of CO, and, among the independent variables, the leak diameter had the strongest effect on the TTC. The regression equations with logarithmic conversion were validated and found to have higher accuracy than those without logarithmic conversion. The findings provide useful information for developing emergency response plans regarding leak size in the case of hazardous chemical leakage. However, empirical studies of different gas types and leakage scenarios are required.

Lead in umbilical cord blood and associated factors in Casablanca Morocco: A preliminary results

BackgroundLead is the most common toxic metal to which Moroccans are exposed. Given the susceptibility of the fetus to lead, it is crucial to assess prenatal lead exposure. However, in Morocco, no study has assessed prenatal exposure to lead. The main goals of the present study are to determine lead concentration in umbilical cord blood and identify risk factors for prenatal lead exposure in Casablanca, Morocco. MethodsTo achieve these purposes, 87 cord blood lead samples were collected from mothers-baby pairs from January to December 2019. Indeed, a structured questionnaire was used to collect socio-demographic characteristics, obstetric data, leisure, cultural habits, and environmental information. Cord blood lead level was analyzed by inductively coupled plasma-mass spectrometry. ResultsThe median lead concentration was 4.902 µg/dl with a minimum and maximum of 0.833 µg/dl and 23.593 µg/dl, respectively. A high proportion of the newborns (65.52 %) had cord blood lead levels above the Centers for Disease Control (CDC) allowable threshold limit (3.5 µg/dl). Statistical analysis was performed to assess the association between blood levels and the above factors. Lead levels in cord blood were significantly associated with the maternal educational level, anemia history, delivery mode, passive smoking during pregnancy as well as with the frequency of consumption of tea. ConclusionThis study provides the first data on lead levels in newborns. Cord blood lead levels were high in the majority of the participants, these results reinforce the need to establish health surveillance programs in Morocco.

Fault root cause analysis using degree of change and mean variable threshold limit in non-linear dynamic distillation column

The chemical industrial processes are both dynamic and complex. The presence of instability and danger in the production process poses significant challenges to safety management. Early and accurate fault diagnosis is essential to ensure a sustainable and stable chemical process performance. Most studies in literature do not provide detailed information about diagnosing the root cause of faults in distillation columns using contribution plots. Using principal component analysis (PCA) in conventional contribution plots leads to a large number of contributing variables, making it difficult to identify the root cause of a specific fault. In this study, the authors suggest employing the Degree of Change of Contribution Values (DCC) and Mean Variable Threshold Limit (LMVT) techniques alongside the Wavelet Transform-Principal Component Analysis (WT-PCA) method to decrease the quantity of fault identification variables in a non-linear system (distillation column). The Aspen Plus software is utilized to perform a dynamic simulation of a distillation column, generating data for both normal and faulty operations. Two distinct types of faults are considered, which include loss of feed flow and feed temperature changes. This study aims to analyze the results obtained from the Hotelling T2 and SPE contribution plots by calculating the average difference between the normal and faulty conditions using the Degree of Change in Contribution Values. This procedure is performed to determine the extent of deviation from the standard state. Subsequently, the variables that have surpassed the threshold limit for means variables (LMVT) are designated as the variables that serve as the primary underlying cause of the fault. The technique was employed in a case study involving a nonlinear distillation column, and the results indicate that only one "dominant" variable intersects the LMVT by Hotelling T2, which represents the true underlying cause of the corresponding fault.

Intermittent low-dose far-UVC irradiation inhibits growth of common mold below threshold limit value.

