Groundwater quality indicators were monitored over 6 years (2007–2012) from 55 drinking water supply wells in Gharbiya Governorate (Egypt). The prime objective was to characterize, for the first time, the governorate-wide significant and sustained trends in the concentrations of the groundwater pollutants. Quality indicators included turbidity, pH, total dissolved solid (TDS), electric conductivity (EC), Cl⁻, SO₄ ²⁻, Na⁺, total alkalinity, hardness (total, Mg, and Ca), Fe²⁺, Mn²⁺, Cu²⁺, Zn²⁺, F⁻, NH₄ ⁺, NO₂ ⁻, NO₃ ⁻, PO₄ ³⁻, dissolved oxygen (DO), and SiO₂ contents. Detection and estimation of trends and magnitude were carried out applying the non-parametric Mann–Kendall and Thiel–Sen trend statistical tests, respectively. Factor analysis was applied to identify significant sources of quality variation and their loads. Violation of groundwater quality standards clarified emergence of Mn²⁺ (46%), Fe²⁺ (35%), and NH₄ ⁺ (33%). Out of the 55 wells, notable upward trends (deterioration) were significant (>95% level) for TDS (89%), NO₃ ⁻ (85), PO₄ ³⁻ (75%), NH₄ ⁺ (65%), total alkalinity (62%), Fe²⁺ (58%), NO₂ ⁻ (47%), Mg hardness (36%), turbidity (25%), and Mn²⁺ (24%). Ranges of attenuation rates (mg/l/year) varied for TDS (24.3, −0.7), Mg hardness (3.8, −0.85), total alkalinity (1.4, −1.2), NO₃ ⁻ (0.52, −0.066), PO₄ ³⁻ (0.069, −0.064), NH₄ ⁺ (0.038, −0.019), Mn²⁺ (0.015, −0.044), Fe²⁺ (0.006, −0.014), and NO₂ ⁻ (0.006, −0.00003). Highest rates marked Tanta (total alkalinity and Fe²⁺), Al-Mehala Al-Kubra (TDS, Mg hardness, and NO₃ ⁻), Kafr Al-Zayat (NH₄ ⁺), Zifta (Mn²⁺), Bassyun (NO₂ ⁻), and Qutur (PO₄ ³⁻). Precision of the trend estimate varied in goodness of fit, for TDS (86%), Mg hardness (76%), total alkalinity (73%), PO₄ ³⁻ (67.4%), NH₄ ⁺ (66.8%), Mn²⁺ (55%), and Fe²⁺ (49.6%), arranged in decreasing order. Two main varimax-rotated factors counted for more than 55% of the quality variance and, in particular, significant loads of salinity (TDS, EC, Cl⁻, Na⁺, and SO₄ ²⁻), followed by the alkalinity, hardness, redox potentials (Mn²⁺ and Fe²⁺), and NH₄ ⁺, in decreasing order were identified. The spatial-temporal variation in pollutants originated from organic matter degradation, either naturally from the aquifer peaty sediments or anthropogenic due to improper well head protection in the urban centers or from the agricultural drains in low relief areas. Considering the latest contents of indicators and their rate of increase, the time that the permissible limits would be reached can be accurately estimated and alleviative actions could be effectively set.

