Assessment of land use effect, mapping of human health risks and chemometric analysis of potential toxic elements in topsoils of Aran-o-Bidgol, Iran.

This study examines topsoil contamination in Aran-o-Bidgol urban region of central Iran, with a focus on potentially toxic elements (PTEs). A total of 135 topsoil samples in different land types were characterized, ranging from areas with agricultural farms, desert, industrial and residential activity, and brick kilns. The average concentrations of Cd, Pb, Cu, Ni, Cr, Co, Fe, Zn, and Mn were 0.72, 11.41, 14.82, 29.87, 51.13, 106.69, 8741.87, 48.59, and 346.42 mg kg-1, respectively, which all exceed the local background levels. The results reveal that land use significantly affected PTE concentrations. Cr, Co, Mn, and Fe concentrations in soils of residential and brick kiln areas were especially high. In contrast, concentrations of Cu, Ni, and Zn were higher in agricultural and residential areas. Risk assessment analysis showed that the sum of toxic units for PTEs for brick kilns (1.72), residential (1.82), and agricultural (1.79) areas exceeded those of other land types and that Ni and Cr contributed the most to the high toxic risk index values. Both carcinogenic and non-carcinogenic risk indices of PTEs in soils were within an acceptable limit, except for the cancer risk of Ni (3.52E-04) and Cr (3.00E-04) among children. The spatial hazard index and carcinogenic health risk of PTEs showed that samples from the southwestern parts of the study area might pose significant health problems to adults and children. This study demonstrates how combining different techniques can help spatially characterize PTE accumulation and protect populations at risk.

Macronutrients, trace metals and health risk assessment in agricultural soil and edible plants of Mahshahr City, Iran.

In this study, we evaluate the geochemistry of macro- (Fe, P, Ca, S, K, Na, Mg) and micronutrients (Mo, Cu, Pb, Zn, Co, Mn, Cd, Sr, Cr, Hg, Se), along with possible health risks of heavy metals contamination in agricultural soils and vegetables of the Mahshahr industrial port in Iran. Calculation of geochemical coefficients revealed the low pollution load of Mahshahr agricultural soils. Most of the investigated elements exhibited lower concentrations in soil than international standards. Element concentrations in plant samples were far below the permissible values set by environmental agencies. Based on permissible values, there was deficiency of several soil elements, including Cu, in vegetables because they are mostly present in the soil residual phase. An exception was Mn, which is the most mobile element in soil. The transfer factor (TF) of elements showed the following trend: K > Na > P > S > Mo > Hg > Se > Zn > Cd > Cu > Mg > Mn > Ca > Cr > Co ≈ Fe = Pb. There was high transfer of major elements from soil to plants, and lower values for micronutrients and heavy metals. The calculated daily intake (DIM) and health risk index (HRI) for ten plant species for adults were < 1, while the HRI was larger than 1 for Mn via radish consumption. According to geochemical investigations and statistical tests such as principal component analysis, Kruskal-Wallis, and correlation coefficient calculations, plant species play the most important role in elemental uptake by plants.

Foliar surfaces as dust and aerosol pollution monitors: An assessment by a mining site.

Recent studies in the southwestern United States have shown that smelting processes and mine tailings emit heavy metal(loid)s that are distributed via wind dispersion to nearby communities. With increased attention regarding the effect of air pollution on environmental health, communities have begun to use citizen/community-based monitoring techniques to measure the concentration of metal(loid)s and evaluate their air quality. This study was conducted in a mining community to assess the efficacy of foliar surfaces as compared to an inverted disc (frisbee) to sample aerosol pollutants in ambient air. The assessment was conducted by evaluating As, Pb, Cd, Cu, Al, Ni, and Zn concentrations versus distance from a former smelter, statistical and regression analyses, and enrichment factor calculations compared to similar sites worldwide. Both the foliar and frisbee collection methods had a decrease in metal(loid)s concentration as a function of distance from the retired smelter. Statistical calculations show that the collection methods had similar mean concentrations for all of the metal(loid)s of interest; however, the tests also indicate that the frisbee collection method generally collected more dust than the foliar method. The enrichment factors from both collection methods were comparable to similar studies by other mining areas referenced, except for aluminum. Since there is evidence of enrichment, correlation between methods, and citizen/community science potential, these efforts show promise for the field. Further studies should consider alternating the types of plant used for foliar collection as well as collecting samples on a more frequent basis in order to sufficiently categorize results based on meteorological conditions.

A wavelet-based random forest approach for indoor BTEX spatiotemporal modeling and health risk assessment.

This study reports on BTEX concentrations in one of the largest parking garages in Iran with a peak traffic flow reaching up to ~9300 vehicles in the last few days of the Nowruz holidays. Samples were obtained on different days of the week at three main locations in the Zaer Parking Garage. A novel wavelet-based random forest model (WRF) was trained to estimate BTEX concentrations by decomposing temperature, day of the week, sampling location, and relative humidity data with a maximal overlap discrete wavelet transform (MODWT) function and subsequently inputted into the WRF model. The results suggested that the WRF model can reasonably estimate BTEX trends and variations based on high R2 values of 0.96, 0.95, and 0.98 for training, validation, and test data subsets, respectively. The carcinogenic (LTCR) and non-carcinogenic health risk (HI) assessment results indicated a definite carcinogenic risk of benzene (LTCR = 2.22 × 10-4) and high non-carcinogenic risk (HI = 4.51) of BTEX emissions. The results of this study point to the importance of BTEX accumulation in poorly ventilated areas and the utility of machine learning in forecasting air pollution in diverse airsheds such as parking garages.

Predicting Vertical Concentration Profiles in the Marine Atmospheric Boundary Layer With a Markov Chain Random Walk Model.

