Value At Risk Research Articles

Insight Study of Trace Elements in PM2.5 During Nine Years in Delhi, India: Seasonal Variation, Source Apportionment, and Health Risks Assessment.

This study investigated the concentrations, seasonal variations, sources, and human health risks associated with exposure to heavy elements (As, Al, Pb, Cr, Mn, Cu, Zn, and Ni) of PM2.5 at an urban location of Delhi (28° 38' N, 77° 10' E; 218m amsl), India, from January 2013 to December 2021. The average mass concentration of PM2.5 throughout the study period was estimated as 127 ± 77µgm-3, which is exceeding the National Ambient Air Quality Standards (NAAQS) limit (annual: 40µgm-3; 24h: 60µgm-3). The seasonal mass concentrations of PM2.5 exhibited at the order of post-monsoon (192 ± 110 µgm-3) > winter (158 ± 70 µgm-3) > summer (92 ± 44 µgm-3) and> monsoon (67 ± 32 µgm-3). The heavy elements, Al (1.19µgm-3), Zn (0.49µgm-3), Pb (0.43µgm-3), Cr (0.21µgm-3), Cu (0.21µgm-3), Mn (0.07µgm-3), and Ni (0.14µgm-3) exhibited varying concentrations in PM2.5, with the highest levels observed in the post-monsoon season, followed by winter, summer, and monsoon seasons. Six primary sources throughout the study period, contributing to PM2.5 were identified by positive matrix factorization (PMF), such as dust (paved/crustal/soil dust: 29.9%), vehicular emissions (17.2%), biomass burning (15.4%), combustion (14%), industrial emissions (14.2%), and Br-rich sources (9.2%). Health risk assessments, including hazard quotient(HQ), hazard index(HI), and carcinogenic risk(CR), were computed based on heavy elements concentrations in PM2.5. Elevated HQvalues for Cr and Mn linked with adverse health impacts in both adults and children. High carcinogenic risk values were observed for Cr in both adults and children during the winter and post-monsoon seasons, as well as in adults during the summer and monsoon seasons. The combined HIvalue exceeding one suggests appreciable non-carcinogenic risks associated with the examined elements. The findings of this study provide valuable insights into the behaviour and risk mitigation of heavy elements in PM2.5, contributing to the understanding of air quality and public health in the urban environment of Delhi.

Evaluation and health risk assessment of arsenic and potentially toxic elements pollution in groundwater of Majha Belt, Punjab, India.

Concentrations of potentially toxic elements (PTEs) like arsenic, uranium, iron, and nitrate in the groundwater of the Majha Belt (including Tarn Taran, Amritsar, Gurdaspur, and Pathankot districts) in Punjab, India were measured to evaluate the health risks associated with its consumption and daily use. The average concentrations of these elements in some locations exceeded the WHO-recommended values. Arsenic and iron toxicity levels were found to be higher in the Amritsar district, while uranium toxicity was more prevalent in Tarn Taran. The Trace Element Evaluation Index suggests that Amritsar is one of the districts most affected by toxic elements. According to the US Environmental Protection Agency's (USEPA) guidelines, the HQ values of U, Fe, and nitrate were less than one, indicating that there is no non-carcinogenic health risk for adults and children. However, the hazard quotient (HQ) value for arsenic was greater than one, indicating a higher possibility of health risk due to arsenic in the study area. The total hazard index values of 44.10% of samples were greater than four for arsenic, indicating that people in the Majha Belt are at a very high health risk due to the usage of water for drinking and domestic purposes. The cancer risk assessment values for arsenic in children (5.69E + 0) and adults (4.07E + 0) were higher than the accepted limit of USEPA (10-4 to 10-6) in the Majha Belt. The average radiological cancer risk values of U for children and adults were 8.68E-07 and 9.45E-06, respectively, which are well below the permissible limit of 1.67 × 10-4 suggested by the Atomic Energy Regulatory Board of DAE, India. The results of this study confirm that the residents of the Majha Belt who use contaminated groundwater are at a serious risk of exposure to arsenic in the Amritsar district and uranium in Tarn Taran district.

