共查询到20条相似文献,搜索用时 500 毫秒
1.
化学品的浓度水平、排放量都与具体的地理位置密切相关,发展具有空间分异特性的多介质环境逸度模型,可更加准确地描述化学品的多介质环境归趋.本研究基于我国的区域环境属性,建立了 50 kmx50 km分辨率的空间分异Ⅲ级多介质环境逸度模型.以阻燃剂十溴二苯醚(BDE-209)为例,模拟和预测了 BDE-209在我国的多介质环境中的分布.结果表明,上海、山东和广东等东部地区大气与土壤中BDE-209浓度较高,陕西、山西等中西部地区水与沉积物内BDE-209浓度较高.BDE-209在大气、水、土壤和沉积物中的平均浓度分别为2.02×10-6 μg·m-3、6.64×10-6μg·m-3、1.93 μg·kg-1 和3.65×10 μg·kg-1.土壤和沉积物是BDE-209主要的汇,其含量占其环境总量的98.65%.所构建的具有空间分异特性的多介质环境逸度模型,适用于持久性有毒化学物质在我国环境中的归趋模拟,有助于化学品的环境风险预测与管理. 相似文献
2.
持久性有机污染物(Persistent Organic pollutant,POPs)是指通过各种环境介质(大气、水、生物体等)能够长距离迁移并长期存在于环境中的人工合成的有机污染物。本文阐述了全球POPs的主要环境过程和各环境介质中POPs的暴露水平,探讨了作物对POPs的吸收过程、吸收机制和生态效应,并基于现有的环境多介质逸度模型和根区水质模型,分析了持久性有机污染物作物吸收过程模拟模型中存在的问题及未来的发展方向。目前,对POPs作物吸收机制及其模拟的研究较少,但随着我国对粮食安全和农业可持续发展的持续关注,这一领域的模拟研究将对科学解析POPs归趋、合理制定风险管控措施和有效确保粮食质量安全等提供重要科学支撑。 相似文献
3.
4.
5.
阐明污染物的环境归趋对于其污染控制和生态风险评价具有重要意义。本文构建了三级环境多介质逸度模型,研究全氟辛烷磺酸(PFOS)在大连区域环境多介质中的分布及其迁移规律。结果表明,PFOS在大气、水、土壤和沉积物相的模拟浓度分别为5.10 pg·m-3、22.60 ng·L-1、2.25μg·kg-1和0.34μg·kg-1,与实测值较为一致。环境相间的迁移主要是大气向土壤中迁移和土壤向水中的迁移,水和土壤是大连区域PFOS的主要的汇。PFOS在大气和水相的平流输入为主要的污染来源,而大气的平流输出是其主要的输出途径。灵敏度分析表明,有机碳分配系数、溶解度、水和气相平流输入、土壤中水的径流速率以及温度是影响模型结果的主要参数。不确定分析则表明,整体参数的变化对水体输出结果影响最大,对沉积物影响最小。本研究较好地模拟了PFOS在大连区域环境多介质中的迁移和归趋,可为其污染控制和生态风险评价提供科学依据。 相似文献
6.
7.
8.
基于环境逸度模型的化学物质暴露与风险评估研究进展 总被引:1,自引:0,他引:1
工业化学品通过各种迁移转化过程后在环境区间中广泛分布,同时新化学品正被大量的生产并进入环境,使得对于化学品管控的需求和压力不断增加。基于这一背景,多国政府颁布了相应的政策法规对化学品进行管控。除了用相应的政策法规进行预先管控之外,使用基于逸度概念的多介质环境模型来表征化学品的行为与归趋是一个相对简单而有效的方法,不仅适用于环境中存在的现有化学品的暴露评估,也成为各国化学品管理中对新化学品的环境暴露进行预测的有力工具。本文综述逸度概念与方法、相关环境模型、建模过程、应用验证等方面的国内外研究进展,希望能够对我国化学品环境暴露评估与风险评估的模型构建、优化与方法应用提供信息和借鉴。 相似文献
9.
碘代X射线造影剂(ICMs)是使用最广泛的血管内药物,近年来在水生环境中频繁检出.由于其高稳定性、高极性和持久性,ICMs会在水生环境中持续存在并且难以被降解.在水生环境中会与消毒剂、天然有机物结合生成具有毒性的消毒副产物(DBPs),由于其本身毒性以及转化产物DBPs的毒性增强了环境健康风险,进而引发了人们的密切关注.本文介绍了ICMs的环境浓度、分析方法以及毒性风险.重点描述了ICMs的前处理技术、检测方法及ICMs毒性评价现状,并展望了以后ICMs毒性的研究方向. 相似文献
10.
