县域土地利用细碎度综合度量与空间分异研究——以江苏省东海县为例

土地细碎化是与土地规模经营理念相背离的一种土地形态,细碎化的土地经营模式会造成土地利用效率下降、粮食减产以及景观美观度降低等一系列问题。目前,土地细碎化程度的衡量多通过细碎度表征,但尚无统一标准,且主要针对农用地。以江苏东海县为例,首先结合景观指数与主成分分析,分别计算耕地、基础设施用地、居民点用地以及生态用地的细碎度,再通过系统聚类,分析不同地类细碎度组合的地域分异特征。结果显示：不同用地类型的细碎度是自然、社会经济的综合影响结果,耕地细碎度与居民点细碎度有着较显著的正相关关系,与生态用地细碎度有着较显著的负相关关系,基础设施用地细碎度和居民点细碎度存在一定的正相关关系,与生态用地细碎度存在一定的负相关关系,土地细碎度基于不同自然、社会经济条件,其分区也有着特定的区位特征。探讨不同用地类型细碎度间的关联性及空间分异特征可以为土地利用、经济发展以及景观改善等提供科学的引导     

Toxicological responses in Laeonereis acuta (annelida, polychaeta) after arsenic exposure

Several environmental pollutants, including metals, can induce oxidative stress. So, the objective of this study was to evaluate the effects of arsenic (As(III), as As(2)O(3)) on the antioxidant responses in the polychaete Laeonereis acuta. Worms were exposed to two environmentally relevant concentrations of As, including the highest previously allowed by Brazilian legislation (50 microg As/l). A control group was kept in saline water (10 per thousand) without added metal. It was observed that: (1) a peak concentration of lipid peroxide was registered after 2 days of exposure to 50 microg As/l (61+/-3.2 nmol CHP/g wet weight) compared to the control group (43+/-4.5 nmol CHP/g wet weight), together with a lowering of the activity of the antioxidant enzyme catalase (-47 and -48%, at 50 or 500 microg As/l respectively) and a higher superoxide dismutase activity (+305% at 50 microg As/l with respect to the control group); (2) a lower conjugation capacity through glutathione-S-transferase activity was observed after 7 days of exposure to 50 microg As/l (-48% compared to the control group); (3) a significant increase in As concentration was verified after 1 week of exposure to both As concentrations (50 and 500 microg/l); (4) worms exposed to As showed a limited accumulation of related methylated As species and the levels of non-toxic As species like arsenobetaine (AsB) and arsenocholine (AsC) remained unchanged during the exposure period when compared with the controls. Overall, it can be concluded that As interfered in the antioxidant defense system of L. acuta, even at low concentrations (50 microg/l) that Brazilian legislation previously considered safe. The fact that worms exposed to As showed high levels of methylated As species indicates the methylation capability of L. acuta, although the high levels of inorganic As suggest that not all the administered As(III) (as As(2)O(3)) is completely removed or biotransformed after 7 days of exposure.     

Local community acceptance of the rare earth industry: the case of the Lynas Advanced Materials Plant (LAMP) in Malaysia

This paper provides a detailed analysis of the local community response to a newly installed rare earth (RE) refinery facility and the factors underlying its acceptance. House-to-house interviews, using structured questionnaire, were conducted in 2013 (N = 370). Results show that the community was divided into deciding whether they agreed with the presence of the facility, 41.36 % (for) and 41.62 % (against). The remaining fraction of the community was undecided, which made up 17.03 % of the total respondents. This paper identifies six significant predictors of risk acceptance: gender, education status, place of residence, Factor 1 (variables—perception of safety, concern on effects, and trust in the operators), Factor 2 (variables—social and individual benefits), and Factor 3 (variables—no confidence in government). This study gives insights on how the public respond to potential hazardous facilities and highlights the need for policy makers to consider public sentiment which can interfere with further expansion of the RE industry.     

Methods for more accurate determination of explosion severity parameters

Accurate determination of explosion severity parameters (p_max, (dp/dt)_max, and K_St) is essential for dust explosion assessment, identification of mitigation strategy, and design of mitigation measure of proper capacity. The explosion severity parameters are determined according to standard methodology however variety of dust handled and operation circumstances may create practical challenge on the optimal test method and subsequent data interpretation. Two methods are presented: a statistical method, which considers all test results in determination of explosion severity parameters and a method that corrects the results for differences of turbulence intensity. The statistical method also calculates experimental error (uncertainty) that characterises the experimental spread, allows comparison to other dust samples and may define quality determination threshold. The correction method allows to reduce discrepancies between results from 1 m³ vessel and 20-l sphere caused by difference in the turbulence intensity level. Additionally new experimental test method for difficult to inject samples together with its analysis is described. Such method is a versatile tool for explosion interpretation in test cases where different dispersion nozzle is used (various turbulence level in the test chamber) because of either specific test requirements or being “difficult dust sample”.     

An integrated approach to assessing the environmental and health impacts of pollution in the urban environment: Methodology and a case study

This paper presents a new decision-support methodology and software tool for sustainable management of urban pollution. A number of different methods and tools are integrated within the same platform, including GIS, LCA, fate and transport modelling, health impact assessment and multi-criteria decision analysis. The application of the framework is illustrated on a case study which investigates the environmental and health impacts of pollution arising from different industrial, domestic and transport sources in a city. The example city chosen for the study is Sheffield, UK, and the main pollutants considered are NO_x, SO₂ and PM10. The results suggest that the absence of the current large industrial sources in the city would lead to a 90% reduction of the SO₂ and 70% of the NO₂ ground concentrations, consequently preventing 27 deaths and 18 respiratory hospital admissions per annum for a population of 500,000. Based on the total annual mortality and hospital admissions in Sheffield for the year of the assessment, this means that 0.53% of premature deaths and 0.49% of respiratory hospital admissions would be prevented by the estimated reduction in air pollution.     

