HI Values Research Articles

Human health risk ​and receptor model-oriented sources of heavy metal pollution in commonly consume vegetable and fish species of high Ganges river floodplain agro-ecological area, Bangladesh

This study was intended to assess heavy metal contents and sources in commonly consumed vegetables and fish collected from the Jashore district of Bangladesh and to evaluate the probable human health risks via the ingesting of those vegetables and fish species. A total of 130 vegetable and fish samples were analyzed for As, Mn, Cu, Cr, Ni, and Pb concentration by an atomic absorption spectrophotometer. Metals and metalloids like As, Pb, and Cr in vegetable species were greater than the maximum allowable concentration (MAC), while Pb and cu in fish species exceeded the MAC. Pollution evaluation index values were ranges from 0.40-10.35 and 1.53–2.78 for vegetable and fish species, respectively, indicating light to serious pollution. Lactuca sativa followed by Cucurbita moschata, Amaranthus gangeticus for vegetables and Channa punctate, Oreochromis mossambicus, followed by Dendrobranchiata for fish are the most contaminated food items. The positive matrix factorization model showed that As (81.9%), Ni (48%), Cr (49.6%), Mn (46%), Pb (44.3%), and Cu (44.4%) for vegetable species and As (86.9%), Ni (90.5%), Mn (67.6%), Pb (65.3%), Cr (57%) and Cu (46.2%) for fish species were resulting from agrochemical, atmospheric emission, irrigation, contaminated feed, and mixed sources. The self-organizing map and principle component analysis indicates three spatial patterns e.g., As–Mn–Cu, Pb–Cr, and Ni in vegetables and As–Mn–Cr, Cu–Ni, and Pb in fish samples. The THQ values for single elements were less than 1 (except As for vegetables and Pb for fish species) for all food items but the HI values for all of the vegetables (2.18E+00 to 2.04E+01) and fish (1.07E+00 to 9.39E+00) samples were exceeded the USEPA acceptable risk level (HI > 1E+00). While the cancer risks only induced by As for all vegetables and fish species, which exceeded the USEPA safe level (TCR>1E-04). Sensitivity analysis indicates that metal concentration was the most responsible factor for carcinogenic risk.

Hydrocarbon Potential of Middle Jurassic Sediments (Stefanets Mb. of Etropole Fm.) from the Western Part of Balkan Orogenic System, Bulgaria

Sediments of Stefanets Mb. (Etropole Fm.), consisting mainly of shale and siltstones, are investigated by Rock-Eval pyrolysis. The samples from the Middle Jurassic section (Bajocian in age), outcropping within the western part of the Balkan orogenic system in Bulgaria, were analyzed to study their hydrocarbon generative potential. The obtained TOC contents are in the range of 0.69–1.97 wt.%. Inorganic carbon (TIC) and total sulphur (TS) contents are low and coincide with previously published data. The values of S1 and S2 are between 0.01 and 0.10 (mg HC/g rock) because of the high thermal maturity level, as indicated by Tmax values of 566-610 °C. The rocks are in the postmature stage and consequently the HI values are very low (< 10 mg HC/g TOC). The fair to good quantity, low quality, as well as the high level of thermal maturity of the organic matter, assume minor remaining gas-prone generation potential of Stefanets Mb.

Risk assessment of metal(loid)s in tea from seven producing provinces in China

To evaluate metal(loid) contamination in tea leaves and assess health risks of tea drinking in China, metal(loid) concentrations in tea leaves from major tea-producing provinces were determined. Nine metal(loid)s (Al, Cr, Co, Ni, Cu, Zn, As, Cd and Pb) were measured in a total of 217 tea samples representing five tea varieties (black tea, dark tea, green tea, oolong tea and white tea) from seven major tea-producing provinces of China (Fujian, Guangdong, Henan, Hunan, Jiangsu, Yunnan and Zhejiang). The results indicated that tea samples from Hunan Province had the highest metal(loid) concentrations, likely due its high prevalence of heavy industrial activities and soil pollution. The concentrations of As and Pb in dark tea were markedly higher than those in other tea varieties. A strong Spearman correlation coefficient (0.78, P < 0.001) of As and Pb in all the tea varieties has also been found, indicating their similar sources. Human health risk assessment for the nine analyzed metal(loid)s indicated that co-exposure to these metal(loids) may not cause significant health risks (hazard index [HI] > 1 suggests considerable health risks). Among the five tea varieties, metal(loids)s in dark and green tea induced relatively higher health risks, with 90th percentile HI values approached 0.8. Co (53.6 %–84.5 %) and Al (3.33 %–15.8 %) made the highest contributions to the HI of the selected tea commodities. Thus, public and regulatory agencies should reduce excessive Co and Al accumulation in these tea varieties during cultivation and production processes.

