The concentration and probabilistic health risk assessment of nitrate in Iranian drinking water: a case study of Ilam city

LED-light-driven over ZnO/biochar nanocomposite for activation of peroxymonosulfate to enhanced photocatalytic removal of methyl orange dye in aqueous solutions

ABSTRACTOrganic dyes are stable and persistent toxic compounds in the aquatic environment that are refractory to decompose by removal methods such as physico-chemical, optical and biological. Their presence in the aquatic media threatens human and wildlife. Herein, ZnO nanoparticles (NPs) due to good chemical durability, low cost and good photocatalytic performance was anchored on biochar (ZnO@biochar) nanocomposites were synthesized towards activation of peroxymonosulfate (PMS) for the photocatalytic removal of methyl orange (MO) dye. Several methods were used to characterization of the nanocomposites including FESEM, XRD, PL, EDS, FT-IR spectroscopy, and N2 adsorption/desorption. The results of the techniques demonstrated that the well-dispersed ZnO NPs were loaded onto the biochar surface. According to the particle size distribution graph, the average particle size of 64 nm was obtained for the ZnO NPs. BET analyzes showed that pore volume, the specific surface area (SSA) and average pore size of the synthesized nanocomposite increased. The survey of effective operational parameters indicated that the highest photocatalytic activity for MO removal was in the pH 3 of solution, 5 ppm initial dye concentration, 30 mg ZnO/biochar nanocomposite, and 20 mg PMS dose under LED-50W lamp irradiation (97.03% in the reaction time of 80 min). During the process, the reduction of the total organic carbon (TOC) contents and chemical oxygen demand (COD) were observed. Moreover, the MO degradation kinetics under optimal operating conditions were determined. It is concluded that the ZnO@biochar nanocomposite/PMS process was an efficient degradation method for the decomposition of the dye pollutant.

Concentration of potential toxic elements in canned tuna fish: systematic review and health risk assessment

The health risks (non-carcinogenic and carcinogenic risk) were calculated in both adults and children, using target hazard quotient (THQ) and carcinogenic risk (CR). The concentrations of Cd, Pb, and Ni were higher than the standard limits but they did not pose any non-carcinogenic health risks in adult and children's consumers (THQ <1). Meanwhile, the risk assessment of iAs indicates THQ > 1 for children in Egypt. Moreover, the THQ value due to Me Hg for adult in Tunisia and for children in Tunisia, Malta, Portugal, Latvia, Cambogia, Peru, South Korea, Romania, Hong Kong, United Arab Emirates, Morocco, and Egypt was higher than 1 value. In addition, the calculated CR values of iAs for the adults and children were within the threshold risk of developing cancer (Between 1.00E-4 to 1.00E-6). Therefore, it is recommended to continuously monitor the concentration of PTEs in canned tuna.

Emerging nitrate contamination in groundwater: Changing phase in a fast-growing state of India

The consumption of nitrate-contaminated groundwater is often associated with potential health risks, particularly in children. This study aimed to assess the hydrochemistry and nitrate contamination in groundwater of Kerala state, India for the years 2010 and 2018 and evaluate the potential human health risks due to nitrate exposure in adults, and children through oral ingestion and dermal contact pathways. Nitrate-contaminated zones were identified by spatial mapping of nitrate concentration based on groundwater quality data of 324 wells. Groundwater is typically acidic to slightly alkaline, and the electrical conductivity (EC) varied from 33 to 1180 μS/cm in 2010 and 34.6-2500 mg/L in 2018 indicating a noticeable increase over the years. Most samples fall within low salt enrichment category. The nitrate concentration in groundwater varied from 0 to 173 mg/L with a mean of 15.4 mg/L during 2010 and 0 to 244 with a mean of 20.3 mg/L during 2018. Though nitrate concentrations show uneven spatial distributions due to both natural and anthropogenic sources, the spatial clustering of higher concentrations remains almost same in both periods. In 2010, non-carcinogenic risk, as measured by Health Index Total (HITotal) values in groundwater for the investigated region, ranged from 0.005 to 4.170 (mean of 0.349) for males, 0.005 to 4.928 (mean of 0.413) for females, and 0.008 to 7.243 (mean of 0.607) for children, while in 2018, the corresponding values varied from 0.001 to 5.881 (mean of 0.501) for males, 0.002 to 6.950 (mean of 0.592) for females, and 0.003 to 10.215 (mean of 0.870) for children, indicating a substantial increase in risk, for females and children. Greater health risk is observed in children during both the periods. The findings emphasize the need for proper water quality management, especially in regions with higher vulnerability to nitrate pollution, to safeguard human health and well-being.