Bioretention, also known as rain garden, allows stormwater to soak into the ground through a soil-based medium, leading to removal of particulate and dissolved pollutants and reduced peak flows. Although soil organic matter (SOM) is efficient at sorbing many pollutants, amending the bioretention medium with highly effective adsorbents has been proposed to optimize pollutant removal and extend bioretention lifetime. The aim of this research was to investigate whether soil amended with activated carbon produced from sewage sludge increases the efficiency to remove hydrophobic organic compounds frequently detected in stormwater, compared to non-amended soil. Three lab-scale columns (520 cm³) were packed with soil (bulk density 1.22 g/cm³); activated carbon (0.5% w/w) was added to two of the columns. During 28 days, synthetic stormwater—ultrapure water spiked with seven hydrophobic organic pollutants and dissolved organic matter in the form of humic acids—was passed through the column beds using upward flow (45 mm/h). Pollutant concentrations in effluent water (collected every 12 h) and polluted soils, as well as desorbed amounts of pollutants from soils were determined using GC-MS. Compared to SOM, the activated carbon exhibited a significantly higher adsorption capacity for tested pollutants. The amended soil was most efficient for removing moderately hydrophobic compounds (log K ₒw 4.0–4.4): as little as 0.5% (w/w), carbon addition may extend bioretention medium lifetime by approximately 10–20 years before saturation of these pollutants occurs. The column tests also indicated that released SOM sorb onto activated carbon, which may lead to early saturation of sorption sites on the carbon surface. The desorption test revealed that the pollutants are generally strongly sorbed to the soil particles, indicating low bioavailability and limited biodegradation.

Cuba is a country in transition with a considerable potential for economic growth. Soils are recipients and integrators of chemical pollution, a frequent negative side effect of increasing industrial activities. Therefore, we established a soil monitoring network to monitor polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in soils of Mayabeque, a Cuban province southeast of Havana. Concentrations of the sum of the 16 US EPA PAHs and of the seven IRMM PCBs in soils from 39 locations ranged from 20 to 106 μg kg⁻¹ and from 1.1 to 7.6 μg kg⁻¹, respectively. While such concentrations can be considered as low overall, they were in several cases correlated with the distance of sampling sites to presumed major emission sources, with some of the concomitantly investigated source diagnostic PAH ratios, and with black carbon content. The presented data adds to the limited information on soil pollution in the Caribbean region and serves as a reference time point before the onset of a possible further industrial development in Cuba. It also forms the basis to set up and adapt national environmental standards.

Shuang’an in Ziyang is a typical high-selenium (Se) area in China, where human selenium (Se) poisoning was reported 30 years ago. To assess the risk of Se poisoning in the area, the Se content in agricultural soil, plant, and water in Naore, Shuang Hekou, and Lin Benhe villages of Ziyang was systematically investigated. The probable daily intake (PDI) was calculated on the basis of Se contents in food, water, and dietary habits to evaluate the risk of selenosis. Se content in hair from local habitants (32 men and 34 women) was determined to further verify the risk. Results showed that Se content in the soil ranged from 0.21 to 36.07 mg/kg, with a geometric means of 3.02 ± 5.16 mg/kg, respectively. Approximately 60% of soil reached the Se toxicity threshold (>3 mg/kg). The Se content in plants ranged from 0.02 to 17 mg/kg, with an average of 0.76 ± 2.51 mg/kg. Approximately 40% of the plant reached the toxicity standard (1 mg/kg). Se content in soil and plant of Naore village was significantly higher than that from two adjacent villages. The Se content in vegetables (on fresh weight basis) was higher than that in cereals. Se contents were 3.73 ± 9.08 and 1.32 ± 3.50 mg/kg in eggplant and pepper, respectively. The Se content in drinking water was 7.85 ± 6.04 μg/L, lower than the upper tolerable limit (40 μg/L) set by WHO. The Se content in stream water (18.5 μg/L) was significantly higher than that in drinking water because of soil erosion. The calculated PDI of habitants in Naore village (1801 μg/day) was significantly higher than that in Lin Benhe (666 μg/day) and Shuang Hekou (686 μg/day), all of which was higher than the tolerable upper Se intake (400 μg/day) set by WHO. The calculated blood Se content was relatively high, especially for habitants of Naore village (2783–2824 μg/L). Moreover, the Se content in the hair of local habitants reached as high as 12.72 ± 13.81 mg/kg, and 78.79% exceeded hair Se toxicity threshold (>3 mg/kg), which further verified the potential selenosis risk. Our study provides significant implications of the potential Se intoxication of local residents. Therefore, governments and other institutions should implement various measures to reduce the daily Se intake and to mitigate the associated health risks.

