The biomixture composition and the presence of a grass layer in a biobed bioremediation system can improve the performance of these systems to minimize pesticide point-source contamination. In this study, a novel biomixture composed with organic wastes from vineyards and wine industries (vermicompost of winery wastes and vine shoots) and top soil (W) was elaborated. The impact of three pesticides, commonly used in vineyards, on its microbial activity and on the development of turfgrass was determined in a short-term experiment. Moreover, the dissipation of the assayed pesticides was evaluated to stablish their distribution patterns between the turfgrass and the biomixture. For comparison, the original biomixture composed with top soil, peat, and straw (P) was also studied. After 15 days of pesticide application, the development of the turfgrass in both biomixtures was similar. However, the oxidoreductases (dehydrogenase and ortho-diphenol oxidase) and the hydrolytic (FDA and β-glucosidase) enzyme activities were greater in W-biomixture than in P-biomixture. The dissipation of metalaxyl and imidacloprid recorded in the W-biomixtures was significantly greater than in the P-biomixtures. The pesticide dissipation in W-biomixtures followed the same order of their octanol water partition coefficients. Except for tebuconazole, the lower biological activity in the P-biomixture would explain the limited pesticide dissipation. In the grassed biomixtures, most (> 83%) of the non-dissipated imidacloprid and tebuconazole remained in the biomixtures, while metalaxyl was rapidly translocated to the aerial part of the turfgrass. Our results show the potential capability of the novel biomixture as an alternative to the original one in a biobed.

The objective was to evaluate removal efficacy of agrichemicals from water using a small-scale granular activated carbon (GAC) system. The GAC system consisted of a series of three 1.9- to 4.1-L filter canisters filled with 8 × 30 US mesh (595 to 2380 μm) bituminous coal GAC. In experiment 1, 11 agrichemicals (acephate, bifenthrin, chlorpyrifos, flurprimidol, glyphosate, hydrogen peroxide + peracetic acid, imidacloprid, paclobutrazol, didecyldimethylammonium chloride (DDAC), triclopyr, and uniconazole) used in greenhouse and nursery production were exposed to 0, 12, or 64 s of GAC contact time. Chemical concentrations were prepared at a 1:10 dilution of a recommended label rate for ornamental crops to represent a possible residual concentration found in recaptured irrigation or surface water. In experiment 2, three other chemicals [iron ethylene diamine-N,N′-bis(hydroxy phenyl acetic acid) (iron-EDDHA, a chelated iron fertilizer), soracid blue dye (a fertilizer dye), and sodium hypochlorite (a sanitizing agent)] were also tested with 0, 12, 38, or 64 s of GAC contact time. Agrichemical concentration was reduced with 12 s of GAC contact time compared with the 0 s for all chemicals tested, and in most cases was further increased at 64-s contact time. Chemicals reduced below their minimum detection limits with 64 s GAC included acephate, flurprimidol, paclobutrazol, uniconazole, peracetic acid, DDAC, and chlorine (free and total). Percent reduction for other chemicals with 64 s GAC was 72.2% for bifenthrin, 89% chlorphyrifos, 85.3% imidacloprid, 99% glyphosate, 99.4% triclopyr, 99.3% hydrogen peroxide, 47.6% iron-EDDHA, and 94.6% soracid blue dye. Iron-EDDHA and soracid blue dye could be used as indicator chemicals for onsite monitoring of GAC filter efficacy. Results indicate that GAC filtration can remove a wide range of agrichemical contaminants commonly used in greenhouse and nursery production, although the required contact time in commercial production is expected to be greater than in this research study.

Plastic pollution is one of the most acute environmental topics of our time. While there is a great scientific effort to tackle this problem, it has not always been well-coordinated or properly targeted. In this short review, we call for scientists to get involved in three crucial topics (threats) underestimated—or ignored—in freshwater systems: (i) plastic-species entanglement, (ii) plastic as nesting material, and (iii) macroplastic debris coming from mismanaged household solid waste. Reducing the knowledge gaps between marine and freshwater environments will be crucial to solute the plastic pollution problem effectively and globally. Therefore, we make a plea here to reinforce research activities on these three issues in freshwater environments worldwide.

It was investigated the potential of Rhodococcus erythropolis AW3 as a biosorbent for the removal of crystal violet (CV) dye from natural water and real effluents. The biosorbent was characterized by flow cytometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy X-ray dispersive spectroscopy (EDS), and point of zero charge (pHZPC). Batch biosorption experiments were performed to optimize different parameters involved in the biosorption process. The equilibrium was reached at 90 min at the optimum biosorbent dose of 0.50 g L⁻¹ and pH of 9.0. Results indicated that Langmuir isotherm model was the most suitable to represent the experimental data, and the highest biosorption capacity was 289.8 mg g⁻¹. Kinetic data were well fitted with the pseudo-second-order model. The thermodynamic study showed that the process was favorable, exothermic, and associated with an increase of entropy. Finally, it was demonstrated that the biosorption process using Rhodococcus erythropolis AW3 could be successfully applied to remove CV from natural water and effluents derived from clinical and industrial activities.