Predictive value of tooth loss risk with 2018 new classification of periodontitis:a literature review

The occurrence, progression and treatment efficacy of periodontitis are affected by many factors. Development on accurate estimation of prognosis is essential for treatment plan determination. The application of the 2018 new classification of periodontitis is one of the most important advances in the prognosis and risk assessment of periodontitis. The predictive value of the new classification on tooth loss risk had been evaluated by several latest researches, however, consensus still lacks. This review focused on the predictive efficacy of the 2018 new classification of periodontitis on tooth loss risk in periodontitis patients, in order to provide scientific evidence for clinical application and further improvement of the new classification system.

Research on Sustainable Supplier Evaluation Index System in Architectural Design Industry

Sustainable development has been popularized and emphasized in many industries. Great attention has been paid to the sustainability performance of the whole supply chain, with evaluating suppliers’ sustainability being particularly critical. However, research on sustainable development in the consulting service industry remains to be discovered, and few academic studies have analyzed the supplier selection indices derived from this industry. This paper conducted a case study in a design institute using the Delphi method to investigate the concept and characteristics of sustainable suppliers. Keywords derived from surveys and literature were collected, sorted, and established into a comprehensive hierarchy index system for sustainability evaluation. Finally, based on the improved failure mode and effects analysis (FMEA) and analytic hierarchy process (AHP), the failure risk of the indices was analyzed with weighted risk factors to obtain the high-risk key evaluation indices, which provided a simplified scheme for enterprises to streamline the evaluation process on sustainable suppliers. The results show the reliability of the improved FMEA model by differentiating the risk value and ranking. Suggestions for sustainable improvement are provided.

Remaining Life Assessment of Kotabaru 2x7 MW Coal Fired Power Plant Circulating Water A252 Gr 2 Intake Pipe by Inspection Method

Kotabaru power plant is a power plant that was built in 2010 and currently the construction work is pending. The construction work stopped in 2014 and based on Kotabaru power plant construction final quantity report, Kotabaru construction work progress is 79,61% up to now. Kotabaru power plant uses open cooling system and takes seawater as cooling water resources. The seawater distribute through intake pipeline which use A252 grade 2 material 600 mm and 800 mm diameter pipeline with 3PL coating and rubber lining inside the pipe. The pipeline distribute the water in 3.184.739 kg/hr flow rate and 5 kg/cm2 G pressure. These pipeline material was on site in 2013 and it was not constructed yet. In 2022 Kotabaru power plant is planned to continue the construction work progress. It was about 9 years of pipeline material on Kotabaru power plant site and these pipeline is exposed to the environment such as sunlight, temperature, oxygen, water, and contaminants and cause a primer failure, especially ultraviolet light (UV) from the sunlight is the main damaging factor. Ultraviolet light from sunlight is high enough to break the coating of pipeline. Inspection and assess the pipeline can help the management to figure out pipeline actual condition. More effective inspections can reduce the risk level by reducing the frequency of future failures, through corrective and preventive action. In general, the purpose of this method is classify all risk level equipment, calculate the risk value of all equipment and it can help to make a decision to the next construction period. The service lifetime of pipeline prediction can be determined by actual pipe condition by use corrosion test and actual thickness dimension of the pipeline. This method will inform the life time prediction of the pipeline that should be meet the 15 years life time required and also inform the risk matrix value of all pipeline equipment on the site.

A comprehensive study on the spatial and temporal variation of BTEX and asbestos in the northwest of Iran: Human risk assessment

Substances like asbestos and other air pollutants, such as BTEX (benzene, toluene, ethylbenzene, and xylene), are hazardous compounds due to their adverse effects on human health. This study aims to investigate the levels, seasonal variations, spatial distribution, potential sources, and associated health risks associated with BTEX compounds and asbestos fibers in the ambient air of Tabriz. Air samples were taken at 16 different locations during the 2020–2021 period. Glass containers with charcoal were used for sample collection, and the BTEX content was determined using the GC-FID method. Phase-contrast microscopy (PCM) analysis was conducted with a low-volume peripheral pump for asbestos fiber sampling. The results showed that the average concentration of ∑BTEX was 37.94 and 27.98 μg/m3 in autumn and spring, respectively. The same parameter was 2.26 and 1.68 f/L for asbestos in the autumn and winter, respectively. The contribution of BTEX to ozone formation potential (OFP) in the research area showed that xylene and toluene were the major contributors to ozone production in different seasons. The risk of exposure to benzene compounds was 24 × 10−4 in children and 55.9 × 10−4 in adults, while the risk of exposure to ethylbenzene was 3.78 × 10−4 in children and 3.25 × 10−4 in adults. The estimated lifetime cancer risk was found to be the highest for benzene, followed by ethylbenzene. The estimated cancer risk for benzene and ethylbenzene exceeded the threshold values set by EPA, which signals a significant carcinogenic risk due to exposure to these substances in the ambient air of Tabriz. According to the EPA guidelines, the low carcinogenicity risk levels are between 10−4 and 10−6. According to the findings for the exposure to asbestos fibers, the maximum values of excess cancer risk (ECR) and estimated lifetime cancer risk (ELCR) were observed in the 16–30 age range across all locations, suggesting increased exposure to asbestos fibers compared to other age groups.