Mold infestations in buildings pose significant challenges to human health, affecting both private residences and hospitals. While molds commonly trigger asthma and allergies in the immunocompetent, they can cause life-threatening diseases in the immunocompromised. Currently, there is an unmet need for new strategies to reduce or prevent mold infestations. Far-UVC technology can inactivate microorganisms while remaining safe for humans. This study investigates the inhibitory efficacy of far-UVC light at 222 nm on the growth of common mold-producing fungi, specifically Penicillium candidum, when delivered in low-dose on-off duty cycles, a configuration consistent with its use in real-world settings. The inhibitory effect of the low-dose duty cycles was assessed on growth induced by i) an adjacent spore-producing P. candidum donor and ii) P. candidum spores seeded directly onto agar plates. In both setups, the far-UVC light significantly inhibited both vertical and horizontal growth of P. candidum, even when the UV doses were below the Threshold Value Limit of 23 mJ/cm2. These results suggest that far-UVC light holds the potential to improve indoor air quality by reducing or preventing mold growth, also when people are present.

Consistency between the ACGIH TLV for hand activity and proposed action levels for wrist velocity and forearm muscular load based on objective measurements: an example from the assembly industry

Objectives. This study aimed to investigate the consistency between results of the American Conference for Governmental Occupational Hygienists (ACGIH) threshold limit value (TLV) for hand activity and proposed action levels of objective measurements in risk assessments of work-related musculoskeletal disorders. Methods. Wrist velocities and forearm muscular load were measured for 11 assemblers during one working day. Simultaneously, each assembler’s hand activity level (HAL) during three sub-cycles was rated twice on two separate occasions by two experts, using a HAL scale. Arm/hand exertion was also rated by the assemblers themselves using a Borg scale. In total, 66 sub-cycles were assessed and assigned to three exposure categories: A) below ACGIH action limit (AL) (green); B) between AL and TLV (yellow); and C) above TLV (red). The median wrist velocity and the 90th percentile of forearm muscular load obtained from the objective measurements corresponding to the sub-cycles were calculated and assigned to two exposure categories: A) below or C) above the proposed action level. Results. The agreement between ACGIH TLV for hand activity and the proposed action level for wrist velocity was 87%. Conclusions. The proposed action level for wrist velocity is highly consistent with the TLV. Additional studies are needed to confirm the results.

Analysis of the pharmacoeconomic effectiveness of the tyrosine kinase inhibitors therapy in patients with chronic myeloid leukemia in a Single Hematology Center in Plovdiv, Bulgaria

