Sorption is an effective process for the remediation of mine water with low metal concentrations. To identify promising low-cost organic sorbents for nickel (Ni), adsorption and retention properties of peat, compost, brown algae, sawdust, and wood ash were compared. Batch adsorption and desorption experiments were conducted at pH 7 in 0.05 M NaNO₃ solutions to simulate the ionic strength and pH of a contaminated neutral drainage. Results of adsorption kinetic experiments were best represented by the Elovich model and the fastest rates were obtained with peat (796,075 mg g⁻¹ min⁻¹) and compost (791 mg g⁻¹ min⁻¹). Results of equilibration adsorption experiments were fitted to Langmuir and Freundlich isotherms and the highest adsorption capacities were observed for peat (around 22 mg g⁻¹) and compost (around 9 mg g⁻¹). Desorption experiments revealed that peat and compost adsorbed more Ni and also released a lower percentage of the adsorbed metal upon exposure to Ni-free solutions.

Composting has various benefits to achieve sustainability, such as substituting the use of fertilizers and preventing organic residues from being dumped in landfills. Thus, the objective was to evaluate nutrient and heavy metal release dynamics during composting with different mixtures of organic residues containing food wastes. The study was conducted in a community association in Mossoró, Rio Grande do Norte, Brazil, and the chemical analysis was carried out at the Universidade Federal Rural do Semi-Árido. Proportions between bovine manure (BM) and food wastes (FW) were Pile 1–0:3 (0% BM and 30% FW); Pile 2–1:2 (10% BM and 20% FW); Pile 3–1:1 (15% BM and 15% FW); Pile 4–2:1 (20% BM and 10% FW); Pile 5–3:0 (30% BM and 0% FW) (Pile considered as control), and the remaining 70% was filled with plant residues (tree prunings). Increment of BM proportion in compost piles with FW led to increase in C mineralization, but C mineralization decreased in the pile with only tree prunings and BM. Nitrogen immobilization occurred only in the pile with 15% BM and 15% FW; in the others, N was mineralized. Food wastes showed greater amounts of potentially mineralizable K fractions. For the micronutrients copper and zinc, in general, the initial contents decreased, whereas iron contents increased. The contents of all heavy metals diminished in the final product of the composting process, with no risk of contamination.

The palm (Elaeis guineensis), known as dendê, is an important oleaginous Brazilian plant with a high performance of oil production. In this work, a 2³ full experimental design was performed and the response surface method (RSM) was used to indicate the optimum parameter of caffeine adsorption on Elaeis guineensis endocarp activated carbon, since the endocarp is the main by-product from dendê oil production. It was set the adsorbent point of zero charge (pHₚzc), and the material was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The RSM results indicate removal efficiency (%) at the optimal conditions, 0.20 g of adsorbent, and caffeine initial concentration of 20 mg/L, and acidic medium was about 95%. Based on ANOVA and F test (Fcₐₗcᵤₗₐₜₑd > Fₛₜₐₙdₐᵣd), the mathematical/statistical model obtained fits well to the experimental data. The overall kinetic studies showed time was achieved after 5 h and caffeine adsorption followed the pseudo-second-order model suggesting chemisorption is a predominant mechanism. Redlich-Peterson and Sips models best represented the experimental data (0.967 < R² < 0.993). Thermodynamic revealed that caffeine adsorption was spontaneous at all temperatures studied, exothermic, and probably with changes in the adsorbate-adsorbent complex during the process. The tests conducted in different water matrixes corroborate the suitability of this adsorbent to be used in caffeine removal even in a complex solution.

The accumulation of heavy metals by crops irrigated with wastewater has been considered as a serious environmental problem in many developing countries, where the wastewater irrigation has emerged as a common practice. In this research, we were concerned with the highly toxic metal lead (Pb) in water, agricultural soils, and wheat crops, and the possible risk on human health in the peripheral agricultural regions of Punjab, Pakistan. Various types of irrigated water (ground, sewage, industrial), soil, and wheat plant (root, shoot, grain) samples of five different varieties (Seher-2006, Punjab-2011, Faislabad-2008, Watan, and Galaxy-2013) were collected from seven different districts and then pooled up to make one composite sample and analyzed for Cd concentration. The various pollution and mobility indices (pollution load index, enrichment factor, daily intake of metal, health risk index, translocation factor, bioaccumulation factor, and bio-concentration factor) were also calculated. The descending order for Pb concentration was as follows: water>soil>wheat plant. The range of concentration of Pb in all types of water, soil, and wheat plant (root, shoot, grains) samples was (7.05–7.83 mg/l), (6.32–7.74 mg/kg), (3.23–4.82, 1.14–2.75, 0.09–0.51 mg/kg), respectively. The concentration of Pb in all types of water samples exceeded the maximum permissible limit. There were values found to be < 1.00 in all the pollution and mobility indices for all types of samples. These results reveal that high levels of Pb in irrigated water may pollute the soil and wheat plants of these regions in the near future, if various control measures have not been taken. It may pose a great health risk to the local human and animal populations. Preventive measures should be taken to reduce heavy metal pollution of irrigation water and soils to protect both human and animal health in various regions of Punjab, Pakistan.

