A bacterial strain CMGCZ was isolated from an abandoned oil field soil sample and identified as Rhodococcus sp. by 16S rRNA sequencing. Rhodococcus sp. CMGCZ was investigated for the degradation of model polycyclic aromatic hydrocarbons (PAHs) and Iranian light crude oil (ILCO) as a sole carbon source in minimal medium. Biodegradation enhancement was attained by supplementing the minimal medium with yeast extract (YE). Rhodococcus sp. CMGCZ was capable to degrade 13.2 % naphthalene (Nap), 13.1 % phenanthrene (Phe), and 99.3 % fluoranthene (Fla) in 1 week and 11 % aliphatic fraction of ILCO in 2 weeks as a sole carbon and energy source. Effect of YE supplementation on degradation potential of Rhodococcus sp. CMGCZ depended upon the added hydrocarbon in the medium. YE completely inhibited Nap degradation, slightly enhanced degradation of Phe (14.8 %) and ILCO aliphatics (13.2 %), and promoted a more rapid degradation of Fla (100 %). YE addition promoted rapid degradation of Fla and eliminated delay of 24 h in Fla degradation that was observed in minimal medium. Rhodococcus sp. CMGCZ was capable to degrade high concentrations of Fla (1000 mg l⁻¹). Rieske [Fe₂-S₂] center was amplified in Rhodococcus sp. CMGCZ that exhibited homology with Rieske [Fe₂-S₂] domain protein of Mycobacterium species and pahAC gene of uncultured bacterium clones.

The aim of this study was to evaluate the spatial distribution of total petroleum hydrocarbons (TPH) in rhizoplane and non-rhizosphere of Leersia hexandra, known as Japanese grass, the effect of oil on the aerial biomass of L. hexandra, the population of plant growth-regulating bacteria, and microbial respiration in rhizosphere and non-rhizospheric soil. Samples of rhizosphere and soil were collected at 14 points across a surface of 2.3 ha, layer 1 (0–15-cm depth), layer 2 (15–30 cm), and layer 3 (30–70 cm), to measure TPH (mg kg⁻¹). The spatial distribution of TPH defined four study zones (Z): Z1: 1393, Z2: 3455, Z3: 5574, and Z4: 7544. TPH were higher in underlying layers in the four zones. Zone 2 produced the largest amount of aerial biomass; oil induced hormesis in the grass, but inhibited it at doses ≥5574. For the rhizosphere of L. hexandra, it was cut with a sterilized knife, stimulated the population of N-fixing and phosphorus solubilizing, heterotrophic bacteria, as well as microbial respiration (day 1, 14, 21, 42, and 63 after incubation) in the four zones. The population of the three groups of bacteria was more stimulated by weathered oil in rhizosphere soil, compared to non-rhizosphere soil and with control treatment, suggesting that the rhizosphere system of L. hexandra has the potential to bioestimulate beneficial microbial activity in unpolluted and polluted areas compared to non-rhizosphere soil. We recommend the use of L. hexandra to recover soils degraded by weathered oil in farms located in the Mexican humid tropics.

The ultraviolet light (UV-A) range of 320–400 nm is widely used as light trap for insect pests. Present investigation was aimed to determine the effect of UV light-A radiation on development, adult longevity, reproduction, and development of F₁ generation of Mythimna separata. Our results revealed that the mortality of the second instar larvae was higher than the third and fourth instar larvae after UV-A radiation. As the time of UV-A irradiation for pupae prolonged, the rate of adult emergence reduced. Along with the extension of radiation time decreased the longevity of adult females and males. However, the radiation exposure of 1 and 4 h/day increased fecundity of female adults, and a significant difference was observed in a 1 h/day group. The oviposition rates of female adults in all the treatments were significantly higher than the control. In addition, UV-A radiation treatments resulted in declined cumulative survival of F₁ immature stages (eggs, larvae, and pupae). After exposure time of 4 and 7 h/day, the developmental periods of F₁ larvae increased significantly, but no significant effects on F₁ pupal period were recorded.

