全国大气扩散输送模态与区划研究

基于NCEP再分析气象资料,使用HYSPLIT模式对我国大陆区域进行了一整年的连续轨迹计算.轨迹以1°×1°的网格化经纬度分辨率进行计算.考虑气候、地理及经济因素,将全国计算区域分为10个大区,分别统计各大区出发的轨迹在全国的分布频率.根据全年和各季的轨迹统计结果,分析我国不同区域的大气输送扩散特征以及区域间大气环境的相互影响潜势.结果表明,全国10个大区的大气扩散输送模态可分为特性不同的7大类,其中以西北方向的3个大区为一类,西南高原的2个大区为另一类,其它各区自成一类.10个大区大气扩散物质的累积效应差异显著且季节变化特征各异.全国以西南区(XN)东部大气累积效应最强,东北区(DB)累积效应最弱.     

Enhanced electrochemical oxidation of phenol by introducing ferric ions and UV radiation

The mineralization of phenol in aerated electrochemical oxidation has been investigated.The results show that a cathodic Fenton process can occur when the Ti-0.3Mo-0.8Ni alloy material is used as cathode in solution containing ferric or ferrous ions; moreover,the reinforcement of cathodic Fenton process on the total organic carbon (TOC) removal rate of phenol is quite distinct.Among the metallic ions investigated,the ferric ion is the best catalyst for the electrochemical mineralization of phenol at initial...     

Could biochar amendment be a tool to improve soil availability and plant uptake of phosphorus? A meta-analysis of published experiments

Environmental Science and Pollution Research - As one of the most important nutrients for plant growth, phosphorus was often poorly available in soil. While biochar addition induced improvement of...     

人工浮床技术开发与应用研究进展

人工浮床作为一种新型的生态修复技术,主要依靠植物、微生物和水生动物的共同作用实现对水体的净化,具有不占用土地、不消耗能源、成本低、管理简单等优点,在地表水修复和污水净化中得到了越来越多的应用.然而,受植物生长速度和温度的影响,其在应用中仍存在净化能力差、适用范围有限等缺陷.优势植物筛选与植物刈割、微生物强化技术和水生动物强化法等途径可以在一定程度上解决这些问题.人工浮床中植物、微生物和水生动物在污染物去除中的耦合过程、微生物活性及影响因素和人工浮床的设计、构建及日常管理标准的制定等研究尚不深入,是限制人工浮床技术进一步推广的主要因素,也是未来研究的重点和难点.     

Identification of cadmium-excluding welsh onion (Allium fistulosum L.) cultivars and their mechanisms of low cadmium accumulation

Purpose

Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain.

Methods

A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms.

Results

The concentration of Cd in the pseudostem of welsh onions was 0.08?C0.20, 0.18?C0.41, and 0.26?C0.61?mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0?mg/kg), respectively. The significant (p? ₃ ^? ?CN, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041?±?0.003 and 0.046?±?0.002?mg/kg FW, and 0.054?±?0.001 and 0.066?±?0.011?mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99?mg/kg, respectively.

Conclusions

Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars.     

石油污染土壤的生物修复室内模拟实验研究

在实验室模拟的条件下,利用从克拉玛依的石油污染土壤中筛选出的4株高效降解菌,以石油烃降解率、脱氢酶活性、呼吸强度、微生物量碳氮和土壤毒性作为评价指标,研究不加生物菌剂不翻耕、不加生物菌剂翻耕、加生物菌剂不翻耕、加生物菌剂翻耕、加固定化菌剂不翻耕和加固定化菌剂翻耕6种不同实验条件对石油污染土壤修复的效果。结果表明,在63 d的修复过程中,加固定化菌剂翻耕实验F组的石油去除率达到了78.7%,比不加生物菌剂不翻耕实验A组的石油去除率提高了49.5%。随着土壤毒性逐渐降低,玉米(Zea mays L.)和赤子爱胜蚓(Eisenia fetida)可以在F组土壤中良好的生长,达到了修复的效果。     

