A study of ozone variation trend within area of affecting human health in Hong Kong

As far as the impact of air pollutants on human health being concerned, ozone is one of the main pollutants in atmosphere. In particular, the ground level ozone is responsible for a variety of adverse effects on both human being and plant life. To protect the humankind from such adverse health effects, early information and precautions of high ozone level need to be supplied in times. In this study, statistical characteristics of ground level ozone is analyzed according to the field monitoring data in mixed residential, commercial and industrial areas, e.g., Tsuen Wan area in Hong Kong. The study deals with the characteristics of hourly and daily mean ozone levels under different climatic conditions such as temperature, solar radiation, wind speed, and other pollutant concentration levels. The study aims to investigate the importance of meteorological factors and their impact on relevant pollutant concentration levels from chemical aspect. Further, reasons causing the spatial and temporal variations of ozone levels are discussed. All these results will provide a physical basis for accurately predicting ozone concentration in extensive, future research.     

Team creativity/innovation in culturally diverse teams: A meta‐analysis

This meta‐analysis investigates the direction and strength of the relationship between diversity in culturally diverse teams and team creativity/innovation. We distinguish the effects of two diversity levels (i.e., surface level vs. deep level) in culturally diverse teams and examine the moderators suggested by the socio‐technical systems framework (i.e., team virtuality and task characteristics in terms of task interdependence, complexity, and intellectiveness). Surface‐level diversity in culturally diverse teams is not related to team creativity/innovation, whereas deep‐level diversity in culturally diverse teams is positively related to team creativity/innovation. Moreover, surface‐level diversity in culturally diverse teams and team creativity/innovation are negatively related for simple tasks but unrelated for complex tasks. Deep‐level diversity in culturally diverse teams and team creativity/innovation is positively related for collocated teams and interdependent tasks but unrelated for noncollocated teams and independent tasks. We discuss the theoretical and practical implications.     

POTENTIAL CLIMATE CHANGE IMPACTS ON MOUNTAIN WATERSHEDS IN THE PACIFIC NORTHWEST1

ABSTRACT: Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO₂ concentration. The RCM results indicate an average warming of about 2.5°C, and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds, the American River and Middle Fork Flathead, in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate, there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore, under the specific climate change scenario, the impacts are largely driven by the warming trend rather than the precipitation trend, which is small.     

Online update of model state and parameters of a Monte Carlo atmospheric dispersion model by using ensemble Kalman filter

For an atmospheric dispersion model designed for the assessment of nuclear accident consequences, some uncertain model parameters, such as source term and weather conditions, may influence the reliability of model predictions. In this respect, good estimations of both model state and uncertain parameters are required. In this paper, an ensemble Kalman filter (EnKF) based method for simultaneous state and parameter estimation, using off-site radiation monitoring data, is presented. This method is based on a stochastic state space model, which resembles the parameter errors with stochastic quantities. Three imperfect parameters, including the source release rate, wind direction and turbulence intensity were perturbed simultaneously, and multiple parameter estimation were performed. Having been tested against both simulated and real radiation monitoring data, the method was found to be able to realistically reconstruct the real scene of dispersion, as well as the uncertain parameters. The estimated parameters given by EnKF nicely converge to the true values, and the method also tracks the temporal variation of those parameters.     

广州城市污泥中重金属的含量、排放通量及农用风险评价

分析了广州市中心城区5个主要的污水处理厂污泥的基本理化性质和7种重金属(Cr、Cu、Mn、Ni、Pb、Cd和Zn)在不同雨期的浓度变化,估算了广州市污水处理厂污泥重金属的年排放通量,并对其污泥农用做了潜在风险评价。结果表明,各污水厂污泥均达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)对重金属的排放要求,污泥的基本理化性质满足《城镇污水处理厂污泥处置农用泥质》(CJ/T309-2009)标准,沥滘、猎德、京溪和大坦沙污水厂的污泥重金属满足CJ/T309-2009要求,而西朗污水处理厂2013年12月采集的污泥中Cu和Cd未达标。通过估算,广州市污水处理厂污泥中Cr、Cu、Mn、Ni、Pb、Cd和Zn的年排放通量分别为16.1、18.8、90.3、5.9、7.9、0.2和48.3 t。通过Hakanson生态风险评估,污泥在农用过程中除西朗污水处理厂污泥重金属危害为中等风险,其他厂污泥属于低风险。     

Partnerships and governance at the environment–health nexus in Ontario: lessons from five case examples

The move towards partnerships and collaborative governance models has been advocated in global health discussions for many years now. A case example methodology was applied to this study. It was composed of a document review and semi-structured interviews with key informants from five environment and public health partnerships in the province of Ontario, Canada. These case examples highlight the merits and the challenges of diverse partnerships, and the importance of governance and leadership models, scaling up (and out) impact, and cross-cultural communications to these arrangements. Further work is required to articulate situations in which public health partnerships can be strengthened.     