The sorption behavior of 17α-ethinylestradiol by a surface-modified zeolitic tuff with hexadecyltrimethylammonium (HDTMA) was investigated. The zeolitic material (clinoptilolite) was treated with 0.1 M of sodium chloride solution and then with 25 and 50 mM of HDTMA solutions. The sorption kinetics shows that the maximum removal percentage of 96.87 % was reached at 36 h for the zeolite with 25 mM HDTMA, while with 50 mM of HDTMA, the maximum removal of 98.34 % was achieved at 44 h. Furthermore, pseudo-first-order, pseudo-second-order, and Elovich models were analyzed and the kinetic data exhibited a good fit with the pseudo-second-order model, indicating that the sorption mechanism is chemisorption. The isotherms for the sorption of 17α-ethinylestradiol showed that sorption capacity was 0.7073 and 0.6943 mg/g for 25 and 50 mM, respectively, at 25 °C and showed a partition mechanism. Moreover, the pH influence on the sorption process was studied and the sorption capacity was increased as the pH decreases.

The accidental release of organic contaminants in the form of non-aqueous phase liquids (NAPLs) into the subsurface is a widespread and challenging environmental problem. Successful remediation of sites contaminated with NAPLs is essential for the protection of human health and the environment. One technology that has received significant attention is the injection of chemical additives (such as cosolvents) upgradient of the NAPL zone for the enhanced dissolution and mobilization of the NAPL mass. A key process influencing the effectiveness of NAPL mass recovery is the interphase mass transfer which is the transfer of components across the interface separating the different phases. In this work, we examine the impact of cosolvent content, flushing solution velocity, and injection pattern (continuous versus intermittent) on the interphase mass transfer rate. A series of flushing experiments were conducted using an intermediate-scale tank which allows for the impact of density variations on DNAPL mobility. The target DNAPL selected in this study was trichloroethylene while the flushing solutions consisted of ethanol–water mixtures with ethanol contents ranging from 0 to 50% by volume. The experimental results were also modeled using the UTCHEM multiphase flow simulator that was modified to model cosolvent flushing. Results show that the observed interphase mass transfer coefficient, expressed as a modified Sherwood number, was much lower than predicted based on published correlations developed under idealized conditions. Moreover, interphase mass transfer rate decreased with time, indicating that a single interphase mass transfer coefficient cannot accurately model the entire flushing solution. The data also suggest that the interphase mass transfer coefficient is dependent on cosolvent content.

Ore mining and processing have greatly altered ecosystems, often limiting their capacity to provide ecosystem services critical to our survival. The soil environments of two abandoned uranium mines were chosen to analyze the effects of long-term uranium and heavy metal contamination on soil microbial communities using dehydrogenase and phosphatase activities as indicators of metal stress. The levels of soil contamination were low, ranging from ‘precaution’ to ‘moderate’, calculated as Nemerow index. Multivariate analyses of enzyme activities revealed the following: (i) spatial pattern of microbial endpoints where the more contaminated soils had higher dehydrogenase and phosphatase activities, (ii) biological grouping of soils depended on both the level of soil contamination and management practice, (iii) significant correlations between both dehydrogenase and alkaline phosphatase activities and soil organic matter and metals (Cd, Co, Cr, and Zn, but not U), and (iv) multiple relationships between the alkaline than the acid phosphatase and the environmental factors. The results showed an evidence of microbial tolerance and adaptation to the soil contamination established during the long-term metal exposure and the key role of soil organic matter in maintaining high microbial enzyme activities and mitigating the metal toxicity. Additionally, the results suggested that the soil microbial communities are able to reduce the metal stress by intensive phosphatase synthesis, benefiting a passive environmental remediation and provision of vital ecosystem services.

Waste water treatment plants (WWTP) have attracted attention in numerous studies in their impact on receiving surface waters because of the presence of varied contaminants in their effluents. This study investigated the relevance of particle-bound contaminants using suspended particulate matter (SPM) to monitor the temporal variability of the impact of a WWTP discharge in a chalk stream (Loue River) in France. We performed five sampling campaigns of SPM and sediment during a year at different seasons and analyzed polycyclic aromatic hydrocarbons (PAHs) and phosphorus in both matrix. PAH contents in SPM ranged from 675 to 3709 μg kg⁻¹ dry weight (dw) and in sediment from 668 to 7712 μg kg⁻¹ dw. Levels of phosphorus ranged from 364 to 1380 mg kg⁻¹ dw in SPM and from 315 to 523 mg kg⁻¹ dw in sediment. The WWTP increased significantly PAH levels in SPM to the Loue River. However, our results did not allow to evidence significant differences on particulate phosphorus concentration in SPM. Nevertheless, we evidenced significant seasonal variations of PAH and phosphorus concentrations in SPM. Besides sediment sampling, the collection of SPM allowed to monitor changes in contamination from the WWTP and highlighted impact of WWTP on PAH concentrations and changes of PAH and phosphorus concentrations over time. Contamination of SPM of the Loue River was driven by mixed inputs from point source like WWTP and from diffuse sources in the catchment like runoff from impervious and pervious surfaces. Combining monitoring of SPM and sediment proved to be an improved approach to assess contamination of local and diffuse sources in chalk streams.

