Groundwater quality assessment using water quality index and principal component analysis in the Achnera block, Agra district, Uttar Pradesh, Northern India.

The qualitative and quantitative assessment of groundwater is one of the important aspects for determining the suitability of potable water. Therefore, the present study has been performed to evaluate the groundwater quality for Achhnera block in the city of Taj, Agra, India, where groundwater is an important water resource. The groundwater samples, 50 in number were collected and analyzed for major ions along with some important trace element. This study has further investigated for the applicability of groundwater quality index (GWQI), and the principal component analysis (PCA) to mark out the major geochemical solutes responsible for origin and release of geochemical solutes into the groundwater. The results confirm that, majority of the collected groundwater samples were alkaline in nature. The variation of concentration of anions in collected groundwater samples were varied in the sequence as, HCO3- > Cl- > SO42- > F- while in contrast the sequence of cations in the groundwater as Na > Ca > Mg > K. The Piper diagram demonstrated the major hydro chemical facies which were found in groundwater (sodium bicarbonate or calcium chloride type). The plot of Schoellar diagram reconfirmed that the major cations were Na+ and Ca2+ ions, while in contrast; major anions were bicarbonates and chloride. The results showed water quality index mostly ranged between 105 and 185, hence, the study area fell in the category of unsuitable for drinking purpose category. The PCA showed pH, Na+, Ca2+, HCO3- and fluoride with strong loading, which pointed out geogenic source of fluoride contamination. Therefore, it was inferred that the groundwater of the contaminated areas must be treated and made potable before consumption. The outcomes of the present study will be helpful for the regulatory boards and policymaker for defining the actual impact and remediation goal.

Variability of groundwater fluoride and its proportionate risk quantification via Monte Carlo simulation in rural and urban areas of Agra district, India.

This study quantifies the groundwater fluoride contamination and assesses associated health risks in fluoride-prone areas of the city of Taj Mahal, Agra, India. The United States Environmental Protection Agency (USEPA) risk model and Monte Carlo Simulations were employed for the assessment. Result revealed that, among various rural and urban areas Pachgain Kheda exhibited the highest average fluoride concentration (5.20 mg/L), while Bagda showed the lowest (0.33 mg/L). Similarly, K.K. Nagar recorded 4.38 mg/L, and Dayalbagh had 1.35 mg/L. Both urban and rural areas exceeded the WHO-recommended limit of 1.5 mg/L, signifying significant public health implications. Health risk assessment indicated a notably elevated probability of non-carcinogenic risk from oral groundwater fluoride exposure in the rural Baroli Ahir block. Risk simulations highlighted that children faced the highest health risks, followed by teenagers and adults. Further, Monte Carlo simulation addressed uncertainties, emphasizing escalated risks for for children and teenagers. The Hazard Quotient (HQ) values for the 5th and 95th percentile in rural areas ranged from was 0.28-5.58 for children, 0.15-2.58 for teenager, and 0.05-0.58 for adults. In urban areas, from the range was 0.53 to 5.26 for children, 0.27 to 2.41 for teenagers, and 0.1 to 0.53 for adults. Physiological and exposure variations rendered children and teenagers more susceptible. According to the mathematical model, calculations for the non-cancerous risk of drinking water (HQ-ing), the most significant parameters in all the targeted groups of rural areas were concentration (CW) and Ingestion rate (IR). These findings hold relevance for policymakers and regulatory boards in understanding the actual impact and setting pre-remediation goals.

Benzo (a) pyrene in infant foods: a systematic review, meta-analysis, and health risk assessment.

Exposure of infants to chemicals during their development will have major effects on their health. One of the major exposures of infants to chemicals is through their food. The main structure of infant food is milk, which is high in fat. There is a possibility of accumulation of environmental pollution, including benzo (a) pyrene (BaP). In this systematic review, the amount of BaP in infant milk was surveyed for this purpose. The chosen keywords were: benzo (a) pyrene, BaP, Infant formula, dried milk, powdered milk, and baby food. A total of 46 manuscripts were found in the scientific database. After initial screening and quality assessment, 12 articles were selected for extraction of data. By meta-analysis, the total estimate of BaP in baby food was calculated to be 0.078 ± 0.006 µg/kg. Estimation of daily intake (EDI) and Hazard Quotient (HQ) for noncarcinogenic risk and Margin of exposure (MOE) for carcinogenic risk were also calculated for three age groups 0-6 months, 6-12 months, and 1-3 years. HQ was lower than 1 and MOE was more than 10,000 for three age groups. Therefore, there is no potential carcinogenic and non-carcinogenic risk for infant health.