Heavy Metal Pollution and Source Contributions in Agricultural Soils Developed from Karst Landform in the Southwestern Region of China.

Heavy metal pollution of soil in agricultural areas is the most prominent environmental pollution problem in China, seriously affecting human health and food security. It has become one of the environmental problems to which all sectors of society attach great importance. Soil heavy metals in the weathering area of hazardous geological bodies in southwest China have naturally high background attributes. Therefore, ecological risk assessment and analysis of potential sources of soil heavy metals in southwest China is of great significance for soil health management, soil heavy metal pollution control and territorial spatial planning. In this study, we collected 787 soil samples (0–20 cm) in Xuanwei County in China and analyzed the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in soils. Igeo, RI, HI and CR were used to calculate the pollution levels, ecological risks and human health risks. Additionally, the PMF model and one-way ANOVA were used to identify the potential sources and discuss the factors affecting the enrichment of heavy metals. The results showed that the mean contents of the surface soils were 1.190 (Cd), 139.4 (Cr), 96.74 (Cu), 0.081 (Hg), 56.97 (Ni), 46.66 (Pb) and 130.1 (Zn) mg/kg. All heavy metals exceeded the background values of the A layer soil in Yunnan Province. The Igeo showed that Cd was the most hazardous element in the study area, followed by Cu, Cr, As, Ni and Pb. The RI showed that low ecological risks, moderate ecological risks, considerable ecological risks and strong ecological risks accounted for 3.81%, 55.27%, 37.74% and 3.18%, respectively, of the total samples, and Cd was the main dominant element. The HI values of the As element in children were greater than 1, indicating a non-carcinogenic risk, and other elements’ risks were acceptable. The CR values of Cr and Ni were higher than their limits (1 × 10−4), and both had carcinogenic risks in children and adults, as did As in children. According to the PMF model, four heavy metals sources were identified: geological sources (32%), sources from mining activities (19.38%), atmospheric deposition sources (17.57%) and agricultural sources (31.05%). Thereinto, As and Pb were mainly derived from agricultural sources, Cd and Cr were mainly associated with geological sources, Cu was largely from mining activity sources, Hg was mainly from atmospheric deposition sources and Ni and Zn were mainly from geological sources, mining activities and agricultural activities. The parent material has a significant influence on the enrichment of heavy metals in the soil, and the heavy metals are significantly enriched in the carbonate parent material and quaternary parent material. Topography also plays a role in heavy metal accumulation; Cd, Cr, Cu, Ni and Zn gradually decreased with the increase in altitude, and As and Pb increased with the increase in altitude. Mn-oxide played a crucial part in the enrichment of Cu and Zn, while SOC, K2O and pH had little influence on the accumulation of heavy metals.

Patterns of long-term variations of nitrate concentration – Stream discharge relationships for a drained agricultural watershed in Mid-western USA

