海南小海沉积物中的重金属分布特征及潜在生态风险评价

对小海沉积物进行采集,测定了沉积物中的Cu、Pb、Cd、Zn、Hg、As重金属的含量,用单因子指数法和Hakanson生态风险指数法评价了沉积物中重金属综合污染效应.研究结果表明:小海湾内沉积物中Cu、Pb、Cd、Zn、Hg、As的平均含量分别为0.20 mg/kg、0.18 mg/kg、0.30 mg/kg、0.22 mg/kg、0.44 mg/kg、0.23 mg/kg.沉积物所监测的重金属中,Hg金属的空间波动程度最高,其他重金属的空间波动程度较低.沉积物质量评价结果表明:小海沉积物中主要的重金属污染因子是As,其重金属影响因子的顺序为As＞Hg＞Pb＞Cr＞Zn＞Cu＞Cd;各种重金属的潜在生态危害系数大小顺序为Hg＞As＞Cd＞Pb＞Cu＞Cr＞Zn;潜在生态风险指数 RI平均值为37.06,属于轻微潜在生态风险.     

基于PMF和PCA-APCS-MLR模型的煤矿区地下水多环芳烃分布特征及来源解析

为明确典型矿业活动区浅层地下水多环芳烃(PAHs)污染特征及来源,通过水样采集与测试分析,综合采用多元统计分析方法、正矩阵因子分解(PMF)和绝对主成分得分-多元线性回归(APCS-MLR)模型,研究了某煤矿区地下水中PAHs的分布特征与影响因素、污染来源及贡献率。结果表明：研究区地下水中PAHs的总浓度为12.65～127.08 ng/L,平均值为70.99 ng/L。PAHs总体分布呈现中南部高四周低的特征,主要受矿业生产活动、地下水流向和径流强度影响。利用PMF和APCS-MLR两种模型均识别出4个污染源,每个潜在污染源的主要负荷种类相似。PMF中观测值与模型预测值之间的R²为0.60～0.99,PCA-APCS-MLR中R²为0.51～0.91。研究区地下水中PAHs主要来源为煤炭燃烧源、石油源/生物质燃烧源、炼焦排放源、交通排放源,前两者总贡献率超过60%。研究结果可为研究区地下水资源绿色开发与保护提供一定依据。     

库房火灾事故中弹药热安全性研究

为研究不同火灾条件下弹药发生慢速烤燃的升温速率,以典型地面仓库和舰船舱室火灾为研究对象,建立仿真模型,模拟计算发生火灾时弹药贮存环境的热激源强度及其演化规律,针对发动机在此类环境下的热安全性开展仿真计算,分析其响应规律。研究结果表明：不同火灾条件下弹药慢速烤燃的升温速率有很大区别且往往高于标准慢速烤燃试验常用的升温速率3.3 K/h。随着慢速烤燃升温速率的提高,发动机烤燃点火时间提前,点火时刻发动机中间位置温度下降,两端温度升高,且点火位置向发动机喉部移动。研究结果可以指导弹药库房的设计及弹药安全性增强设计。     

基于人员心理-环境因素的火灾疏散速度修正方法研究

为探究人在火灾环境下的行为心理对疏散效率的影响,基于火灾下人员行为心理特征具有复杂、抽象、难以直接量化的特性,通过模糊逻辑方法,应用模糊集合、模糊规则和隶属度函数量化人的行为心理,研究其对疏散速度的影响;考虑火灾烟气和群体行为对疏散的影响,通过对高层建筑火灾状况下的烟气进行数值分析,并运用公式法得出人员的疏散速度折减值;以某高层商业建筑火灾疏散为例,将修正后人员的疏散速度和疏散路径引入疏散分析并与未修正的结果进行比较。结果表明:未修正的商业建筑疏散时间为470 s,修正后的疏散时间为670 s,修正后的疏散时间更长,人员危险性更大。     

某地区铁路职工ASCVD总体发病危险评估调查分析

评估某地区铁路职工ASCVD总体发病危险,为健康干预提供依据。按照《中国成人血脂异常防治指南(2016年修订版)》分析该地区2 910名铁路职工ASCVD总体发病危险、ASCVD危险因素及降LDL-C/非-HDL-C达标率。结果表明,铁路职工中ASCVD极高危、高危、10年高危、10年中危、10年低危和余生危险人数比例分别为1.48%、9.48%、5.36%、11.75%、68.76%和2.16%;危险因素中前三位为超重和肥胖、吸烟、血脂异常;降LDL-C/非-HDL-C达标情况极高危人群、高危人群、10年高危人群均低于30%。说明该地区铁路职工ASCVD发病危险高,中青年人群余生危险应引起重视;ASCVD危险因素多,高危人群降LDL-C/非-HDL-C达标率低;应采取积极措施,根据ASCVD发病危险分层进行不同强度健康干预。     

