The functional classification of β-lactamases is done through assessing their ability to hydrolyze specific β-lactams and its inactivation by inhibitors. This study investigated the β-lactamases encoding genes present in soil samples from different origins (landfill, preservation area, and soil from a farm). Genes codifying for ESBL enzymes bla SHV, bla TEM₋₁₁₆ and bla OXA₋₁ were found in all analyzed samples. Gene for ESBL bla CTX₋M₋₁₄ was detected in the landfill and farm soil samples, but they were not found in the preservation area, while bla OXA₋₄₈₋ₗᵢₖₑ was present just in the soil from the landfill. The gene for the MBL bla VIM was found in the soil sample from a farm. The results indicate that bla SHV, bla TEM₋₁₁₆, and bla OXA₋₁ genes are scattered in soils with and without potential contaminants; however, genes bla CTX₋M₋₁₄, bla OXA₋₄₈, and bla VIM were detected just in polluted areas.

The progressive development of civilization and intensive industrialization has contributed to the global pollution of the natural environment by heavy metals, especially the soil. Degraded soils generally contain less organic matter, and thus, their homeostasis is more often disturbed, which in turn manifests in changes in biological and physicochemical properties of the soil. Therefore, new possibilities and solutions for possible neutralization of these contaminations are sought, inter alia, through reclamation of degraded land. At present, the use of additives supporting the reclamation process that exhibit heavy metal-sorbing properties is becoming increasingly important in soil recovery. Research was conducted to determine the role of compost in stabilizing the microbial and biochemical balance of the soil due to the significant problem of heavy metal-contaminated areas. The study was conducted on loamy sand, to which zinc was applied at the following doses: 0, 250, 500, 750, 1000, and 1250 mg Zn²⁺ kg⁻¹ DM of soil. Compost was introduced to the appropriate objects calculated on the basis of organic carbon content in the amount of 0, 10, and 20 g Cₒᵣg kg⁻¹ DM of soil. The study was conducted over a period of 20 weeks, maintaining soil moisture at 50% capillary water capacity. Zinc significantly modified soil microbiome status. The abundance of microorganisms and their biological diversity and the enzymatic activity of the soil were affected. The negative effects of contaminating zinc doses were alleviated by the introduction of compost into the soil. Organic fertilization led to microbial growth intensification and increased biochemical activity of the soil already 2 weeks after compost application. These effects persisted throughout the experiment. Therefore, it can be stated that the use of compost is an appropriate method for restoring normal functions of soil ecosystems contaminated with zinc.

Treated wastewater (TWW) is an imperative nonconventional water resource for reuse in irrigation to cope with the water shortage and agricultural expansion in Egypt. The Bahr El-Baqar drain in Sharqia, Egypt, is one of the main drains in the Nile Delta that receives various types of wastewater. Monitoring and assessing the drain’s water quality were achieved by collecting georeferenced water samples along the drain during the 2015 summer and winter cropping seasons. Chemical, microbial, and parasitic analyses were performed. Additionally, surface soil samples irrigated with the drain water were gathered from the adjacent area to quantify the main physicochemical properties. Water analysis results revealed that the concentrations of most trace elements were within international standards and the Egyptian allowable levels for TWW reuse in agriculture. Oxygen depletion was observed for all samples collected. The microbial analysis indicated that there was fecal coliform contamination (>1000 per 100 mL) in the summer and winter samples. Concentrations of PO₄ and SO₄ were within the permissible level for irrigation use, whereas NH₄, NO₃, and MoO₄ concentrations were higher than the recommended values for reusing Bahr El-Baqar water in irrigation. Based on the soil analysis results, Cd contamination was observed, whereas the Pb concentration in soils was slightly higher than its normal range. Mixing Bahr El-Baqar water with freshwater and implementing appropriate on-farm treatment before the reuse are recommended as a prerequisite for reusing Bahr El-Baqar water for irrigation. Bio-diesel fuel and energy oil crops are recommended for the studied region.

Arsenic poisoning from contaminated drinking water has evolved as one of the major health hazards in recent times. High concentrations of arsenic in water and soil have been found in many parts of the world. Developing countries like Taiwan, Chile, Argentina, Bangladesh, Nepal and Vietnam are most affected by the contamination of groundwater with arsenic. These countries also cannot afford expensive and large-scale treatments to remove arsenic from drinking waters to acceptable limits (10 ppb, as recommended by WHO and US EPA). The aim of this review is to summarize low-cost, effective conventional technologies currently described in the literature for arsenic removal that can be used in the third world and developing countries, compare them with the emerging technologies and discuss their advantages and disadvantages along with a brief analysis of arsenic chemistry.

