Chemical methods and phytoremediation of soil contaminated with heavy metals

The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants.     

Key features of new particle formation events at background sites in China and their influence on cloud condensation nuclei

New particle formation (NPF) event at multi rural sites in China Identifying the characteristics of NPF event Comparing NPF event between clean and polluted conditions Quantifying contribution to the cloud condensation nuclei Implication of climate and air quality Long-term continuous measurements of particle number size distributions with mobility diameter sizes ranging from 3 to 800 nm were performed to study new particle formation (NPF) events at Shangdianzi (SDZ), Mt. Tai (TS), and Lin’an (LAN) stations representing the background atmospheric conditions in the North China Plain (NCP), Central East China (CEC), and Yangtze River Delta (YRD) regions, respectively. The mean formation rate of 3-nm particles was 6.3, 3.7, and 5.8 cm⁻³·s⁻¹, and the mean particle growth rate was 3.6, 6.0, and 6.2 nm·h⁻¹ at SDZ, TS, and LAN, respectively. The NPF event characteristics at the three sites indicate that there may be a stronger source of low volatile vapors and higher condensational sink of pre-existing particles in the YRD region. The formation rate of NPF events at these sites, as well as the condensation sink, is approximately 10 times higher than some results reported at rural/urban sites in western countries. However, the growth rates appear to be 1–2 times higher. Approximately 12%–17% of all NPF events with nucleated particles grow to a climate-relevant size (>50 nm). These kinds of NPF events were normally observed with higher growth rate than the other NPF cases. Generally, the cloud condensation nuclei (CCN) number concentration can be enhanced by approximately a factor of 2–6 on these event days. The mean value of the enhancement factor is lowest at LAN (2–3) and highest at SDZ (~4). NPF events have also been found to have greater impact on CCN production in China at the regional scale than in the other background sites worldwide.     

团花锦蛇、绿锦蛇和三索锦蛇的核型及Ag-NORs

报道了锦蛇属团花锦蛇（Ｅ．ｄａｖｉｄｉ）、绿锦蛇（Ｅ．ｐｒｖｓｉｎａ）和三索锦蛇（Ｅ．ｒａｄｉａｔａ）３个种的核型和Ａｇ－ＮＯＲｓ,团花锦蛇的型２ｎ＝３６（８Ｖ＋６ｓＶ＋２Ｉ＋２０Ｍ）,绿锦蛇的核型２ｎ＝３６（７Ｖ＋７ｓＶ＋２Ｉ＋２０ｍ）,三索锦蛇的核型２ｎ＝４０（６Ｖ＋３ｓＶ＋２ｓＩ＋５Ｉ＋２４ｍ）;①团花锦蛇和绿锦蛇的染色体数目和结构与此属大多数咱的相似,;②此种为雄性,未见染色体异型。③Ａｇ     

新型混凝剂在废水处理中的应用研究

自行研发出一种新型混凝剂，它能广泛应用于印染废水、生活污水和餐饮废水等的处理。经过一步强化混凝处理后，各种废水的COD、色度和浊度等均有良好的去除效果。混凝污泥可以再生重复利用。     

锌在不同磷源条件下对铜绿微囊藻生长与产毒的影响

针对磷和微量元素对藻类生长的共同作用,研究不同磷源条件下锌对藻细胞生长与产毒的影响。实验选用铜绿微囊藻为藻种,分别以无机磷磷酸氢二钾(K_2HPO_4)、小分子有机磷甘油磷酸钠(NaGly)和大分子有机磷卵磷脂(LEC)为磷源,研究不同锌(Zn~(2+))含量对藻细胞的藻密度、碱性磷酸酶活性(alkaline phosphatase activity,APA)以及胞内藻毒素(MC-LR)的影响。研究发现:以NaGly为磷源时微量元素锌对藻细胞生长的促进效果显著,而以K_2HPO_4或LEC为磷源时,锌含量的变化对藻细胞生长无显著影响。APA不仅与磷源有关而且与锌含量相关,以LEC为磷源时的APA显著高于以K_2HPO_4或NaGly为磷源时的APA,且锌含量越低APA越低,以K_2HPO_4为磷源时锌含量越低APA越高,而锌对以NaGly为磷源时的APA几乎没有影响。磷源与微量元素锌对藻细胞的产毒均产生影响,NaGly有利于藻毒素的产生; LEC不利于藻细胞的产毒,但锌含量越低藻细胞的产毒量越多。综上所述,磷源与微量元素锌共同作用对藻细胞的生长与产毒产生影响,小分子有机磷NaGly与锌的效果显著。     

N2O emission from a sequencing batch reactor for biological N and P removal from wastewater

