Incorporating differences between genetic diversity of trees and herbaceous plants in conservation strategies

Reviews that summarize the genetic diversity of plant species in relation to their life history and ecological traits show that forest trees have more genetic diversity at population and species levels than annuals or herbaceous perennials. In addition, among-population genetic differentiation is significantly lower in trees than in most herbaceous perennials and annuals. Possible reasons for these differences between trees and herbaceous perennials and annuals have not been discussed critically. Several traits, such as high rates of outcrossing, long-distance pollen and seed dispersal, large effective population sizes (N_e), arborescent stature, low population density, longevity, overlapping generations, and occurrence in late successional communities, may make trees less sensitive to genetic bottlenecks and more resistant to habitat fragmentation or climate change. We recommend that guidelines for genetic conservation strategies be designed differently for tree species versus other types of plant species. Because most tree species fit an LH scenario (low [L] genetic differentiation and high [H] genetic diversity), tree seeds could be sourced from a few populations distributed across the species’ range. For the in situ conservation of trees, translocation is a viable option to increase N_e. In contrast, rare herbaceous understory species are frequently HL (high differentiation and low diversity) species. Under the HL scenario, seeds should be taken from many populations with high genetic diversity. In situ conservation efforts for herbaceous plants should focus on protecting habitats because the typically small populations of these species are vulnerable to the loss of genetic diversity. The robust allozyme genetic diversity databases could be used to develop conservation strategies for species lacking genetic information. As a case study of reforestation with several tree species in denuded areas on the Korean Peninsula, we recommend the selection of local genotypes as suitable sources to prevent adverse effects and to insure the successful restoration in the long term.     

Biological elimination of H2S and NH3 from wastegases by biofilter packed with immobilized heterotrophic bacteria

Biotreatment of various ratios of H₂S and NH₃ gas mixtures was studied using the biofilters, packed with co-immobilized cells (Arthrobacter oxydans CH8 for NH₃ and Pseudomonas putida CH11 for H₂S). Extensive tests to determine removal characteristics, removal efficiency, removal kinetics, and pressure drops of the biofilters were performed. To estimate the largest allowable inlet concentration, a prediction model was also employed. Greater than 95% and 90% removal efficiencies were observed for NH₃ and H₂S, respectively, irrespective of the ratios of H₂S and NH₃ gas mixtures. The results showed that H₂S removal of the biofilter was significantly affected by high inlet concentrations of H₂S and NH₃. As high H₂S concentration was an inhibitory substrate for the growth of heterotrophic sulfur-oxidizing bacteria, the activity of H₂S oxidation was thus inhibited. In the case of high NH₃ concentration, the poor H₂S removal efficiency might be attributed to the acidification of the biofilter. The phenomenon was caused by acidic metabolite accumulation of NH₃. Through kinetic analysis, the presence of NH₃ did not hinder the NH₃ removal, but a high H₂S concentration would result in low removal efficiency. Conversely, H₂S of adequate concentrations would favor the removal of incoming NH₃. The results also indicated that maximum inlet concentrations (model-estimated) agreed well with the experimental values for space velocities of 50–150 h⁻¹. Hence, the results would be used as the guideline for the design and operation of biofilters.     

Processes in informal end-processing of e-waste generated from personal computers in Vietnam

Informal treatment of e-waste plays an important role in many countries which have no or weak formal waste management structures. One of the challenges for assessing informal e-waste recycling technologies is to identify their disadvantages and potential technology improvement. The analysis of informal recycling processes starts with a balance of input and output materials for each of the processes. Main obstacles are the fact that in most cases, mixed or variety materials serve as input and, secondly by nature, the informal sector does not systematically measure and monitor the process. This study presents the processes and available data for informal e-waste recycling of desktop personal computer as it consists of components made of plastic and many metals within the Vietnamese context. To identify the most relevant processes, critical flows and technology gap, two scenarios are compared: (1) current situation in which recycling activities are taken in recycling craft villages and (2) appropriately selected BAT. The selected materials from e-waste cover a wide range of recycling processes and technologies: Printed Circuit Board treatment, metal (ferrous metal, aluminum and copper) and plastic recycling.