Fundamental Science and Engineering Questions in Planetary Cave Exploration.

Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using mathematical models. Today, armed with an array of orbiting and fly-by satellites and survey instrumentation, we have now acquired cave data across our solar system-including the identification of potential cave entrances on the Moon, Mars, and at least nine other planetary bodies. These discoveries gave rise to the study of planetary caves. To help advance this field, we leveraged the expertise of an interdisciplinary group to identify a strategy to explore caves beyond Earth. Focusing primarily on astrobiology, the cave environment, geology, robotics, instrumentation, and human exploration, our goal was to produce a framework to guide this subdiscipline through at least the next decade. To do this, we first assembled a list of 198 science and engineering questions. Then, through a series of social surveys, 114 scientists and engineers winnowed down the list to the top 53 highest priority questions. This exercise resulted in identifying emerging and crucial research areas that require robust development to ultimately support a robotic mission to a planetary cave-principally the Moon and/or Mars. With the necessary financial investment and institutional support, the research and technological development required to achieve these necessary advancements over the next decade are attainable. Subsequently, we will be positioned to robotically examine lunar caves and search for evidence of life within Martian caves; in turn, this will set the stage for human exploration and potential habitation of both the lunar and Martian subsurface.

Spatial analysis and probabilistic risk assessment of exposure to fluoride in drinking water using GIS and Monte Carlo simulation.

Prevalence of fluorosis is a worldwide public health problem especially in many states of India. It is necessary to find out the fluoride endemic areas to adopt remedial measures to the people on the risk of fluorosis. The target goals of this research were to assess (a) the exposure of fluoride concentration; (b) probabilistic risk assessment, sensitivity analysis, and uncertainty through intake of groundwater among population of Agra City (infants, children and adults) by Crystal Ball software; and (c) spatial distribution of HQ and fluoride concentration. A total of sixty samples from standing tube wells/hand pumps were gathered from selected and identified fluoride prevalent areas in Agra City. The concentration of fluoride scrutinized was obtained to be ranging from 1.32 to 4.60 mg/L with mean value of 2.36 in Agra City, and more than 91% of samples investigated surpassed the allowable level set for fluoride concentration in potable water 1.5 mg/L, although 9% of the samples were well within the drinking water guidelines (0.5-1.5 mg/L). The hazard quotient (HQ) was obtained to an enormous difference in the exposure dose in infants (1.66-3.91), children (1.87-4.4), and adults (0.92-2.16), correspondingly. The non-carcinogenic HQ values in the group of infants, children, and more than 90% of adults were higher than those of the safety level (i.e., HQ >1). Consequently, the non-carcinogenic risks (HQ level) of fluoride vary from the most to the least: children, infant, and adults, respectively. With 87.41% certainty, the results indicated that the HQ values are between 1 and 3.42. So, infant is the most vulnerable group to fluoride consumption in study area. Uncertainty analysis results indicated that the children group's HQ level was between 1 and 1.90 with 38.48% certainty. To avoid further worsening of the situation as far as health is concerned, remedial actions like alternate sources of water supply and appropriate treatment of water need to be adopted besides required medical attention to affected people.

Non-carcinogenic risk assessment of exposure to heavy metals in underground water resources in Saraven, Iran: Spatial distribution, monte-carlo simulation, sensitive analysis.

Groundwater aquifers are considered the second most abundant water supply for drinking water all over the world. In Iran, ground waters are commonly employed for drinking water, irrigation, and industrial purposes. Heavy metals (HMs) pose human concerns about the groundwater contamination; these pollutants are recognized to be capable of bio-accumulation, long persistence in the natural environment, and toxic effects. In the present research, the content of HMs: Chromium (Cr), Cadmium (Cd), and Lead (Pb) were detected in 89 water samples collected in 2018 by underground water supplies (active wells) of Saravan city. Hazard Quotient (HQ) and Monte Carlo Simulation approach with 10,000 repetitions were applied to discover the human non-carcinogenic impacts of HMs in four groups of ages (adults, teenagers, children, and infants) of consumers. The concentrations of Cr, Pb, and Cd were in the range of 0.49-20, 0.1 to 58.34, and 0.11-12.8 µg/L, respectively. The mean HQ calculated due to exposure to Pb (0.0018-0.0023), Cr (0.0112-0.0186), and Cd (0.0370-0.0615) were lower than one. The findings of sensitivity analysis revealed that HMs concentration had the most contribution effect on human non-carcinogenic risk analysis in four different exposed populations. This study could assist researchers to perform more comprehensive studies with more samples. Therefore, further research is required for decision-makers to plan proper measurements properly.