Guaranteed minimum withdrawal benefits with high-water mark fee structure.

The Guaranteed Minimum Withdrawal Benefit (GMWB), an adjunct incorporated within variable annuities, commits to reimbursing the entire initial investment regardless of the performance of the underlying funds. While extensive research exists in financial and actuarial literature regarding the modeling and valuation techniques of GMWBs, much of it is founded on a static fee structure. Our study introduces an innovative fee structure based on the high-water mark (HWM) principle and a regime-switch jump-diffusion model for the pricing of GMWBs, employing numerical solutions through the Monte Carlo method for solving the stochastic differential equation (SDE). Furthermore, a companion piece of research addresses the risk management of GMWBs within the same analytical framework as the pricing component, an aspect that has received limited attention in the existing literature. In assessing the necessary capital reserves for unforeseen losses, our methodology involves the computation of two risk metrics associated with the tail distribution of net liability from the insurer's perspective, Value-at-Risk (VaR) and Conditional-Tail-Expectation (CTE). Comprehensive numerical results and sensitivity analyses are also provided.

Characterization and risk assessment of polycyclic aromatic hydrocarbons from the emission of different power generator

Epileptic power supply in Sub-Saharan countries of Africa has warranted the use of power generators as an alternative source of power supply. Exhaust emission from these generators is associated with Polycyclic Aromatic Hydrocarbon (PAHs). Hence, this study focused on the determination of levels of PAHs in the emission of different brands of power generators used in Nigeria. Exhaust emissions of different power generators were sampled using a filter-sorbent sampling system with polyurethane foam (PUF) as an adsorbent material. Analysis of PAHs was carried out using a Gas Chromatograph coupled to a mass selective detector (GC- MS) operated on Electron Ionization (EI) mode. The results showed the ∑ PAHs range 14.91–26.0 μgm−3. Bap was the most abundant of all the compounds with a concentration of 2.6 μgm−3 with a range of 2.08–3.07 μgm−3. The Incremental Life Cancer Risk (ILCR) values of all the generator's emission sampled are higher than 10− 4 for both children and adult which indicate a high potential cancer risk from inhalation of emission from these generators while Hazard Quotient (HQ) values from all the power generating set in this study are all above 1 which indicated high associated non-carcinogenic. The study revealed the levels of PAHs associated with the emission of power generators in Nigeria.

Innovations in Risk Measurement and Management for Strategic Financing Decisions

This study aims to explore the integration of innovative quantitative models, behavioral finance insights, and advanced analytics techniques in contemporary risk management practices to bolster organizations' resilience and informed decision-making within dynamic financial landscapes. Through a systematic literature review spanning disciplines such as finance, psychology, and technology, this research synthesizes diverse insights to comprehensively understand the evolving nature of risk management strategies. The findings elucidate that incorporating advanced quantitative models like Value at Risk (VaR) and Conditional Value at Risk (CVaR) empowers organizations to meticulously assess and quantify financial risks, thereby enhancing risk management accuracy and granularity. Furthermore, the assimilation of behavioral finance insights illuminates the psychological determinants shaping risk perception and decision-making behaviors, leading to the development of more robust risk management frameworks that accommodate both rational and irrational factors. Moreover, leveraging advanced analytics techniques, notably natural language processing (NLP) algorithms, enables proactive risk management by analyzing textual data and market sentiments with heightened precision. This study underscores the imperative of perpetual innovation and adaptability in risk management practices to adeptly navigate the intricacies of modern financial landscapes. By harnessing emerging technologies, behavioral insights, and interdisciplinary methodologies, organizations can fortify their risk management capabilities, mitigate threats, and seize opportunities in today's globally interconnected economy. Addressing the challenges associated with implementing innovative risk management practices necessitates proactive leadership, resource allocation, and organizational culture transformation. Ultimately, this research contributes to advancing the understanding and application of innovative risk measurement and management approaches, fostering sustainable growth and success for organizations.