Summary: Chronic myelogenous leukemia (CML) is a pluripotent hemopoietic stem cell malignancy characterized by the presence of a BCR-ABL1 fusion gene derived from a balanced translocation between the long arms of chromosomes 9 and 22 [t(9;22) (q34; q11)] known as the Philadelphia (Ph) chromosome. CML is an acquired hematopoietic stem cell disease common to myelo- and lymphopoiesis, characterized by uncontrolled proliferation of granulopoiesis (Shuvaev et al. 2015; Yordanov and Varbanova 2019). Relevance and goals: Second-generation tyrosine kinase inhibitors (TKIs) (nilotinib, dasatinib, and bosutinib) have an advantage over imatinib (first-generation) in the frequency and speed of achieving cytogenetic and molecular responses in the treatment of chronic myelogenous leukemia (CML), but they cause severe adverse effects and are much more expensive than imatinib, especially if we compare them to the prices of the registered generic products of Imatinib and Dasatinib. “Novartis Tasigna® trial shows superior results to Glivec® in patients with early-stage chronic myeloid leukemia”, reported on 10/20/2021 by Pierre Perrin-Montlouis. In the first direct comparison of these two oral therapies back in 2009 (Тasigna (nilotinib) 2009), as first-line treatment for CML, the results of Tasigna showed statistically significant improvement over Glivec in every measure of efficacy, including major molecular response (MMR), complete cytogenetic response (CCyR) and prevention of progression to accelerated or blast phase, with responses achieved faster in the Tasigna group than in the Glivec group. Furthermore, in the last ten years, CML patients who have achieved a stable deep molecular response for at least 2 years have been included in clinical trials for the management of treatment-free remission (TFR) (Kim et al. 2013; Saußele et al. 2016). On the other hand, the ever-increasing costs of diagnosis, treatment and monitoring of the response of CML to the various therapeutic strategies require conducting pharmacoeconomic analyses of the cost-effectiveness and cost-utility types in order to evaluate which are the cost-effective strategies with a view to introducing them into therapeutic practice. The present study aims to analyze the pharmacoeconomic efficiency of the TKI inhibitors used by the patients with CML-CP in the first and second lines, treated in the hematology clinic at UMHAT “St. George”, MU- Plovdiv during the period 2018–2022. Methods: An economic analysis of the medicinal use of TKIs for a 5-year period (2018–2022) was performed at the national level according to data from the National Health Insurance Fund and the availability, accessibility, and usability of original and generic TKIs in Bulgaria were evaluated. The direct medical costs for the therapy of all patients were calculated, including the costs of the TKI therapy, laboratory tests, and monitoring of the molecular response for the entire treatment period from the appointment of the TKI therapy until the end of 2022. A comparative analysis was conducted to assess the cost-effectiveness of the different therapeutic strategies with TKIs on the first and second lines of treatment of patients with CML-CP in the hematology clinic at UMHAT “St. George” Medical University, Plovdiv, using the decision analysis method and conducting one-way and probalistic sensitivity analyses. Results: The sensitivity analyzes of all pharmacoeconomic models showed the robustness and reliability of the obtained results. The threshold limits of medical costs and the frequency of achieving a deep molecular response determining the choice of first- and second-generation tyrosine kinase inhibitors as first- and second-line therapy for patients with chronic myeloid leukemia in the chronic phase have been determined. Prescribing doctors prefer the original MPs to generic analogues, which is also assumed by the current regulations, according to which even for expensive MPs dispensing by protocols, the prescription is by trade and not by international non-proprietary names (INN), which is why the use of the much cheaper generic MPs is negligibly low compared to original MPs. A personalized approach to the patient’s therapy and monitoring the patient’s molecular response to it, as well as stopping therapy in 25–30% of patients suitable to stop it safely when in TFR phase with a probability of more than 50% of not having a relapse will save additional costs that, by improving the cost-effectiveness of therapy for patients with CML, will be directed towards the treatment of new patients with this or other diseases. Conclusion: These pharmacoeconomic models can be applied to improve diagnostic and therapeutic standards in clinical practice and for the efficient use of the very limited resources for health care in countries like Bulgaria. The conducted cost-effectiveness analyses confirmed that the hematologists at the University Center in Plovdiv adhere to the recommendations of Leukemia Net and the Bulgarian Medical Society of Hematology and achieve not only good therapeutic but also pharmacoeconomic efficiency in the treatment of CML-СР patients in first- and second- line therapy.

Impacts of unregulated dumpsites: a study on toxic soil contamination, associated risks, and call for sustainable environmental protection in Nnewi, Nigeria

The accumulation of leachates from unlined dumpsites laden soil-water environment with toxic elements poses imminent threats to both the environment and humans. This study evaluated the seasonal levels of potentially toxic elements (PTEs), their health-related risks, contamination factors (CF), pollution load index, geo-accumulation index (Igeo), ecological risk index, polymetallic contaminant index and Nemerow's synthetic pollution index of soils near a waste dump in Nnewi, Anambra State, Nigeria. The PTE results indicated that levels of Cd (1.54–3.40 mg/kg) were above the World Health Organization's threshold limit for soil. The studied soil samples had PTE levels higher than the control samples due to their proximity to the dumpsite. The CF of the PTE in the soil indicated moderate to considerable contamination, while the control areas showed moderate contamination for both seasons. The pollution load indices of the soil indicated heavy and moderate pollution for the study sample (2.207–2.517) and control samples (1.445–1.659). However, the ecological risk indices ranged from 85.72 to 164.84, indicating a low ecological risk. The Igeo of the PTE in the soil ranged from unpolluted, moderately polluted to very strongly polluted. The Nemerow's synthetic pollution index values ranged from 3.560 to 3.564 for the study samples and 2.070–2.502 for the control samples, indicating heavy and moderate pollution of the soil respectively. The polymetallic contaminant index values for the study samples (23.22–26.43) and control samples (15.02–17.23) showed high and considerable contamination respectively. Health risk examination highlighted that both adults and children have a low risk for non-cancer health threat via ingestion route, while a high risk was obtained for children for cancer health dangers via ingestion routes. For the dermal pathway, children and adults have minimal chances of exposure to cancer risks, while a high exposure to non-cancer risk was observed for children. Pearson's correlation and principal component loadings revealed the sources of pollution to be of similar origins linked to anthropogenic activities. Awareness programs are necessary to educate the populace about the dangers of using contaminated soil for farming or recreational activities. The use of sanitary dumpsites should be encouraged and adopted as a waste disposal method by the government to mitigate the spread of PTE into the environment.