Health risk assessment of heavy metals in cosmetic products sold in Iran: the Monte Carlo simulation.

Cosmetics can contain harmful compounds such as heavy metals. Several metals have a cumulative effect on the body, especially fatty tissues, and may have different health effects on the human body over the long term. Therefore, the main objective of this study was to assess the health risks of heavy metals in cosmetics in Iran. Also, in this study, Monte Carlo simulation was used to investigate uncertainties. In this study, heavy metals data of cosmetics were extracted from studies carried out at intervals 2010-2018. International and Iranian databases such as Google Scholar, Web of Science, Springer, Science Direct, PubMed, Scopus, Irandoc, Magiran, Scientific Information Database (SID), and Information Institute for Scientific (ISC) were searched for this purpose. In this study, the index of the Margin of Safety was calculated to determine the risk of human contact with metallic impurities in cosmetic products used by humans. In the selected period, 11 studies were conducted on the measurement of heavy metals in cosmetics in Iran. In these studies, cosmetics such as eye shadow, eye pencil, powder, cream, and lipstick were studied. The Margin of Safety (MoS) values calculated for different metals were higher than the established safe standard by WHO. The highest and lowest amount of systemic exposure dosage in all types of cosmetic investigated (lipstick, cream, eye pencil, face powder, and eye shadow) was related to Fe and Hg. The mean hazardous quotient (HQ) for Cd, Cr, Ni, Cu, Mn, Zn, Pb, and Hg was 1.05E-03, 1.03E-01, 7.95E-03, 2.59E-03, 1.05E-03, 4.98E-03, 7.22E-04, 1.85E-01, and 1.35E-05, respectively. The highest HQ (6.10E-01) was found for Pb, which was observed in the cream.

Assessment of Heavy Metal Pollution and Human Health Risks Assessment in Soils Around an Industrial Zone in Neyshabur, Iran.

Heavy metal pollution of soils in industrial zones continues to attract attention because of its potential human health risks. The present research is an attempt to assess the pollution status of heavy metals including As, Cd, Cr, Ni, and Pb using various indices like contamination factor (CF), pollution index (IPOLL), and geo-accumulation index (Igeo). In total, 60 surface soil samples were collected from four area (north, south, east, and west) in Khayyam industrial zone from depths of 10-20 cm. The results indicated that average metal concentration ranges (in mg/kg) observed in study soils were 8.84, 1.9, 37.66, 15.77, and 57.33 for As, Cd, Cr, Ni, and Pb, respectively. The concentrations of heavy metals As, Cr, Ni, and Pb with the exception of Cd in soils of southern areas of the industrial zone were higher. Cd concentration vary negligibly in sampling sites of north, south, east, and west. Based on the CF, IPOLL, and Igeo indices, the pollution of soil in regard to concentration of heavy metals was in the following order: Cd > As > Pb > Ni > Zn. Industrial activities have therefore resulted in elevated concentrations of so in the soil environments in the Khayyam industrial zone. Based on the results of human health risk assessments, the soil metals pose negligible carcinogenic and non-carcinogenic risks to the adults and children living in this area. The need for the monitoring of the soil around the industrial zone, especially for Cd and As, is needed to reduce potential environmental issues.

Assessment of groundwater quality around municipal solid waste landfill by using Water Quality Index for groundwater resources and multivariate statistical technique: a case study of the landfill site, Qaem Shahr City, Iran.

