Using neural networks and a fuzzy inference system to evaluate the risk of wildfires and the pinpointing of firefighting stations in forests on the northern slopes of the Zagros Mountains, Iran (case study: Shimbar national wildlife preserve).

Predicting potential fire hazard zones in natural areas is one of the means of mitigating and managing fires. The current research focuses on the prioritizing of elements which contribute to the spread of fire and the special zoning of potentially dangerous areas in addition to the pinpointing of locations for the establishment of fire stations in forested areas in the Shimbar national reserve based on historical data spanning 2001 to 2018. The study utilizes elements (physiological, vegetation cover, meteorological, anthropological factors) contributing to wildfires as inputs into an artificial neural network and the development of a fuzzy inference system in order to produce fire zoning maps for the region under study. The map is divided into five sectors, i.e., minimum, low, moderate, high, and maximum risk of fire. The validation of the fire zoning map was evaluated at 0.83 and the RMSE error was 0.75. The results obtained show that 20% of the area under study is within the average risk category, 11% is within the high-risk category, and 10% is within the very high-risk category of a potential fire hazard. The most important variables were distance from a flowing source, i.e., river or stream, the land formation type, elevation, and the minimum temperature. The identification of suitable locations for firefighting stations was carried out by merging the fuzzy inference system model and Arc GIS, and the results obtained defined 16 possible locations. It was concluded that the application of hybrid models when dealing with the aforementioned variables is effective when seeking to determine locations for the establishment of firefighting stations and rural safety services; moreover, such hybrid models are highly efficacious for determining of fire hazard zones. It is proposed that hybrid models be applied on a large scale for the prevention, control, and management of fires throughout the country.

Mineralogy, geochemistry, 13C and 16O isotopic characteristics of urinary stones in Iran, a case study of Lorestan Province.

Owing to the importance of urinary stones as one of the biominerals in the human body, it is necessary to investigate their chemical composition and mineralogy. In this matter, a mineralogical study using X-ray diffraction and scanning electron microscopy indicated that urinary stones in Lorestan Province were divided into 5 groups of calcium oxalate, urate, cysteine, phosphate and mixed stones (Whewellite, uric acid, phosphate). In this regard, the microscopic studies revealed that Whewellite was the most important mineral phase among various phases. In the following, the major and rare elements of each group were determined by inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence analysis. The obtained results demonstrated that Ca was found the most abundant element in urinary stones. In the analysis results of the major oxides, compared to other major oxides, CaO had the highest frequency in urinary stones. The reason was due to the role of calcium in most of the basic functions in cell metabolism. The average values of isotope 13C and 16O in the studied urinary stones were obtained - 33.71 and - 20.57, respectively. Overall, the values of 13C isotope in urinary stones were lower than those in the similar stones and human hard tissues in other countries.

An integrated approach for spatial distribution of potentially toxic elements (Cu, Pb and Zn) in topsoil.

In this study, statistical analysis and spatial distribution were performed to compare raw data and centred log-ratio (clr) transformed data of three copper (Cu), lead (Pb), and zinc (Zn) potentially toxic elements (PTEs) concentration for 550 surface soil samples in Khuzestan plain. The results of both approaches showed that classical univariate analysis and compositional data analysis are essential to find the real structure of data and clarify its different aspects. Results also indicated that spatial distributions of raw data and clr-transformed data were completely different in three studied metals. Raw data necessarily shows the effects of anthropogenic activities and needs an additional evaluation of human health risk assessment for these three studied elements. Data obtained from clr-coefficient maps also demonstrated the role of geological processes in the distribution pattern of potentially toxic elements (PTEs). To improve the understanding of the implications for PTE pollution and consequences for human health, a RGB colour composite map was produce to identify the potential origin of PTEs from areas with higher than typical baseline concentrations.

Status, source, human health risk assessment of potential toxic elements (PTEs), and Pb isotope characteristics in urban surface soil, case study: Arak city, Iran.

