广元市建设川陕甘结合部生态强市的思考

通过对广元市生态市的建设现状、指导思想、奋斗目标、建设路径进行深入分析,提出建设生态强市的可行性措施,并从法制、组织、资金、技术方面提供保障。     

板桥河小流域降雨事件中地表水磷浓度的变化特征

为定量揭示降雨对地表水中磷浓度和形态的影响,于2020年6—8月对巢湖入湖河流南淝河的支流板桥河进行了人工加密监测.共监测了4场降雨,采集了409个河道水样并测定了总磷（TP）、溶解态总磷（DTP）、颗粒态磷（PP）、溶解性反应活性磷（DRP）等指标,分析了降雨事件中磷浓度和形态的时空变化规律,以及降雨特征参数和土地利用方式对磷浓度的影响.分析结果显示：降雨过程中各形态磷的浓度均会显著上升,表明河道中磷的浓度变化与降雨过程密切相关.降雨结束12 h后,各形态磷的浓度会恢复到降雨前的水平.在空间上,河道流经城镇区后磷的浓度会显著高于流经农业区.此外,在无降雨时段和降雨频繁的时段,河道中各点位的磷主要以溶解态为主,只有在前期干燥天数较长的情况下,颗粒态磷的比例才会显著上升.监测结果表明,在汛期要结合降雨特征参数和城镇区、农村区不同的污染特征来进行精细化管理,将河道中溶解态磷的去除纳入到管控方案中,同时要重视河道两岸城镇区的面源污染削减.     

The profiles of chiral pesticides in peri-urban areas near Yangtze River: Enantioselective distribution characteristics and correlations with surface sediments

Chiral pesticides account for 30% of pesticides. Pesticides are inevitably leached into the groundwater by runoff. At the watershed level, the distribution characteristics of enantiomers in sediments collected from the river network of an agricultural area near the middle and lower reaches of the Yangtze River were tested, and their potential correlations with the physicochemical properties and microbial communities of the sediments were analyzed. The sediment pollution was serious at sites 8 and 9, with their pollution source possibly being agricultural or industrial sewage. Moreover, there were higher cumulative contents of pesticide residues at sites 4, 8, and 9. Specifically, Cycloxaprid was the most detected chiral pesticide in the study area, followed by Dinotefuran and Diclofop-methyl. Additionally, Ethiprole and Difenoconazole had strong enantioselectivity in the study area. Interestingly, the enantiomers of some chiral pesticides, such as Tebuconazole, had completely different distributions at different sites. Pearson correlation analysis showed that sediment catalase and microbial biomass carbon were important factors for enantioselectivity of chiral pesticides. The effect of sediment physicochemical properties on enantioselective distribution was achieved by influencing the microorganisms in the sediment. Furthermore, the enantioselective distribution of Tebuconazole was closely related to the genus Arenimonas. Overall, the enantioselective distribution of most of the chiral pesticides was positively correlated with the prokaryotic microbial community. This study provides empirical support for agricultural non-point source pollution caused by chiral pesticides, and also lays a research foundation for exploring the factors that affect the fate of chiral pesticides in the environment.     

黔中木本植物叶功能性状对退化喀斯特土壤特性的响应

研究不同退化背景下优势木本植物功能性状的适应机制,有助于从功能生态学的角度来解释喀斯特山区的群落演替过程。本研究以贵州普定不同退化背景样地优势木本为研究对象,测定LT、LA、SLA、LDMC、LTD、Chlc6个叶片功能性状指标,分析土壤特性对区域内植被叶片功能性状的作用及影响,揭示喀斯特山区植物对不同环境的适应策略及其演替过程。结果表明:①喀斯特区退化环境下植被叶片向增大化趋势发展,以退耕地经济林最显著;火烧、火烧砍伐、退耕下植被性状差异显著,以LA、LTD、SLA变化范围最大,在相应样地可分别高达121.9%、118.08%、86.00%。②退化样地内叶片性状在乔木、灌木和藤本物种间差异显著,总体上灌木与藤本物种种间变异高于乔木物种,群落处于演替前中期阶段。③不同退化背景下土壤特性差异较大,与植被叶功能性状间具有显著相关性,其中土层深度、土壤养分与土壤含水率是植被叶功能性状的关键土壤特性因子。④退化区域植被叶性状表现出LA大、LT较小、SLA和LTD低、LDMC高、Chlc较低,趋向于发展贫瘠干旱性状组合。揭示了黔中退化喀斯特次生林内在差异性的演替规律,为喀斯特次生林的管理和生物多样性保护提供科学依据。     

Biotransformation of N-phenyl-β-naphthylamine to β-naphthylamine in a laboratory sludge system

$\text{N}$-Phenyl-$\text{β}$-naphthylamine, a widely used rubber antioxidant and antiozonant, was biotransformed into $\text{β}$-naphthylamine, a potent carcinogen, in a laboratory sewage sludge system. $\text{β}$-Naphthylamine appeared to accumulate in the aqueous phase of the system while the undegraded parent compound appeared to be associated with the sludge solids.     