Groundwater is a precious natural water resource which can be considered as an available and safe source of water for domestic uses. In some cities in northern Iran, groundwater is being polluted due to various human activities. In this regard, the located municipal solid waste landfills close to these areas without the requested controls regarding the landfill leachate and gas emission are among the major sources of environmental pollution, which are deteriorating groundwater quality around landfill sites. In this context, the current study was aimed to assess the quality of collected groundwater samples around a landfill site using the modified Water Quality Index for groundwater resources (WQIG). Also, the water quality map has been prepared by using WQIG in GIS environment. Therefore, thirty-three groundwater samples were collected and analyzed around 11 water wells close to the landfill site. Variety of physicochemical parameters including nitrate (NO3), fecal coliform, sodium absorption ratio (SAR), electrical conductivity, biological oxygen demand (BOD5), phosphate (PO4), total dissolved solids, dissolved oxygen, pH were assessed in groundwater samples based on recommended standard methods by American Public Health Association (APHA). Geostatistics analysis including Kriging, semi-variogram, and variogram methods also was used to evaluate the spatial variations in the variables and to provide the necessary data for further interpolation. According to the results of WQIG, most of the groundwater wells (98.85%) are polluted due to the existing of the landfill site in the investigated area. Generally speaking, based on the WQIG the water samples were defined as not suitable for drinking applications. Also, the high concentrations of nitrate and hardness in the downstream wells (W1-W11) of the landfill were demonstrated by the results of Kriging assay which can be correlated with the penetration of leachate into these wells. Considering the SAR results, all wells in the studied area are classified as (C3S1) that means the groundwater of this area is suitable for agricultural approaches. Moreover, the reduction in the water quality from the south to the north and northeast was demonstrated by the results of spatial dispersion. Evaluation of the changes in water quality near landfill sites showed that 2149.56 m2 of total area had a relatively poor potential for the region's groundwater recharge.

Non-Carcinogenic Health Risk Assessment due to Fluoride Exposure from Tea Consumption in Iran Using Monte Carlo Simulation.

Excessive intake of fluoride can cause adverse health effects. Consumption of tea as a popular drink could be a potential source of fluoride exposure to humans. This research aimed to evaluate the fluoride concentration in tea among the Iranian people using the available data in the literature and to assess the health risk related to the consumption of tea in men, women, and children. The health risk assessment was conducted using the chronic daily intake and hazard quotient according to the approach suggested by the Environmental Protection Agency. The fluoride content in published studies varied noticeably, ranging from 0.13 to 3.27 mg/L. The results revealed that the hazard quotient (HQ) in age groups of women (21-72 years) and children (0-11 years) was within the safe zone (HQ < 1) which showed that there was no potential of non-carcinogenic risk associated with drinking tea in these groups. However, in one case of the men (21-72 years), the HQ > 1 which shows a probable risk of fluorosis. The order of non-carcinogenic health risks in the studied groups was in the order of men > women > children. The results of this can be useful for organizations with the responsibility of human health promotion.

Carcinogenic and non-carcinogenic health risk assessment of heavy metals in drinking water of Khorramabad, Iran.

The continuous urbanization and industrialization in many parts of the world and Iran has led to high levels of heavy metal contamination in the soil and then on the surface and groundwater. In this study, the concentrations of 8 heavy metals were determined in forty water samples along distribution drinking water of Khorramabad, Iran. The ranges of heavy metals in this study were lower than EPA and WHO drinking water recommendations and guidelines and so were acceptable. The mean values of CDItotal of heavy metals concentrations in adults were found in the order of Zn > Ba > Pb > Ni > Cr > Cu > Cd > Mo. The health-risk estimation indicated that total hazard quotient (HQing + HQderm) and hazard index values were below the acceptable limit, representing no non-carcinogenic risk to the residents via oral intake and dermal adsorption of water. Moreover, the results of total risk via ingestion and dermal contact showed that the ingestion was the predominant pathway. This study also presents that the carcinogenic risk for Pb, Cr, Cd and Ni were observed higher than the acceptable limit (1 × 10-6). The present study will be quite helpful for both inhabitants in taking protective measures and government officials in reducing heavy metals contamination of urban drinking water. •The data analyzed in this study show a clear situation regarding the quality of drinking water in Khorramabad.•The results of this study can be used to improve and develop the quality of drinking water that directly affects the health of consumers.•The present study will be quite helpful for both inhabitants in taking protective measures and government officials in reducing heavy metals contamination of urban drinking water.

Distribution of fluoride contamination in drinking water resources and health risk assessment using geographic information system, northwest Iran.