南亚排放的持久性有机污染物(POPs)可随大气传输到青藏高原,然而POPs在高原多介质间的迁移与分配尚不清晰。本研究利用三级逸度模型对4种POPs(六六六α-HCH,滴滴涕p,p'-DDT,菲Phe和苯并芘Ba P)在纳木错流域的迁移与归趋进行了模拟。结果表明,大气沉降是该区域污染物的主要输入过程,而降解损失则是主要的输出途径。就最终归趋而言,土壤是POPs在纳木错流域的重要储库,其存储了大于50%的POPs。此外,湖水和沉积物分别对α-HCH和PAHs具有较强的存储能力。灵敏度分析的结果表明,环境温度、大气中POPs的浓度及其理化性质是影响POPs在环境中分布的关键参数。本研究明确了纳木错流域不同POPs的迁移方向和归趋特征,这将为青藏高原生态安全评估提供科学依据。 相似文献
11.
This paper presents a theoretical model of withdrawing resources based on Odum's energy systems diagrams. According to the theory of a general pulsing principle, withdrawing resources changes in time shifting from the initial phases of growth and maturity to the phases of descent and low energy restoration. A simulation was performed in order to hypothesize potential future trends of withdrawing renewable and non-renewable resources and to show some aspects of their sustainability–unsustainability, respectively. According to Odum's theory, after the rapid growth of the last century, our civilization is living in a climax transition phase and it is now approaching a descent phase. A “way down” will be necessary due to the exhaustion of non-renewable and to the limited use of renewable resources. An integrated “renew–non-renew” model was developed by Odum to show how a “business as usual” trend will bring us to a drastic transition to a world that uses scarce renewable resources. Nevertheless, a different choice is possible, based on Daly's concept of quasi-sustainability that can inspire a new model. The latter argued that the exploitation of a non-renewable resource must be paired with a compensating investment in a renewable substitute. Our model shows that we can use non-renewable resources better to considerably improve our capacity of capturing renewable resources in the future. We present this as a necessary condition to address a sustainable environmental policy. 相似文献
12.
13.
Rapidly eroding soft rock cliffs typically retreat at rates in excess of several metres per year, thus allowing the resolution of linkages between cliff dynamics and a range of climatic and marine forcing factors. New evidence from UK coastline of East Anglian coastline, southern North Sea shows that unprotected soft rock cliffs at three widely-spaced locations all show similar variability in retreat behaviour on decadal timescales, which we attribute to changing patterns of storminess in these decades. The 1990s were characterized by frequent months in which the North Atlantic Oscillation (NAO; a well-established measure of inter-annual climatic variability in North-West Europe) was extremely positive (more positive than +3) or extremely negative (more negative than ?3), while the 2000s showed few occurrences of such extreme values. Depression tracks in positive NAO phases make the East Anglian coast prone to storm surges in which raised water levels result from deeply developed low pressure systems, generally associated with westerly air streams. In negative NAO phases the region is prone to easterly airflow which results in periods of strong onshore wind. Both phases are associated with high energetics in the forcing factors. Decadal-scale variability in cliffline retreat rates has implications for the practice of coastal management and policy making and suggests that cliff system responses to global environmental change are not simply driven by secular sea level rise. 相似文献
14.
Three cyclic volatile methylsiloxanes (cVMS) were widely used in various processes of production and industrials and frequently added to consumer products. cVMS are continuously released into the environment, causing increasing environmental and human exposing risks. cVMS were investigated in air, water, biogas, soil, sediment, biosolid and organism. Many scholars focused on the occurrence, behaviours, fate and effects of cVMS in environmental matrices all over the world. However, few studies paid attention to the environmental behaviour of cVMS in the solid phase. We assessed their environmental behaviour and fate in soil, biosolid and sediment. High concentrations of cVMS were detected in biosolids. Volatilisation, adsorption and degradation were the major environmental behaviours for cVMS in the solid phase. Although some aquatic organisms showed an appropriate level of bioaccumulation and bioconcentration, there were no obvious evidence of trophic biomagnification in aquatic food webs for octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5). In addition, cVMS in the environment have not impacted for natural organisms because the concentrations in soil and sediment have not exceeded the maximum no-observed-effect-concentration threshold. Finally, regarding the major environmental behaviour in soil and sediment, suggestions for further study are proposed. 相似文献
15.
Roughly 40 years after its introduction, the metapopulation concept is central to population ecology. The notion that local populations and their dynamics may be coupled by dispersal is without any doubt of great importance for our understanding of population-level processes. A metapopulation describes a set of subpopulations linked by (rare) dispersal events in a dynamic equilibrium of extinctions and recolonizations. In the large body of literature that has accumulated, the term "metapopulation" is often used in a very broad sense; most of the time it simply implies spatial heterogeneity. A number of reviews have recently addressed this problem and have pointed out that, despite the large and still growing popularity of the metapopulation concept, there are only very few empirical examples that conform with the strict classical metapopulation (CM) definition. In order to understand this discrepancy between theory and observation, we use an individual-based modeling approach that allows us to pinpoint the environmental conditions and the life-history attributes required for the emergence of a CM structure. We find that CM dynamics are restricted to a specific parameter range at the border between spatially structured but completely occupied and globally extinct populations. Considering general life-history attributes, our simulations suggest that CMs are more likely to occur in arthropod species than in (large) vertebrates. Since the specific type of spatial population structure determines conservation concepts, our findings have important implications for conservation biology. Our model suggests that most spatially structured populations are panmictic, patchy, or of mainland-island type, which makes efforts spent on increasing connectivity (e.g., corridors) questionable. If one does observe a true CM structure, this means that the focal metapopulation is on the brink of extinction and that drastic conservation measures are needed. 相似文献
16.
