鄂西长江小流域土地利用方式对土壤团聚体稳定性的影响

探究土地利用方式对长江中游小流域土壤团聚体稳定性的影响,为鄂西地区土地合理利用与管理以及土壤结构改良提供借鉴.以下牢溪小流域5种不同土地利用方式(柏树林、蔬菜地、石坎农田、撂荒地、天然林)土壤为研究对象,对比分析各土地利用方式间土壤团聚体粒径组成及稳定性差异.结果 表明:(1)柏树林、石坎农田、撂荒地和天然林土壤团聚体以＞2 mm为优势粒级,平均为57.66％,蔬菜地以＜0.25 mm微粒径团聚体为主,均值为60.86％;(2)林地(柏树林和天然林)土壤稳定性和抗蚀性要优于农用地(石坎农田和蔬菜地),耕地撂荒提升团聚体稳定性;(3)分形维数D与破坏率PAD、可蚀性K呈正相关,与团聚体直径(MWD和GMD)和水稳性大团聚体WR0.25呈负相关,分形维数较好反映小流域土壤团聚体的稳定性和抗侵蚀性.对流域内林区的封育是提升土壤结构稳定性的最优管理方式.     

Combination with catalyzed Fe(0)-carbon microelectrolysis and activated carbon adsorption for advanced reclaimed water treatment: simultaneous nitrate and biorefractory organics removal

A process combining catalyzed Fe(0)-carbon microelectrolysis (IC-ME) with activated carbon (AC) adsorption was developed for advanced reclaimed water treatment. Simultaneous nitrate reduction and chemical oxygen demand (COD) removal were achieved, and the effects of composite catalyst (CC) addition, AC addition, and initial pH were investigated. The reaction kinetics and reaction mechanisms were calculated and analyzed. The results showed that CC addition could enhance the reduction rate of nitrate and effectively inhibit the production of ammonia. Moreover, AC addition increased the adsorption capacity of biorefractory organic compounds (BROs) and enhanced the degradation of BRO. The reduction of NO₃^?–N at different pH values was consistently greater than 96.9%, and NH₄⁺–N was suppressed by high pH. The presence of CC ensured the reaction rate of IC-ME at high pH. The reaction kinetics orders and constants were calculated. Catalyzed iron scrap (IS)-AC showed much better nitrate reduction and BRO degradation performances than IS-AC and AC. The IC-ME showed great potential for application to nitrate and BRO reduction in reclaimed water.

     

Boosting freshwater fish conservation with high-resolution distribution mapping across a large territory

The lack of high-resolution distribution maps for freshwater species across large extents fundamentally challenges biodiversity conservation worldwide. We devised a simple framework to delineate the distributions of freshwater fishes in a high-resolution drainage map based on stacked species distribution models and expert information. We applied this framework to the entire Chinese freshwater fish fauna (>1600 species) to examine high-resolution biodiversity patterns and reveal potential conflicts between freshwater biodiversity and anthropogenic disturbances. The correlations between spatial patterns of biodiversity facets (species richness, endemicity, and phylogenetic diversity) were all significant (r = 0.43–0.98, p < 0.001). Areas with high values of different biodiversity facets overlapped with anthropogenic disturbances. Existing protected areas (PAs), covering 22% of China's territory, protected 25–29% of fish habitats, 16–23% of species, and 30–31% of priority conservation areas. Moreover, 6–21% of the species were completely unprotected. These results suggest the need for extending the network of PAs to ensure the conservation of China's freshwater fishes and the goods and services they provide. Specifically, middle to low reaches of large rivers and their associated lakes from northeast to southwest China hosted the most diverse species assemblages and thus should be the target of future expansions of the network of PAs. More generally, our framework, which can be used to draw high-resolution freshwater biodiversity maps combining species occurrence data and expert knowledge on species distribution, provides an efficient way to design PAs regardless of the ecosystem, taxonomic group, or region considered.     

压力容器制造监检中对若干问题的处理

针对压力容器制造监检中某些受检单位在法规标准的理解上存在误区或者疏忽、不知如何进行后续整改工作的现状,笔者结合多年压力容器监督检验的工作经验,提出自己的解决方案,以供参考,也希望广大读者在遇到类似情况时能够正确理解并执行相关法规标准。     

Road traffic injuries among riders of electric bike/electric moped in southern China

Objective: Electric bike/moped-related road traffic injuries have become a burgeoning public health problem in China. The objective of this study was to identify the prevalence and potential risk factors of electric bike/moped-related road traffic injuries among electric bike/moped riders in southern China.

Methods: A cross-sectional study was used to interview 3,151 electric bike/moped riders in southern China. Electric bike/moped-related road traffic injuries that occurred from July 2014 to June 2015 were investigated. Data were collected by face-to-face interviews and analyzed between July 2015 and June 2017.