Petroleum hydrocarbon, a complex mixture including aliphatic and aromatic hydrocarbons, is known to have negative effects on the environment. We determined the effectiveness of persulfate (PS) (5% w/w) activated using 1% (w/w) of various types of soil minerals, goethite (α-FeOOH), hematite (Fe₂O₃), magnetite (Fe₃O₄), maghemite (γ- Fe₂O₃), manganese oxide (MnO₂), and zeolite (clinoptilolite) to treat petroleum hydrocarbon-contaminated soil. Total petroleum hydrocarbon (TPH) was 4200 ± 124 mg kg⁻¹. The TPH removal efficiency was in the order: Fe₃O₄ > MnO₂ > γ-Fe₂O₃ > Fe₂O₃ > α-FeOOH > clinoptilolite. When the PS dosage and the moisture content of the soil increased, the degradation rate (k ₒbₛ) of TPH removal increased; on the other hand, lowering the pH increased the k ₒbₛ of TPH removal. The PS oxidation of TPH was optimized using response surface methodology (RSM). The interactive effects of three factors, namely, persulfate dosage (X ₁), pH (X ₂), and soil moisture content (X ₃), were investigated. The optimum removal of TPH by PS oxidation activated using 1% (w/w) magnetite was obtained at 5.5% (w/w) PS and 85% (w/w) moisture content at an initial pH of 4.5. However, the soil treated by PS showed a negative effect on soil health. The germination of mung bean (Vigna radiata (L.) R. Wilczek) and the CO₂ release for the treated soil were low, indicating that toxicity had occurred in the treated soil. To restore the treated soil, adding a soil amendment, like CaCO₃, fly ash, or crop residue, was able to improve plant growth and soil microbial activity.

In this study, five different fillers: coal ash, fiber-ball, polypropylene, ceramic, and polyhedron empty ball were used for cultivating nitrifying bacteria by increasing influent ammonia concentration gradually in sequencing batch reactors (SBRs). The results of ammonia removal performance showed that the reactor with coal ash has the highest NH₄⁺-N removal rate all the time. The ammonia removal rate of it averagely reached ≥ 95% under the condition of hydraulic retention time (HRT), dissolved oxygen (DO), pH was 12 h, 4.5 ± 0.5 mg/L, 7.5–8.5, respectively, even when the ammonia nitrogen loading reached 1000 mg/L. MiSeq Highthrough sequence was used for analyzing microbial community. The results revealed that obvious variation have occurred among the reactors after 48 days of operation; however, Nitrosomonas was enriched in large amount and became the dominant genus except in the reactor with polypropylene. Compared with other carriers, coal ash can enrich more nitrifying bacteria, the cell biomass of Nitrosomonas increased from 12.25 to 384.18 mg/L, which was 5.5 times more than the negative control. The use of coal ash as filler realizes the enrichment of a large amount of nitrifying bacteria in a short period, which guarantees a highly efficient nitrification.

Bisphenol B (BPB) exhibited higher estrogenic activity and anti-androgenic effects than bisphenol A (BPA) in vitro assays. This result indicates that BPB has higher priority for entry into expensive and stressful testing on animals. However, the disrupting mechanisms of BPB on steroid hormone signaling pathway by in vivo assay have not been investigated yet. In this study, the potential disrupting mechanisms of BPB on the hypothalamic–pituitary–gonadal (HPG) axis and liver were probed by employing the Organization for Economic Co-operation and Development (OECD) 21-day short-term fecundity assay with zebrafish. We found that BPB exposure (1 mg/L) could impair the reproductive function of zebrafish and decline the egg numbers, hatching rate, and survival rate. This finding is related to modifications of the testis and ovary histology of the treated zebrafish. The homogenate T levels in male zebrafish decreased in a concentration-dependent manner, and the E2 level significantly increased when exposed to 0.01, 0.1, and 1 mg/L BPB. Real-time polymerase chain reaction (PCR) was performed to examine the gene expressions in the HPG axis and liver. Hepatic vitellogenin (vtg) expression was upregulated in all exposure males, suggesting that BPB possesses estrogenic activity. The disturbed hormone balance was contributed by the significant alteration of the genes along the HPG axis. These alterations suggest that BPB can lead to adverse effects on the endocrine system of teleost fish, and these effects were more prominent in males than in females.

