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921.
孙浩  郭劲光 《自然资源学报》2022,37(12):3234-3251
在中国向高质量发展转型下,探究环境规制、产业集聚对能源效率的作用,对实现“双碳目标”具有重要的现实意义。系统梳理了三者间的作用机制,并基于中国2006—2018年的数据,运用多种“近邻”权重下的空间杜宾模型,检验环境规制、产业集聚以及二者的融合发展对能源效率的溢出效应及其区域差异。研究发现:(1)环境规制和能源效率二者间存在“波特假说”,但这种效应却具有“度”的限制;产业集聚(专业化、多样化)能够有效地助推自身以及与之“相邻”(地理邻近、经济互动)地区能源效率的提升。(2)环境规制对能源效率的作用表现出明显的区域差异,且在中国东、中以及西部三区域间也具有显著的经济地理关联性;产业集聚对能源效率的影响也表现出明显的区域差异,东部来源于多样化集聚,而中西部来源于专业化与多样化集聚。(3)在效应分解方面,无论是全样本还是分区域样本中,环境规制、产业集聚对能源效率的空间溢出效应并不单单是由于地理“相邻”造成的,更多是地区间地理邻近与经济互动协同的结果。(4)环境规制与专业化集聚的融合发展,抑制了专业化带来的正效应,而其与多样化集聚的融合发展对推动能源效率提升具有更强效果。  相似文献   
922.
选取中国2000~2018年30个省市的面板数据,构建了能源消费结构低碳化指数,基于多期双重差分、三重差分等方法实证检验碳交易政策与能源消费结构低碳转型之间的关系及异质性影响,并进一步利用多重中介效应模型探讨碳交易政策推动地区能源消费结构低碳转型的作用路径.结果表明:碳交易政策可以显著提升地区能源消费结构低碳化水平且作用效果逐年增强.从作用路径看,“四大效应”激励作用彰显,作用效果由大到小依次为结构优化效应、行为驱动效应、生态创新效应和环保支出效应;从异质性影响看,GDP增速较慢地区的政策实施加快了能源消费结构低碳转型,影响明显高于GDP增速较快地区;碳交易政策对东部地区的正向推动效应显著,对中西部地区无明显促进作用.  相似文献   
923.
Hwang HM  Green PG  Young TM 《Chemosphere》2008,71(11):2139-2149
To assess potential health risks to benthic organisms from exposure to toxic contaminants, sediment chemistry data from five salt marshes along the coast of California were compared with threshold effects levels (TELs) and probable effects levels (PELs). As an integrated estimate of toxicity potential of multiple contaminants, mean PEL quotients (mPELQs) were used to categorize sampling stations into three groups: high (>0.5), medium (0.1–0.5) and low (<0.1). In all sediments from Stege Marsh located in San Francisco Bay, at least one contaminant exceeded PELs by up to 18-fold and mPELQs were higher than 0.7. Mean PELQs in two core sediments from eastern Stege Marsh ranged from 0.7 to 2.1, indicating that benthic organisms in Stege Marsh may have been adversely affected for several decades. To investigate bioavailability and bioaccumulation of contaminants in sediments, longjaw mudsuckers (Gillichthys mirabilis) were transplanted to six Stege Marsh stations for 60 days. Body burdens of organic contaminants clearly showed that they were readily available for benthic organisms. Measured concentrations of organic contaminants in mudsuckers were similar to estimated levels computed using a theoretical bioaccumulation potential model. Levels of PCBs and arsenic in mudsuckers were higher than screening values set as guidelines for the protection of humans and levels of PCBs and DDTs were higher than criteria for wildlife. The results of this study indicate that the levels of contaminants in Stege Marsh sediments may not fully support the well-being of benthic organisms and also may provoke adverse effects on fish-eating animals and humans through trophic transfer.  相似文献   
924.
Sediments from Polish coastal environments were classified by a quality assessment approach that took into account trace metal and organic micropollutant concentrations, grain-size distribution, and organic carbon content. Generally, no benthic organisms were found at sites where sediments were classified as heavily polluted. However, areas characterized by a moderate contamination showed a variable composition of the benthic community and changing bioaccumulation patterns; therefore, no single species found in the Gulf of Gdańsk could be considered representative of the whole benthic environment. Although sediment monitoring must be considered a suitable tool to detect hot-spot pollution areas in coastal and inland waters, it should be complemented by bioaccumulation measurements to evaluate the actual risk posed by contaminants to benthic organisms. This “biological information” allows a better appreciation of the real benthic infaunal community exposure to chemicals and can usefully complement the existing sediment quality guidelines.  相似文献   
925.
本文概述了深圳市宝安区石岩河人工湿地二期工程的工程概况扣工艺调试内容,介绍了石岩河人工湿地工艺调试的过程,阐明了工艺调试的效果和运行模式,分析了工程运行的电费成本,得出了工艺调试和运行的结论,并提出了改进工艺的建议。  相似文献   
926.
