The influence of diesel—truck exhaust particles on the kinetics of the atmospheric oxidation of dissolved sulfur dioxide by oxygen

The automobile exhausts are one of the major sources of particulate matter in urban areas and these particles are known to influence the atmospheric chemistry in a variety of ways. Because of this, the oxidation of dissolved sulfur dioxide by oxygen was studied in aqueous suspensions of particulates, obtained by scraping the particles deposited inside a diesel truck exhaust pipe (DEP). A variation in pH showed the rate to increase with increase in pH from 5.22 to about ～6.3 and to decrease thereafter becoming very slow at pH?=?8.2. In acetate-buffered medium, the reaction rate was higher than the rate in unbuffered medium at the same pH. Further, the rate was found to be higher in suspension than in the leachate under otherwise identical conditions. And, the reaction rate in the blank reaction was the slowest. This appears to be due to catalysis by leached metal ions in leachate and due to catalysis by leached metal ions and particulate surface both in suspensions. The kinetics of dissolved SO₂ oxidation in acetate-buffered medium as well as in unbuffered medium at pH?=?5.22 were defined by rate law: k _obs ?=?k ₀?+?k _cat [DEP], where k _obs and k ₀ are observed rate constants in the presence and the absence of DEP and k _cat is the rate constant for DEP-catalyzed pathway. At pH?=?8.2, the reaction rate was strongly inhibited by DEP in buffered and unbuffered media. Results suggest that the DEP would have an inhibiting effect in those areas where rainwater pH is 7 or more. These results at high pH are of particular significance to the Indian subcontinent, because of high rainwater pH. Conversely, it indicates the DEP to retard the oxidation of dissolved SO₂ and control rainwater acidification.

     

Effects of soil moisture depletion on vegetable crop uptake of pharmaceuticals and personal care products (PPCPs)

Agricultural crops have a long history of being irrigated with recycled wastewater (RW). However, its use on vegetable crops has been of concern due to the potential prevalence of microcontaminants, such as pharmaceuticals and personal care products (PPCPs) in the latter, which represents a possible health hazard to consumers. We investigated the uptake of three PPCPs (atenolol, diclofenac, and ofloxacin), at three different concentrations in irrigation water (0.5, 5, and 25 μg L^?1) in relation to three varying volumetric soil moisture depletion levels of 14 % (?4.26 kPa), 10 % (?8.66 kPa), and 7 % (?18.37 kPa) by various vegetable crop species. Experiments were conducted in a split-split block completely randomized design. PPCPs were extracted using a developed method of accelerated solvent extraction and solid phase extraction and analyzed via liquid chromatography mass spectrometry (LCMS). Results indicate that all treated crops were capable of PPCP uptake at nanogram per gram concentrations independent of the applied soil moisture depletion levels and PPCP concentrations. Ofloxacin was the chemical with the highest uptake amounts, followed by atenolol and then diclofenac. Although the results were not statistically significant, higher concentrations of PPCPs were detected in plants maintained under higher soil moisture levels of 14 % (?4.26 kPa).     

Identification of a novel hydroxylated metabolite of 2,2′,3,5′,6-pentachlorobiphenyl formed in whole poplar plants

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants consisting of 209 congeners. Oxidation of several PCB congeners to hydroxylated PCBs (OH-PCBs) in whole poplar plants has been reported before. Moreover, 2,2′,3,5′,6-pentachlorobiphenyl (PCB95), as a chiral congener, has been previously shown to be atropselectively taken up and transformed in whole poplar plants. The objective of this study was to determine if PCB95 is atropselectively metabolized to OH-PCBs in whole poplar plants. Two hydroxylated PCB95s were detected by high-performance liquid chromatography-mass spectrometry in the roots of whole poplar plants exposed to racemic PCB95 for 30 days. The major metabolite was confirmed to be 4′-hydroxy-2,2′,3,5′,6-pentachlorobiphenyl (4′-OH-PCB95) by gas chromatography-mass spectrometry (GC-MS) using an authentic reference standard. Enantioselective analysis showed that 4′-OH-PCB95 was formed atropselectively, with the atropisomer eluting second on the Nucleodex β-PM column (E2-4′-OH-PCB95) being slightly more abundant in the roots of whole poplar plants. Therefore, PCB95 can at least be metabolized into 4′-OH-PCB95 and another unknown hydroxylated PCB95 (as a minor metabolite) in whole poplar plants. Both atropisomers of 4′-OH-PCB95 are formed, but E2-4′-OH-PCB95 has greater atropisomeric enrichment in the roots of whole poplar plants. A comparison with mammalian biotransformation studies indicates a distinctively different metabolite profile of OH-PCB95 metabolites in whole poplar plants. Our observations suggest that biotransformation of chiral PCBs to OH-PCBs by plants may represent an important source of enantiomerically enriched OH-PCBs in the environment.     

Polychlorinated biphenyls and links to cardiovascular disease

The pathology of cardiovascular disease is multi-faceted, with links to many modifiable and non-modifiable risk factors. Epidemiological evidence now implicates exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), with an increased risk of developing diabetes, hypertension, and obesity; all of which are clinically relevant to the onset and progression of cardiovascular disease. PCBs exert their cardiovascular toxicity either directly or indirectly via multiple mechanisms, which are highly dependent on the type and concentration of PCBs present. However, many PCBs may modulate cellular signaling pathways leading to common detrimental outcomes including induction of chronic oxidative stress, inflammation, and endocrine disruption. With the abundance of potential toxic pollutants increasing globally, it is critical to identify sensible means of decreasing associated disease risks. Emerging evidence now implicates a protective role of lifestyle modifications such as increased exercise and/or nutritional modulation via anti-inflammatory foods, which may help to decrease the vascular toxicity of PCBs. This review will outline the current state of knowledge linking coplanar and non-coplanar PCBs to cardiovascular disease and describe the possible molecular mechanism of this association.     