Risk Modeling and Connectedness Across Global and Industrial US Fintech Stock Market: Evidence from the COVID‑19 Crisis

The main purpose of this paper is to test the performance of GARCH models in estimating and forecasting VaR (value at risk) of the US Fintech stock market from July 20, 2016, to December 31, 2021. In addition, this study examines the impact of COVID‑19 on the risk spillover between the adequate VaR series of the US global KFTX index and the five Fintech industries. Specifically, we compare different VaR estimates (862 in‑sample daily returns) and predictions (550 out‑of‑sample daily returns) of several GARCH model specifications under a normal and Student‑t distribution with 1% and 5% significance. The Backtesting results indicate that I‑GARCH with Student‑t distribution is a good model for estimating and forecasting VaR of the US Fintech stock market before and during COVID-19. Moreover, the total connectedness results suggest that global and each Fintech industry increases significantly under turbulent market conditions. Given these considerations, this paper provides policymakers and regulators with a better understanding of risk in the Fintech industry without inhibiting innovation.

Study on spatial distribution, regional differences and dynamic evolution of rural financial risk in China.

Based on panel data from 2009 to 2021, covering 30 provinces in China, we have been constructed the Rural Financial Risk Index using the objective entropy weighting method to study rural financial risk in China systematically from the perspective of spatial distribution. Specifically, we discuss the spatial distribution, regional differences and dynamic evolution of rural financial risk across Chinese four different regions divided into the Northeast, East, Central and West. It's found that Local government debt and Land transfer income are the two primary determinants influencing the level of rural financial risk in China. Furthermore, we conclude the ranking value of rural financial risk across four regions that the central exhibits the highest level, followed by the West, the East, and finally the Northeast, where the reasons for such ranking results as follows. Firstly, although the highest level of risk among provinces in the West is equivalent to that in the Central, there exists a smaller minimum rural financial risk in the former compared to the latter. Then, it should be noted that there's a low-low agglomeration of rural financial risk in the Northeast, while it demonstrates a high-high agglomeration in the Central according to the Moran Index test analysis. Again, there's a declining trend in rural financial risk disparity within the region and an upward trend is observed when comparing different regions (except the East vs West), especially increase largely between the Northeast and Central in past two years after analyzing the decomposition of Dagum Gini coefficient. Moreover, we study the absolute differences and dynamic evolution in different four regions through three-dimensional diagram of kernel density estimation, and it's found that the change of rural financial risk in four regions moved to the right as a whole, while the tail distribution remains inconspicuous. The absolute difference is diminishing in the Northeast, and the two-level differentiation characteristics tend to weaken as a whole in the Central, with a disordered wave peak height observed in both the East and West. Finally, the article presents pertinent policy implications but limitations according to the research findings.

Natural Radionuclides Concentrations and Associated Radiation Hazard of Some Building Rocks Used in Taiz City, Yemen