This paper considers exposure to the concentration of fluoride in drinking water resources of Showt city in West Azerbaijan Province in, Iran, and its related potential health risk assessment issues to the resident populations. For this purpose, 88 drinking water samples were analyzed in 2016 by using the spectrophotometric method. Non-carcinogenic health risks due to F exposure through consumption of drinking water were assessed using the US EPA method. In addition, the associated zoning maps of the obtained results were presented using a geographic information system (GIS). The results indicated that fluoride concentration in drinking water ranged from 0.0 to 5.5 mg L-1 of the study area. Based on this research, 36.36% of the samples had a fluoride level higher than the permissible level, 13.63% had less than the permissible limit, and 50% of the samples had a level within the optimum limit of 0.5-1.5 mg L-1. The Hazard Quotient index (HQ) for children, teenager and adults had health hazards (HQ > 1) in 54.55%, 31.82%, and 22.73% of samples, respectively. Groundwater resources having a risk of more than one were located in the villages of Khilajajam, Kolos, and Shorboulagh. So, in these study areas, there are potential risks of dental and skeletal fluorosis.

Estimate the effective dose of gamma radiation in Iran cities: lifetime cancer risk by Monte Carlo simulation model.

Background radiation can be different in both indoor and outdoor places. Background radiation is always in the environment, and all people in the community are constantly exposed to it. The most important source of exposure to gamma ray is natural radionuclides. Gamma rays can have harmful effects on the human body. The purpose of this study was to evaluate the health risk of gamma-ray exposure and to simulate using the Monte Carlo simulation. In this study, gamma-ray data were extracted from the studies carried out at intervals January 1, 2000, to December 31, 2018. Iranian and international databases were used to search for the articles. A total of 11 studies were found. To determine the health effects of gamma-ray radiation, the annual effective dose and excess lifetime cancer risk were calculated. To determine the uncertainty, a health risk assessment was conducted via Monte Carlo simulation. In outdoor, the mean, highest, and lowest absorbed dose of gamma ray were 117.82 nSv/h, 295.17 nSv/h, and 49 nSv/h, respectively. Ardabil Province and Chaharmahal and Bakhtiari Province have the highest and lowest gamma ray concentrations, respectively. In indoor, the mean, highest, and lowest absorbed dose of gamma ray were 118.22 nSv/h, 141 nSv/h, and 60.2 nSv/h, respectively. The last column, the mean, maximum, and minimum of excess lifetime cancer risk values for gamma-ray radiation were 2.45E-3, 4.17E-3, and 4.61E-4, respectively.

Spatial Distribution Variation and Probabilistic Risk Assessment of Exposure to Fluoride in Ground Water Supplies: A Case Study in an Endemic Fluorosis Region of Northwest Iran.

Prevalence of fluorosis is a worldwide public health issue, especially in the West Azerbaijan province of Iran. The aim of this study was to investigate fluoride concentration in drinking water resources within Maku city, in both the warm and cold seasons, to perform a health risk assessment. Fluoride were measured using UV-visible spectrophotometry. The spatial distribution was calculated by the software ArcGIS and Hazard Quotients (HQs) were calculated according to the US EPA method. The fluoride concentrations ranged between 0.29 to 6.68 and 0.1 to 11.4 mg/L in the cold and warm seasons, respectively. Based on this report, 30.64 and 48.15% of the samples revealed a fluoride level higher than the permissible level in the cold and warm seasons, respectively. Moreover, results showed that the HQ value in the warm season for different age groups was higher than the HQ value in the cold season. In both seasons, the non-carcinogenic risks of fluoride for the four exposed populations varied according to the order: children > teenagers > adults > infants. The HQ values for three age groups (children, teenager and adults) for both seasons were higher than 1 with a high risk of fluorosis. The results of this study, support the requests that government authorities better manage water supplies to improve health quality.

Carcinogenic and Non-carcinogenic Risk Assessment of Heavy Metals in Groundwater Wells in Neyshabur Plain, Iran.

