北京官厅水库周边农药类POPs暴露的土壤生态效应研究

在前期研究的基础上,围绕北京官厅水库周边2-10 km范围内按不同农药类POPs残留量划分4个区域,监测了土壤中主要农药类POPs(HCHs和DDTs)的含量,分析了土壤酶活性和土壤呼吸强度特征.结果表明,4个区域中有机氯农药残留最高为北辛堡区,其次是怀来县区和官厅镇区,最低为延庆县区,平均含量分别为27.59 ng·...     

纳米膜覆盖对畜禽粪便好氧堆肥进程及恶臭气体排放的影响

好氧堆肥是处理畜禽粪便的重要途径,但传统堆肥存在效率低和恶臭气体污染严重等问题.为了加快畜禽粪便堆肥进程,减少恶臭气体排放,探究了覆盖纳米膜对提升畜禽粪便堆肥效率的作用机制.设置槽式好氧堆肥发酵实验,通过堆肥过程中堆体物料的理化性质,酶活性和排放的恶臭气体来评估纳米膜对畜禽粪便堆肥效果的影响.结果表明,覆盖纳米膜能够加快升温,降低堆体物料的p H、有机质(OM)和氨氮(NH₄⁺-N),提高电导率(EC),增强脲酶、蛋白酶、纤维素酶、木聚糖酶和过氧化物酶的活性,并且NH₃、H₂S和TVOC的总累积排放量分别减少了58%、100%和61%.相关性分析显示,大多数酶活性易受温度(T)、EC、OM和C/N的影响.在一定范围内,NH3的排放速率与T呈极显著正相关,与p H呈极显著负相关,TVOC的排放速率与多种理化性质显著相关.覆盖纳米膜能够加快堆体腐熟,减少恶臭气体的排放,是一种无害化、低排放的技术手段,能够有效解决畜禽粪便堆肥发酵带来的污染物排放难题,促进养殖业的绿色可持续发展,为推动生物质废弃物的资源化...     

Preliminary investigation on the role of microorganisms in the production of phosphine

The relationships between the phosphine content and various microbial populations,activities of different enzymes were investigated firstly.The results indicated that the phosphine content of samples from various environments was positively related to total anaerobic microorganisms,organic phosphate compound-dissolving bacteria,denitrifying bacteria,and the activities of alkaline phosphatase and dehydrogenase,with correlation coefficients (R~2) up to 0.93,0.90,0.69,0.79,and 0.82,respectively.Results also...     

Assessing sensitivities of marine areas to stressors based on biological traits

Analysis of the biological traits (e.g., feeding mode and size) that control how organisms interact with their environment has been used to identify environmental drivers of, or impacts on, species and to explain the importance of biodiversity loss. Biological trait analysis (BTA) could also be used within risk-assessment frameworks or in conservation planning if one understands the groups of traits that predict the sensitivity of habitats or communities to specific human activities. Deriving sensitivities from BTA should extend sensitivity predictions to a variety of habitats, especially those in which it would be difficult to conduct experiments (e.g., due to depth or risk to human life) and to scales beyond the norm of most experiments. We used data on epibenthos, collected via video along transects at 27 sites in a relatively pristine region of the seafloor, to determine scales of natural spatial variability of derived sensitivities and the degree to which predictions of sensitivity differed among 3 stressors (extraction of species, sedimentation, and suspended sediments) or were affected by underlying community compositions. We used 3 metrics (weighted abundance, abundance of highly sensitive species, and number of highly sensitive species) to derive sensitivity to these stressors and simulated the ability of these metrics to detect a range of stressor intensities. Regardless of spatial patterns of sensitivities across the sampled area, BTA distinguished differences in sensitivity to different stressors. The BTA also successfully separated differences in community composition from differences in sensitivity to stressors. Conversely, the 3 metrics differed widely in their ability to detect simulated impacts and likely reflect underlying ecological processes, suggesting that use of multiple metrics would be informative for spatial planning and allocating conservation priorities. Our results suggest BTA could be used as a first step in strategic prioritization of protected areas and as an underlying layer for spatial planning.     

节庆营销对景区年内客流量的边际弹性及调节限度--以内蒙古阿拉善盟5个4A级景区为例

节庆营销是影响旅游活动年内变化的重要因素。优化节庆活动,拉长旅游活动“旺季”,是推动旅游业平稳发展的重要问题。以内蒙古阿拉善盟5个4A级景区为例,采用带虚拟变量的回归模型分析了节庆营销对景区客流量年内变化的边际弹性。结果发现:5个景区4年节庆活动边际弹性≥3.0,气候舒适度边际弹性≥1.0。为缓解旅游活动的年内集中性,需要把节庆活动调整至4—9月,平滑客流量的年内分布。     

大型活动拥挤踩踏事故BP神经网络安全评估方法应用分析

根据大型活动拥挤踩踏事故是一个极其复杂的多因素、多变量、多层次的人-机-环境系统,利用数学建模的思路,引入人工神经网络评估方法;以沈阳世博会开幕式为例,通过前馈型BP网络训练和测试,将开幕式举办过程中的人员拥挤踩踏事故风险系统划分为人的因素、物的因素、环境因素、管理因素4个子系统和拥挤踩踏事故综合评估总系统,分别对其进行拟合分析,在各个系统的拟合残差满足条件的情况下,得出量化的评估预测值及BP神经网络的使用范围。研究实例表明,BP神经网络评估结果直观易懂,可操作性强,是值得推广运用的一种评估方法。     