Nitrate Concentration–discharge (C-Q) relationshipshave been used to infer nitrate sources, storage, reactions, and transport in watersheds, and to reveal key processes that control runoff chemistry. Yet, studies on long-term nitrate C-Q relationships are limited due to scarce high frequency (e.g., daily) concentration data. In this paper, using a long-term high-frequency dataset (1976–2019) comprising stream flow and nitrate concentrations, we quantitatively analyzed the long-term variations of event-scale hysteresis patterns (quantified by hysteresis index, HI, and flushing index, FI) to infer the leaching mechanisms of nitrate in an artificially drained agricultural watershed in Mid-western U.S. Our results revealed that most events exhibited anti-clockwise behaviors (HI < 0), regardless of whether nitrate was flushed or diluted during events. This means that water with high levels of nitrate-N reaches the stream network slower than water with lower nitrate concentrations. Long-term mean FI was close to zero but had strong seasonal patterns with dilution patterns observed during Winter and Summer, and flushing patterns during late Spring and Fall. The consistently negative HI values regardless of the FI value gave a strong indication of the preponderant role of the near-drain zone that usually exhibits accelerated leaching and less accumulation of nitrate in the soil profile in these drained agricultural watersheds. Both HI and FI depicted strong but opposite seasonality because of weather patterns and agricultural activities, particularly N fertilization. Overall, our findings suggest a little evidence of the role of deep groundwater and instead a strong evidence of the role of subsurface drainage as the primary pathway for nitrate transport in drained agricultural watersheds. Therefore, artificial drainage could dampen N legacy caused by the historically intensive N fertilization in drained agricultural landscapes.

Geochemical investigation and basin modelling of the Al renk shale formation in the Melut Basin, south Sudan: Implications for estimation of thermogenic gas generation potential

This study uses organic geochemical and basin modelling results to examine the potential for thermogenic gas generation from oil-to-gas conversion of the organic-rich Lower Cretaceous Al Renk shales in the Melut Basin, South Sudan. The overall geochemical results show that the Al Renk shales are considered good gas-source rocks with total organic carbon (TOC) content >1 wt % and a low hydrogen index (i.e., HI < 150 mg HC/g TOC; mainly Type III kerogen). This finding contrasts with the source of organic matter and biomarkers related to the depositional environment. Based on biomarker indicators, the Al Renk shales contains a mixture of aquatic organic matter with some terrigenous land plants and was deposited under suboxic to relatively oxic settings in a lacustrine environment. The presence of mixed aquatic and terrigenous organic matter in lacustrine shale sediments suggests a mix of Types II and III kerogen as the original organic matter input during deposition. The geochemical and optical maturity indicators represent late-mature oil to gas generation windows, implying that the Al Renk shale has substantial thermogenic gas generation potential. Therefore, high thermal maturation is a crucial factor in drastically altering the original organic matter (OM) and decreasing HI values (conversion of kerogen to hydrocarbons). The kerogen to oil conversion and the subsequent cracking of the retained oil into thermogenic gas have been simulated by the burial/thermal/generation models in the Agordeed-1 well. These models show that nearly 10–50% of kerogen was transformed into oil during the Late Cretaceous (78–68 Ma), correlating with the early to peak mature of oil generation window (0.62–0.85 %Ro). Moreover, oil was expelled from the Al Renk source rock system during the Late Cretaceous to Late Eocene. From the Late Eocene until the present, significant amounts of residual oil were cracked into gas due to the maturation of the gas generation window (>1.30 Easy % Ro), which is ideal for wet gas generation. Consequently, the findings of this study advocate for conventional gas exploration in the Melut Basin's deeper stratigraphic succession, where the Al Renk Shale Formation has reached a high maturity level of the gas generation window.

Pollution Evaluation and Health Risk Assessment of Trace Metals in Eleven Tissues of Mylopharyngodon piceus Collected from an Aquaculture Pond in Huzhou, near Southern Taihu Lake

Pollution evaluation and health risk assessment are critical procedures for residents consuming black carp (Mylopharyngodon piceus) contaminated with non-essential hazardous trace elements in an artificial wetland also known as an aquaculture pond. Samples were collected, dissected and digested to analyze the pollution status and health risk associated with four heavy metals present in eleven tissues of black carp fish based on the metal pollution index (MPI) and target hazard quotient (THQ). The results indicated that the concentrations of Cd, Cr, Cu and Pb were 1.36 ± 0.04 mg/kg, 13.70 ± 0.50 mg/kg, 2.85 ± 0.10 mg/kg, and 4.98 ± 0.18 mg/kg in large black carp, while the concentrations of Cd, Cr, Cu and Pb were 4.27 ± 0.08 mg/kg, 50.84 ± 0.82 mg/kg, 9.33 ± 0.18 mg/kg, and 22.49 ± 0.42 mg/kg in small specimens. The MPI values showed that the heavy metal pollution detected in small fish was much more significant than in large fish. Notably, the polluted metals were more likely to accumulate in the viscera (e.g., brain and heart) rather than in the external tissues (e.g., muscle and epidermis). In addition, the estimated THQ and HI values for three edible tissues demonstrated that the health risk associated with muscle tissue intake of both small and large black carp was within the acceptable range, while the contaminants were likely to pose health risks associated with the consumption of fish head tissue. Small black carp are generally not fit for human consumption, thus both the epidermis and muscle of the fish are often cooked in China. However, the ingestion of large black carp is relatively safe. The contributions to THQ values of these four heavy metals decreased in the following sequence: Cr &gt; Pb &gt; Cd &gt; Cu. Cr is the critical pollutant with its contribution to HI values measuring over 50%. We suggest that in artificial wetlands (e.g., aquaculture ponds) more attention should be paid to heavy metal pollution, the conservation of the aquaculture ecosystem, and effects on human health.