     

Friction measurements on “anti-slip” floors under shoe sole,contamination, and inclination conditions

Friction measurements were conducted to study the effects of shoe sole, floor, contamination, and inclined angle of the floor surface on friction coefficient. The shoe sole samples included composite rubber outsole samples with and without V-shaped tread design. Unglazed ceramic tiles of both flat and tiles with molded profile design were tested. The contamination conditions included dry, wet, and glycerol-contaminated conditions. The inclined angles included 0°, 5°, and 10°. A Brungraber Mark II slipmeter was used. The results showed that all the four factors affected friction coefficient significantly (p < 0.0001). Flat rubber soles had higher friction coefficients than the soling samples with V-shaped tread design on all tested floors and inclined angles under wet conditions. Flat soles, however, had extremely low friction when tested on flat floors under glycerol-contaminated conditions. The floors with molded grooves perpendicular to friction measurement direction had the highest friction coefficients than all other floor conditions under both the wet and glycerol-contaminated conditions except the wet/flat sole/10° condition. A regression model with a cosine function was established to describe the relationship between friction coefficient and inclined angle of the floor under the experimental conditions. This model is statistically significant at p < 0.0001 with an R² of 0.97.     

Use of residence time distribution for evaluation of gaseous pollutant volatilization from stored swine manure

Abstract

A quantification analysis for evaluation of gaseous pollutant volatilization as a result of mass transfer from stored swine manure is presented from the viewpoint of residence time distribution. The method is based on evaluating the moments of concentration vs. time curves of both air and gaseous pollutants. The concept of moments of concentration histories is applicable to characterize the dispersal of the supplied air or gaseous pollutant in a ventilated system. The mean age or residence time of airflow can be calculated from an inverse system state matrix [B]‐1 of a linear dynamic equation describing the dynamics of gaseous pollutant in a ventilated airspace. The sum elements in an arbitrary row i in matrix [B]‐1 is equal to the mean age of airflow in airspace i. The mean age of gaseous pollutant in airspace i can be obtained from the area under the concentration profile divided by the equilibrium concentration reading in that space caused by gaseous pollutant sources. Matrix [B]‐1 can also be represented in terms of the inverse local airflow rate matrix ([W]‐1), transition probability matrix ([P]), and air volume matrix ([V]) as, [B]‐1 =[W]‐1[P][V]. Finally the mean age of airflow in a ventilated airspace can be interpreted by the physical characteristics of matrices [W] and [P]. The practical use of the concepts is also applied in a typical pig unit.     

Geographical distribution of polybrominated diphenyl ethers (PBDEs) and organochlorines in small cetaceans from Asian waters

Polybrominated diphenyl ethers (PBDEs) are one of the flame retardants widely used in plastics, textiles, electronic appliances, and electrical household appliances. In this study, PBDEs and organochlorine compounds (OCs) were determined in the archived samples from the Environmental Specimen Bank for Global Monitoring (es-BANK) at Ehime University. The blubber of cetaceans found stranded along the coasts of Japan, Hong Kong, the Philippines and India during the period from 1990 to 2001 were employed for chemical analysis to understand the present status of contamination and the specific accumulation of PBDEs. PBDEs were detected in all the cetacean samples analyzed, and concentrations were one or two orders of magnitude lower than for PCBs and DDTs. Concentrations of PBDEs ranged from a low value of 6.0 ng/g lipid wt. in spinner dolphin (Stenella longirostris) from India to a high value of 6000 ng/g lipid wt. in Indo-Pacific humpback dolphin (Sousa chinensis) from Hong Kong. No difference in PBDE levels between coastal and offshore species from Japan was observed, implying the existence of pollution sources in this region other than Japan. Highest concentrations of PBDEs were found in animals from Hong Kong, followed by Japan, and much lower levels from the Philippines and India, suggesting that developing nations may also have pollution sources of PBDEs. Geographical distribution of PBDEs in Asian waters was different from PCBs but similar to DDTs.     

The Value-Action Gap in Waste Recycling: The Case of Undergraduates in Hong Kong

The discrepancy between verbal and actual commitment in waste recycling and environmental behavior is thought to have attenuated the effectiveness of many environmental policy and measures. Studies purport to show the existence of such a value-action gap in environmental issues has been largely based on matching the verbal commitment to environmental value through self-reported environmental behavioral data. Therefore, there is a lack of direct evidence to prove that such a discrepancy exists. This study demonstrates a methodology (contrasting on-site observation with self-reported results) to measure the gap between verbal commitment and actual recycling behavior and provides an explanation on the recycling behavior of students at Hong Kong Baptist University in the hope that the lessons learnt can be generalized to a wider context. Our findings indicate that a gap between verbal recycling commitment and corresponding action does exist in waste recycling on this university campus. By using multiple linear regression analysis, we found that the self-reported recycling behavior of undergraduates cannot be meaningfully explained by most variables previously suggested in the general value-action model.     

Preface

Water, Air, &; Soil Pollution: Focus -