During a 1-year study, organic aerosol indoor air samples were collected from sites in a library in Rio de Janeiro, Brazil. Indoor air is a cause for public concern in Brazil. This study presents an indoor air survey wherein the concentrations of aliphatic hydrocarbons, phthalates, phenyl phosphates, aldehydes, limonene, organic acids, and particulate matter were determined. Acids were estimated to be ranging between 0.01 and 30.26 ng m−3, whereas furfural ranged between 0.5 and 3.6 g m−3. Compounds such as furfural, hexanal, benzaldehyde, and vanillin were only detected indoors. Results showed that total suspended particle concentrations were higher outdoors than indoors. Interestingly, 1, 1, 1-trichloro-2, 2-bischlorophenylethane (DDT), and its derivatives were also present. Pesticides are used in libraries to control paper-degrading pests. Therefore, DDT and other chemicals remain nondegraded and pollute the library rooms. This study demonstrates the relevance of monitoring indoor air quality in libraries and the pollutants that can affect the well-being of occupants. Moreover, indoor air quality monitoring can provide early warning to library managers about the effects of indoor air characteristics on unprotected and/or preserved items.

Sediment collected from the rivers of southern Alberta, Canada, presents patterns of polycyclic aromatic hydrocarbons (PAHs) that demonstrate a varied origin within the Rocky Mountains. An influx of PAHs from sub-bituminous coal sources from erosional processes as the river exit the mountains dominates the pattern of PAHs in the river sediment across the prairies to the Alberta-Saskatchewan border (a distance of 750 km for the Red Deer River and 925 km for the Bow River) continues much further downstream. The concentrations of PAHs are similar to the well-studied Athabasca River in the Alberta Oil Sands Region. Although these results relate to rivers flowing east from the Rocky Mountains in Canada, it is likely that coal-sourced PAHs will contribute to any river where erosion of coal formations is possible within the watershed. A distinctive natural pattern of strongly pyrogenic PAHs from nearby thermal hot springs was also discovered near Banff. Natural pyrogenic PAH sources, aside from wildfires, are uncommon and generally related to hydrothermal vents and igneous intrusions into source rocks. This is the first time the authors are aware of sediment from a thermal spring presenting such PAH patterns.

Pakistan is a developing country and its population is growing rapidly. The trend towards economic growth and satisfying the needs of the growing population is increasing daily. For this purpose, industrial activities, vehicle emissions, and household-related activities pollute the atmospheric environment and release different types of toxic gases. Particulate matter assessments (PM2.5 and PM10) were reviewed in different cities of Pakistan. Respectively, the PM2.5 evaluation was carried out in 15 cities, while the PM10 concentration was in 18 cities in Pakistan. According to the review, the highest concentrations of PM2.5 were 302, 211.97, 88, 163.63, 113.09, 110.81, 110.81, 139.43, 126.97, 107.68, 109.81, 172, 150, 66, 354, 43.9, 2305 µg/m3 in Lahore, Faisalabad, Karachi, Gujranwala, Multan, Vehari, Bahawalnagar, Okara, Pakpattan, Jehlum, Sargodha, Peshawar Quetta, Islamabad, Haripur, Mingora, and Mardan (Jalala). Specifically, the highest concentration of PM10 were 301, 568, 638, 160.5, 200, 384.15, 301.38, 311.61, 700 µg/m3 in Lahore, Faisalabad, Peshawar, Charsada, Karachi, Gujranwala, Multan, Rawalpindi, and Quetta. Only, these cities are the most polluted in the whole country and the concentration of PM2.5 was above the normal range those prescribed by the National Environmental Quality Standred (NEQS). Commonly, the main problem is the suspended particulate matter (PM2.5 and PM10) in the atmosphere. The increasing level of pollution leads to different types of problems such as respiratory problems, eye irritation, throat infections, asthma, and cancer, and it also increases the level of death ratio in the country. The main reason for PM is the burning of solid waste near cities; industrial emission, vehicular emission, lack of proper green belt and solid waste management are the main reasons for atmospheric pollution. Given the existing state of the air, urgent action is required to address the low air quality.