Low bone density and renal dysfunction following environmental cadmium exposure in China

This paper presents the main findings of a study on health effects of environmental cadmium pollution in China, performed in 1998, i.e. approximately 25 years after the first warnings of such effects were published in Ambio. Forearm bone mineral density (BMD) and renal dysfunction were assessed in population groups exposed to cadmium via rice. Decreased BMD was found in postmenopausal women with elevated urinary cadmium (CdU) or cadmium in blood (CdB) and among men with elevated CdB. Also, clear and statistically significant dose-effect and dose-response relationships were found between CdB or CdU and renal dysfunction (increased excretion of retinol-binding protein). This is the first report of bone effects among Cd-exposed population groups in Asia outside Japan. The report is also of interest since it demonstrates that bone effects, a comparatively severe adverse health effect of Cd, in combination with renal dysfunction, still occurs in environmentally exposed population groups in Asia. Recent reports on bone effects in Cd-exposed population groups in Europe are discussed.     

An assessment of the sensitivity and reliability of the relative reduction factor approach in the development of 8-hr ozone attainment plans

The updated regulatory framework for demonstrating that future 8-hr ozone (O3) design values will be at or below the National Ambient Air Quality Standards (NAAQS) provides guidelines for the development of a State Implementation Plan (SIP) that includes methods based on photochemical modeling and analytical techniques. One of the suggested approaches is the relative reduction factor (RRF) for estimating the efficacy of emission reductions. In this study, the sensitivity of model-predicted responses towards emission reductions to the choice of meteorology and chemical mechanisms was examined. While the different modeling simulations generally were found to be in agreement on whether predicted future-year design values would be above or below the NAAQS for 8-hr O3 at a majority of the monitoring locations in the eastern United States, differences existed for a small percentage of monitors (approximately 6.4%). Another issue investigated was the ability of the attainment demonstration procedure to predict changes in monitored O3 design values. A retrospective analysis was performed by comparing predicted O3 design values from model simulations using emission estimates for 1996 and 2001 with monitored O3 design values for 2001. Results indicated that an average gross error of approximately 5 ppb was present between modeled and observed design values and that, at approximately 27% of all sites, model-predicted and observed design values disagreed as to whether the design value was above or below the NAAQS. Retrospective analyses such as the one presented in this study can provide valuable insights into the strengths and limitations of modeling and analysis techniques used to predict future design values over time periods of a decade or more for the purpose of developing SIPs. Furthermore, such analyses could provide avenues for improvement and added confidence in the use of the RRF approach for addressing attainment of the NAAQS.     

Enrichments of methanotrophic–heterotrophic cultures with high poly-β-hydroxybutyrate (PHB) accumulation capacities

Methanotrophic–heterotrophic communities were selectively enriched from sewage sludge to obtain a mixed culture with high levels of poly-β-hydroxybutyrate(PHB)accumulation capacity from methane.Methane was used as the carbon source,N_2as sole nitrogen source,and oxygen and Cu content were varied.Copper proved essential for PHB synthesis.All cultures enriched with Cu could accumulate high content of PHB(43.2%–45.9%),while only small amounts of PHB were accumulated by cultures enriched without Cu(11.9%–17.5%).Batch assays revealed that communities grown with Cu and a higher O_2content synthesized more PHB,which had a wider optimal CH_4:O_2range and produced a high PHB content(48.7%)even though in the presence of N_2.In all methanotrophic–heterotrophic communities,both methanotrophic and heterotrophic populations showed the ability to accumulate PHB.Although methane was added as the sole carbon source,heterotrophs dominated with abundances between 77.2%and 85.6%.All methanotrophs detected belonged to type II genera,which formed stable communities with heterotrophs of different PHB production capacities.     

阿哈水库枯水期入库河流可溶性氮、磷含量分布特征

以贵阳市阿哈水库五条入库河流为研究对象,研究了阿哈水库枯水期入库河流水体可溶性氮、磷含量分布特征,可溶性氮组分比例及沿程变化规律。结果表明：五条入库河流水体可溶性氮、磷含量差异较大,可溶性总氮（DTN）、可溶性总磷（DTP）平均含量分别为1.71~9.74 mg/L和0.03~0.52 mg/L。蔡冲河、烂泥沟河、金钟河受人类活动影响较大,水体DTN、DTP含量较高。不同河流水体可溶性氮组分比例差异显著,受人类活动影响小的游鱼河、白岩河,其水体可溶性氮以可溶性有机氮（DON）为主,DON占DTN的比例高达94%。受人类活动影响大的蔡冲河、烂泥沟河、金钟河则相反,以可溶性无机氮（DIN）为主。不同河流氮、磷含量自上到下游沿程波动较大,人为源造成的氮、磷污染远高于自然源。金钟河的DTN、DTP年输入量分别为97.03 t、46.64 t,对阿哈水库的DTN、DTP输入贡献最大,分别达到45%和66%。