Organic geochemistry of Cambro-Ordovician succession of Ny Friesland, Svalbard, High Arctic Norway: Petroleum generation potential and bulk geochemical properties

Lower Paleozoic source rock (SR) characteristics and paleo-depositional environments are not well understood in the Barents Sea region. Organic and inorganic geochemical analyses of 17 carbonaceous samples from the Lower Cambrian Tokammane Formation, the Lower to Middle Ordovician Kirtonryggen and Valhallfonna formations in Ny Friesland, north-east Spitsbergen, show that there is a striking difference in petroleum generation potential and bulk geochemical properties between the Cambrian and Ordovician samples, and also within the Ordovician samples. TOC contents of <0.20 wt% for the Lower Cambrian Tokammane Formation samples indicate poor source rock richness. TOC contents in the range between 0.3 and 2.1 wt% and HI values between 123 and 424 mg HC/g TOC for the Valhallfonna and Kirtonryggen formation samples suggest significant variation in remaining petroleum generation potential with oil-prone (Type II) to mixed oil- and gas-prone (Type II/III) kerogen. Source rock maturity parameters such as Tmax (range 435–449 °C) and production indices for most Ordovician samples suggest relatively uniform maturity levels, ranging from the early-, to the peak-, of the oil generation window (i.e. ca. 0.70–0.85% Ro). This maturity level could have significant implication on the original petroleum potential assuming early generation from carbonate source rocks. Bulk carbon isotope data show that the Lower Cambrian Tokammane Formation samples are heavier (δ13C range from −28.4 to −28.8‰) than the Lower to Middle Ordovician Valhallfonna Formation samples (δ13C range from −29.7 to −30.9‰). The differences in the source rock richness and kerogen type within the Ordovician samples are attributed to organic facies variation. Tentatively, three categories of source rock organic facies (B, BC and C) are supported based on assumed-initial hydrogen index values for the Ordovician samples. The reliability of the indicated organic facies could be supported by addition of biomarker data from bitumen extracts. To our knowledge, this is the first study revealing the existence of a potential Lower Paleozoic source rocks in this part of the High Arctic, and this facies may also exist on the continental shelf to the north and NE.

Study on health risk assessment of potentially toxic elements in the soil around landfill site in Shannan City, Tibet

ABSTRACT This paper takes the soil around the Luqionggang landfill in Shannan city of Tibet Autonomous Region as the research object and studies the soil around the Luqionggang landfill by setting points and sampling. Then ICP-MS and AFS were used to analyze the contents of potentially toxic elements (PTEs) (Cu, Pb, Zn, Cr, Ni, Cd, As, Hg) in soil, and the health risk index method was used for risk assessment. The results showed that the primary exposure route of non-carcinogenic risk in the population was the oral route. And adults’ HI value is 0.1692, which is less than children’s HI value of 1.192, indicating that children are more affected than adults. Attention should be paid to the impact of PTEs As, Pb, and Cr in non-carcinogenic risk distribution. In the whole life cycle, the carcinogenic risk of the oral route is higher than that of the respiratory and skin contact routes.

Hydrochemical evaluation of groundwater for drinking and irrigation purposes using multivariate indices along Indus Suture Zone, North Pakistan.