Assessing water quality index and health risk using deterministic and probabilistic approaches in Darab County, Iran; A machine learning for fluoride prediction

The present study employed deterministic and probabilistic approaches to determine the Water Quality Index (WQI) and assess health risks associated with water consumption in Darab County, Iran. Additionally, pollution levels were predicted using a machine-learning algorithm. The study's findings indicate that certain physicochemical parameters of water in some locations exceeded permissible limits (WHO or EPA), with 79.00 % of total hardness (TH) and 21.74 % of Total dissolved solids (TDS) levels exceeding standard values. The WQI for drinking water was determined to be 94.56 % using the deterministic approach, and 98.4 % of samples included the excellent and good categories according to the WQI classification system using the probabilistic approach. Fluoride (F) exhibited the most substantial impact on WQI values. The Artificial Neural Network (ANN) analysis findings suggest that the pH, nitrate (NO3), and TDS are the most significant factors affecting the prediction of F concentration in water. Multivariate analysis demonstrated that anthropogenic, especially agriculture and geogenic factors, contributed to the water quality in this area. The health risk assessment (HRA) using deterministic methods revealed that water consumption posed a relatively high risk in certain areas. However, Monte Carlo simulation demonstrated that the 5th and 95th percentiles of Hazard Index (HI) for children, teenagers, and adults were within limits of (0.14-2.38), (0.09-1.29), and (0.10-1.00) respectively, with a certainty level of 70 %, 91 %, and 95 %. Interactive indices revealed that the intake of IR and NO3-IR in children, BW and F-BW in teenagers, and NO3 and NO3-IR in adults significantly impacted health risks. Based on these findings, augmenting water treatment processes, regulating fluoride concentrations, and advocating for sustainable agricultural practices complemented by continuous monitoring is imperative.

Investigating the correlation between chemical parameters, risk assessment, and sensitivity analysis of fluoride and nitrate in regional groundwater sources using Monte Carlo

Groundwater is one of the most important sources of drinking and irrigation water in arid and semi-arid areas. This study aimed to investigate the chemical quality of groundwater for drinking and irrigation, assess the non-carcinogenic risk factors resulting from the concentration of fluoride and nitrate ions, and analyze the sensitivity among children, teenagers, and adults using Monte Carlo method. A total of 171 samples were obtained from confined groundwater in Arsanjan. Among other hydrological parameters of water, EC had the highest average (1135.97). TDS ranged from 67.90 to 1878.30 mg/L, with the lowest and highest total hardness values being 2.90 and 680.8, respectively. The water quality index (WQI) results indicated that 33% of the samples were at the poor water level and the irrigation (IWQI) was less than 25 in 96.36% of the samples, which were categorized as excellent. Thus, the majority of the samples were suitable for irrigation purposes. Additionally, the oral and dermal health risks of fluoride and nitrate were less than 1 in all age groups. Concentration factor was the main indicator in the assessment of the non-carcinogenic risk factors of nitrate and fluoride. The results of sensitivity analysis revealed a reverse relationship with body weight. Further, the results of principal component analysis (PCA) showed a negative relationship between fluoride concentration and pH. Hierarchical cluster analysis also showed that the study variables belonged to three main clusters. Some elements in C1 were also found in the first factor in PCA. The elements in C2 were among the dominant compounds of the groundwater resources of the study area, which may be caused by earth cations or human activities. C3 variables may also be one of the consequences of fertilizer use in areas around groundwater sources.

Nitrate in Groundwater Resources of Hormozgan Province, Southern Iran: Concentration Estimation, Distribution and Probabilistic Health Risk Assessment Using Monte Carlo Simulation

High nitrate concentration in drinking water has the potential to cause a series of harmful effects on human health. This study aims to evaluate the health risk of nitrate in groundwater resources of Hormozgan province in four age groups, including infants, children, teenagers, and adults, based on the US EPA methodology and Monte Carlo technique to assess uncertainty and sensitivity analysis. A Geographic Information System (GIS) was used to investigate the spatial distribution of nitrate levels in the study area. The nitrate concentration ranged from 0.3 to 30 mg/L, with an average of 7.37 ± 5.61 mg/L. There was no significant difference between the average concentration of nitrate in all study areas (p > 0.05). The hazard quotient (HQ) was less than 1 for all age groups and counties, indicating a low-risk level. The HQ95 for infants and children in the Monte Carlo simulation was 1.34 and 1.22, respectively. The sensitivity analysis findings showed that the parameter with the most significant influence on the risk of toxicity in all age groups was the nitrate content. Therefore, implementing a water resources management program in the study area can reduce nitrate concentration and enhance water quality.

