River Ganga is one of the prime sacred National Rivers of India, closely associated with economic, social, and cultural heritage of Indian people. Recently, it has been subjected to immense degradation and pollution as a result of receiving huge amounts of domestic and industrial wastewater as well as religious ritual activities and surface runoff. The present study attempts to study spatial and temporal changes in water quality of River Ganga while calculating its Water Quality Index (WQI) by analyzing 9 physico-chemical, 7 trace metal, and 4 microbiological parameters at eleven sampling stations, on the basis of River Ganga index of Ved Prakash. Thus it can assess water’s suitability for drinking and irrigation purposes along with other human uses. The study is directed towards the use of WQI to describe pollution level in the river for a period of 1 year (from January to December 2014). It has been shown that index values as per CPCB class range between medium to good, while the ones as per NSF Index range from bad to good water quality. The study also identifies critical pollutants, affecting the river water quality within its course through the city. Finally, pH, DO, BOD, DO, EC, and FC have been found to be critical parameters for the stretch in each season of this research.

Due to rapid industrialization and urbanization, environmental pollution has become a major concern in developing countries; therefore, the main objective of the current study is to determine heavy metal contents of Pb, and Ni for 42 topsoil samples, collected from 14 green spaces along the 1st and 2nd ring roads in Hamedan City in 2016. For this purpose, after determining some chemical properties as well as acid digestion of soil samples, Pb and Ni concentrations have been found in the soil samples with ICP-OES. All statistical analyses have been conducted, using SPSS 18.0 statistical package, with the results showing that the metal levels in soil samples, collected from green space of 1st and 2nd ring road, have been 34.86±10.28 and 41.57±10.08 mg/kg for Pb and 14.0-20.33 and 14.0-20.0 mg/kgfor Ni, respectively. Also the mean concentration of Pb and Ni have been lower than MPL. According to heavy metal concentration maps, the spatial distribution patterns of Pb, and Ni contents in the soil samples are generally similar along the 1st and 2nd ring road. Due to the fact that traffic volume in the 2nd ring was higher than the 1st one, there has been a significant difference in the mean contents of Pb between the topsoil samples, collected from the 1st and 2nd ring roads; therefore, it is recommended to keep environmental health in order to control the anthropogenic sources, causing the pollutants discharge into the environment is recommended.

The present study monitors BTEX concentration in outdoor and indoor air of eight different microenvironments during summer 2017 and winter 2018 at Asaloyeh city, Iran's energy capital. It samples BTEX compounds by charcoal tubes, analyzing the samples by means of a gas chromatograph with a flame ionization detector. According to the obtained results, outdoor concentrations of BTEX have been higher than the indoor ones, for both seasons, with the highest outdoor and indoor BTEX being 21.70 and 18.59 μg/m3, respectively. Toluene has been the most abundant substance, among the investigated BTEX in all sampling points. Based on the MIR scale, m, p-xylene is the most dominant contributor to ozone formation potential among BTEX species. Indoor to outdoor (I/O) ratios of BTEX compounds range from 0.53 to 0.88 and 0.41 to 0.77 in winter and summer, respectively. The cumulative hazard index (HI) is within an acceptable range. The LTCR value of benzene concentration, obtained, exceeds the value of 1.0E-06, recommended by USEPA. Sensitivity analysis shows that benzene concentration, exposure duration, and inhalation rate have a greater impact on health risk assessment.

The influence of regional transport on aerosol pollution has been explored in previous studies based on numerical simulation or surface observation. Nevertheless, owing to inhomogeneous vertical distribution of air pollutants, vertical observations should be conducted for a comprehensive understanding of regional transport. Here we obtained the vertical profiles of aerosol and its precursors using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) at the Nancheng site in suburban Beijing on the southwest transport pathway of the Beijing-Tianjin-Hebei (BTH) region, China, and then estimated the vertical profiles of transport fluxes in the southwest-northeast direction. The maximum net transport fluxes per unit cross-sectional area, calculated as pollutant concentration multiply by wind speed, of aerosol extinction coefficient (AEC), NO₂, SO₂ and HCHO were 0.98 km⁻¹ m s⁻¹, 24, 14 and 8.0 μg m⁻² s⁻¹ from southwest to northeast, which occurred in the 200–300 m, 100–200 m, 500–600 m and 500–600 m layers, respectively, due to much higher pollutant concentrations during southwest transport than during northeast transport in these layers. The average net column transport fluxes were 1200 km⁻¹ m² s⁻¹, 38, 26 and 15 mg m⁻¹ s⁻¹ from southwest to northeast for AEC, NO₂, SO₂ and HCHO, respectively, in which the fluxes in the surface layer (0–100 m) accounted for only 2.3%–4.2%. Evaluation only based on surface observation would underestimate the influence of the transport from southwest cities to Beijing. Northeast or weak southwest transports dominated in clean conditions with PM₂.₅ <75 μg m⁻³ and intense southwest transport dominated in polluted conditions with PM₂.₅ >75 μg m⁻³. Southwest transport through the middle boundary layer was a trigger factor for aerosol pollution events in urban Beijing, because it not only directly bringing air pollutants, but also induced an inverse structure of aerosols, which resulted in stronger atmospheric stability and aggravated air pollution in urban Beijing.