The present study is aimed to investigate the hydrochemical characteristics, spatial distribution and suitability of groundwater for drinking and irrigation purposes along the Indus Suture Zone (ISZ), north Pakistan. Physicochemical parameters and hazardous trace elements (HTEs) like Cd, Co, Cu and Mn were determined following standard methods. The mean and median concentrations were found below the World Health Organization (WHO) drinking water guidelines values. Hydrochemical results indicate that groundwater sources were mainly attributed to rock-water interaction category. Piper diagram shows that most of the groundwater samples fall in Ca-HCO3─ class presenting weak-alkaline proportion type. The drinking water quality index (DWQI) ranking was categorized as good to excellent, indicating the overall quality of the groundwater may pose no health hazard concern. Based on irrigation WQI (SAR, Na%, MAR, KR), the groundwater was found fit for irrigation except SAR whereas 36% of the groundwater samples fall within the poor class. The total HI values through dermal contact exceeded the safe non-carcinogenic threshold of HI = 1. Therefore, there is required an effective groundwater monitoring and management facility in the study area to safeguard residents from various illnesses associated with varying HTEs concentrations in drinking water. The major response actions needed for groundwater bodies restoration are including the installation of a continuous groundwater monitoring network and control of agricultural fertilizers that seems to be the most effective and tangible for immediate action.

Impact of deforestation and temporal land-use change on soil organic carbon storage, quality, and lability.

Soil organic carbon (SOC) plays a key role in regulating soil quality functions and ecosystem services. The objective of our study was to evaluate the impact of deforestation and subsequent land-use change on the SOC and total nitrogen (TN) concentration, quality, and lability under otherwise similar soil and environmental conditions. Geo-referenced composite soils (0 to 30 cm depth at 7.5 cm interval) sampled from agriculture, bioenergy plantations (Miscanthus x giganteus), Conservation Reserve Program (CRP), and wetland were analyzed for SOC, TN, active C (AC), humic- and fulvic acid (HA and FA), non-humic C (NH), E4: E6 ratio, humification indices (HI, HR, and DH), and carbon and nitrogen management indices (CPI, NPI, and CMI), compared to soils under protected forest as a control. Results showed that the CRP had the highest depth distribution and profile-wise stocks of SOC, TN, AC, and FA with respect to the lowest in agriculture upon conversion of forest. Moreover, the SOC and TN contents were significantly stratified in the CRP when compared to agriculture. While agriculture had the wider HA: FA ratios with highest HI and HR but lowest DH values, the CRP, in contrast, had the narrow HA: FA ratios with lowest HI but highest DH values, when compared to the forest. Spectral analyses have shown lower E4: E6 ratios under the forest when compared to both agriculture and the CRP; however, the later had significantly higher E4: E6 ratios than that of agriculture. The CPI, as measures of SOC accumulation or depletion, significantly decreased by 16% under agriculture but increased by 12% under the CRP. While the CMI, as measures of SOC accumulation or depletion and lability, with higher values under the CRP suggested a proportionally more labile SOC accumulation, in contrast, the smaller values under agriculture indicated a greater depletion of labile SOC over time. Moreover, the CRP may have favored a more labile SOC accumulation with higher proportions of aliphatic C compounds, whereas agriculture may have a SOC with high proportions of non-labile aromatic C compounds. Principal components analysis clearly separated and/or discriminated the land-use impacts on soil carbon pools and TN. Likewise, redundancy analysis of the relationship between measured soil parameters and land-use validated that the TOC, TN, FA, humin, and CPI were significantly impacted due to synergism among soil properties as positively influenced by the CRP upon conversion of agriculture.

Prediction of Hazardous Effect of Heavy Metals of Point-Source Wastewater on Fish (Anabas cobojius) and Human Health.