Comparative study of natural radioactivity levels in soil samples from the Upper Siwaliks and Punjab,India using gamma-ray spectrometry

Natural radioactive materials under certain conditions can reach hazardous radiological levels. So, it becomes necessary to study the natural radioactivity levels in soil to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The natural radionuclide (²²⁶Ra, ²³²Th, and ⁴⁰K) contents in soil were determined for 26 locations around the Upper Siwaliks of Kala Amb, Nahan and Morni Hills, Northern India, using high-resolution gamma-ray spectrometric analysis. It was observed that the concentration of natural radionuclides viz., ²²⁶Ra, ²³²Th and ⁴⁰K, in the soil varies from 28.3 ± 0.5 to 81.0 ± 1.7 Bq kg⁻¹, 61.2 ± 1.3 to 140.3 ± 2.6 Bq kg⁻¹ and 363.4 ± 4.9 to 1002.2 ± 11.2 Bq kg⁻¹ respectively. The total absorbed dose rate calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 71.1 to 162.0 nGy h⁻¹. The radium equivalent (R_eq) and the external hazard index (H_ex), which resulted from the natural radionuclides in soil, were also calculated and found to vary from 149.4 to 351.8 Bq kg⁻¹and from 0.40 to 0.95 respectively. These values in Upper Siwaliks area were compared with that from the adjoining areas of Punjab. The radium equivalent activities in all the soil samples were lower than the limit (370 Bq kg⁻¹) set in the Organization for Economic Cooperation and Development (OECD) report and the dose equivalent was within the safe limit of 1 mSv y⁻¹.     

Assessment of typical pollutants in waterborne by combining active biomonitoring and integrated biomarkers response

Organic pollutants, heavy metals and pharmaceuticals are continuously dispersed into the environment and have become a relevant environmental emerging concern. In this study, a situ assay to assess ecotoxicity of mixed pollutants was carried out in three typical sites with different priority contaminations in Guangzhou, China. Chemical analysis of organic pollutants, metals and quinolones in three exposure sites were determined by GC-ECD/MS, ICP-AES and HPLC, as well as, a combination of biomarkers including: ethoxyresorufin O-deethylase (EROD); aminopyrine N-demethylase (APND); erythromycin N-demethylase (ERND); glutathione S-transferase (GST); malondialdehyde (MDA); CYP1A; and P-glycoprotein (P-gp) mRNA expressions were evaluated in Mugilogobius abei. Results of chemical analysis in sediment samples revealed that the dominant chemicals were organic pollutants and heavy metals in Huadi River while quinolones in the pond. Bioassays indicated that differences among sites were in relation to some specific biomarkers. EROD and GST activities significantly increased after 72 h in situ exposure, but no difference was observed among the exposure sites. APND, ERND and MDA exhibited dissimilar change patterns for different priority pollutants. CYP1A and P-gp mRNA expressions were significantly induced at all exposure sites, whilst P-gp activity was typical for S2 with the highest levels of quinolones. The molecular biomarkers seemed to be more susceptible than enzyme activities. These assays confirmed the usefulness of applying a large array of various combined biomarkers at different levels, in assessing the toxic effects of mixed pollutants in a natural aquatic environment.     

毒死蜱对紫金山森林土壤酶活力及微生物毒性影响研究

毒死蜱是有机磷类农药,对乙酰胆碱酯酶具有抑制作用,在农业虫害防治中应用广泛。为掌握毒死蜱对森林土壤酶活力和土壤微生物生态效应,选择紫金山森林土作为受试土壤,采用室内培养法,研究了毒死蜱对土壤蔗糖酶、脲酶、酸性磷酸酶和过氧化氢酶,以及土壤呼吸强度和氮素硝化作用的影响。结果表明:试验期间,1.25 mg a.i.·kg-1、12.5 mg a.i.·kg-1和125 mg a.i.·kg-1毒死蜱对土壤脲酶、酸性磷酸酶总体表现为抑制作用;对土壤蔗糖酶和过氧化氢酶的影响与暴露剂量和暴露时间有关,在60 d时,Z1低剂量处理组(1.25 mg a.i.·kg-1)蔗糖酶和过氧化氢酶可恢复,Z100高剂量处理组(125 mg a.i.·kg-1)抑制作用不能解除。试验初期,毒死蜱对土壤呼吸强度有一定刺激作用随后逐渐恢复;对土壤氮硝化作用影响表现为先促进后抑制,且抑制作用有长期影响。由此可知,毒死蜱使用对紫金山森林土的土壤酶活性和土壤微生物产生毒性效应,具有一定生态风险。     

Resilience to heat in public space: a case study of Adelaide,South Australia

During summer heatwaves, heat load exacerbates in urban heat islands (especially in hot climates) and threatens public life in cities. This paper examines the links between urban microclimates, outdoor thermal discomfort and public life through an exploratory case study. Heat resilience is highlighted as the ability of the space to support its normal activities when experiencing out-of-comfort temperatures. It also reports on the correlations between heat sensitive outdoor activities and urban greenery in three disparate case studies in Adelaide. Results indicate that necessary and optional activities start to decline after the apparent temperature reaches the threshold of 28?°C–32 °C, while activities in public spaces with more urban greenery show higher resilience to heat stress. Research findings propose heat resilience as a quality indicator in public space and support the application of urban greenery to make urban settings more resilient to heat stress.