A novel procedure for acid-catalysed K2FeO4 oxidation of benzyl alcohol in organic phase 总被引:1,自引:0,他引:1
Recent investigations have shown that ferrate(VI) salts oxidize organic compounds in aqueous phases with fast reaction from
seconds to minutes and poor selectivity. Few studies have used ferrate(VI) in organic phases. The main issues are the poor
solubility of K2FeO4 in common organic solvents and the low reaction rate. Therefore the interests to date are focused on finding a more effective
catalyst in the organic oxidation. Up to now no work has been reported on acids as catalysis for the oxidative abilities of
K2FeO4 in organic phases. Here we present a novel procedure for oxidizing benzyl alcohol to benzaldehyde without an overoxidation
to benzoic acid by K2FeO4 in an organic phase. Using benzyl alcohol as a model, the catalytic activity of various acid solutions was measured. We found
that the reactivity of K2FeO4 to the oxidation of benzyl alcohol can be highly enhanced by addition of a small amount of acid solution at room temperature.
The catalytic ability of acid solutions follows the order acetic acid < oxalic acid < phosphomolybdic acid < phosphotungstic
acid. On the basis of a theoretical analysis, a reaction mechanism is proposed. This method provides a new green way for oxidizing
organic substances by K2FeO4 in nonaqueous media. 相似文献
17.
Joe B Stevens 《Journal of Environmental Economics and Management》1984,11(3):264-281
How (and whether) people perceive environmental change is a question which economists have generally chosen to finesse rather than explore. The three components of attitudes (cognitive, affective, behavioral) are identified and a “satisfaction” metric is used to evaluate the nonbehavioral components for recent in-migrants to Oregon. An interaction model is used to relate changes in satisfaction to changes in air quality and to personal characteristics of the migrants. In general, a valid cognitive dimension exists; changes in satisfaction are in fact consistent with changes in air quality data. 相似文献
18.
A simple mathematical fate model, Multi‐Phase Non‐Steady State Equilibrium Model (MNSEM) is proposed to evaluate distribution, persistence, and concentrations of chemicals in a model environment consisting of air, water, soil and sediment phases. The model is applied to evaluation of environmental fate and concentration of trichloroethylene and 1,4‐dichlorobenzene under generic conditions representative of Japan. Evaluated chemical concentrations in air are within a factor of 3 of average values in Japanese atmosphere, and evaluated concentrations in water, sediment, or fish are greater than an order of magnitude below detection limits in real environments, so that evaluated concentrations are in reasonable agreement with environmental measurement data in Japan. Although MNSEM is not a model for site‐specific evaluation of environmental fate, results suggested that this model is an adequate method to aid in evaluation of fate of chemicals under generic environment conditions. Evaluated concentration‐profiles may be used to estimate average chemical exposure concentrations for humans and the environment. 相似文献
19.
20.
Several species of sandy beach invertebrates regularly switch between burial in the sand during the day and surface activity
at night to feed on stranded organic matter. Because all species consume essentially the same type of food (i.e., wrack) deposited
over a restricted area, the potential for competition exists. Conversely, spatial and temporal segregation of surface activity
behaviour is predicted to allow for niche separation. Here, we tested whether such behavioural niche separation occurs in
three species of sympatric crustaceans (the talitrid amphipods Talitrus saltator (Montagu 1808) and Talorchestia brito Stebbing 1891, and the oniscoidean isopod Tylos europaeus Arcangeli 1938). We also assessed whether surface activity is modulated by weather, sea conditions and moon phases. Surface
activity was measured over three consecutive moon phases on an exposed beach on the Atlantic Coast of Spain using pitfall
traps along three transects from the foredunes to the swash. Adults of the amphipod T. saltator and the isopod T. europaeus overlapped spatially and temporally in their surface activity for most of the night. By contrast, the activity of T. brito was strongly disjunct in time and concentrated into significantly shorter bouts around dawn or dusk. Niche differentiation
was also evident along the space axis, where T. brito occurred distinctly lower on the beach. Although several environmental factors (e.g., air and sand temperature, humidity,
atmospheric pressure, wind speed and wind direction) were correlated with surface activity, this was highly variable amongst
species, life stages, and synodic phases, and did not obscure the fundamental mosaic of spatio-temporal heterogeneity amongst
species. Nocturnal feeding on beach wrack creates the potential for competition amongst sympatric crustaceans which can, however,
be mitigated by behaviour patterns that separate consumers in time and space. 相似文献