Aquatic ecosystems are exceedingly contrived due to industrial dispenses, as a huge amount of toxicants especially heavy metals are released, causing drastic effects on aquatic lives and the human body. This study was performed to assess the quality of point-source industrial wastewater at varying percentage levels and their subsequent hazardous effect on fish (Anabas cobojius) and human health. The perceived value revealed that water quality parameters declined with the increase of wastewater concentration and trace metal evaluation index (TEI) ascertained a high level of water pollution due to Cr, Mn, Fe, Co, Ni, Cu, Zn, and As content for all percentages of wastewater. Concentration of wastewater and culture treatment duration largely impacted on fish mortality rate, body dis-pigmentation, mucus secretion rate, coagulation of mucus all over the body, and accumulation of heavy metals by fish samples. Metal pollution index (MPI) indicated low contamination of fish by the measured elements. Zn and Hg exceeded the threshold limit of target hazard quotient (THQ > 1) and contributed significantly to non-carcinogenic health implications for both the population group. Maximum hazard index in adults and children was observed to be 10.638 and 16.548 for 100% effluent at 96-h exposure period and the overall HI value manifested a very high to medium significant health effects regardless of age. Carcinogen Pb showed insignificant risk but Cr and Ni showed extremely high to medium-high risk for both the population group, and children were found more vulnerable receptors than adults. However, source of heavy metals in wastewater and fish samples stipulated anthropogenic sources.

Potentially toxic element contamination and health risk assessment in bottled mineral waters consumed in Turkey

ABSTRACT This study aimed to evaluate the human health risk posed by potentially toxic elements (PTEs) in 59 bottled mineral water (BMW) samples of 25 different brands marketed in Turkey. The concentrations of Ag, Al, As, Cd, Cr, Co, Cu, Fe, Mn, Ni, and Pb in the BMW samples were analyzed using an ICP-OES and compared with maximum allowable concentrations (MACs). A higher concentration of As than MAC was detected in five BMW samples. The concentrations of Cd, Pb, Cr, Ni, and Al in the majority of BMW samples are higher than the MACs. The human health risk was evaluated for adults estimating non-carcinogenic risk index (HI), incremental lifetime cancer risk (ILCR) and total cancer risk (TCR). All HI values estimated for PTEs in BMW samples are less than one, except for one sample. ILCR values for Cd in approximately half of the BMW samples are above the upper limit.

Evaluation of organic matter in sakesar and patala formations in Southern and Northern potwar basin, Pakistan

The investigation of organic matter contents present in Eocene-Paleocene formations of Southern and Northern Potwar Basin, part of Upper Indus Basin Pakistan was conducted using geochemical and petrological techniques. The organic carbon content of Sakesar and Patala formations were evaluated using thirty well cutting samples from two wells, and results of both wells were compared for the first time. Patala Formation is known to be one of Potwar Basin's major petroleum bearing source rocks. Both Sakesar and Patala formations samples lie in early maturity (oil window) and peak of oil generation window for hydrocarbon generation, indicated by both vitrinite reflectance VR (%Ro) and Tmax data. Sakesar and Patala formations source rock properties shows good to very good generative potential. Sakesar Formation samples showed good TOC contents, ranging from 1.36-2.3 wt%, with 1.88 wt. % mean TOC and had HI values up to 375 mg HC/g TOC, however, Patala Formation also had good to very good TOC contents ranging from 2.65-4.2 wt% in well A and 3.1-3.9 in well B, with HI values ranging between 2.4-369 mg HC/g TOC. The samples have primarily mixed Type II/III kerogen and Type III kerogen. Results show that both formations have potential to produce hydrocarbons.

Analysis and Risk Assessment of Insulin-Potentiating Elements in Addua (Balanites Aegyptiaca) Leaf, Seed and Bark.

Purpose: This study investigated certain trace elements having therapeutic properties related to diabetes mellitus and to look into the health risk assessment of the elements. The investigated samples were the bark, leaf and seed of Balanites aegyptiaca, desert date (Addua). These plants are traditionally used in the management of diabetes in Eritrea, Egypt, and Ethiopia.&#x0D; Methodology: The elemental analysis was conducted using Flame Emission Photometer and Atomic Absorption Spectroscopy (AAS) techniques. The accuracy of the methods was verified using in-house reference materials (CRMs) and no significant differences were observed between the measured and certified values.&#x0D; Findings: The analysis displayed variable concentrations of the different trace elements found to be in the permissible limit defined by WHO. The metals are in the order of decreasing concentrations in the bark sample K &gt; Ca &gt; Mg &gt; Co &gt; Fe &gt; Cu &gt; Zn &gt; Mn. In the leaf, the ranking order is K &gt; Ca &gt; Mg &gt; Fe &gt; Zn &gt; Mn. The seed sample appeared in the order K &gt; Ca &gt; Mg &gt; Fe &gt; Zn &gt; Mn. The THQ for the non-carcinogenic risk were all &lt; 1 for all metals and the various exposure pathways. The trend is same for HI for both children and adults. This is a pointer to the fact that no immediate danger due to presence of potential carcinogens. Furthermore, the study revealed the order of pathway in the following decreasing order HIingestion &gt; HIdermal &gt; HIinhalation and most of all, the HI values for adults generally higher than that of the children. However, this suggests that adults are at greater risks of and could be more susceptible to potential carcinogenic risk from continual exposure.&#x0D; Recommendation: The findings calls for concern on the regular use of some of the infusion from this plant.