Results: The prevalence of electric bike/moped-related road traffic injuries among the investigated riders was 15.99%. Electric bike/moped-related road traffic injuries were significantly associated with category of electric bike (adjusted odds ratio [AOR] = 1.36, 95% confidence interval [CI], 1.01–1.82), self-reported confusion (AOR = 1.77, 95% CI, 1.13–2.78), history of crashes (AOR = 6.14, 95% CI, 4.68–8.07), running red lights (AOR = 3.57, 95% CI, 2.42–5.25), carrying children while riding (AOR = 1.96, 95% CI, 1.37–2.85), carrying adults while riding (AOR = 1.68, 95% CI, 1.23–2.28), riding in the motor lane (AOR = 2.42, 95% CI, 1.05–3.93), and riding in the wrong traffic direction (AOR = 1.63, 95% CI, 1.13–2.35). In over 77.58% of electric bike/moped-related road traffic crashes, riders were determined by the police to be responsible for the crash. Major crash-causing factors included violating traffic signals or signs, careless riding, speeding, and riding in the wrong lane.

Conclusion: Traffic safety related to electric bikes/moped is becoming more problematic with growing popularity compared with other 2-wheeled vehicles. Programs need to be developed to prevent electric bike/moped-related road traffic injuries in this emerging country.     

强夯地基处理工艺在换流站场平施工中的应用

针对西北部分地区地表层粉砂分布不均、砂岩不易破碎、块石回填方量大、回填厚度深等问题,考虑特高压换流站工程地基处理的适用性及其成效、工期、造价等多方面因素,提出强夯地基处理方案。应用结果表明:该方法具有快速提高填土密实程度,加速填土前期固结,提高填土的物理力学性能,减少填土的后期沉降和建(构)筑物及地面设备基础的沉降等优点,可广泛应用于西北地区特高压换流站及其他大面积土石方开挖、回填及地基处理施工工程。     

基于压力响应关系法的湖泊营养物基准制定

湖泊富营养化与氮、磷及有机物含量过高密切相关,建立数字型营养物基准能够防止富营养化对水体指定用途造成影响.太湖流域是我国华东地区经济腹地,近年来流域内湖泊水质每况愈下,对其基准研究可为湖泊治理提供依据.详细介绍了压力响应关系法制定湖泊营养物基准的步骤,并将此方法运用到太湖流域营养物基准制定研究中.为满足大多数水体指定用途,研究中将该流域湖泊基本功能确定为娱乐、永生生物栖息地及饮用水,以此构建流域概念模型.选择压力变量为总氮(TN)、总磷(TP)和有机物,响应变量为叶绿素a(chl-a).用非参数分析法和线性回归法分别建立压力-响应模型,通过2种方法相互验证得到TN、TP和CODMn基准分别为0.593、0.067和4.092 mg/L.     

Dissipation kinetics and residues of triazolopyrimidine herbicides flumetsulam and florasulam in corn ecosystem

The dynamic and residues of florasulam and flumetsulam in corn field ecosystem were investigated using quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limits of quantification (LOQs) of the proposed method ranged from 0.005 to 0.01 mg/kg. Mean recoveries and relative standard deviations (RSDs) of the two compounds in all samples at three spiking levels ranged 94–110 % and 2.0–9.2 %, respectively. Florasulam and flumetsulam degradation followed first-order kinetics with half-lives 1.7–2.9 and 3.3–8.7 days in soil and 1.3–1.8 and 0.9–1.7 days in plant, respectively. The residues in all the samples were found to be less than the LOQs at preharvest intervals of 53 and 78 days. The results suggest that the combined use of florasulam and flumetsulam on corn is considered to be safe under the recommended conditions and can be utilized for establishing the maximum residue limit (MRL) of florasulam in corn in China.     

SPE-HPLC法测定水中硝基苯酚类化合物

建立了以固相萃取为前处理条件,用液相色谱法测定水中10种硝基苯酚类化合物的分析方法。实验使用HLB(6 L/150 g)固相萃取柱富集水样中的目标化合物,二氯甲烷与乙酸乙酯体积比1:2的混合溶剂洗脱,采用Phenyl柱(4.6 mm×250 mm,5 μm)分离目标化合物,以乙腈(1%甲酸)/水(1%甲酸)为流动相进行梯度洗脱,二极管阵列检测器检测。10种硝基苯酚类物质在0.02~10 mg/L范围内呈现良好的线性。方法检出限为0.1~0.3 μg/L,水样加标相对标准偏差为5.19%~18.2%,平均加标回收率为49.8%~124%。该方法适用于水中10种硝基苯酚类化合物的测定。     

Biodegradation of Poly(Aspartic Acid-Itaconic Acid) Copolymers by Miscellaneous Microbes from Natural Water

Poly(aspartic acid-itaconic acid) copolymers (PAI) is a new scale inhibitor for water treatment. Thus, it is necessary to investigate its biodegradability. The biodegradability of PAI was investigated through CO₂ evolution tests under different conditions based on determination of carbon dioxide production. The investigation results showed that the degradation rate of PAI on day 10 and day 28 were respectively 38.7 and 79.5%, indicating that PAI was one kind of easily biodegradable scale inhibitors. With the increase in the content of itaconic acid in copolymerization process, the biodegradability of PAI was significantly reduced. In addition, the high biodegradability might be attributed to the existence of C–N bone-structure and more –COO–. Finally, Cu²⁺ could decrease the degradation percentage and the enzyme inhibition effect of Cu²⁺ was not the linear effect, but the “low-dosage effect”.