Biogenic polycyclic aromatic hydrocarbons in sediments of the San Joaquin River in California (USA), and current paradigms on their formation

Biogenic perylene and higher plant pentacyclic triterpenoid-derived alkylated and partially aromatized tetra- and pentacyclic derivatives of chrysene (3,4,7-trimethyl- and 3,3,7-trimethyl-1,2,3,4-tetrahydrochrysene, THC) and picene (1,2,9-trimethyl- and 2,2,9-trimethyl-1,2,3,4-tetrahydropicene, THP) were two- to four-fold more abundant than pyrogenic PAH in two sediment cores from the San Joaquin River in Northern California (USA). In a core from Venice Cut (VC), located in the river, PAH concentrations varied little downcore and the whole-core PAH concentration (biogenics?+?pyrogenics) was 250.6?±?73.7 ng g^?1 dw; biogenic PAH constituted 67?±?4 % of total PAH. THC were 26?±?9 % of total biogenic PAH, THP were 36?±?7 %, and perylene was 38?±?7 %. PAH distributions in a core from Franks Tract (FT), a former wetland that was converted to an agricultural tract in the late 1800s and flooded in 1938, were more variable. Surface sediments were dominated by pyrogenic PAH so that biogenic PAH were only ~30 % of total PAH. Deeper in the core, biogenic PAH constituted 60–93 % of total PAH; THC, THP and perylene were 31?±?28 %, 24?±?32 %, and 45?±?36 % of biogenic PAH. At 100–103 cm depth, THP constituted 80 % of biogenic PAH and at 120–123 cm perylene was 95 % of biogenic PAH. Current concepts related to precursors and transformation processes responsible for the diagenetic generation of perylene and triterpenoid-derived PAH are discussed. Distributions of biogenic PAH in VC and FT sediments suggest that they may not form diagenetically within these sediments but rather might be delivered pre-formed from the river’s watershed.     

Constructed wetlands may lower inorganic nutrient inputs but enhance DOC loadings into a drinking water reservoir in North Wales

Environmental Science and Pollution Research - The objective of this study was to monitor a newly constructed wetland (CW) in north Wales, UK, to assess whether it contributes to an improvement in...     

Benchmarking Optical/Thermal Satellite Imagery for Estimating Evapotranspiration and Soil Moisture in Decision Support Tools

Generally, one expects evapotranspiration (ET) maps derived from optical/thermal Landsat and MODIS satellite imagery to improve decision support tools and lead to superior decisions regarding water resources management. However, there is lack of supportive evidence to accept or reject this expectation. We “benchmark” three existing hydrologic decision support tools with the following benchmarks: annual ET for the ET Toolbox developed by the United States Bureau of Reclamation, predicted rainfall‐runoff hydrographs for the Gridded Surface/Subsurface Hydrologic Analysis model developed by the U.S. Army Corps of Engineers, and the average annual groundwater recharge for the Distributed Parameter Watershed Model used by Daniel B. Stephens & Associates. The conclusion of this benchmark study is that the use of NASA/USGS optical/thermal satellite imagery can considerably improve hydrologic decision support tools compared to their traditional implementations. The benefits of improved decision making, resulting from more accurate results of hydrologic support systems using optical/thermal satellite imagery, should substantially exceed the costs for acquiring such imagery and implementing the remote sensing algorithms. In fact, the value of reduced error in estimating average annual groundwater recharge in the San Gabriel Mountains, California alone, in terms of value of water, may be as large as $1 billion, more than sufficient to pay for one new Landsat satellite.     

Biogas production from pistachio (Pistaciavera L.) de-hulling waste

Pistachio processing wastes create significant waste management problems unless properly managed. However, there are not well-established methods to manage the waste generated during the processing of pistachios. Anaerobic digestion can be an attractive option not only for the management of pistachio processing wastes but also producing renewable energy in the form of biogas. This study investigated anaerobic digestibility and biogas production potential of pistachio de-hulling waste from wet de-hulling process. Best to our knowledge, this is the first report on biogas production from pistachio de-hulling waste. The results indicated that (1) anaerobic digestion of pistachio de-hulling wastewater, solid waste, and their mixtures in different ratios is possible with varying levels of performance; (2) 1 L of de-hulling wastewater (chemical oxygen demand concentration of 30 g/L) produced 0.7 L of methane; (3) 1 L of de-hulling wastewater and 20 g of pistachio de-hulling solid waste produced 1.25 L of methane; and (4) 1 g of de-hulling solid waste produced 62.6 mL of methane (or 134 mL of biogas).     

Production and optimization of biodiesel using mixed immobilized biocatalysts in packed bed reactor

Vegetable oils are used as raw materials for biodiesel production using transesterification reaction. Several methods for the production of biodiesel were developed using chemical (alkali and acidic compounds) and biological catalysts (lipases). Biodiesel production catalyzed by lipases is energy and cost-saving processes and is carried out at normal temperature and pressure. The need for an efficient method for screening larger number of variables has led to the adoption of statistical experimental design. In the present study, packed bed reactor was designed to study with mixed immobilized biocatalysts to have higher productivity under optimum conditions. Contrary to the single-step acyl migration mechanism, a two-step stepwise reaction mechanism involving immobilized Candida rugosa lipase and immobilized Rhizopus oryzae cells was employed for the present work. This method was chosen because enzymatic hydrolysis followed by esterification can tolerate high free fatty acid containing oils. The effects of flow rate and bed height on biodiesel yield were studied using two factors five-level central composite design (CCD) and response surface methodology (RSM). Maximum biodiesel yield of 85 and 81 % was obtained for jatropha oil and karanja oil with the optimum bed height and optimum flow rate of 32.6 cm and 1.35 L/h, and 32.6 cm and 1.36 L/h, respectively.     