Comparisons of diatoms and fishes as toxic metal bioindicator: a case study of an A-class wetland in northwest Turkey under effect of an intensive paddy cultivation stress.

In this research, diatoms as the first step and fishes as the last step of the food chain were compared as toxic metal accumulation bioindicator in an A-class wetland in Turkey. Bioaccumulations of potentially toxic elements (PTEs) were determined in liver, gill and muscle tissues of two commercially consumed fish species Carassius gibelio and Cyprinus carpio and in frustules of epiphytic diatom communities living on submerged macrophytes. Samples were collected seasonally from the Gala Lake, which is among the best stopover habitats of birds migrating between Europe and Africa, considering the paddy harvest period that is a major stress factor for the ecosystem. Also, potential human health risks associated with the consumption of fishes and consumption - dermal contact of diatoms were evaluated both for summer - before paddy harvest (BPH) and autumn - after paddy harvest (APH) periods. As a result of this research, the investigated toxic metal concentrations were increased significantly in diatoms in the APH period, while less significant exchanges were recorded in fishes. The bioaccumulations of PTEs were ranked as follows: Zn > Mn > Se > Cu > B > Cr > Ni > As > Pb > Cd for C. gibelio; Zn > Mn > Se > Cu > B > Cr > As > Ni > Pb > Cd for C. carpio; and Mn > Zn > Se > Pb > B > Ni > Cr > Cu > As > Cd for diatom frustules. Although the HI values in diatoms detected in the APH period were statistically significantly higher (about 1000 times; p < 0.05) than detected in the BPH period, they were less than the limit of 1 in both seasons. However, the HI coefficients of fishes were quite higher than the limit (an average of 23.59 for C. gibelio and 19.18 for C. carpio), which means quite high probable non-carcinogenic health risks for humans. Furthermore, the CR coefficients of Cr, Ni and As in muscle tissues of fishes were considerably higher than the limit of 10-4, which reflects a significant carcinogenic health risk for consumers. The data showed that although the fishes at the top of the food chain bioaccumulate the PTEs in their tissues much higher than the diatoms at the bottom of the food chain, the diatoms are much more sensitive to changes in the environmental conditions than the fishes and they are more effective biological tools as toxic metal accumulation bioindicators.

Fluoride and nitrate contaminations of groundwater and potential health risks assessment in the Khyber district, North-Western Pakistan

ABSTRACT The current study was conducted to assess the concentration of nitrate (NO3) and fluoride (F), and associated health risks in the four tehsils of district Khyber i.e. Jamrud, Bara, Landi Kotal, and Mula Gori. A total of 61 samples from various groundwater sources were collected and analysed. Groundwater results showed that the mean values of F were 0.86, 0.83, 0.67, and 2.9 mg/l, and that of NO3 15.8, 8.38, 9.76, 4.22 mg/l in Bara, Jamrud, Landi Kotal, and Mula Gori, respectively. Furthermore, health risk assessment was carried out for different age groups i.e. adult male/female (66 years), teens male/female (16 years), and children (6 years). The results revealed that HI values of F through groundwater consuption was > 1 in 39.3% and 16.4% of the samples for children and other age groups (teen and adults), respectively. Similarly, HI values of NO3 for children, adults, and teens were higher than the threshold value in 62.3%, 34.4%, and 39.3% of the samples, respectively. The principal component analysis (PCA)revealed that the predominant source of F enrichment in groundwater was geogenic. However, for the NO3 proportion in the region, the potential causes were agricultural activities. Results revealed that the region requires immediate attention, and remedial measures must be implemented to protect residents from the adverse effects of NO3 and F in the district of Khyber.