The present work reports the As, Cr, Cu, Pb, Zn, and Fe concentrations of drinking water samples in Neyshabur Plain, Iran. This study aimed also to ascertain the potential consumers' health risk of heavy metal intake. Heavy metal concentrations were analyzed by inductively coupled plasma optical emission spectrometry. The highest and lowest average values in the analyzed water samples were observed for Fe (9.78 ± 5.61 µg/L) and As (1.30 ± 2.99 µg/L), respectively. These values were well below the limits recommended by the World Health Organization and the Iranian national standard. Heavy metal pollution index and heavy metal evaluation index were used to evaluate drinking water quality. The risk index was calculated by chronic daily intake and hazard quotient according to the United States Environmental Protection Agency approach. Heavy metal pollution index in all the samples was less than 100, indicating that it is a low-level heavy metal. The total risk of all heavy metals in the urban environment varied from 40.164 × 10-7 to 174.8 × 10-7. In this research, the maximum average of risk belonged to lead and copper with the respective values of 60.10 × 10-7and 33.99 × 10-7 from the selected wells. However, considering the toxic effect of some elements, including Pb and As, in the chronic exposure of consumers, we suggest a continuous evaluation and monitoring of drinking water resources.

Assessment health status of ICU medical equipment levels at Neyshabur hospitals using ICNA and ACC indices.

This study was conducted to evaluate the health status of medical equipment's in Neyshabur hospital's intensive care units (ICU) before and after daily cleaning in order to compare the efficiency of the observational and microbial methods in evaluating hygienic conditions and cleaning of the environmental surfaces at the hospitals in Neyshabur. The study was performed in a ten-week period, twice a week before and after daily cleaning according to the ICNA observational method and the ACC microbial method were performed on the selected sites. (before and after daily cleaning in order to compare ICNA observational method and the ACC microbial method which performed on the selected sites). Result showed in total, 826 ICNA checklists were completed in this research for the 13 studied spots, 27.12% of the spots were contaminated before cleaning procedures, which dropped to 7.75% after cleaning. Data of the samples using the ACC index revealed that 74.82 were contaminated and 7.75% were clean. Bottle suction with 8.2% and Electroshock with 1% were the most and the least contaminated spots, respectively. As the results proved, the microorganism of Staphylococcus epidermises is the most grown organism in the intensive care unit. This study suggests that visual assessment is not enough to ensure quality of the process and it is necessary to document the level of cleanliness by quantitative methods. Also preparing the integrated instructions and guidelines of cleaning and disinfection and its continuous monitoring with standard methods would be effective in reducing the microbial contamination.

Data on microbiological quality assessment of rural drinking water supplies in Poldasht county.

In this research, the villages with water supply systems under the supervision of the Water and Wastewater Company in Poldasht County, Iran in 2015 was studied. 648 samples were taken from 57 villages during 12month period to test for microbial quality according to the latest guidelines of WHO. Fecal coliform, coliform, turbidity, pH and free residual chlorine were analyzed. Also we used linear Regression statistical analysis for collected data. Result of Data showed that 13.6% of the villages under study had contaminated water resources. In 100 percent of the water sample resource the turbidity level was less than Iranian maximum permissible levels (5 NTU). There was a linear relation between the Free residual color and Coliform in different month of follow up (r = -0.154, P < 0.001). Data suggests water resources should be comprehensively planned and monitored keeping in view the WHO recommended parameters.

Diarrhea deaths in children among countries with different levels of the human development index.

The present study investigated the effect of human development index (HDI) on diarrheal deaths per 1000 live births in children under 5 years old in 2015. In addition, the association between HDI, and the use of improved drinking-water sources and sanitation facilities were evaluated in this year. 75 countries that their information was available in Global Analysis and Assessment of Sanitation and Drinking-Water (GLAAS) conducted by the World Health Organization (WHO) were included in this study. The data required was obtained from WHO and United Nations Development Programme (UNDP) websites. Pearson's correlation coefficient and linear regression were used to evaluate the correlation and association between the variables, respectively. The results showed that there is a significant relationship between HDI and diarrhea-associated deaths per 1000 live births in children during 2015 (B = -354.85, CI95%: -408.91, -300.79). In addition, HDI was associated with the use of improved drinking-water sources (B = 83.93, CI95%: 64.71, 103.15) and improved sanitation facilities (B = 199.90, CI95%: 174.39, 225.42) in 2015. These findings indicate the association between HDI and the measures relevant to diarrheal disease among children. Therefore, in order to achieve to the Millennium Development Goals regarding child health, policymakers should concentrate on environmental and social factors affecting health.