Mechanistic insights into the specificity of human cytosolic sulfotransferase 2A1 (hSULT2A1) for hydroxylated polychlorinated biphenyls through the use of fluoro-tagged probes

Determining the relationships between the structures of substrates and inhibitors and their interactions with drug-metabolizing enzymes is of prime importance in predicting the toxic potential of new and legacy xenobiotics. Traditionally, quantitative structure activity relationship (QSAR) studies are performed with many distinct compounds. Based on the chemical properties of the tested compounds, complex relationships can be established so that models can be developed to predict toxicity of novel compounds. In this study, the use of fluorinated analogues as supplemental QSAR compounds was investigated. Substituting fluorine induces changes in electronic and steric properties of the substrate without substantially changing the chemical backbone of the substrate. In vitro assays were performed using purified human cytosolic sulfotransferase hSULT2A1 as a model enzyme. A mono-hydroxylated polychlorinated biphenyl (4-OH PCB 14) and its four possible mono-fluoro analogues were used as test compounds. Remarkable similarities were found between this approach and previously published QSAR studies for hSULT2A1. Both studies implicate the importance of dipole moment and dihedral angle as being important to PCB structure in respect to being substrates for hSULT2A1. We conclude that mono-fluorinated analogues of a target substrate can be a useful tool to study the structure activity relationships for enzyme specificity.     

Glyphosate input modifies microbial community structure in clear and turbid freshwater systems

Since it was commercially introduced in 1974, glyphosate has been one of the most commonly used herbicides in agriculture worldwide, and there is growing concern about its adverse effects on the environment. Assuming that glyphosate may increase the organic turbidity of water bodies, we evaluated the effect of a single application of 2.4?±?0.1 mg l^?1 of glyphosate (technical grade) on freshwater bacterioplankton and phytoplankton (pico, micro, and nanophytoplankton) and on the physical and chemical properties of the water. We used outdoor experimental mesocosms under clear and oligotrophic (phytoplanktonic chlorophyll a?=?2.04 μg l^?1; turbidity?=?2.0 NTU) and organic turbid and eutrophic (phytoplanktonic chlorophyll a?=?50.3 μg l^?1; turbidity?=?16.0 NTU) scenarios. Samplings were conducted at the beginning of the experiment and at 1, 8, 19, and 33 days after glyphosate addition. For both typologies, the herbicide affected the abiotic water properties (with a marked increase in total phosphorus), but it did not affect the structure of micro and nanophytoplankton. In clear waters, glyphosate treatment induced a trend toward higher bacteria and picoeukaryotes abundances, while there was a 2 to 2.5-fold increase in picocyanobacteria number. In turbid waters, without picoeukaryotes at the beginning of the experiment, glyphosate decreased bacteria abundance but increased the number of picocyanobacteria, suggesting a direct favorable effect. Moreover, our results show that the impact of the herbicide was observed in microorganisms from both oligo and eutrophic conditions, indicating that the impact would be independent of the trophic status of the water body.     

Effect of feeding dried sweet orange (<Emphasis Type="Italic">Citrus sinensis</Emphasis>) peel and lemon grass (<Emphasis Type="Italic">Cymbopogon citratus</Emphasis>) leaves on growth performance,carcass traits,serum metabolites and antioxidant status in broiler during the finisher phase

The current experiment was conducted to evaluate the effects of feeding dried sweet orange peel (SOP) and lemon grass leaves (LGL) as feed additives on broiler growth performance, serum metabolites, and antioxidant status. A total of 192-day-old (Ross 308) broiler chickens were distributed randomly into 4 dietary treatments with 4 replicates per each treatment. The dietary treatments included a control diet without any feed additive (T1), a diet containing 0.8 % SOP (T2), a diet containing 0.8 % LGL (T3), and a diet containing combination of 0.4 % SOP?+?0.4 % LGL (T4) was fed during the growth period from 22 to 42 days. Feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), carcass traits, serum components, and antioxidant status were measured. At the end of the experimental period, the results indicated that supplementation of SOP and LGL alone or in combination did not significantly (P?>?0.05) affect BWG, FI, FCR, and carcass characteristics in broiler chickens. Serum total protein was increased significantly (P?<?0.05) in T3 and T4 compared to the other treatments. Also, serum globulin increased significantly (P?<?0.05) in the treated groups. Serum glucose, low density lipoprotein, triglyceride, and very low density lipoprotein decreased significantly (P?<?0.05) in the treatment groups, while cholesterol and high-density lipoprotein decreased in T2 compared to the other groups. Significantly (P?<?0.05) higher total antioxidant status was observed in T2 compared to the other treatments. In conclusion, these results indicate that SOP, LGL, and their combination may positively modify some serum components and the antioxidant status without any beneficial effect on growth performance and carcass traits in broiler chickens.