The preliminary survey on the concentration of potentially toxic elements (PTEs) in salt samples collected from Tehran, Iran: a probabilistic health risk assessment

The present study aimed to assess the potentially toxic elements (PTEs), including copper (Cu), zinc (Zn), arsenic (As), lead (Pb), and mercury (Hg) in refined, rock, and sea salt samples collected (n=60) from Tehran's local market by the aid of an inductively coupled plasma-mass spectrometry (ICP-MS). Besides, the carcinogenic and non-carcinogenic risks for children and adults were estimated with the aid of the Monte Carlo simulation (MCS) method. The rank order of PTEs in refined salt was Pb (13.378 μg/g) > Cu (6.448 μg/g) > Zn (0.363 μg/g) > As (0.184 μg/g) > Hg (0.049 μg/g); in sea salt was Pb (22.972 μg/g) > Cu (3.963 μg/g) > Zn (0.986 μg/g) > As (0.387 μg/g) > Hg (0.224 μg/g); and in rock salt was Cu (31.622 μg/g) > Pb (22.527 μg/g) > Zn (0.638 μg/g) > As (0.235 μg/g) > Hg (0.095 μg/g). It was concluded that the average concentration of some of the investigated PTEs was higher than the national standard limits and Codex's guidelines. A significant non-carcinogenic risk (TTHQ > 1), except for adult consumers, was noted based on the health risk assessment who consume refined salt. All consumers were also at the threshold carcinogenic risk of As (between 10^-4 and 10^-6). Given the considerable health risks due to consumption (refined, rock, and sea salt), approaching effective monitoring plans to control the PTEs concentrations in salt distributed in Tehran are recommended.

Potentially Toxic Elements (PTEs) in the Fillet of Narrow-Barred Spanish Mackerel (Scomberomorus commerson): a Global Systematic Review, Meta-analysis and Risk Assessment

The contamination of seafood like narrow-barred Spanish mackerel (Scomberomorus commerson) fillets by potentially toxic elements (PTEs) has converted to worldwide health concerns. In this regard, the related citations regarding the concentration of PTEs in fillets of narrow-barred Spanish mackerel were collected through some of the international databases such as Scopus, Cochrane, PubMed, and Scientific Information Database (SID) up to 10 March 2020. The concentration of PTEs in fillets of narrow-barred Spanish mackerel fish was meta-analyzed and the health risk (non-carcinogenic risk) was estimated by the total target hazard quotient (TTHQ). The meta-analysis of data indicated that the rank order of PTEs in fillet of narrow-barred Spanish mackerel was Fe (10,853.29 μg/kg-ww) > Zn (4007.00 μg/kg-ww) > Cu (1005.66 μg/kg-ww) > total Cr (544.14 μg/kg-ww) > Mn (515.93 μg/kg-ww) > Ni (409.90 μg/kg-ww) > Pb (180.99 μg/kg-ww) > As (93.11 μg/kg-ww) > methyl Hg (66.60 μg/kg-ww) > Cd (66.03 μg/kg-ww). The rank order of health risk assessment based on the country by the aid of TTHQ for adult consumers was Malaysia (0.22251) > Philippines (0.21912) > Egypt (0.08684) > Taiwan (0.07430) > Bahrain (0.04893) > Iran (0.03528) > China (0.00620) > Pakistan (0.00316) > Yemen (0.00157) > India (0.00073). In addition, the rank order of health risk assessment based on the country by the aid of TTHQ for child consumers was Malaysia (1.03838) > Philippines (1.02257) > Egypt (0.40523) > Taiwan (0.34674) > Bahrain (0.22832) > Iran (0.16466) > China (0.02892) > Pakistan (0.01474) > Yemen (0.00731) > India (0.00340). Therefore, the children in Malaysia and the Philippines were at considerable non-carcinogenic risk. Hence, approaching the recommended control plans in order to decrease the non-carcinogenic risk associated with the ingestion of PTEs via the consumption of narrow-barred Spanish mackerel fish fillets is crucial.

Concentration of Potentially Harmful Elements (PHEs) in Trout Fillet (Rainbow and Brown) Fish: a Global Systematic Review and Meta-analysis and Health Risk Assessment