The mechanism of Cr(VI) immobilization in soils by organic substances are not well understood. In the present study, two crop residues (maize stalk and peanut shell) and their biochars obtained at various pyrolysis temperatures were prepared to investigate their influences on the immobilization of Cr(VI) in two contaminated soils via an incubation test and a bioassay. The results showed that Cr(VI) immobilization in soils was ascribed to dominant reduction (52–99%) coupled with secondary surface adsorption (1.2–48%) by organic substances. The maximum reduction capacity (Yₘ, 238 mg/kg) was found in an acidic brown soil with maize stalk amendment, secondly, with peanut shell amendment (Yₘ, 231 mg/kg). Their biochars presented a weaker capacity in reducing Cr(VI) to Cr(III) of soils than raw crop residues since carbonization accelerated the decomposition of oxygen-containing functional groups of organic substances. Soil properties, mainly soil pH, were negatively related to Cr(VI) reduction in soils remarkably, while concomitant anions in soils mainly the phosphate could compete with Cr(VI) for surfaces of soil particles and decrease Cr(VI) adsorption and subsequent reduction. The bioassay in pots with wheat seedlings further validated that maize stalk was a better organic substance for Cr(VI) immobilization and subsequent decrease of its bioavailability in contaminated soils than its biochar according to the results of wheat biomass and Cr contents in shoots and roots. Accordingly, to develop a cost-effective method for immobilizing Cr(VI) in contaminated soils, the raw maize stalk is more advantageous than the carbonaceous counterparts because no pyrolysis is required for the application.

The present study presented an inclusive analysis of engine exhaust emission characteristics of direct injection diesel engine fuelled with diesel and biofuel. Biofuel used in this investigation was obtained by steam distillation from pine oil. A single-cylinder, four-stroke diesel engine was used for this purpose. In this work, performance characteristics like brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC) were analysed. The engine pollutants, namely nitrogen oxide (NO), carbon monoxide (CO), hydrocarbon (HC), and smoke, were examined. In addition, combustion characteristics like in-cylinder pressure and heat release rate were presented. Two engine modification techniques, namely thermal barrier coating and the addition of antioxidant to biofuel, were attempted. The advantage of thermal barrier coating is to reduce heat loss from the engine and convert the accumulated heat into useful piston work. In this work, partially stabilised zirconia was used as the coating material. The usage of antioxidant-treated biofuel in a diesel engine was said to be the prominent approach for NOx emission reduction. Three different antioxidants, namely butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary-butyl hydroquinone (TBHQ), were exclusively dissolved at a concentration of 1% by volume with PO fuel. The obtained performance and emission characteristics of the uncoated engine were compared with the thermally coated engine. From the results, it was observed that the PO biofuel may be a promising alternative in the near prospect with the thermal barrier coating technique to enhance the performance, combustion and emission characteristics of diesel engine. The PO+TBHQ blend was considered as more beneficial than PO+BHT and PO+BHA on account of its performance, combustion and emission characteristics. The effectiveness of the antioxidant was shown in the order of TBHQ>BHA>BHT.

This paper reports the effects of single and combined application of biochar and phosphate fertilizer on immobilization of heavy metals in e-waste-contaminated soils. The results showed that combined amending biochar and phosphate fertilizer improved physical and chemical characteristics of soil but resulted in ammonium nitrogen loss. Biochar combined with phosphate fertilizer increased shoot biomass of lettuce while biochar applied alone could inhibit the growth of lettuce. A distinct decrease of heavy metal concentrations in lettuce was observed in phosphate fertilizer + biochar (3.0%) treatments while highest heavy metal concentrations in shoots and roots were observed in control treatments. In phosphate fertilizer (0.8%) + biochar (3.0%) treatment, Cd, Cu, Pb, and Zn concentrations of lettuce leaf were reduced by 34.78%, 29.37%, 46.59%, and 40.95%, respectively. Biochar + phosphate fertilizer and biochar both reduced bioconcentration of Cd, Cu, Pb, and Zn in different tissues of lettuce while transshipment of Cd, Cu, Pb, and Zn from root to shoot increased after combined amendment of biochar with phosphate fertilizer. Application of phosphate fertilizer + biochar enhanced the immobilization of Cd, Cu, Pb, and Zn by decreasing the exchangeable Cd, Cu, Pb, and Zn in the soil. Precipitation, adsorption, ionic exchange, and chelation contributed to the good immobilization capacity of biochar + phosphate fertilizer on Cd, Cu, Pb, and Zn in e-waste-contaminated soils.