In an effort to better represent aerosol transport in mesoscale and global-scale models, large eddy simulations (LES) from the National Center for Atmospheric Research (NCAR) Turbulence with Particles (NTLP) code are used to develop a Markov chain random walk model that predicts aerosol particle profiles in a cloud-free marine atmospheric boundary layer (MABL). The evolution of vertical concentration profiles are simulated for a range of aerosol particle sizes and in a neutral and an unstable boundary layer. For the neutral boundary layer we find, based on the LES statistics and a specific model time step, that there exist significant correlation for particle positions, meaning that particles near the bottom of the boundary are more likely to remain near the bottom of the boundary layer than being abruptly transported to the top, and vice versa. For the unstable boundary layer, a similar time interval exhibits a weaker tendency for an aerosol particle to remain close to its current location compared to the neutral case due to the strong nonlocal convective motions. In the limit of a large time interval, particles have been mixed throughout the MABL and virtually no temporal correlation exists. We leverage this information to parameterize a Markov chain random walk model that accurately predicts the evolution of vertical concentration profiles. The new methodology has significant potential to be applied at the subgrid level for coarser-scale weather and climate models, the utility of which is shown by comparison to airborne field data and global aerosol models.

The urgent need for integrated science to fight COVID-19 pandemic and beyond.

The COVID-19 pandemic has become the leading societal concern. The pandemic has shown that the public health concern is not only a medical problem, but also affects society as a whole; so, it has also become the leading scientific concern. We discuss in this treatise the importance of bringing the world's scientists together to find effective solutions for controlling the pandemic. By applying novel research frameworks, interdisciplinary collaboration promises to manage the pandemic's consequences and prevent recurrences of similar pandemics.

Characteristics and health risk assessment of polycyclic aromatic hydrocarbons associated with dust in household evaporative coolers.

This study reports a characterization of indoor polycyclic aromatic hydrocarbons (PAHs) associated with dust (dust-PAHs) in household evaporative coolers and their associated health effects. Extensive analysis showed that the indoor dust-PAHs stemmed mostly from pyrogenic sources (vehicular emissions) with mean total concentrations limited between 131 and 429 ng g-1. The distribution pattern of PAHs based on number of rings exhibited the following order of decreasing relative abundance: 4 > 3 > 5 > 6 > 2 rings. Results indicate that the mutagenicity of dust-PAHs exceeded their carcinogenicity, but that the potential carcinogenic effects are still significant. The mean lifetime cancer risk for different age groups for three pathways based on Model 2 (dermal (1.39 × 10-1 to 1.91 × 10-2), ingestion (2.13 × 10-3 to 8.08 × 10-3) and inhalation (1.62 × 10-7 to 4.06 × 10-7)) was 7.4-146 times higher than values predicted by Model 1 (dermal (5.13 × 10-5 to 3.03 × 10-3), ingestion (9.34 × 10-5 to 1.31 × 10-3) and inhalation (7.13 × 10-20 to 1.68 × 10-20)). Hence, exposure to dust-PAHs in household evaporative coolers lead to high risk, especially for children (less than 11 years) (HQ = 2.71 × 10-20 to 54.8 and LTCRs = 7.13 × 10-20 to 1.39 × 10-1). Strategies should be considered to eliminate such pollutants to protect people, especially children, from the non-carcinogenic and carcinogenic effects by changing household evaporative coolers with other cooling systems.

Contamination Level, Source Identification and Risk Assessment of Potentially Toxic Elements (PTEs) and Polycyclic Aromatic Hydrocarbons (PAHs) in Street Dust of an Important Commercial Center in Iran.

The geochemical nature and health hazards of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in the street dust of Bandar Abbas, Iran, are investigated in this study based on 27 street dust samples. Mean concentrations of Cu, Pb, Zn, As, Sb, and Hg revealed elevated concentrations as compared to the world soil average. Calculated enrichment factors (EFs) indicated that there is very high contamination in dust particles owing to anthropogenic emissions. Two main sources of PTEs are traffic emissions (Cu, Pb, Zn, Co, Mn, Fe, As, Cd, Sb, and Hg) and resuspended soil particles (Al, Ti, Ni, and Cr). Statistical analysis shows that Al, Mn, Ni, Ti, Cr, Fe, and Co are geogenic, whereas PAHs are mainly derived from traffic emissions. Values of incremental lifetime cancer risk (ILCR), as derived from a modified model of the United State Environmental Protection Agency (USEPA), indicate that Bandar Abbas residents are potentially exposed to high cancer risk, especially via dust ingestion and dermal contact, whereas the level of hazard index (HI), hazard quotients (HQ), and cancer risk associated with exposure to the elements in street dust fall lower than threshold values representative of health risks.

Heavy metal contamination and health risk assessment in three commercial fish species in the Persian Gulf.

Five heavy metals/metalloids and related potential health risks were investigated in three commercially important fish species (Anodontostoma chacunda, Belangerii, and Cynoglossurs arel) in Musa Estuary and Mahshahr Harbour of the Persian Gulf. A total of 116 fish samples were collected, and their liver and muscle organs were separately analyzed using ICP-MS. Results revealed that studied metals concentrations (with some exceptions) varied among sampling stations, fish species and their organs. Human health risk is evaluated using different indices. The results indicated that arsenic and mercury are the most hazardous elements. Estimated daily intake (EDI) for the metals exceeded the provisional tolerable daily intake (PTDI) for all studied fish species. Also, target risk (TR) of arsenic indicated that consumption over a long period of time may result in a carcinogenic effect. The results are expected to create awareness among the public on the safety of consuming food products grown in particular areas.