The removal efficiencies of two horizontal subsurface flow constructed wetlands (HSSF CWs, down-flow (F1) and up-flow (F2)) filled with the zeolite-slag hybrid substrate for the rural landfill leachate treatment were investigated. The adsorption experiment was conducted to evaluate the potential of zeolite and slag as the wetland substrate. The effects of distance variations along the longitudinal profile of wetland bed on pollutant removal were assessed by sampling at four locations (inlet, outlet, 0.55 m, and 1.10 m from the inlet). During the operation time, the influent and effluent concentrations of chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), total nitrogen (TN), heavy metals, and polycyclic aromatic hydrocarbon (PAH) were measured. The results showed that the constructed wetlands were capable of removing COD, 20.5–48.2% (F1) and 18.6–61.2% (F2); NH₃-N, 84.0–99.9% (F1) and 93.5–99.2% (F2); TN, 80.3–92.1% (F1) and 80.3–91.2% (F2); and heavy metals, about 90% (F1 and F2). The zeolite-slag hybrid substrate performed excellent removal efficiency for the nitrogen and heavy metals. The inlet area was the most active region of leachate removal. The up-flow constructed wetland (F2) has a higher removal efficiency for the PAH compounds. The significant removal efficiency illustrated that the rural landfill leachate can be treated using the horizontal subsurface flow constructed wetland filled with the zeolite-slag hybrid substrate.

Chemical analyses of the environment can document contamination by various xenobiotics, but it is also important to understand the effect of pollutants on living organisms. Thus, in the present work, we investigated the effect of the pesticide imidacloprid on the detoxifying enzyme glutathione S-transferase (GST) from Folsomia candida (Collembola), a standard test organism for estimating the effects of pesticides and environmental pollutants on non-target soil arthropods. Test animals were treated with different concentrations of imidacloprid for 48 h. Changes in steady-state levels of GST messenger RNA (mRNA) and GST enzyme activity were investigated. Extracted proteins were separated according to their sizes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the resolved protein bands were detected by silver staining. The size of the glutathione (GSH) pool in Collembola was also determined. A predicted protein sequence of putative GSTs was identified with animals from control group. A 3-fold up-regulation of GST steady-state mRNA levels was detected in the samples treated with 5.0 mg L⁻¹ imidacloprid compared to the control, while a 2.5- and 2.0- fold up-regulation was found in organisms treated with 2.5 and 7.5 mg L⁻¹ imidacloprid, respectively. GST activity increased with increasing imidacloprid amounts from an initial activity of 0.11 μmol min⁻¹ mg⁻¹ protein in the control group up to 0.25 μmol min⁻¹ mg⁻¹ protein in the sample treated with the 5.0 mg L⁻¹ of pesticide. By contrast, the total amount of GSH decreased with increasing imidacloprid concentration. The results suggest that the alteration of GST activity, steady-state level of GST mRNA, and GSH level may be involved in the response of F. candida to the exposure of imidacloprid and can be used as biomarkers to monitor the toxic effects of imidacloprid and other environmental pollutants on Collembola.

China has been the largest producer and emitter of perfluorooctanoic acid and its salts (PFOA/PFO). However, the flows of PFOA/PFO from manufacture and application to the environment are indistinct, especially flows from waste treatment sites to the environment. Here, a life cycle analysis of PFOA/PFO is conducted in which all major flows of PFOA/PFO have been characterized for 2012. Processes related to uses and possible releases of PFOA/PFO include manufacture and use, waste management, and environmental storage. During manufacture and use, emission from application was the most important (117.0 t), regardless of whether it flowed first to waste treatment facilities or was directly released to the environment, followed by manufacture of PFOA/PFO (3.9 t), while flows from the service life and end of life of consumer products were the lowest (1.2 t). Among five waste treatment routes, flows through wastewater treatment plants (WWTPs) were the highest (10.6 t), which resulted in 12.8 t of PFOA/PFO being emitted into the environment. Masses of PFOA/PFO emission were estimated to be 96.3 t to the hydrosphere, 25.6 t to the atmosphere, and 3.2 t to soils. Therefore, control over reduction of PFOA/PFO should focus on application of reliable alternatives and emission reduction from WWTPs using effective treatment techniques.