Forest soils (mainly soil organic carbon) play an important role in the retention of nitrogen and mercury, and loss of the forest floor during wildfires can stimulate N and Hg losses. In this paper, we investigate long-term impacts of forest fire on soil N and Hg concentrations at Acadia National Park (ANP) in Maine. Acadia National Park experienced a severe fire in 1947. Within the national park, Hadlock Brook watershed was left unburned, whereas most of Cadillac Brook watershed was intensely burned, with substantial loss of the forest floor. Post-fire regeneration in Cadillac was mostly as hardwood species, whereas vegetation in Hadlock remained predominantly softwood. We sampled soils in both watersheds in 2015, approximately 70 years after the fire. The soils were analyzed for total carbon (TC), total nitrogen (TN), total mercury (THg), and methylmercury (MeHg) content. Compared to Hadlock, Cadillac soils had ~ 50% lower TC, ~ 40% lower TN, and ~ 50% lower THg content, reflecting the loss of forest floor 70 years ago. Methylmercury concentrations in Cadillac were approximately 2 times the concentrations in Hadlock, indicating that conditions were more conducive to methylation, potentially due to differences in forest type. Long-term comparisons of stream DOC, NO₃⁻, and THg concentrations between the two watersheds demonstrated that concentrations were significantly lower in Cadillac Brook, reflecting greater retention in Cadillac and a legacy of lower atmospheric deposition in the hardwood as compared to softwood watershed. This study provides insights on the multi-decadal recovery from a stand-replacing disturbance and underscores the persistence of altered soil biogeochemistry.

In this study, some different selected plant leaves grown in Jordan such as Citrus limon (Rutaceae), Ceratonia siliqua L., Olea europaea (Oleaceae), Washingtonia filifera, and Myoporum (Myoporaceae) were examined for removal of copper (Cu) and zinc (Zn) ions from aqueous solutions. Cu and Zn were analyzed by atomic absorption spectrometry. A pH S-2 acidometer was used for determining the acidity of leaves solution system. Our findings showed the plants leaves were relatively efficient for removal of Cu and Zn compared to activated carbon. Removal of a 5 mg/L aqueous metal solution of Cu and Zn was treated with 2.5 g oven-dried plant in a 50 mL deionized water. The removal of Cu and Zn was expressed in terms of a time function ranged between 0 and 192 hours of contact time. The uptake of Cu and Zn by plant leaves was arranged in the following order:(i)Cu: Activated carbon > Washingtonia filifera > Ceratonia siliqua L. > Olea europaea (Oleaceae) > Myoporum (Myoporaceae) > Citrus limon (Rutaceae)(ii)Zn: Activated carbon > Olea europaea (Oleaceae) > Citrus limon (Rutaceae) > Ceratonia siliqua L. > Washingtonia filifera > Myoporum (Myoporaceae)

Phosphorus is a dominant environmental factor in fostering eutrophication, and its biogeochemical behavior has attracted much attention. This study investigated the distribution of phosphorus fractions and the adsorption-desorption characteristic in the soils of wetlands converted from paddy fields with a restoration duration of 1, 2, 3, 5, 13, or 19 years. The results demonstrated the content of total phosphorus (TP) first increased, which was then reversed until the process stabilized after 5 restoration years. Labile inorganic phosphorus (L-Pi), labile organic phosphorus (L-Po), iron-aluminum–bound phosphorus (Fe.Al-P), and humic phosphorus (Hu-P) peaked at 1–3 restoration years, respectively, while moderately labile organic phosphorus (Ml-Po), calcium-magnesium–bound phosphorus (Ca.Mg-P), and residual phosphorus (Re-P) decreased within 0–5 restoration years. During the 5th to 19th restoration years, the contents of all phosphorus fractions stabilized within a minor fluctuating range. Redundancy analysis (RDA) results indicated that total nitrogen (TN) and soil organic matter (SOM) are the important environmental factors controlling redistribution of phosphorus fractions. The capability of restored wetlands to retain phosphorus increased first and then decreased with the extension of the restoration duration. Path analysis (PA) results demonstrated that pH, TN, and Fe are the primary factors for the capacity of soil to retain phosphorus, followed by SOM, Mn, and electrical conductivity(EC). Fe.Al-P and Hu-P had a higher release risk with approximate amounts of 197.25–337.25 and 113.28–185.72 mg/kg during the first stage of restoration, which needs to be focused.