Building materials comprise a diverse range of natural rocks that contain varying mineral components including radionuclides. Gamma spectrometry-based high-purity Germanium detectors were utilized to measure the activity concentrations of natural radionuclides: Radium-226 (226Ra), Thorium-232 (232Th), and Potassium-40 (40K) in various building rock samples found within and surrounding Taiz city. The activity concentrations of 226Ra, 232Th, and 40K vary from 27.79 ± 0.77 to 234.49 ± 3.13 Bq.kg-1, 25.82 ± 0.40 to 415.31 ± 2.47 Bq.kg-1, and 457.91±2.61 to 1139.56 ± 5.43 Bq.kg-1 with overall average value of 71.55 Bq.kg-1, 93.87 Bq.kg-1, 966.88 Bq.kg-1 respectively, these values were higher than the permissible thresholds. Furthermore, several radiation hazard indices were estimated including the radium equivalent (Raeq), the external hazard index (Hex), the internal hazard index (Hin), the gamma level index (Iɤ), the dose rate(Dɤ), the annual effective dose equivalent (AEDE), the excess lifetime cancer risk (ELCR), and the annual gonadal dose equivalent (AGDE). The findings illustrated that Basalt rocks have the minimum values of radiation hazard indices while the Himatite rocks have the maximum values of radiation hazard. The average values of radiation risks for most of building rocks fall below the recommended limits for safety. Based on the Radiation hazard indices of building rock samples, it can be concluded that with the exception of hematite rocks, all the examined rocks are considered safe for use in construction materials and pose non-significant radiation risks. The awareness about natural radioactivity levels of building rocks is critical for planning and performing strategies in radiation safety of buildings.

Potential ecological and human health risk assessments of soil heavy metals in orchards of Antalya province in Türkiye

ABSTRACT Agricultural inputs containing heavy metals are used intensively in Türkiye. However, studies on the assessment of the effects of heavy metals on the environmental and human health risks of agricultural areas in Türkiye are very limited. The aim of this study was to determine the concentrations, sources and potential ecological and human health risks of heavy metals in soils from orchards in Antalya, Türkiye. A total of 127 soil samples were collected and analysed for cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), cobalt (Co), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn). The mean concentrations of total Cd, Pb, Ni, Cr, Co, Fe, Mn, Cu and Zn were found to be 4.54, 64.68, 145.80, 94.00, 23.92, 28264, 763.30, 44.91, and 63.67 mg kg−1, respectively. The mean concentrations of Cd, Co, Ni, Pb, Cu and Mn of soils were higher than the European soil mean values. Enrichment factor (EF) and contamination factor (CF) values of soils indicate serious enrichment for Cd, Pb and Ni. According to the principal component analysis, Cd concentration in the soil from was anthropogenic sources, Ni, Cr and Pb from both anthropogenic and lithogenic origin while other heavy metals from natural sources. Total hazard index (THI) values of heavy metals were <1, suggesting that there were currently absent non-carcinogenic health risks to residents through ingestion, inhalation and dermal contact. Hazard index (HI) indicated that children (3.75) were sensitive 9.4 times more than adults (0.40) to non-carcinogenic risks of heavy metals. The carcinogenic risk values of Cd, Cr, Co and Ni were acceptable range and not expected carcinogenic risks.

A Reliability and Risk Assessment of Solar Photovoltaic Panels Using a Failure Mode and Effects Analysis Approach: A Case Study

Solar photovoltaic (PV) systems are becoming increasingly popular because they offer a sustainable and cost-effective solution for generating electricity. PV panels are the most critical components of PV systems as they convert solar energy into electric energy. Therefore, analyzing their reliability, risk, safety, and degradation is crucial to ensuring continuous electricity generation based on its intended capacity. This paper develops a failure mode and effects analysis (FMEA) methodology to assess the reliability of and risk associated with polycrystalline PV panels. Generalized severity, occurrence, and detection rating criteria are developed that can be used to analyze various solar PV systems as they are or with few modifications. The analysis is based on various data sources, including field failures, literature reviews, testing, and expert evaluations. Generalized severity, occurrence, and detection rating tables are developed and applied to solar panels to estimate the risk priority number (RPN) and the overall risk value. The results show that the encapsulant, junction box, and failures due to external events are the most critical components from both the RPN and risk perspectives. Delamination and soiling are the panels’ most critical FMs, with RPN values of 224 and 140, respectively, contributing 16.2% to the total RPN. Further, moderately critical FMs are also identified which contribute 56.3% to the RPN. The encapsulant is the most critical component, with RPN and risk values of 940 (40.30%) and 145 (23.40%), respectively. This work crucially contributes to sustainable energy practices by enhancing the reliability of solar PV systems, thus reducing potential operational inefficiencies. Additionally, recommendations are provided to enhance system reliability and minimize the likelihood and severity of consequences.

Linking extinction risk to the economic and nutritional value of sharks in small-scale fisheries.