The current study was conducted to assess the level of potentially toxic elements (PTEs) contamination (Cu, Pb, Zn, Cr, As, Cd, and Ni) in surface soils from Arak city. Arak, which is an industrial city, is a prominent center of chemicals, metal/electric, manufacturing factories, and other industries. Forty-three surface soil samples were collected from 0-20 cm after removing the visible surface contamination in the dry season in June 2017. Metal concentrations were found highly variable, ranging from 174-3950 mg/kg for Cu, 181-3740 mg/kg for Pb, 48-186 mg/kg for Zn, 105-1721 mg/kg for Ni, 0.8-0.9 mg/kg for As, 114-1624 mg/kg for Cr, and 3.45-12.36 mg/kg for Cd. The results of geochemical fraction indicated that the main components of Pb, Cr, and Zn at most of the sampling sites are Fe-Mn bound/reducible. Meanwhile, the residual fraction is the dominant fraction of sequence extraction for Ni, Cu, and Cd. Higher values of reducible bound for Pb, Cr, and Zn, as well as a considerable percentage of Ni, Cu, and Cd, imply that the main source of the studied PTEs (except As) in the study area is both anthropogenic and geogenic inputs. The results of principal component analysis (PCA), correlation analysis, enrichment factor (EF), enrichment index (EI), and top enrichment factor (TEF) confirm that Pb, Ni, Cu, Cr, Cd, and Zn had a similar anthropogenic source which is confirmed by geochemical fractionation analysis. Carcinogenic risks (CR) of studied PTEs were estimated to be higher than the target limit of 1.0E-06, for adults and children except for Cr with values of 5.91E-04, and 3.81E-04 for children and adults, respectively. Higher CR values of Cr compared to other PTEs in Arak surface soil demonstrate that living target populations, including children and adults, particularly children, are more at risk of carcinogenic risks of PTEs. 206Pb/207Pb ratios of the collected samples indicated that Pb in Arak surface sample was derived from industrial inputs and deposition, as well as re-suspension vehicle exhaust emission from previously leaded gasoline. The findings concerning the applied end-member contribution of geogenic and industrial and vehicle emission represented that the contribution could vary from 68.0% to 15% (mean: 39.3) for industrial emission, 65% to 19% for vehicle exhaust (mean: 39), and 46% to 10% (mean: 21.6) for geogenic sources.

Assessment of the potential ecological and human health risks of heavy metals in Ahvaz oil field, Iran.

The potential hazard to human health from exposure to heavy metals in surface soil was assessed using 66 soil samples collected from Ahvaz oil field. To this end, the contents of heavy metals were measured by the inductively coupled plasma spectroscopy (ICP-OES). Mean levels of As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn were 5.9, 0.4, 7.1, 36.5, 41.2, 39.8, 67.4, 31.5, and 77.6 mg/kg, respectively. Contents of all studied heavy metals, with the exception of Co, Cr, and V, were several times higher than that of baselines. Correlation coefficients and principal component analysis (PCA) identified two main groups as sources of heavy metals in the surface soil of Ahvaz oil-field. Metals such as Co, Cr, and V were observed to originate from natural sources and As, Cd, Cu, Ni, Pb, and Zn originated from anthropogenic sources such as petroleum leakage and the pollution caused by drilling mud from oil wells. Pb and Zn were of significantly high EF mean enrichment value, and Co, Cu, Cd, and As had high enrichment in surface soil. Pb, Cr, V, Zn, Co, Cu, Ni, and As had a low potential ecological risk (PER) whereas Cd had a moderate PER. The risk of carcinogenic and non-carcinogenic diseases was detected to be higher in children than in adults. The carcinogenic risk (Cr) calculation was more than 1 × 10-6 for children and adults. Additionally, the CR of Cr for both children and adults indicated risk under control conditions.

Application of exploratory and Spatial Data Analysis (SDA), singularity matrix analysis, and fractal models to delineate background of potentially toxic elements: A case study of Ahvaz, SW Iran.

It is essential to study spatial distribution of Potentially Toxic Elements (PTEs) in surface soil, and separate PTEs geochemical background from their human sources, and also determine their correlation with other environmental factors in order to assess their impacts on humans, provide realistic environmental geochemical maps, and carry out soil management. For this purpose, this study was designed to investigate the surface soil in Ahvaz, Southwest of Iran. The applied methods were exploratory data analysis (EDA), including boxplot, Q-Q plot, probability plot (PP), concentration-area (C-A), number-size (N-S) fractal model, and singularity index (SI) model. The obtained results revealed that the fractal models led to a more realistic distinction among the geochemical population compared to the EDA methods such as probability plot. Furthermore, the C-A model was found to be more effective on the separation of subpopulation compared to the N-S and PP models. The studied elements exhibited a similar pattern implying that pollution is a function of geochemical dispersion regarding the surface soil in Ahvaz (Zn â‰« Pb > Cu > As). The studied metals-major elements plot also indicated that there was no meaningful relationship between Pb, Zn, Cu, and major elements in the study area. Plots of association of Pb, Zn, Cu, and As distinctly showed two general geogenic and anthropogenic populations. Moreover, the results of SI revealed that the highly contaminated area was consistent with the main defined hotspots and anthropogenic sources of elements as well as places affected by the contaminated area that have not been reported in previous studies. Furthermore, a combination of geochemical and geographical model comprising different statistical models was developed to more effectively separate geogenic from anthropogenic sources. Also, the geochemical background for the studied elements (Pb 180 mg/kg; Cu 200 mg/kg; Zn 90 mg/kg; As 65 mg/kg) was shown to be higher than the Iranian soil quality guideline with Pb, Zn, Cu, and As of 100, 80, 200, and 18 mg/kg, respectively.