Taking advantage of the different histories of Hg deposition in Davos Seehornwald in E-Switzerland and Changbai Mountain in NE-China, the influence of atmospheric deposition on Hg soil dynamics in forest soil profiles was investigated. Today, Hg fluxes in bulk precipitation were similar, and soil profiles were generally sinks for atmospherically deposited Hg at both sites. Noticeably, a net release of 2.07 μg Hg m⁻² yr⁻¹ from the Bs horizon (Podzol) in Seehornwald was highlighted, where Hg concentration (up to 73.9 μg kg⁻¹) and soil storage (100 mg m⁻³) peaked. Sequential extraction revealed that organic matter and crystalline Fe and Al hydr (oxide)-associated Hg decreased in the E horizon but increased in the Bs horizon as compared to the Ah horizon, demonstrating the coupling of Hg dynamics with the podzolisation process and accumulation of legacy Hg deposited last century in the Bs horizon. The mor humus in Seehornwald allowed Hg enrichment in the forest floor (182–269 μg kg⁻¹). In Changbai Mountain, the Hg concentrations in the Cambisol surface layer with mull humus were markedly lower (<148 μg kg⁻¹), but with much higher Hg soil storage (54–120 mg m⁻³) than in the Seehornwald forest floor (18–27 mg m⁻³). Thus, the vertical distribution pattern of Hg was influenced by humus form and soil type. The concentrations of Hg in soil porewater in Seehornwald (3.4–101 ng L⁻¹) and in runoff of Changbai Mountain (1.26–5.62 ng L⁻¹) were all low. Moreover, the pools of readily extractable Hg in the soils at both sites were all <2% of total Hg. Therefore, the potential of Hg release from the forest soil profile to the adjacent aquatic environment is currently low at both sites.

Soil polycyclic aromatic hydrocarbons (PAHs) generated from industrial processes are highly spatially heterologous, with limited quantitative studies on their main influencing factors. The present study evaluated the soil PAHs in three types of industrial parks (a petrochemical industrial park, a brominated flame retardant manufacturing park, and an e-waste dismantling park) and their surroundings. The total concentrations of 16 PAHs in the parks were 340–2.43 × 10³, 26.2–2.63 × 10³, and 394–2.01 × 10⁴ ng/g, which were significantly higher than those in the surrounding areas by 1–2 orders of magnitude, respectively. The highest soil PAH contamination was observed in the e-waste dismantling park. Nap can be considered as characteristic pollutant in the petrochemical industrial park, while Phe in the flame retardant manufacturing park and e-waste dismantling park. Low molecular weight PAHs (2–3 rings) predominated in the petrochemical industrial park (73.0%) and the surrounding area of brominated flame retardant manufacturing park (80.3%). However, high molecular weight PAHs (4–6 rings) were enriched in the other sampling sites, indicating distinct sources and determinants of soil PAHs. Source apportionment results suggested that PAHs in the parks were mainly derived from the leakage of petroleum products in the petroleum manufacturing process and pyrolysis or combustion of fossil fuels. Contrarily, the PAHs in the surrounding areas could have been derived from the historical coal combustion and traffic emissions. Source emissions, wind direction, and local topography influenced the PAH spatial distributions.

The pollution of energetic compounds (ECs) in military ranges has become the focus of worldwide attention. However, few studies on the contamination of ECs at Chinese military ranges have been reported to date. In this study, two different types of military demolition range in China, Dunhua (DH) and Taiyuan (TY), were investigated and the ECs in their soils were determined. 10 ECs were detected at both ranges. While all the contamination characteristics were distinct, 2,4,6-trinitrotoluene (TNT) was the most abundant contamination source in soils at DH range, with an average concentration of 1106 mg kg⁻¹ and a maximum concentration of 34,083 mg kg⁻¹. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and two mono-amino degradation products of TNT were also found to have high concentrations, with potential ecological and human health risks. In contrast, the concentrations of ECs in soils of TY range were much lower. The content of RDX was most significant, with average and maximum concentrations of 7.8 and 158 mg kg⁻¹, respectively. However, the potential threat to human health of 2,4-dinitrotoluene and 2,6-dinitrotoluene in soils at both ranges should not be ignored. The differences in pollution characteristics of the ECs at DH and TY are closely related to the types and amounts of the munitions destroyed. Moreover, the spatial distribution of ECs at the demolition ranges was extremely heterogeneous, which may be attributed to the use of open burning / open detonation and the non-homogeneous composition of the munitions.