17α-Methyltestosterone (MT) is widely used synthetic androgenic steroid in the tilapia aquaculture industry for masculinization: a sex reversal process in which hormones are utilized to induce production of male fish. Although MT is beneficial for aquaculture, release of residual MT can cause adverse effects on wild organisms. The aims of this study were to identify MT-degrading bacteria and to characterize their degradation abilities under the conditions experienced in the environment. Nocardioides nitrophenolicus S303, Acinetobacter radioresistens B051, and Ochrobactrum haematophilum B052 were the most efficient MT-degrading bacterial strains, with the shortest degradation half-life of 10–70 h. The MT degradation by Acinetobacter and Ochrobactrum has not been reported before. After comparing their degradation rates and for reason of biosafety, N. nitrophenolicus S303 was selected for further study. Although this strain degraded MT and testosterones, it could not degrade estrogens (estrone, 17β-estradiol, nor 17α-ethinylestradiol). Glucose amendment did not affect the MT degradation rate. No metabolites with androgenic activity were observed after 264-h treatment with this strain under aerobic conditions. Methandrostenolone was found as the major intermediate during 39–90 h. This is the first report indicating the 1,2-dehydrogenase activity in steroid clevage in N. nitrophenolicus. Our study provides important information concerning the application of N. nitrophenolicus S303 to enhance MT degradation in the environment.

Agricultural land use is widely accepted to elicit changes on surrounding environment and neighboring ecosystems. Meanwhile, the impact of different types of agricultural land use likely cause a variety of impacts on nearby ecosystems and the organisms that inhabit them. Freshwater systems support a wide range of organisms—from infaunal or epifaunal invertebrates to mobile pelagic and littoral fish species. The focus of this study was to determine how agricultural activity in the upstream catchment influences sediment properties and the resulting ability of three distinct invertebrate species to survive and reproduce in these different sediments. This will be the first study that evaluates the utility of the sediment quality triad when assessing the impact of agricultural activity on invertebrate growth, reproduction, and survival. In analyzing sediment and water chemistry, as well as metal and pesticide levels, none of the predictor variables were able to adequately explain the variation seen in any of the biological endpoints (reproduction, mortality, growth, or biomass). Although none of the factors measured in this experiment could explain the variation seen in biological endpoints, the experimental approach was informative in delineating biological trends between sediments subject to varying levels of agricultural activity. Although an experiment of this nature was not able to identify a causal mechanism to explain the variation in invertebrate biological endpoint, it is still extremely useful as an exploratory approach to assess relative sediment toxicity.

Qaroun and Wadi El-Rayan lakes are exposed to a huge amount of discharges from different sources and numerous anthropogenic activities. Therefore, the present work aimed to evaluate the impacts of metal pollution on two wild fish species; Tilapia zillii and Mugil cephalus collected from lake Qaroun (eastern and western parts) and Wadi El-Rayan lakes (upper and lower lakes). Accumulation of metals (Cu, Zn, Cd, and Pb) in water, sediment, and five vital tissues as well as metal pollution index (MPI), contamination factor (CF), and pollution load index (PLI) were integrated as metal pollution biomarkers. Generally, these integrated endpoints had the same trend and indicated that the eastern part of lake Qaroun was the most polluted site followed by the lower lake of Wadi El-Rayan. To assess the environmental genotoxicity, the percentage DNA damage in different tissues of both fish species was estimated using the comet assay technique. The percentage of DNA damages showed tissue-, species- and site-specification. Hazard index (HI) has been used as an evaluation index for human health associated with fish consumption at the studied sites. This index showed that all metals were in the safe limits at normal consumption levels while adverse health effects are expected to occur at the subsistence consumption level. The safe HI for each metal at normal consumption level does not neglect that the combined cumulative risk impact of all metals is a sign of warning and the health of fish consumers nearby contaminated sites is threatened.