A dramatic increase in winter (December–February) temperature by 7.2 K (1.1 K per decade) since 1950 has occurred in the Ulan Bator basin, Mongolia. This increase in temperature strongly exceeds the global average of late twentieth century warming and even exceeds warming in most of the polar regions with pronounced increases in temperature. The exceptional warming is restricted to Ulan Bator within the Mongolian forest-steppe region and to wintertime. This suggests that the observed warming could result from radiative forcing by black carbon aerosols. In winter, Ulan Bator’s air is heavily polluted by particulate matter, including black carbon, originating from the combustion of low-quality fuel at low temperature. Winter smog has strongly increased in recent decades, concomitant to the increase in winter temperature, as the result of a strong increase in the city’s population. Exponential growth of Ulan Bator’s population started in the mid-twentieth century, but since 1990, altered socioeconomic frame conditions and a warming climate have driven more than 700,000 pastoralists from rural Mongolia to Ulan Bator where people live in provisional dwellings and cause Ulan Bator’s heavy air pollution. Tree-ring analysis from larch trees growing at the edge of the Ulan Bator basin shows negative correlation of stem increment with December temperature. This result suggests that milder winters promote herbivores and, thus, reduce the tree’s productivity. The negative impact of winter warming on the larch forests adds to adverse effects of summer drought and the impact of high sulfur dioxide emissions. Winter warming putatively associated with high atmospheric concentrations of black carbon aerosols in the Ulan Bator basin is an interesting example of a case where greenhouse gas-mediated climate warming in an area where people themselves hardly contribute to global greenhouse gas emissions affects both humans and ecosystems and causes additional local climate warming.

This study aimed to investigate the characteristics of the event mean concentration (EMC) and first flush effect (FFE) during typical rainfall events in outfalls from different drainage systems and functional areas. Stormwater outfall quality data were collected from five outfalls throughout Fuzhou City (China) during 2011–2012. Samples were analyzed for water quality parameters, such as COD, NH₃-N, TP, and SS. Analysis of values indicated that the order of the event mean concentrations (EMCs) in outfalls was intercepting combined system > direct emission combined system > separated system. Most of the rainfall events showed the FFE in all outfalls. The order of strength of the FFE was residential area of direct emission combined system > commercial area of separated system > residential area of intercepting combined system > office area of separated system > residential area of separated system. Results will serve as guide in managing water quality to reduce pollution from drainage systems.

Livestock manure and compost are commonly used to supply nutrients for crops and improve soil quality. However, excess application may increase the risk of nutrient loss and eutrophication. We investigated the potential leaching losses of nitrogen (N), phosphorus (P), and non-purgeable organic carbon (NPOC) over 105 days in the laboratory. Soils were amended with four treatments: (1) manure (BM) and (2) compost (BC) from cattle fed a typical finishing diet, (3) manure (DDGSM), and (4) compost (DDGSC) from cattle fed diets containing 60 % wheat dried distillers’ grains with solubles (DDGS) replacing barley grain. A non-amended control soil was included for comparison. Leachate samples were collected 0, 7, 21, 42, 70, and 105 days after amendment application. Amendment application significantly increased leaching loss of total nitrogen (TN), NO₃ ⁻-N, NH₄ ⁺-N, total phosphorus (TP), ortho-P (PO₄ ³⁻-P), and NPOC from soils by 2.2 to 154.8 times compared with the control. Regardless of whether DDGS was included in cattle diet, cumulative leaching losses of TN, NO₃ ⁻-N, TP, and PO₄ ³⁻-P were significantly higher, while NH₄ ⁺-N and NPOC were lower from compost-amended soil than manure-amended soil. The proportion of cumulative N leaching losses relative to the total N applied was greater with DDGSM and DDGSC than BM and BC, while a greater proportion of total P was leached from DDGSM and DDGSC than BM. Based on the results, more attention should be paid to the potential risk of soil nutrient leaching posed after applying manure and compost, and the higher risk of N and P leaching losses from soil amended with DDGS manure and compost than manure from beef cattle fed typical finishing diets.