To achieve sustainable shark fisheries, it is key to understand not only the biological drivers and environmental consequences of overfishing, but also the social and economic drivers of fisher behavior. The extinction risk of sharks is highest in coastal tropical waters, where small-scale fisheries are most prevalent. Small-scale fisheries provide a critical source of economic and nutritional security to coastal communities, and these fishers are among the most vulnerable social and economic groups. We used Kenya's and Zanzibar's small-scale shark fisheries, which are illustrative of the many data-poor, small-scale shark fisheries worldwide, as case studies to explore the relationship between extinction risk and the economic and nutritional value of sharks. To achieve this, we combined existing data on shark landings, extinction risk, and nutritional value with sales data at 16 key landing sites and information from interviews with 476 fishers. Shark fisheries were an important source of economic and nutritional security, valued at >US$4 million annually and providing enough nutrition for tens of thousands of people. Economically and nutritionally, catches were dominated by threatened species (72.7% and 64.6-89.7%, respectively). The most economically valuable species were large and slow to reproduce(e.g. mobulid rays, wedgefish, and bull, silky, and mako sharks) and therefore more likely to be threatened with extinction. Given the financial incentive and intensive fishing pressure, small-scale fisheries are undoubtedly major contributors to the decline of threatened coastal shark species. In the absence of effective fisheries management and enforcement, we argue that within small-scale fisheries the conditions exist for an economically incentivized feedback loop in which vulnerable fishers are driven to persistently overfish vulnerable and declining shark species. To protect these species from extinction, this feedback loop must be broken.

Urban air PCDD/Fs: Atmospheric concentrations, temporal changes, gas/particle partitioning, possible sources and cancer risks

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) are pollutants of concern due to their toxic effects. No active sampling study on PCDD/Fs has been conducted in Bursa. This study aimed to fill this gap by measuring PCDD/F levels in the region. Accordingly, the samples were collected from an urban area in Bursa, covering four seasons between June 2022 and April 2023. The total (gas+particulate) ambient air concentrations were between 312.23 and 829.80 fg/m3 (mean: 555.05 ± 173.62 fg/m3). In terms of toxic equivalents (TEQ), the average concentration was 43.29 ± 9.18 fg WHOTEQ/m3. Based on the concentration values obtained, cancer and non-carcinogenic risk values of PCDD/Fs were calculated for three different age groups. The results indicated negligible health risks for all age groups. In addition, a seasonal assessment was also made and it was observed that PCDD/F concentration values varied with the ambient air temperatures. In general, higher values were measured in colder months compared to warmer months. This was probably due to the additional sources and adverse meteorological conditions. Moreover, the gas/particle partitioning of PCDD/Fs was investigated in detail. The average gas and particulate phase concentrations for PCDD/Fs were 101.81 ± 20.77 and 453.24 ± 172.50, respectively. It was found that an equilibrium state was not reached in the gas/particle partitioning. Two different gas/particle partition models based on adsorption and absorption mechanisms were compared, and the absorption model gave more consistent predictions. The Principal Component Analysis (PCA) was employed to identify the possible PCDD/F sources. The results indicated that the region was influenced by vehicle emissions, residential heating, organized industrial zones and metal recycling facilities. In addition, 72-hour backward air mass trajectory analyses were performed to understand the long-range transported air masses. However, it was found that the transported air masses did not significantly affect the concentration values measured in the sampling site.

Effect of fertilization on the accumulation and health risk for heavy metals in native Andean potatoes in the highlands of Perú

Soil infertility is a global problem, amendments such as organic fertilizers and mineral fertilizers are used to improve crop yields. However, these fertilizers contain heavy metals as well as essential mineral elements. The objective of the study was to determine the effect of organic and inorganic fertilizer on the accumulation and health risk of heavy metals in tubers. The plants were cultivated at an altitude of 3970 m using four treatments (poultry manure, alpaca manure, island guano and inorganic fertilizer) and a control group. Soil contamination levels and the degree of metal accumulation in the tubers were also determined. As a result, it was found that the use of inorganic fertilizer and poultry manure increased the values of Cu and Zn in soils, exceeding the recommended standards. The accumulation of heavy metals in potato tubers did not exceed the maximum recommended limits with the exception of Pb, which exceeded the limit allowed by the FAO/WHO (0.1 mg kg−1). Poultry manure contributed to the highest accumulation of Zn, Cu and Pb in tubers with 11.62±1.30, 3.48±0.20 and 0.12 ±0.02 mg kg-1 respectively. The transfer of metals from the soil to the tubers was less than 1. Individual and total non-carcinogenic risk values were less than 1, indicating a safe level of consumption for children and adults. The cancer risk was found to be within an acceptable range. However, poultry manure and inorganic fertilizer treatments had the highest total cancer risk values in both age groups, suggesting a long-term carcinogenic risk.