The primary considerations within aquatic ecosystems are water and sediment quality, rendering it imperative to assess their concentrations, pollution levels, origins, and ecological hazards. In this study, heavy metal concentrations in surface waters and sediments of the Pülümür Stream were investigated to assess the level, distribution, source of pollution and the associated human risks. Water and sediment samples from the river were collected monthly from February 2021 to January 2022 and examined using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Metal concentrations in the sediment followed a decreasing or derivative sequence of Fe > Al > Mn > Ni > Cr > Zn > Cu > Pb > As >Cd > Hg. The ecological indices of the stream water have low degrees of contamination by heavy metals. Igeo and EF showed that most of the sites are moderately to highly polluted due to Ni, and Cr, while PLI and PERI showed a progressive deterioration of the environment at site 9. Moreover, the modified hazard quotient (mHQ) indicates low ecological risk for Cu, Pb, Zn, Cd, Hg metals, while Ni, As and Cr reach high pollution at sediment sites. Pearson correlation analysis revealed that the presence of Zn, Cu, Pb, Hg, and Mn metals in the sediment analysis has a lithogenic source, and As, Ni, Cd, and Cr accumulate due to human activities, mainly domestic and agricultural irrigation wastes and mining wastes, all of which affect the aquatic environment. According to this study, more attention should be paid to the comprehensive monitoring of metals in the water and sediment for both aquatic biota and human risk of the Pülümür River.

The groundwater is a significant source of readily available freshwater. However, these groundwater aquifers are susceptible to contamination by the presence of many potential pollution sources. These potential sources may be active at any location for any duration with an unknown magnitude of source fluxes. The identification of these potential sources is necessary for remediation and management. In this work, the groundwater contamination sources are identified for two probable situations, i.e., Error-free concentration measurements and erroneous concentration measurements. The proposed methodology exploits the capability of the multistage approach of recent hybrid soft computing models (ensemble of Wavelet Neural Network [WNN]; Autoregressive Integrated Moving Average [ARIMA]) to identify potential pollution sources effectively. The models are trained by the simulated concentrations for randomly generated source fluxes by Groundwater Modelling System (GMS). The multistage approach has been adopted here, which includes three-stage models. To exploit the effectiveness of WNN and ARIMA, they are used at different stages in the multistage models, thereby developing various hybrid ensembles. Total of four hybrid models are developed utilising the multi-staging approach of WNN and ARIMA models, Namely Hybrid-II, III, IVA, and IVB. Predicted results from these models were compared on the same data sets. They are compared using various performance indices, such as RMSE, NE, correlation coefficient, etc. Error values of Hybrid II ensemble (employing WNN at first stage and ARIMA at second stage) are lowest as compared to only WNN and other Hybrid models. Hence, the Hybrid-II model can be utilised to accurately predict potential contamination sources in any sample area in groundwater.

Outdoor PM2.5 samples were collected for 34 months in Pretoria, South Africa from 18 April 2017 to 28 February 2020. The average total PM2.5 concentration was 23.2 ± 17.3 µg.m3 (0.69–139 µg.m−3), with the highest mean recorded during winter and the lowest during summer (p < 0.05). The sources were determined by means of cross referencing the US EPA PMF 5.0 program and the NOAA HYsplit model. The sources of the total PM2.5 were mining (33%), resuspended dust (24%), industry (15%), general exhaust (12%), vehicular emissions (12%) and biomass burning (4%). Sources of air pollutants are both ubiquitous and seasonal.

There is a need to study the spatiotemporal distribution of chlorinated solvent releases in groundwater to understand the risk/threat they pose to human health, water quality, and the environment, which then can be used to prioritize clean-up and evaluate regulatory closure with appropriate risk management controls. This paper provides a statistical analysis of spatiotemporal distribution of perchloroethylene (PCE) (and its degradation products including trichloroethene [TCE]) from eighty-three cases across California for which data were available onthe State Water Resources Control Board’s GeoTracker database and the Department of Toxic Substance Control Board’s Envirostor database. These cases consisted of seventy-one dry cleaning sites and twelve other similar small solvent release sites. Statistical analyses of available groundwater data were performed to estimate: maximum concentrations at the source area, groundwater plume length, plume stability; and correlations between plume length, concentrations, and plume age. At 90% of the sites, the PCE and TCE plume lengths were less than 1,569 feet (478 meters) and 1,782 feet (543 meters), respectively. The average plume lengths for PCE and TCE were 670 feet (204 meters) and 701 feet (213 meters), respectively. At 90% of the sites that have reached stable conditions, PCE and TCE concentrations at the source areas were less than 2,670 and 660 micrograms per liter (µg/L) respectively. This study for the first time provides key characteristics of small chlorinated-solvent plume behaviors in California that can be used to prioritize management of small chlorinated-solvent release sites and to develop strategies towards achieving closure at these sites.