Recycling food and agriculture by-products to mitigate climate change: a review

Food loss and waste is a major issue affecting food security, environmental pollution, producer profitability, consumer prices, and climate change. About 1.3 billion tons of food products are yearly lost globally, with China producing approximately 20 million tons of soybean dregs annually. Here, we review food and agricultural byproducts with emphasis on the strategies to convert this waste into valuable materials. Byproducts can be used for animal and plant nutrition, biogas production, food, extraction of oils and bioactive substances, and production of vinegar, wine, edible coatings and organic fertilizers. For instance, bioactive compounds represent approximately 8–20% of apple pomace, 5–17% of orange peel, 10–25% of grape seeds, 3–15% of pomegranate peel, and 2–13% of date palm seeds. Similarly, the pharmaceutical industry uses approximately 6.5% of the total output of gelatin derived from fish bones and animal skin. Animals fed with pomegranate peel and olive pomace improved the concentration of deoxyribonucleic acid and protein, the litter size, the milk yield, and nest characteristics. Biogas production amounts to 57.1% using soybean residue, 53.7% using papaya peel, and 49.1% using sugarcane bagasse.

     

Are the costs worth the benefits? Shared perception and the aggregation of organizational climate ratings

A definitional component of organizational climate is the focus on employees' shared perceptions of the focal climate domain. To operationalize the notion of sharedness, researchers typically aggregate employees' domain‐specific climate perceptions to a higher level and justify this aggregation using quantitative indices of agreement. In the current paper, I argue that although accounting for sharedness among employees can provide some valuable insight, our overreliance on sharedness obscures some of the very organizational phenomena of interest. I discuss this issue by focusing on four costs of making unfounded assumptions regarding sharedness: (a) Aggregation assumes individual differences are a function of random error; (b) aggregation assumes that social situations are uniform across employees; (c) aggregation assumes that the unit of analysis is clear‐cut; and (d) aggregation assumes the group mean is meaningful. I argue that researchers carefully need to weigh the costs of violating these assumptions against the expected benefits of aggregating employees' climate perceptions, recognizing that sometimes employees' perceptions (i.e., psychological climate) might provide greater insight into phenomena of interest. Although I discuss these costs within the context of organizational climate research, these arguments apply to other research areas where individual perceptions are aggregated (e.g., research on leadership and teams).     

Prioritizing sites for conservation based on similarity to historical baselines and feasibility of protection

The concept of shifting baselines in conservation science implies advocacy for the use of historical knowledge to inform these baselines but does not address the feasibility of restoring sites to those baselines. In many regions, conservation feasibility varies among sites due to differences in resource availability, statutory power, and land‐owner participation. We used zooarchaeological records to identify a historical baseline of the freshwater mussel community's composition before Euro‐American influence at a river‐reach scale (i.e., a kilometer stretch of river that is abiotically similar) in the Leon River of central Texas (U.S.A.). We evaluated how the community reference position and the feasibility of conservation might enable identification of sites where conservation actions would preserve historically representative communities and be likely to succeed. We devised a conceptual model that incorporated community information and landscape factors to link the best conservation areas to potential cost and conservation benefits. Using fuzzy ordination, we identified modern mussel beds that were most like the historical baseline. We then quantified housing density and land use near each river reach identified to estimate feasibility of habitat restoration. Using our conceptual framework, we identified reaches of high conservation value (i.e., contain the best mussel beds) and where restoration actions would be most likely to succeed. Reaches above Lake Belton were most similar in species composition and relative abundance to zooarchaeological sites. A subset of these mussel beds occurred in locations where conservation actions appeared most feasible. Our results show how to use zooarchaeological data (biodiversity data often readily available) and estimates of conservation feasibility to inform conservation priorities at a local spatial scale.     

Impacts of climate change on the hydrology of two Natura 2000 sites in Northern Greece

Greece is included among the most vulnerable regions of Europe by climate change on account of higher temperature and reduced rainfall in areas already facing water scarcity. With respect to wetland systems, many ephemeral ones are expected to disappear and several permanent to shrink due to climate change. As regards two specific wetlands of Greece, the change in hydroperiod of Cheimaditida and Kerkini lakes due to climate change was studied. Lakes’ water balance was simulated using historical climate data and the emission scenarios Α1Β for the period 2020–2050 and Α1Β and Α2 for the period 2070–2100. Future climate scenarios, based on emission scenarios A1B and A2, were provided in the context of the study of Climate Change Impacts Study Committee. The surface area of Lake Cheimaditida will undergo a substantial decrease, initially by 20 % during the period 2020–2050 and later until 37 % during the period 2070–2100. In Lake Kerkini, the surface area will decrease, initially by 5 % during the period 2020–2050 and later until 14 % during the period 2070–2100. Climate change is anticipated to impact the hydroperiod of the two wetlands, and the sustainable water management is essential to prevent the wetland’s biodiversity loss.