In this work, articles regarding the concentration on potentially harmful elements (PHEs) in fillet trout (rainbow and brown) fishes were retrieved from Cochrane, Scopus, and PubMed databases between 1 January 1983 and 30 April 2020. The pooled concentration of PHEs in fillet trout fishes was meta-analyzed using a random-effect model (REM) and following the non-carcinogenic and carcinogenic risks was calculated using the Monte Carlo simulation (MCS) method. The meta-analysis of 42 articles (43 data report) revealed that a sort of PHEs in fillet trout was 19,996.64 μg/kg ww for Fe; 1834.75 μg/kg ww for Co; 772.21 μg/kg ww for Cu; 335.78 μg/kg ww for Ni; 290.46 μg/kg ww for Se; 226.20for Cr; 178.11 μg/kg ww for Pb; 77.40 μg/kg ww for Hg; 19.40 μg/kg ww for Cd; and 3.66 μg/kg ww for inorganic As. The non-carcinogenic risk assessment indicated that the lowest and highest hazard index (HI) in the adults was Pakistan (0.0012) and Turkey (0.2388), respectively, and in children was Pakistan (0.0057) and Turkey (1.114), respectively. The non-carcinogenic risk was acceptable for adult consumers in all countries (HI > 1 value) but non-carcinogenic risk for children was not acceptable in Turkey. The sort of countries based on carcinogenic risk in the adults due to inorganic As was China (1.44E-06) > Iran (9.14E-08) > Turkey (4.45E-08) > Portugal (9.04E-10). The carcinogenic risk was threshold for adult consumers in China (CR < 10^-6). Consumption of fillet trout (rainbow and brown) content of PHEs in many countries cannot endanger the health of consumers.

The concentration and probabilistic risk assessment of potentially toxic elements in fillets of silver pomfret (Pampus argenteus): A global systematic review and meta-analysis

The contamination of fish type products such as silver pomfret fish fillets by potentially toxic elements (PTEs) has raised global health concerns. Related studies regarding the concentration of PTEs in fillets of silver pomfret fish were retrieved among some international databases such as Scopus, PubMed and Embase between 1 January 1983 and 10 March 2020. The pooled (mean) concentration of PTEs in fillets of silver pomfret fish was meta-analyzed with the aid of a random-effect model (REM). Also, the non-carcinogenic risk was estimated via calculating the 95th percentile of the total target hazard quotient (TTHQ). The meta-analysis of 21 articles (containing 25 studies or data reports) indicated that the ranking of PTEs in fillets of silver pomfret fish was Fe (11,414.81 µg/kg wet weight, ww) > Zn (6055.72 µg/kg ww) > Cr (1825.79 µg/kg ww) > Pb (1486.44 µg/kg ww) > Se (1053.47 µg/kg ww) > Cd (992.50 µg/kg ww) > Ni (745.23 µg/kg ww) > Cu (669.71 µg/kg ww) > total As (408.24 µg/kg ww) > Co (87.03 µg/kg ww) > methyl Hg (46.58 µg/kg ww). The rank order of health risk assessment by country based on the TTHQ for adult consumers was Malaysia (2.500) > Bangladesh (0.886) > Iran (0.144) > China (0.045) > Pakistan (0.020) > India (0.015), while the corresponding values for child consumers was Malaysia (11.790) > Bangladesh (4.146) > Iran (0.675) > China (0.206) > Pakistan (0.096) > India (0.077). The adult consumers in Malaysia and children in Malaysia and Bangladesh were at considerable non-carcinogenic risk. Therefore, following the recommended control plans in order to reduce the health risk associated with the ingestion of PTEs via consumption of silver pomfret fish fillets is crucial.

Acrylamide content of collected food products from Tehran's market: a risk assessment study

Acrylamide concentration in food products collected from the Tehran market was investigated by the aid of a dispersive liquid-liquid microextraction (DLLME) system coupled with gas chromatography-mass spectrometry (GC-MS). Also, the dietary exposure distribution and related potential risk for acrylamide ingestion were estimated by the Monte Carlo simulation (MCS). The highest and lowest mean concentration of acrylamide was detected in coffee and roasted nuts samples as 549 and 133 μg/kg, respectively. The mean acrylamide dietary exposure values for children (3-10 years), adolescents (11-17 years), adults (18-60 years), and seniors (61-96 years) were estimated to be 1.81, 1.02, 0.61, and 0.53 μg/kg body weight (BW)/day, respectively. In all age groups, except children, the estimated exposure in men and boys was higher than that in women and girls. Bread, despite containing low acrylamide content groups (157 μg/kg while compared with other, except roasted nuts), showed with the highest contribution rate in all age groups due to its high consumption rate. The estimated incremental lifetime cancer risk (ILCR) for all age groups was noted as greater than 10^-4 indicating serious risk to the population. Moreover, the margin of exposure (MOE) values based on carcinogenicity showed health concern to all age groups (< 10,000). Regarding the non-carcinogenic risk, the target hazard quotient (THQ) was lower than 1, and MOE based on neurotoxicity was higher than 125 (safety thresholds), which represented negligible and ignorable risk in all age groups except in a small group of children and adolescents. Graphical abstract.