Seasonal variability and source apportionment of metals in the atmospheric deposition in Belgrade

The primary objective of this study is to assess anthropogenic impacts on the environment by determination of element atmospheric depositions. Bulk depositions were collected monthly, from June 2002 to December 2006, at three urban locations in Belgrade. Concentrations of Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were analyzed by atomic absorption spectrometry and the current deposition fluxes of atmospheric metals were established. Fourier analysis was applied in order to investigate seasonal variation of the monthly data set. Nickel, V, Fe and Al showed pronounced seasonal dependence, while seasonal variation of the other elements was not evident. The enrichment factors of Pb, Zn, Cd and Cu were obviously above those who could have been caused by natural processes, indicating a mainly anthropogenic origin. Nickel was intermediately enriched suggesting participation of both natural and anthropogenic sources. The multivariate receptor model, Unmix, was used to analyze a 5-yr element atmospheric depositions data set. Three main source profiles (mixed road dust, oil combustion and metal processing) were identified and the overall average percentage source contributions determined.     

Treatment of 2,4-D, mecoprop, and dicamba using membrane bioreactor technology

Phenoxyacetic and benzoic acid herbicides are widely used agricultural, commercial, and domestic pesticides. As a result of high water solubility, mobility, and persistence, 2,4-dichlorophenoxyacetic acid (2,4-D), methylchlorophenoxypropionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba) have been detected in surface and waste waters across Canada. As current municipal wastewater treatment plants do not specifically address chronic, trace levels of contaminants like pesticides, an urgent need exists for an efficient, environmentally friendly means of breaking down these toxic herbicides. A commercially available herbicide mix, WeedEx, containing 2,4-D, mecoprop, and dicamba, was subjected to treatment using membrane bioreactor (MBR) technology. The three herbicides, in simulated wastewater with a chemical oxygen demand of 745 mg/L, were introduced to the MBR at concentrations ranging from 300 μg/L to 3.5 mg/L. Herbicides and biodegradation products were extracted from MBR effluent using solid-phase extraction followed by detection using high-performance liquid chromatography coupled with mass spectrometry. 2,4-D was reduced by more than 99.0 % within 12 days. Mecoprop and dicamba were more persistent and reduced by 69.0 and 75.4 %, respectively, after 112 days of treatment. Half-lives of 2,4-D, mecoprop and dicamba during the treatment were determined to be 1.9, 10.5, and 28.3 days, respectively. Important water quality parameters of the effluent such as dissolved oxygen, pH, ammonia, chemical oxygen demand, etc. were measured daily. MBR was demonstrated to be an environmentally friendly, compact, and efficient method for the treatment of toxic phenoxyacetic and benzoic acid herbicides.     

Solid phase microextraction applied to the analysis of organophosphorus insecticides in fruits

Trace amounts of organophosphorus pesticides (OPs) were determined in various fruits by headspace solid phase microextraction (HS-SPME) and gas chromatography–nitrogen phosphorous detection (GC-NPD). Sampling from the headspace enhanced method selectivity, whereas at the same time improved fiber life time and method sensitivity. Diazinon, parathion, methyl parathion, malathion and fenithrothion were determined in various fruits: more than 150 samples of 21 types of fruits were studied. SPME-GC-NPD provided a useful and very efficient analytical tool: method linearity ranged from 1.2 to 700 ng/ml. Limits of detection (LODs) and quantitation (LOQs) ranged from 0.03 to 3 ng/ml and 0.12 to 10 ng/ml respectively, values well below the residue limits set by the EU. Less than 2% of the samples were found positive containing amounts higher than the EU limits. The effect of fruit peeling and washing was also investigated.     

Use of dolomite phosphate rock (DPR) fertilizers to reduce phosphorus leaching from sandy soil

There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leaching volume of 1,183 mm equivalent to the mean annual rainfall of this region during the period of 2001-2003. Leachates were collected and analyzed for total P and inorganic P. Phosphorus in the leachate was dominantly reactive, accounting for 67.7-99.9% of total P leached. Phosphorus leaching loss mainly occurred in the first three leaching events, accounting for 62.0-98.8% of the total P leached over the whole period. The percentage of P leached (in the total P added) from the soil amended with water-soluble P fertilizer was higher than those receiving the DPR fertilizers. The former was up to 96.6%, whereas the latter ranged from 0.3% to 3.8%. These results indicate that the use of N-Viro-based DPR fertilizers can reduce P leaching from sandy soils.     

Lead and zinc accumulation and tolerance in populations of six wetland plants

Wetland plants such as Typha latifolia and Phragmites australis have been indicated to show a lack of evolution of metal tolerance in metal-contaminated populations. The aim of the present study is to verify whether other common wetland plants such as Alternanthera philoxeroides and Beckmannia syzigachne, also possess the same characteristics. Lead and zinc tolerances in populations of six species collected from contaminated and clean sites were examined by hydroponics. In general, the contaminated populations did not show higher metal tolerance and accumulation than the controls. Similar growth responses and tolerance indices in the same metal treatment solution between contaminated and control populations suggest that metal tolerance in wetland plants are generally not further evolved by contaminated environment. The reasons may be related to the special root anatomy in wetland plants, the alleviated metal toxicity by the reduced rooting conditions and the relatively high innate metal tolerance in some species.