Molluscs are sensitive species to the toxic effects of organotin compounds, particularly to masculinisation. Both tributyltin (TBT) and triphenyltin (TPT) have been recently shown to bind to mollusc retinoid X receptor (RXR). If RXR is involved in lipid homeostasis, exposure to TPT would have an immediate effect on endogenous lipids. To test this hypothesis, the ramshorn snail Marisa cornuarietis was exposed to environmentally relevant concentrations of TPT (30, 125, 500 ng/L as Sn) in a semi-static water regime for 7 days. Percentage of lipids and total fatty acid content decreased significantly in TPT-exposed females while the activity of peroxisomal acyl-CoA oxidase, involved in fatty acid catabolism, increased. In addition, fatty acid profiles (carbon chain length and unsaturation degree) were significantly altered in exposed females but not in males. This work highlights the ability of TPT to disrupt lipid metabolism in M. cornuarietis at environmentally realistic concentrations and the higher susceptibility of females in comparison to males.  相似文献   
927.
不同释钾菌对粉煤灰的生态效应   总被引:1,自引:0,他引:1  
粉煤灰治理难度大,但它含有植物生长必需的营养元素钾,将其就地资源化生物利用是一条较好的途径。释钾菌是一种能把矿物中的难溶性钾转化为有效钾的细菌,从土壤中筛选出2种释钾菌,经过在粉煤灰基质中的驯化培养,通过盆栽试验种植紫花苜蓿,比较不同菌株对粉煤灰的改良作用及其对植物生长的影响。结果表明,筛选出的菌株C6对粉煤灰中速效钾的释放效果明显,降低了基质pH,显著地促进了植物的生长,对粉煤灰生态修复具有重要意义。  相似文献   
928.
Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions. However, it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity. To elucidate relationships between them, in a eutrophic shallow lake, Taihu Lake, relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity. The results indicate that water temperature and total phosphorus (TP) played governing roles in phytoplankton dynamics in most seasons (i.e. temperature in winter, spring and summer; TP in spring, summer and autumn); COD (chemical oxygen demand) and BOD (biological oxygen demand) presented significant positive relationships with phytoplankton biomass in spring, summer and autumn. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn, and conversely negative ones in summer. As the predatory factor, zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season. Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were obser,qed between phytoplankton biomass and pH, Trans (transparency of water) and DO. The results indicate that interactions between phyto:plankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.  相似文献   
929.
以京津冀2020年318个地面监测站点的PM2.5数据为估算因子,构建了时空线性混合效应模型(STLME)和时空嵌套线性混合效应模型(STNLME),为AOD数据的补值研究提供了一种新方法.结果表明:在有AOD-PM2.5匹配数据的日期,上述两个模型估算精度相近,交叉验证后决定系数R2分别为0.868和0.874,均方根误差RMSE分别为0.112和0.109;在无AOD-PM2.5匹配数据的日期,嵌套模型估算精度明显高于非嵌套模型,交叉验证后决定系数R2分别为0.63和0.26.经过模型补值后,研究区监测站点所在网格AOD数据空间维有效比率从原始数据的44.35%提高到99.35%,时间维有效比率从87.94%提高到100%;同时,每个站点的年均AOD值都有明显提高,弥补了高PM2.5浓度条件下缺失的AOD数据,可以减少空气污染和健康研究中暴露评估的偏差.  相似文献   
930.
张大为  徐慧  王希  门彬  王东升  段晋明 《环境科学》2017,38(8):3281-3289
为了保证藻类暴发阶段优质的饮用水供应,提高藻类的去除率,缓解藻类对水处理过程的影响,本研究以铜绿微囊藻(蓝藻)、小球藻(绿藻)和小环藻(硅藻)这3种不同形态藻细胞为研究对象,使用了3种具有不同铝形态分布的混凝剂[Al_2(SO_4)_3(AS)、Al_(13)、Al_(30)]进行混凝-超滤实验.在分离胞外有机物(EOM)的情况下,考察混凝过程中絮体的特性(粒径,强度因子,恢复因子)以及不同条件下形成的絮体对膜通量的影响.结果表明Al_(13)与Al_(30)的混凝作用以静电簇作用为主导,AS主要是以电中和作用为主导.对于铜绿微囊藻与小球藻体系,由于藻颗粒表面存在一定的凹陷,当Al_(13)与Al_(30)做混凝剂时,在投加量较低的情况下,吸附在颗粒表面凹陷处的混凝剂“失活”,其他部位由于仍带有一定的负电荷而造成絮体形成不明显,而AS做混凝剂时,混凝机制主要是电中和作用,可以明显降低颗粒之间的排斥力,在较低投加量下即可形成絮体.对于小环藻体系,由于其藻细胞呈现光滑的表面,Al_(13)与Al_(30)可有效发挥其静电簇作用机制,絮体在较低投加量下即可有效形成.膜通量与絮体粒径有明显的相关性,絮体粒径越大,超滤过程中形成的沉积层越疏松,膜比通量越大.  相似文献   
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