Decabromodiphenyl ether (BDE209) is a typical soil contaminant released from e-waste recycling sites (EWRSs). Electrokinetics (EK) has been considered as an excellent treatment technology with a promising potential to effectively remove organic pollutants in soil. In this study, the treatment of BDE209-polluted soil by EK was explored. All the EK experiments were conducted under a constant voltage gradient (2 V cm⁻¹) for 14 days. Deionized water (DI water), hydroxypropyl-β-cyclodextrin (HPCD), sodium dodecyl sulfate (SDS), and humic acid (HA) were applied as the processing fluid. The experimental results showed that all the solubilizers could effectively promote the mobility and transport of BDE209 in the soil via the electro-osmotic flow (EOF) or electromigration. The removal efficiencies achieved in S1 section were 24, 22, and 26% using HPCD, SDS, and HA as the processing fluid. However, the removal of BDE209 for the entire soil cell was not achieved until zero valence iron (ZVI) was inserted at the center of soil column as a permeable reactive barrier (PRB) or (ZVI-PRB), which enhanced the degradation of BDE209. As ZVI-PRB was installed in EK5 and EK6 experiments, the corresponding average removal efficiencies increased to 16 and 13%, respectively. Additionally, the degradation products of BDE209 analyzed by GC-MS suggested that debromination of BDE209 was the main potential degradation mechanism in the EK treatment in the presence of ZVI-PRB.

Dissolved organic matter (DOM), as a very fine colloidal suspension, could inevitably affect the transformation process of dissolved organic nitrogen (DON) in drinking water treatment. Tryptophan and tyrosine were used as representatives of DON to investigate the interactions between amino acids and fulvic-like components of fluorescent DOM using titration experiments. The fluorescence intensity decreased significantly with the increasing fulvic acid (FA) concentration, suggesting that FA could greatly quench the intrinsic fluorescence of amino acids such as tryptophan and tyrosine. The absolute spectrum peaks of amino acids (AA) were changed in the presence of FA, possibly being resulted from non-covalent interactions between amino acids and FA. The specific hydrogen bonding and van der Waals forces played dominant roles in the interactions according to the results of theoretical analysis and thermodynamic calculation. The distance between donor and acceptor was 1.25 and 1.14 nm for the FA–tyrosine and FA–tryptophan system, indicating the energy transfer from tyrosine or tryptophan to FA. The association constant (K) decreased with the increase of temperature and pH value, while the change of ionic strength had no obvious influence on K value.

Mexico City Metropolitan Area (MCMA) is the most populated urban area in the country. In 2010, MCMA required 14.8% of total energy domestic demand, but greenhouse gas emissions accounted for 7.7% of domestic emissions. Mexico has massive renewable energy potential that could be harnessed through solar photovoltaic (PV) technology. The problem to explore is the relationship between local and federal public strategies in MCMA and their stance on energy transition concern, social empowerment, new technology appropriation, and the will to boost social development and urban sustainability. A public policy typology was conducted through instruments of State intervention approach, based on political agenda articulation and environmental local interactions. Social equality is encouraged by means of forthright funding and in-kind support and energy policies focus on non-renewable energy subsidies and electric transmission infrastructure investment. There is a lack of vision for using PV technology as a guiding axis for marginalized population development. It is essential to promote economic and political rearrangement in order to level and structure environmental governance. It is essential to understand people’s representation about their own needs along with renewable energy.