2018—2021年安徽省PM2.5和O3时空分布特征及其健康风险分析

利用2018—2021年安徽省空气质量监测数据分析了PM_2.5和O₃时空分布特征及其引发的健康风险。结果表明:从时间分布来看,2018—2021年安徽省PM_2.5年均值下降25.5%,而O₃-8 h年均值则保持持平;PM_2.5和O₃-8 h月均值具有明显的季节变化特征,PM_2.5月均质量浓度和超标天数均在冬季达到最大值,O₃-8 h月均值和超标天数则在夏季达到最大值。从空间分布来看,PM_2.5、O₃-8 h年均值和超标天数均为皖北最高,其次为皖中,最后为皖南。夏季O₃是主要的健康风险因子,冬季PM_2.5是主要的健康风险因子。当PM_2.5超标时,除2021年皖北地区外(PM₁₀是主要的健康风险因子),PM_2.5均是主要的健康风险因子;当O₃-8 h超标时,O₃是主要的健康风险因子。     

不同水生植物配置对河涌污水的净化效果

研究不同配置的挺水植物组合对河涌污水污染物的净化效果,为在河涌污水治理上构建有效的人工湿地植物处理系统提供依据。选择10种净化能力较强的挺水植物,组成6种不同配置的挺水植物组合,采用无土栽培的方式模拟人工湿地的环境进行静态培养试验,测定出不同水生植物组合及在不同污水的停留时间（HRT）下对河涌污水污染物的去除率。6种不同配置的水生植物组合在HRT为5 d时对NH4＋-N、TN、TP、CODCr、BOD5的去除率（平均去除率分别为98.2%、81.2%、91.3%、71.8%、79.4%）均较高;以组合1：香根草Vetiveria zizanioides＋风车草Cyperus alternifolius＋美人蕉Canna indica＋菖蒲Acorus calamus＋再力花Thalia dealbata的处理效果为最佳。不同水生植物系统对污水的净化效率取决于HRT,当HRT从1～5 d时,NH4＋-N、TN、TP去除率每天的增幅均逐渐增加,当HRT从5～7 d时,NH4＋-N、TN、TP去除率每天的增幅却均迅速下降;说明3种不同配置的水生植物系统对河涌污水NH4＋-N、TN、TP的净化效率均以HRT为5 d时最高。     

NDVI indicated characteristics of vegetation cover change in China��s metropolises over the last three decades

How urban vegetation was influenced by three decades of intensive urbanization in China is of great interest but rarely studied. In this paper, we used satellite derived Normalized Difference Vegetation Index (NDVI) and socioeconomic data to evaluate effects of urbanization on vegetation cover in China??s 117 metropolises over the last three decades. Our results suggest that current urbanization has caused deterioration of urban vegetation across most cities in China, particularly in East China. At the national scale, average urban area NDVI (NDVI_u) significantly decreased during the last three decades (P?<?0.01), and two distinct periods with different trends can be identified, 1982?C1990 and 1990?C2006. NDVI_u did not show statistically significant trend before 1990 but decrease remarkably after 1990 (P?<?0.01). Different regions also showed difference in the timing of NDVI_u turning point. The year when NDVI_u started to decline significantly for Central China and East China was 1987 and 1990, respectively, while NDVI_u in West China remained relatively constant until 1998. NDVI_u changes in the Yangtze River Delta and the Pearl River Delta, two regions which has been undergoing the most rapid urbanization in China, also show different characteristics. The Pearl River Delta experienced a rapid decline in NDVI_u from the early 1980s to the mid-1990s; while in the Yangtze River Delta, NDVI_u did not decline significantly until the early 1990s. Such different patterns of NDVI_u changes are closely linked with policy-oriented difference in urbanization dynamics of these regions, which highlights the importance of implementing a sustainable urban development policy.