Exposure to phthalate esters in Japanese females in Kyoto, Japan from 1993 to 2016: Temporal trends and associated health risks.

Phthalates are used as plasticizers in many products used in daily life worldwide. Due to industrial and economic developments, exposure among general population to phthalates may vary geographically and temporally. However, studies are lacking for investigating temporal changes in phthalate exposure in the Japanese population. In the present study, the temporal trends in exposure to various phthalates were assessed among a group of Japanese adult female population over 1993-2016 and derived associated risks. For this purpose, urine samples of healthy Japanese females in Kyoto, Japan (N=132) collected in 1993, 2000, 2003, 2009, 2011, and 2016, were employed and measured for the concentrations of 18 phthalate metabolites. Over this period, the detection rates of mono(3-carboxypropyl) phthalate (MCPP) and monoisobutyl phthalate (MiBP) decreased, and the geometric means of the urinary concentrations of mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) showed a significant decreasing trend. Cumulative risk due to exposure to dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), butyl benzyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) showed a dramatic decrease only between 1993 and 2000. The maximum hazard quotient (HQM) was attributed to DEHP in most subjects regardless of sampling year. This study showed the temporal trend of the exposure of Japanese females to several phthalate esters over two decades. As of the late 2010's, DEHP was still the predominant component of phthalate ester exposure in the population. The HI value, however, indicates that direct risk due to phthalate exposure was unlikely among the studied population.

Heavy metals and metalloids in edible seaweeds of Saint Martin's Island, Bay of Bengal, and their potential health risks

The present study aimed to assess the levels of heavy metals and metalloids present in six seaweeds and their potential impact on consumption. The highest concentration of 11 metals, i.e., Be (0.47 mg/kg), Co (4.34 mg/kg), Cr (23.46 mg/kg), Cu (11.96 mg/kg), Fe (2290.26 mg/kg), Li (11.55 mg/kg), Ni (13.75 mg/kg), Pb (6.67 mg/kg), Ti (736.62 mg/kg), Tl (0.14 mg/kg), and V (33.09 mg/kg) were observed in Enteromorpha intestinalis (green seaweeds). Besides, the highest concentration of Ca (1071.09 mg/kg), Cd (5.81 mg/kg), Mn (1003.41 mg/kg), Sr (2838.86 mg/kg), and Zn (41.95 mg/kg) were found in Padina tetrastromatica (brown seaweeds). Eight metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) have been used to assess the potential health risk for adults, but no potential health risk was detected (HQ value > 1). The HI value of E. intestinalis and P. tetrastromatica were >1, implying that these two seaweeds are not safe for human consumption as there is a carcinogenic health risk for adults.

Handheld two-stroke engines as an important source of personal VOC exposure for olive farm workers.

Personal exposure to volatile organic compounds (VOCs) is mainly associated with indoor exposures; however, elevated short-term exposures may also occur during ambient activities. Handheld two-stroke gasoline-powered engines have widespread use in agriculture, but so far, no studies have been conducted on the potential health risks due to the inhalation of emitted VOCs. A one-week passive sampling has been conducted on olive farm workers during the harvesting season to monitor personal exposure levels to VOCs. The first group of workers was selected to represent the contribution of gasoline-powered shaker to daily personal VOC exposures, and one another group of workers was selected as the control, whose have not been using the device. Higher concentrations of 1-pentene, n-hexane, isopentane, n-pentene, and toluene were observed in personal samples collected from machine operators. Personal exposure concentrations of a total of 45 monitored VOCs varied between 29.2 ± 10.7 and 3733.4 ± 3300.1µgm-3 among 20 volunteer workers. Estimated carcinogenic risks were between the acceptable levels of 10-4 and 10-6 for all workers. All individual chronic HQs and HIs (as the sum of individual HQs) were below the benchmark value of 1 for regular workers in 3 different sampling sites, whereas HI values in both acute (short term) and chronic exposure scenarios were exceeded 1 for shaker machine operators. This represented potential non-carcinogenic health hazards for exposed shaker operators, along with elevated VOCs.