Source, Spatial Distribution and Pollution Assessment of Pb, Zn, Cu, and Pb, Isotopes in urban soils of Ahvaz City, a semi-arid metropolis in southwest Iran.

This study examined the status of toxic metal contamination of the urban industrial city of Ahvaz in Iran. Two hundred and twenty-seven surface soils from a depth horizon of 0-10 cm were collected from urban areas. In addition, 15 soil samples were collected to recognise the sources of Pb in urban topsoils in Ahvaz city. Mean concentration of Pb, Zn, Cu and As were 181 ± 167, 123 ± 118, 185 ± 167 and 6.9 ± 8.9 mg.kg-1, respectively. Results of inter-element relationship among studied toxic metals revealed that Pb, Zn and Cu may have the same anthropogenic origin, whilst As originated from different sources. The results of pollution index (PI) and Nemerow pollution index (NPI) implied that Pb, Zn, and Cu had a moderate to high level of pollution. The Pb isotopic composition analysis suggested clear anthropogenic origins of Pb including industrial emission, vehicle exhaust and dust storm with the mean contributions of 47%, 15% and 7%, respectively, by a four-end member model.

Ecological and human health risk assessment of toxic metals in street dusts and surface soils in Ahvaz, Iran.

This study aimed to examine the concentrations and environmental health risk of the potentially toxic metals including Pb, Zn, Cu, Cd, Cr, and As in street dusts and surface soils of Ahvaz, the capital of Khuzestan province, located in the southwest of Iran. To this end, a total of 81 street dusts and 96 surface soils were collected from Ahvaz urban areas. Toxic metals were measured by inductively coupled plasma-mass spectrometry and evaluated using enrichment factors, potential ecological risk index and human health risk assessment. Lead in street dusts and Pb and Cu in surface soil showed the highest enrichment factor. The results revealed that there are two major sources of toxic metals in Ahvaz, including industrial activities and road traffic emissions and also resuspension of soil and dust particles. Cu, Pb, Zn, and Cr in Ahvaz soil and dust particles are strongly influenced by anthropogenic activity, mainly industrial and traffic emissions, while As and Co originate from resuspension of soil natural parent particles. The potential ecological risk index (RI) values for dust samples indicated that 58.02% of all samples showed low potential ecological risk. Moreover, 33% and 9% of samples showed moderate and considerable ecological risk, respectively. In addition, the RI values for soil samples indicated that 57% and 40% of all samples had low and moderate ecological risk, respectively, and 3% had a high ecological risk. The hazard index (HI) values of studied potentially toxic metals showed that there is no non-carcinogenic risk for children and adults. Furthermore, the HI value for children was 2-7 times upper than those for adults, which confirm that children show more potential health risks for exposition to these potential toxic metals. Cancer risks of the studied potential toxic elements for both adults and children decreased in the following order Crdust > Crsoil > Cddust > Cdsoil > Asdust > Assoil > Pbdust > Pbsoil. The carcinogenic risk values of Cd, As, and Pb for adults and children was lower than 1 × 10-6, suggesting carcinogenic risk of potentially toxic metals in the street dust and surface soil could be neglected. On the other hand, the carcinogenic risk value of Cr was greater than 1 × 10-6 for both adults and children revealing that the carcinogenic risks of Cr essentially need more consideration for environmental management control.

Spatial distribution and human health risk assessment of mercury in street dust resulting from various land-use in Ahvaz, Iran.

Mercury as a toxic element and its associated health hazard has been an important topic of research for urban pollution for many years. In this paper, the spatial distribution, pollution assessment, and health risk associated with Hg in roadside dust 96 street dust samples, representing differing land-uses, have been investigated. Land-uses included residential areas (RA), industrial areas (IA), public gardens (PG), roadside areas (RS), and suburban areas (SA) in the city of Ahvaz, Iran were investigated. Compared with other cities, the concentration of Hg in Ahvaz was considerably higher with a mean value of 2.53 mg kg-1, ranging from 0.02 to 8.75 mg kg-1. Residential areas exhibited higher Hg in street dust than other areas, as demonstrated by spatial mapping illustrating hot spots associated with old urban areas with high residential density, high volume traffic of roadside areas, and industrial districts: including oil-drilling activities, steel smelting-related industries, and small industrial towns around Ahvaz. However, Hg concentrations in street dust near to the public gardens (PG) and suburban areas (SA) were not at elevated levels compared other land-uses investigated in this study. A health risk assessment model of non-carcinogenic effects was evaluated for both children and adults. The HQ values also revealed that the main exposures route for children and adults decreased as follows: vapour > ingestion > dermal contact > inhalation. The hazard index (HI) in each area is less than the safe level (HI ≤ 1) for children and adults, but higher for children. The HI value decreases as the following order: RS > IA > RA > SA > PG, which indicates potentially serious health hazards for children in the study areas.