Textile industry is responsible for producing a large amount of effluent. The objective of the present study was to treat the raw effluent of a textile manufacturer through heterogeneous photocatalysis (TiO₂/UVₛₒₗₐᵣ). Four types of effluents were evaluated: raw (RE), treated by the manufacturer (MTE), and exposed to photocatalysis in the presence (PTETi) and absence (PTE) of titanium dioxide (TiO₂). They were evaluated for physical, chemical, and toxicological parameters. In regard to dissolved oxygen (DO) contents, MTE, PTETi, and PTE effluents increased values when compared with RE effluent. Color degradation was more efficient by MTE effluent, but the chemical oxygen demand (COD) values of the treated effluents were not in accordance with Brazilian norms. Besides that, the toxicity test with Allium cepa L. shows cytotoxicity by MTE (24 and 48 h) effluent. PTETi and PTE (24 h) effluents did not show cytotoxicity, but PTETi-48 h showed a significant decrease in mitotic index. The immobility/mortality test with Artemia salina L. showed toxicity of the RE and MTE effluents in concentrations of 100% and 50%. In the case of the phototreated effluents, there was only toxicity in the concentration of 100%. Thus, so generally, photocatalytic treatments were more efficient than the treatment applied by the manufacturer; however, it is necessary to improve a new stage in the treatment.

Anaerobic bioremediation of tetrachloroethylene (PCE) under high concentration conditions is difficult. Anaerobic dechlorination of PCE occurs with synergetic reactions, fermentation, and sulfate-reduction; however, the way in which high concentrations of PCE affects these reactions is still poorly understood. This study aims to elucidate how high concentrations of PCE affect fermentation and sulfate-reduction, as well as PCE dechlorination. Laboratory dechlorination tests were performed using a wide concentration range of PCE between 2 and 125 mg/L added to a microbial consortium that had been continuously cultivated in the laboratory and completely dechlorinated PCE for over 4 years. Fermentation of lactate, reduction of sulfate, and dechlorination of PCE were monitored in addition to microbial activities based on RNA. All three reactions, fermentation, sulfate-reduction, and PCE dechlorination were observed to be inhibited. The inhibition for fermentation, sulfate-reduction, and dechlorination occurred when PCE concentrations were higher than 125, 75, and 30 mg/L, respectively. The fermenter, Anaerotignum, and the sulfate-reducer, Desulfosporosinus, were active when the dechlorination was inhibited with 30 mg/L of PCE. These findings suggest that there is interference of PCE dechlorination, despite the occurrence of fermentation and sulfate reduction. Bioaugmentation with a PCE dechlorinator that is tolerant to high PCE concentrations can be a possible solution for bioremediation of PCE when its concentrations are greater than 30 mg/L.

Soil contamination by pharmaceutical and personal care products (PPCPs) has attracted the attention of many researchers. Continued release of these products into the environment can compromise the health of non-target organisms as well as interfere in ecological interactions between species. We hypothesized that contamination of the soil by these products affects the gut microbiota of macrodecomposers that live in symbiosis with these microorganisms and therefore interferes with the assimilation of nutrients by these animals. Therefore, this study aims to evaluate the effects of soil contaminated by triclosan (TCS) and chlorhexidine (CHX) by analyzing changes in nutrient assimilation and in the assimilation pattern of carbon sources from the Balloniscus selowii gut microbiota. The food consumption rate in B. selowii was not altered by biocides, and assimilation rate as well as assimilation efficiency (%) decreased under triclosan treatment. Based on the results obtained, the soil and gut microbiota demonstrated similar response to each study treatment when compared to other treatments. However, there were no significant differences in the diversity, evenness, and richness values. Dehydrogenase activity showed no significant differences between TCS and CHX exposure and control. In this study, exposure to TCS and CHX biocides changed the metabolic profile of the soil microbiota and consequently of the B. selowii digestive tract. With TCS exposure, this change was enough to affect the assimilation of nutrients by B. selowii. The continuous release of antimicrobials such as chlorhexidine and triclosan into the environment may compromise the health of non-target organisms and interfere with symbiotic relationships.