Reservoirs are an important type of drinking water source for megacities, while lots of reservoirs are threatened by odor problems during certain seasons. The influencing factors of odor compounds in reservoirs are still unclear. During August 2019, a nationwide survey investigating the distribution of odor compounds in reservoirs used as drinking water sources was conducted on seven reservoirs. 2-methylisoborneol (2-MIB) and geosmin were detected in almost every reservoir, and some odor compound concentrations even exceeded the odor threshold concentration. The average concentration of 2-MIB was 2.68 ng/L, and geosmin was 3.63 ng/L. The average chlorophyll a concentration was 8.25 μg/L. The dominant genera of phytoplankton in these reservoirs belonged to cyanobacteria and diatom. Statistical analysis showed that odor compound concentration was significantly related to the chlorophyll a concentration and indicated that the odor compounds mainly came from phytoplankton. The concentration of odor compounds in the euphotic zone was significantly related to phytoplankton species and biomass. Therefore, the odor compound concentrations in the subsurface chlorophyll maxima layer was generally higher than in the surface layer. However, the odor compounds in the hypolimnion layer were related to the density current. This research suggests that both phytoplankton proliferation events and heavy storm events are important risk factors increasing odor compounds in reservoirs. Control of algal bloom, in-situ profile monitoring system and depth-adjustable pumping system will greatly reduce the risk of odor problems in reservoirs using as water supplies for large cities.

Horse mackerel is a semi-pelagic species found in abundance in the Moroccan coasts and occupies the first ranks in the catches landed by the coastal fleet. In this study, we investigated the ingestion of Polyamide, Acrylic and Polystyrene by Atlantic horse mackerel, in the Moroccan Atlantic coastal area located between Larache (35°30′N) and Boujdour (26°30′N). The objective is to map the spatial distribution of horse Mackerel containing microplastics (MPs) in their stomachs and identify hot spot areas. We also aim to verify the most ingested polymer by this fish characterized by significant daily vertical migrations. The results show that the three studied polymers were detected in the stomach contents of more than 73% of studied fishes. The hot spot areas are located more in the northern part where urbanization and fishing activity are important. Polyamide, the densest polymer, is the most abundant (86% of cases), followed by acrylic. These two polymers were found in association in 47% of cases. No correlation between the presence of MPs in the stomach contents and the size of the individual fishes was noted. Interestingly, the group of mature specimens ingested more MPs than the immature group.

Soil around the gold tailing due to the smelting process of wastewater and solid waste can lead to metal (loids) contamination, especially arsenic (As). Soil microorganisms have gradually evolved adaptive mechanisms in the process of long-term adaptation to As contamination. However, comprehensive investigations on As metabolism genes and their host microbial communities in soil profiles with different levels under long-term As contamination are lacking. There are selected three typical soil profiles (0–100 cm) with different metal (loids) contamination levels (L-low, M-moderate and H-high) around tailings in this research. It uses a Metagenomic approach to explore the adaptation mechanisms of arsenic metabolism genes and arsenic metabolism gene host microorganisms in both horizontal and vertical dimensions. The results showed that four categories of As metabolism genes were prevalent in soil profiles at different As contamination, with As reduction genes being the most abundant, followed by As oxidation genes, then respiration genes and methylation genes. The As metabolism genes arsBCR, aioE, arsPH, arrAB increased with the increase of metal (loid) contaminants concentration. Longitudinal arsA, arrA, aioA, arsM and acr3 increased in abundance in deep soil. Actinobacteria, Proteobacteria, Acidobacteria, and Chloroflexi were the dominant phylum of As metabolism gene host microorganisms. Different concentrations of metal (loid) contamination significantly affected the distribution of host As metabolism genes. Random forest prediction identified As as the most critical driver of As metabolism genes and their host microorganisms. Overall, this study provides a reference for a comprehensive investigation of the detoxification mechanisms of As metabolism microorganisms in soil profiles with different As contamination conditions, and is important for the development of As metabolism gene host microbial strains and engineering applications of microbial technologies to manage As contamination.