Water quality guidelines for chemicals: learning lessons to deliver meaningful environmental metrics

Many jurisdictions around the globe have well-developed regulatory frameworks for the derivation and implementation of water quality guidelines (WQGs) or their equivalent (e.g. environmental quality standards, criteria, objectives or limits). However, a great many more still do not have such frameworks and are looking to introduce practical methods to manage chemical exposures in aquatic ecosystems. There is a potential opportunity for learning and sharing of data and information between experts from different jurisdictions in order to deliver efficient and effective methods to manage potential aquatic risks, including the considerable reduction in the need for aquatic toxicity testing and the rapid identification of common challenges. This paper reports the outputs of an international workshop with representatives from 14 countries held in Hong Kong in December 2011. The aim of the workshop and this paper was to identify ‘good practice’ in the development of WQGs to deliver to a range of environmental management goals. However, it is important to broaden this consideration to cover often overlooked facets of implementable WQGs, such as demonstrable field validation (i.e. does the WQG protect what it is supposed to?), fit for purpose of monitoring frameworks (often an on-going cost) and finally how are these monitoring data used to support management decisions in a manner that is transparent and understandable to stakeholders. It is clear that regulators and the regulated community have numerous pressures and constraints on their resources. Therefore, the final section of this paper addresses potential areas of collaboration and harmonisation. Such approaches could deliver a consistent foundation from which to assess potential chemical aquatic risks, including, for example, the adoption of bioavailability-based approaches for metals, whilst reducing administrative and technical burdens in jurisdictions.     

Tissue-based environmental quality benchmarks and standards

Although the use of tissue concentrations (residues) of chemical contaminants as the dose metric to characterize chemical toxicity to aquatic organisms has been gaining acceptance over the past 20 years, tissue concentrations are less commonly used in water quality management and have yet to be formally adopted as benchmarks or environmental quality standards (EQS). This synthesis paper addresses advantages and disadvantages for the development and application of tissue-based EQS as an alternative and supplement to exposure-based EQS determined with water and sediment concentration data. Tissue-based EQS can be readily developed in parallel with conventional toxicity tests, and achieved by quantification of chemical concentrations in tissue alongside traditional concentration-response toxicity testing. Tissue-residue toxicity metrics can be used as benchmarks for screening and monitoring water and sediment quality, to derive equivalent water or sediment EQS, and for ecological risk assessments and weight of evidence approaches for assessing ecosystem impairment. Tissue-based toxicity metrics and associated EQS provide several advantages; however, there are some limitations to consider and key knowledge gaps to fill.     

Arbuscular mycorrhizal fungi enhance both absorption and stabilization of Cd by Alfred stonecrop (Sedum alfredii Hance) and perennial ryegrass (Lolium perenne L.) in a Cd-contaminated acidic soil

A greenhouse pot experiment was conducted to compare the phytoextraction efficiencies of Cd by hyper-accumulating Alfred stonecrop (Sedum alfredii Hance) and fast-growing perennial ryegrass (Lolium perenne L.) from a Cd-contaminated (1.6 mg kg⁻¹) acidic soil, and their responses to the inoculations of two arbuscular mycorrhizal (AM) fungal strains, Glomus caledonium 90036 (Gc) and Glomus mosseae M47V (Gm). Ryegrass and stonecrop were harvested after growing for 9 and 27 wk, respectively. Without AM fungal inoculation, the weekly Cd extraction by stonecrop (8.0 μg pot⁻¹) was 4.3 times higher than that by ryegrass (1.5 μg pot⁻¹). Both Gc and Gm significantly increased (P < 0.05) root mycorrhizal colonization rates, soil acid phosphatase activities, and available P concentrations, and thereby plant P absorptions (except for Gm-inoculated ryegrass), shoot biomasses, and Cd absorptions (except for Gm-inoculated stonecrop), while only Gc-inoculated stonecrop significantly accelerated (P < 0.05) the phytoextraction efficiency of Cd by 78%. In addition, both Gc and Gm significantly decreased (P < 0.05) phytoavailable Cd concentrations by 21–38% via elevating soil pH. The results suggested the potential application of hyper-accumulating Alfred stonecrop associated with AM fungi (notably Gc) for both extraction and stabilization of Cd in the in situ treatment of Cd-contaminated acidic soil.     

Droplet size spectra and deposits of Bacillus thuringiensis aerial sprays,following application at two volume rates over an oak forest

Abstract

Dipel® 8AF, a commercial formulation of Bacillus thuringiensis (B.t.) was sprayed undiluted at 30 BIU in 1.8L/ha over a block B1, and sprayed after dilution with water at 30 BIU in 6.2 L/ha over another block B2 in an oak forest infested with the gypsy moth (Lymantria dispar L.) in southeastern Ontario, Canada. Spray was applied in May 1987 using a Cessna 188 Agtruck aircraft equipped with four Hicronair^® AU4000 atomizers. Droplet sizes were measured at mid‐canopy level of oak trees and at ground level using cylindrical Kromekote® cards. Deposit per unit area was assessed on aluminum oak leaves.

At the lower volume rate of 1.8 L/ha, spray droplets were smaller and droplets/cm² were lower on the cylindrical Kromekote cards in B1 than those obtained in B2 which received the higher volume rate of 6.2 L/ha. The average deposit per unit area of the aluminum oak leaves, expressed in nL of the spray volume per cm² surface area, was also correspondingly lower in B1 than in B2. This was attributed to the higher volume rate of spray application used in B2 than in B1, which resulted in larger droplets and a greater volume deposit/cm² in B2.