Water-quality assessment and spatial distribution of water-quality parameters of Dodoma Urban, Tanzania

The study was conducted in 2022 in shallow wells and deep boreholes owned by residents, to investigate the water quality status in the emerging developing area of Dodoma Urban municipality in central Tanzania. Eighteen boreholes and five shallow wells were assessed using the water quality index (WQI), the inverse distance weighting (IDW) method under the ArcGIS environment, and the Euclidean similarity index. The WQI classified the water samples into a good category class with a covered area of 42.5% and an excellent category class with a covered area of 57.5%, indicating that most of the deep boreholes and shallow wells were suitable for residential purposes. The IDW revealed the spatial distribution of the physico-chemical parameters and WQI, indicating that water quality improved from west to east within the study area. Yet, the Euclidean similarity index was dominated by nitrates, pH and heavy metals, with the highest correlation coefficients. Despite the WQI being above the average class, water treatment technologies should be practiced to lower those values of physico-chemical parameters existing above the threshold limits.

Potential cancer risks of metals/metalloids and radionuclides through the intake of food crops grown around the mining area

BackgroundFood crop consumption is one of the primary routes through which the environment is polluted with radionuclides, metals, and metalloids. In recent years, the negative impacts of metals, metalloids, and radionuclides on crop quality via the food-human system have jeopardized both human health and food security. Because some metals, metalloids, and radionuclides are persistent and non-biodegradable, they build up in the human body's essential organs, causing a variety of serious health issues, including cancer. It is therefore absolutely essential to evaluate the potential cancer risks of radionuclides as well as metals and metalloids in the food crops consumed in the study area to avoid negative health consequences. ObjectiveThe aim of this study was to assess the potential cancer risks of metals and metalloids (As, Cd, Cr, and Pb) and Radionuclides (U-238, Th-232, and K-40) via consumption of food crops cultivated around the Riruwai mining area, northeastern Nigeria. MethodologyThirty-three (33) food crops (15 vegetables and 18 cereal crops) were collected directly from the farmlands in the study area. The concentrations of radionuclides, metals, and metalloid in each food crop were assessed using a microwave-plasma atomic emission spectrometry (MP-AES) and a high-purity germanium (HPGe) gamma-ray spectrometer, respectively. The measured concentrations of radionuclides, metals, and metalloid were used to calculate their lifetime cancer risks (LTCRs). ResultsThe findings of the study revealed that the concentrations of As, Cd, Cr, and Pb in all the investigated food crops were above the threshold limits, while lower activity concentrations in all the investigated food crops below the world average standard were observed in U-238, Th-232, and K-40. LTCRs of all the individual metal and metalloid as well as radionuclide in each food crop were determined to be below the global threshold limits, indicating no likelihood of cancer risk from consuming the food crops. However, it was discovered that the total cumulative LTCRs of all the metals and metalloid in all food crops combined were 2.51E-04, which was over twofold the acceptable limit of 1.00E-04 ConclusionThe individual metal, metalloid, and radionuclide LTCRs in each food crop were found to be below global threshold limits, indicating no cancer risk from consumption. However, the cumulative LTCRs of all the metals and metalloid in all food crops were found to exceed the acceptable level, which requires proper monitoring and government intervention. Cancer risk is influenced by factors beyond food consumption, such as alcohol consumption, heredity, and air pollution, so multidimensional studies are needed before making a final decision on cancer risks in the study area.