电动汽车充电桩现场安全问题的研究

国家为了更好地普及电动汽车,首先推进了公共停车位和充电桩的建设。本文依据充电桩的国家标准和能源局标准,对在役充电桩的现场安全问题进行剖析,为在役充电设施主管部门的监管提供理论支持,为充电设施产业的健康长远发展提供理论依据。     

Adsorption characteristics of ciprofloxacin onto g-MoS2 coated biochar nanocomposites

• The g-MoS₂ coated composites (g-MoS₂-BC) were synthesized. • The coated g-MoS₂ greatly increased the adsorption ability of biochar. • The synergistic effect was observed for CIP adsorption on g-MoS₂-RC700. • The adsorption mechanisms of CIP on g-MoS₂-BC were proposed. The g-MoS₂ coated biochar (g-MoS₂-BC) composites were synthesized by coating original biochar with g-MoS₂ nanosheets at 300°C(BC300)/700°C (BC700). The adsorption properties of the g-MoS₂-BC composites for ciprofloxacin (CIP) were investigated with an aim to exploit its high efficiency toward soil amendment. The specific surface area and the pore structures of biochar coated g-MoS₂ nanosheets were significantly increased. The g-MoS₂-BC composites provided more π electrons, which was favorable in enhancing the π-π electron donor-acceptor (EDA) interactions between CIP and biochar. As a result, the g-MoS₂-BC composites showed faster adsorption rate and greater adsorption capacity for CIP than the original biochar. The coated g-MoS₂ nanosheets contributed more to CIP adsorption on the g-MoS₂-BC composites due to their greater CIP adsorption capacity than the original biochar. Moreover, the synergistic effect was observed for CIP adsorption on g-MoS₂-BC700, and suppression effect on g-MoS₂-BC300. In addition, the adsorption of CIP onto g-MoS₂-BC composites also exhibited strong dependence on the solution pH, since it can affect both the adsorbent surface charge and the speciation of contaminants. It was reasonably suggested that the mechanisms of CIP adsorption on g-MoS₂-BC composites involved pore-filling effects, π-π EDA interaction, electrostatic interaction, and ion exchange interaction. These results are useful for the modification of biochar in exploiting the novel amendment for contaminated soils.     

Soil biological characteristic,nutrient contents and stoichiometry as affected by different types of remediation in a smelter-impacted soil

ABSTRACT

In order to evaluate the ecological risk reductions of copper (Cu) and cadmium (Cd) and the change of nutrient contents and stoichiometry in a smelter-impacted farmland in Guixi, Jiangxi Province, China, with ～ 800?mg Cu kg^?1 soil and 0.8?mg Cd kg^?1 soil, an three years in situ experiment was conducted. The field trial consisted of 4 ×?5?m plots in a completely randomised block design. Hydroxyapatite was added at 10?g kg^?1 soil and Sedum plumbizincicola, Elsholtzia splendens, and Pennisetum sp. were planted. Post-treatment soil and plant samples were collected annually and analysed for Cu and Cd bioaccessibility, soil carbon: nitrogen: phosphorus (C:N:P), and the stoichiometries of soil β-glucosidase (BG), N-acetylglucosaminidase (NAG), and acid phosphatase (AP) activity levels. The results indicated that the hydroxyapatite treatments significantly reduced Cu and Cd bioaccessibility as well as the ratio of C:P and N:P. Moreover, BG, NAG, and AP activity levels all increased relative to those in untreated soil. Plants may also influence soil BG, NAG, and AP activity. This study demonstrated that in situ Cu and Cd stabilisation by hydroxyapatite and phytoextraction is ecologically safe and can alter soil mineral nutrient ecological stoichiometry and enzyme activity.     

三亚河红树林自然保护区水环境-红树植物-沉积物重金属污染综合分析

以三亚河红树林自然保护区为研究区,在分析沉积物重金属污染及红树植物对重金属富集转运差异的基础上,探讨了保护区水环境、沉积物重金属和红树植物重金属间的联系及重金属污染来源。结果表明:(1)沉积物中Hg为极强污染,Pb、Zn和Cu为中等污染,其他重金属无污染;研究区整体的潜在生态风险指数为中等,其中Hg为主要贡献者。(2)保护区河段雨季水体污染物浓度明显高于干季,雨、干季水质总体均表现出中上段(A段)中间段(B段)出口段(C段);(3)3种红树植物对Cd均表现出强富集,对Pb表现为弱富集能力;(4)沉积物重金属和水质参数之间有显著的相关性,红树植物会影响沉积物中重金属形态,并通过主动运输方式富集和转移重金属。(5)研究区上游农业生产活动及市区交通和工厂企业综合排污是重金属的主要污染来源。