Ambient PM2.5 samples were collected in Laiwu, a small industrial city in China known for steel production, to measure and evaluate the mass concentrations of PM2.5 and the inorganic water-soluble ions (IWS ions). The highest PM2.5 value recorded was 251.28 μg/m3, which occurred during winter and was lower than other major Chinese cities. The spatial distribution showed that the center of the city, which is connected to the downtown area, was heavily polluted (170 μg/m3 higher) compared to the suburbs. With the exception of winter, the weight of PM2.5 was dominated by IWS ions, with three secondary ions (NO3 -, SO4 2-, and NH4 +) accounting for more than 70% of the total ions in mass. This percentage is higher than that of big cities. An increase in sulfur oxidation ratios (SOR), nitrogen oxidation rate (NOR), and anion equivalent/cation equivalent (AE/CE) indicated that the atmosphere in Laiwu was more oxidized than other big cities. The ion analysis revealed that PM2.5 was highly correlated with NO3 -, SO4 2-, and NH4 +. The principal component analysis indicated that district heating during winter and industrial output and secondary transformation during summer were the major sources of the water-soluble ions. The backward trajectory study identified the north of Shandong Province as the likely source-area that affected air quality in Laiwu.

The rapid rise in the use of MTBE in automotive gasoline in the U.S. in the early 1990s was matched only by its rapid decline in the early 2000s, the latter stemming from its unsettling and detrimental impact on groundwater and drinking water supplies following gasoline leaks and spills. Its decline was promulgated through implementation of numerous legislated, state-level bans, which along with the Energy Policy Act of 2005’s elimination of a minimum oxygen requirement for reformulated gasoline, effectively ended the “MTBE era” by the Spring of 2006. Despite the bans, most of which only prohibited the intentional use of MTBE, opportunities remained for its incidental occurrence in gasoline. In this study, we report on the existence, concentration, and frequency of incidental MTBE and other oxygenates (TAME, ETBE, DIPE, and TBA) in an ad hoc suite of 76 “post-ban” gasolines collected from retail service station dispensers in multiple states between 2004 (in states with early bans) and 2020. These results are compared to those for 75 “pre-ban” (oxygenated, reformulated, and conventional) gasolines. Using GC/MS full scan data with a method detection limit of 10 mg/kg, the results confirm the incidental occurrence of MTBE in 34% of the “post-ban” gasolines at concentrations between 980 and 17 mg/kg (avg. ± σ; 209 ± 307 mg/kg), which generally decreased between 2004 and 2020. MTBE’s origin(s) in “post ban” gasolines is reasonably attributed to cross-contamination with neat MTBE or MTBE-laden gasoline destined for U.S. export, and/or its otherwise lingering presence within the gasoline distribution system. Although less frequently detected, low concentrations (mostly < 1,000 mg/kg) of TAME, ETBE, DIPE and TBA were also found in 17, 14, 13 and 4% of the “post-ban” gasolines studied, respectively. The forensic implications of these results on constraining the “age” of gasoline-derived NAPL containing MTBE or of MTBE-impacted groundwater, which are equally applicable to the other oxygenates measured, are discussed. Of overriding relevance is that any presumption that MTBE completely disappeared from the U.S. gasoline pool after the implementation of the state-level bans and Energy Policy Act is false.

Heavy metal concentrations were determined in four different locations: market, abattoir, mechanic village and farmland in Obollo–Afor and its environs. The samples were digested and subsequently analysed using Atomic Absorption Spectrophotometer (AAS). The mean concentration of metals in the soil samples were in the order Fe > Zn > Mn > Cr > Pb > Cu > Ni > Cd. The mean concentration of metals in the effluent samples were in the order Fe > Cr > Ni > Pb > Zn > Mn > Cd > Cd. The mean concentration of the metals in meat samples were in the order Fe > Zn > Cu > Ni > Mn > Cd > Cr > Pb. The mean concentration of metals in the plant samples were in the order Fe > Mn > Zn > Cu > Ni > Cr > Pb > Cd. Cadmium, zinc, chromium and lead were higher than the World Health Organization (WHO) standard for soil while cadmium, copper and zinc were higher than the WHO standard for plant. Iron, zinc, copper, nickel and chromium were higher than the WHO standard for meat while lead, nickel, iron, were higher than the WHO standard for water. Heavy metal pollution index (HPI) and heavy metal evaluation index (HEI) showed low risk for all locations while degree of contamination (Cdeg) revealed medium to high values for all locations except AB7. Consequently, the environment is not safe due to high concentration of these toxic metals. The multivariate analyses unraveled anthropogenic and geogenic sources of the contamination. With this trend of findings from the forensics entropy analysis, it can be said that Obollo Afor is the epicentre of these contaminants and attenuates towards the farmland area. The study therefore recommends effective and efficient environmental management strategy measures to curb this menace.