Forecasting tail risk of skewed financial returns having exponential‐polynomial tails

AbstractAggregated long and short trading risk positions of speculative assets over time are likely to be unequal. This may be because of irrational decisions of traders and investors as well as catastrophic events that lead to pronounce or salient market crashes. Returns of such assets are therefore more likely to have one polynomial tail and one exponential tail. The generalized hyperbolic (GH) skewed Student‐t distribution is known to handle such situations quite well. In this paper, we use generalized autoregressive conditional heteroscedasticity (GARCH) models to empirically show the superiority of the GH skewed Student‐t distribution in forecasting the extreme tail risks of cryptocurrency returns in the presence of substantial skewness in comparison with some competing distributions. Furthermore, we show the practical significance of the GH skewed Student‐t distribution‐based risk forecasts in computing daily capital requirements. Evidence from the study suggests that the GH skewed Student‐t distribution model tends to be superior in forecasting volatility and expected shortfall (ES) but not value‐at‐risk. In addition, the distribution yields higher value‐at‐risk (VaR) exceptions but surprisingly avoids the red zone of the Basel II accord penalty zones and produces lower but optimal daily capital requirements. Therefore, in the presence of substantially skewed returns having exponential‐polynomial tails, we recommend the use of the GH skewed Student‐t distribution for parametric GARCH models in forecasting extreme tail risk.

Is it healthy urban agriculture? Human exposure to potentially toxic elements in urban gardens from Andalusia, Spain.

Different vegetable species and topsoils were collected from different urban gardens of Seville, Cordoba, and Huelva (South Spain) and from two small towns in a mining area (Riotinto), together with topsoil close to the plants. The concentration of potentially toxic elements (PTEs) (As, B, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn) was evaluated in edible plant parts and in the soils. The same species were also purchased from Seville local markets and from a peri-urban area (domestic garden in a rural area) and also analyzed. Plant/soil pollution relation was studied and human health risk was assessed by different parameters. Soils of urban gardens from the mining area were more contaminated with As, Cr, Cu, Pb, and Zn in comparison with other locations, and generally, soils from cities showed higher values of As, Pb, and Zn than the peri-urban ones. The mean concentration of almost all potentially toxic elements was higher in leafy than in fruiting and bulbous species. Arsenic, Cd, and Pb concentrations were below health-based guidance values in all vegetables except Cd in one sample in the peri-urban area. In general, PTEs concentration in vegetables from city urban gardens did not exceed the one found in market vegetables for almost all studied elements, except in lettuce for almost elements. The hazard quotient (HQ) values were lower than the unit for all PTEs in plant species from the studied gardens, as well as the hazard index (HI), indicating that consumption of these vegetables can be considered safe and without risk to human health. Also, cancer risk values for As were below the established limits in all vegetables from the studied urban gardens, including those from the As-contaminated soils in the mining area.

Assessment of radionuclides in the soil of Bonny Local Government Area Of Rivers State, Nigeria and evaluation of radiological risk

Twenty Samples each of soil from Bonny LGA, Rivers State, Nigeria were analyzed using NaI(IT) gamma detector to estimate radiation hazard due to the anthropogenic sources. The activity concentration of 232Th was found to be in the range 18.78 – 397.13 BqKg-1, 40K in the range 43.72 – 390.62 BqKg-1 and 226Ra in the range 10.77 – 57.84 BqKg-1 all in soil. These results were used to calculate the radiological hazard parameters including the Annual Gonadal Equivalent Dose. The calculated gamma exposure rates ranged between 10.00 – 270.79 nGyh-1 while the average value of the Excess Lifetime Cancer Risk (ELCR) was found to be 0.38 x 10-3 for soil which is higher than the world average of 0.29 x 10-3.