Bioaccumulation of heavy metals, assessment of carcinogenic and non-carcinogenic health risk in various spices

Spices consumption is the main pathway for human exposure to certain environmental pollutants. This study was aimed to evaluate the concentration of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganes (Mn), lead (Pb) and zinc (Zn) in different parts of various spices samples in Arba Minch Ethiopia. The average levels of metals in white cumin, fenugreek, black cumin, turmeric, basil, cardamom, and coriander were varied in the range 0.35–1.8, 1.02–11.96, 1.69–32.19, 20.74–38.98, 7.38–26.01, 2.96–9.57 and 5.38–44.63 mg/kg for Cd, Cr, Cu, Fe, Mn, Pb and Zn, respectively. Principal component analysis (PCA) showed that the robust linkage between Zn, Cr, and Mn in PC1, Cu and Pb in PC2, and Cd and Fe in PC3 comprising 39.10 %, 25.72 % and 18.57 % of the total variance, respectively. The average daily intake values were calculated in the range 5.22 × 10–5–2.69 × 10–4, 1.52 × 10–4–1.78 × 10–3, 2.53 × 10–4–4.81 × 10–3, 3.09 × 10–3–5.82 × 10–3, 1.1 × 10–3–3.88 × 10–3, 4.42 × 10–4–1.43 × 10–3, and 8.18 × 10–4–6.66 × 10–3, for Cd, Cr, Cu, Fe, Mn, Pb and Zn, respectively. The target hazard quotient (THQ) and hazard index (except in white cumin and fenugreek) for heavy metals in various spices were lower than the acceptable limit of unity (THQ and HI <1). The carcinogenic risk values were in the acceptable threshold limit (1 × 10–6–1 × 10–4), indicating that consuming different spices in the studied area will not pose a potential health risk to human health.

Evaluating the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria

Contamination of borehole water by leachates from dumpsites has significantly affected the health of those who use polluted water for domestic activities. This study evaluated the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria. The levels of the potentially toxic elements (PTEs) were compared with the World Health Organization (WHO) and Nigerian standard for drinking water quality (NSDWQ) standard limits. The, sources of PTEs, metal pollution index, water quality index, ecological risk, and health-related risks of using the underground water were evaluated. The chemical results indicated that levels of Cd and Pb were above the WHO and NSDWQ threshold limits for potable water. The Mn and Ni values were above the NSDWQ limits for potable water. The study borehole samples had PTE levels higher than the control samples due to their proximity to the landfill. The water quality index ranged from 1290.29 to 2243.04, showing that the water is unsuitable for drinking and other domestic uses. The metal pollution indices of the underground water samples were above 1, indicating that the water needs treatment before use. The health risk examination highlighted that children are more disposed to non-cancer risk than adults based on the hazard indices obtained. Also, the probability of cancer risks was high, showing that both children and adults are likely to be in danger of cancer risks. However, the ecological risk indices ranged from 11.187 to 51.581, indicating a low ecological risk. Pearson's correlation and principal component analysis revealed that the sources of pollution are from similar origins/sources linked to anthropogenic activities. Awareness programs are necessary to educate the populace about the dangers of using contaminated water. Effective waste management strategies and water treatment techniques should be implemented.