Volatilization is a critical pathway for herbicide loss from agricultural fields, and subsequently deposited downwind from the edge of the field. To better understand the volatilization process, field-scale turbulent volatilization fluxes of metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) were quantified for 13 consecutive years using a combination of herbicide concentration profiles and eddy diffusivities derived from turbulent fluxes of heat and water vapor. Site location, type of herbicides, and agricultural management practices remained unchanged during this study in order to evaluate the effect of soil moisture on metolachlor volatilization. Twenty gravimetric surface soil moisture samples (0–5 cm) were collected immediately after herbicide application and then at 0430 hours each morning to determine the impact of surface moisture on herbicide volatilization. Five days after application, cumulative herbicide volatilization ranged from 5 to 63% of that applied for metolachlor. Metolachlor volatilization remained an important loss process more than 5 days after application when the soil surface was moist. Conversely, if the soil surface was dry, negligible volatilization occurred beyond 5 days. Furthermore, the total amount of metolachlor volatilized into the atmosphere increased exponentially with surface soil water content during application (r ² = 0.78). Metolachlor volatility was found to be governed largely by surface soil moisture.

This study evaluated the effect of crude oil on the intraradical structures and morphospecies of arbuscular mycorrhizal fungi (AMF) and on the aerial and root dry matter of the grass Leersia hexandra Swartz in order to propose indicators of toxicity. An experiment was conducted in a microtunnel for 180 days. The concentrations (g kg⁻¹) of crude oil in the Gleysol were 0.693 (control), 3, 10, 30, 60, 90, 120, 150, and 180. The growth of intraradical hyphae, arbuscules, vesicles, and spores in soil was stimulated by crude oil concentrations of 3, 10, 30 and 60 g, but concentrations of 90, 120, 150, and 180 g kg⁻¹ inhibited it. Eight morphospecies of AMF were identified. The number of spores of Rhizophagus fasciculatus, Rhizophagus intraradices, Funneliformis geosporum, Diversispora eburnea, and Ambispora gerdemannii showed sensitivity to the concentration of crude oil (index values were lower than one). The number of spores of Diversispora sp. was stimulated by exposure to crude oil, with non-toxic values for the eight concentrations. The index based on the aerial dry matter of L. hexandra showed toxicity values lower than one with crude oil concentrations of 60, 90, 120, 150, and 180 g kg⁻¹, but the root dry matter showed non-toxic values with the eight concentrations. We suggest using the number of spores and morphospecies as an index of toxicity of crude oil and recommend using Diversispora sp. and L. hexandra for the phytoremediation of Gleysol contaminated with crude oil in the Mexican humid tropics.

Road dust contains a wide range of potentially health-hazardous pollutant sources. In this study, road dust samples were collected from nine locations along the Sydney orbital motorway during wet weather events and analysed for their mineralogy and heavy metal contents. The aim of this study was to examine for the specific particle size fractions in road dust samples that can be associated with anthropogenic pollutant sources, mainly on the prevalence of heavy metals. Surface morphological and elemental composition of the road dust particles was analysed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The heavy metal contents and degree of contamination were also investigated including in the two specific particle size fractions of <75 and 75–150 μm. It was found that the particle size fraction of <75 μm made up between 6 and 16% of the entire particle size distributions and contributed to more than 90% of the heavy metal contents. In addition, a moderate to high degree of heavy metal contamination was measured in the collected road dust samples, and this was correlated well with the local traffic volumes. The good correlation between heavy metals and traffic volumes in the finer road dust particle size fraction of <75 μm indicated that the finer road dust particles were not only important in terms of heavy metal attachment, accumulation and mobilisation during wet weather events but they could also provide evidence of potential anthropogenic pollution sources. These findings will facilitate our scientific understanding on the specific role and importance of particle size fractions on the mobilisation of pollutant sources, particularly heavy metals during wet weather events. It is anticipated that this study will assist in the development of best management practices for pollution prevention and control strategies on the frequency of road sweeping and retention pond design to trap fine road dust particles.