Дослідження міграції сучасних пестицидів амікарбазону, біциклопірону та підіфлуметофену з ґрунту до ґрунтових вод (результати експериментальних досліджень)

ABSTRACT. The expansion of the range and volume of application of plant protection products in agriculture increases the risk of contamination of soil, and subsequently of underground and surface water sources, especially with highly persistent pesticides in the soil. Аim. Establishing and comparative assessment of migration characteristics of new pesticides — representatives of different chemical classes, from soil to groundwater when modelling different initial concentrations and irrigation regimes. Materials and Мethods. In a laboratory experiment, the migration of the investigated substances in the soil – ground water system was studied with the help of filtration columns designed by the Academician E.H. Honcharuk. Soil Standard Model no 1 (SSM no 1) and leached chernozem were used as arable soil layers. Three hydraulic regimes were simulated: annual, three-month, or monthly precipitation rates were supplied to the column for 30 days. The initial concentrations of amicarbazone, bicyclopyrone, and pydiflumetofen corresponded to both one maximum consumption rate (m.c.r.) and 0.5, 0.2 and 5 m.c.r. respectively. Quantitative determination of the studied substances in the filtrate was carried out by the method of high-performance liquid chromatography. The results. It was established that with higher initial concentrations of all three substances in the topsoil and greater hydraulic load on the filtration column in the case of both herbicides, the concentrations of compounds in the filtrate were higher. At the same time, with the same arable soil layer (SSM no 1) and hydraulic load (maximum) and almost the same initial concentration in the soil (0.05 and 0.06 mg/kg), bicyclopyrone appeared in the filtrate much earlier and in in larger quantities, its maximum concentration in the filtrate was reached much faster, it was 17 times higher. It took much more time to detect pydiflumetofen than bicyclopyrone. The migration levels of bicyclopyrone were almost independent of the type of arable soil layer, while pydiflumetofen in leached chernozem retained longer and migrated more slowly than in SSM no 1. Conclusions. Both general regularities and significant differences in the migration of the studied substances to the ground water depending on the soil profile were revealed. It has been proven that, compared to bicyclopyrone, pydiflumetofen is less mobile, appears in the filtrate much later and migrates from SSM no 1 more slowly. Compared to bicyclopyrone, amicarbazone is more mobile, migrates from leached chernozem longer and more intensively. The highest potential danger of groundwater contamination due to vertical migration from chernozem, the most common soil type in Ukraine, is inherent to amicarbazone, the lowest — to pydiflumetofen. Keywords: plant protection products, herbicide, fungicide, soil, groundwater, migration, pollution, threshold limit value.

Assessment of probable health risk of potentially toxic metals in irrigable wetland soils from Ogun and Lagos States, Southwestern Nigeria

ObjectiveThe present study aimed at investigating the probable health risk associated with potentially toxic metals (PTMs) in irrigable wetland soils from Ogun and Lagos states, Southwestern Nigeria. MethodologyA total of 36 composite soil samples were collected from twelve monitoring sites and analyzed for potentially toxic metals [cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)] using atomic absorption spectrophotometry. PTM data underwent inferential and descriptive statistical analysis using IBM SPSS. Health risk indices were assessed for hazard quotient (HQ), hazard index (HI), and cancer risk (CR) using the standard method. Ecological and pollution risks were also assessed. ResultsFe (1465±977 to 47,785±12,049 mg kg−1) was the most abundant metal observed in irrigable wetland soils. The distribution pattern of PTMs in irrigable wetland soils followed the decreasing order of Fe > Zn > Cu > Cr > Pb > Ni > Co > Cd. The pollution index risk indicated values greater than 1.0 for Cd (2.43–133), Zn (1.60–6.32), Cu (1.49–5.89), and Pb (1.15–2.94). Cadmium indicated a considerable ecological risk index (4002), a moderate-to-high pollution level according to the Nemerov integrated pollution index (12.33), and a very high enrichment factor (14.1–227). The HQs of PTMs were generally less than 1.0 for adults, while a HI greater than 1.0 was observed for children. The CRs exceeding the threshold limit of 1.0 × 10−4 were observed for Co, Cd, Cr, and Ni [at one or more sampling sites] in the wetland soils exposed to by adults and children. ConclusionIn this study, the irrigated wetland soils showed high ecological, pollution, and carcinogenic risks of Cd, particularly at the Odo Aro monitoring site. The findings from the study could offer a theoretical basis and data support for pollution monitoring, assessment, and control in the study area.