Nitrous oxide （N2O） is a greenhouse gas that can be released during biological nitrogen removal from wastewater. N2O emission from a sequencing batch reactor （SBR） for biological nitrogen and phosphorus removal from wastewater was investigated, and the aims were to examine which process, nitrification or denitrification, would contribute more to N2Oemission and to study the effects of heterotrophic activities on N2O emission during nitrification. The results showed that N2O emission was mainly attributed to nitrification rather than to denitrification. N2O emission during denitrification mainly occurred with stored organic carbon as the electron donor. During nitrification, NaO emission was increased with increasing initial ammonium or nitrite concentrations. The ratio of N2O emission to the removed ammonium nitrogen （N2O- N/NH4-N） was 2.5% in the SBR system with high heterotrophic activities, while this ratio was in the range from 0.14% to 1.06% in batch nitrification experiments with limited heterotrophic activities.     

光周期对油桃芽休眠诱导及呼吸代谢的影响

以‘曙光’(Prunus persica var.nectariana cv.Shuguang)油桃为试材,研究光周期对油桃芽休眠诱导进程以及对芽内底物水平的呼吸代谢运行的影响.结果表明:短日照使油桃芽提前进入休眠诱导,并促进休眠迅速加深,而长日照使休眠延迟.整个休眠诱导期内,叶芽和花芽的总呼吸速率先升高后降低.在底物水平上,随着休眠诱导的进行,三羧酸循环(TCA)略有下降,但仍维持高位运行,磷酸戊糖途径(PPP)在总呼吸中比例持续上升.短日照诱导相关的呼吸代谢变化提前出现,而长日照对相关呼吸代谢的变化具有推迟作用.     

Contamination characteristics of trace metals in dust from different levels of roads of a heavily air-polluted city in north China

Concentrations of eight trace metals (TMs) in road dust (RD) (particles?<?25 μm) from urban areas of Xinxiang, China, were determined by inductively coupled plasma mass spectrometry. The geometric mean concentrations of Zn, Mn, Pb, As, Cu, Cr, Ni and Cd were 489, 350, 114, 101, 60.0, 39.7, 31.6, and 5.1 mg kg^?1, respectively. When compared with TM levels in background soil, the samples generally display elevated TM concentrations, except for Cr and Mn, and for Cd the enrichment value was 69.6. Spatial variations indicated TMs in RD from park path would have similar sources with main roads, collector streets and bypasses. Average daily exposure doses of the studied TMs were about three orders of magnitude higher for hand-to-mouth ingestion than dermal contact, and the exposure doses for children were 9.33 times higher than that for adults. The decreasing trend of calculated hazard indexes (HI) for the eight elements was As?>?Pb?>?Cr?>?Mn?>?Cd?>?Zn?>?Ni?>?Cu for both children and adults.     

衡阳盆地紫色土丘陵坡地自然恢复灌丛阶段主要种群空间分布格局

运用植被生态学与恢复生态学的原理与方法,在衡阳盆地紫色土丘陵坡地以受干扰而退化,经封育后自然恢复至灌丛阶段的植物群落为研究对象,通过在其中设置400个5 m×5 m共计1 hm2的相邻网格样方,对其进行群落学调查.应用聚集指数、平均拥挤度、聚块性指数、格林指数、聚集强度、Cassie指标、方差均值比的t检验等方法,研究了衡阳盆地紫色土丘陵坡地自然恢复灌丛阶段群落主要种群的空间分布格局.结果表明:所有种群的空间分布呈显著的聚集分布,同时,各种群在不同的发育阶段也呈聚集分布,且随发育阶段的进展聚集程度逐渐减小.这主要与物种本身的生态学与生物学特性有关,以及与物种的竞争排斥作用有密切联系.聚集程度的大小在一定的程度上可用来表征植物群落的恢复程度,随着恢复过程的向前发展,种群聚集程度将下降.这将丰富该地区植被生态学与恢复生态学的内容.为衡阳盆地紫色土丘陵坡地生态系统的植被恢复与重建提供了一定的理论依据.     

An estimation on budget and control of phosphorus in the Changjiang River catchment

Based on field investigations in the Changjiang River mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literatures, the budget and major control factors of total phosphorus (TP) and dissolved inorganic phosphorus (DIP) in the river catchment were estimated and discussed from the catchment scale. It will supply a base for effective controlling P concentration in the Changjiang River and its mouth. Results show that the export fluxes of TP and DIP were mainly controlled by the river runoff. The TP and DIP in the Changjiang River came mainly from agricultural nonpoint source P losses from fertilizer and soil and point sources of industrial waste and residential sewage discharges. The export fluxes of TP and DIP in the river mouth were only 27.0% and 28.3% of the imports from the river catchment, respectively, suggesting that most of P were removed in transportation. A mass of freshwater marshes in the river catchment were the main areas to remove P. Significant increasing in utilization of fertilizer P and incessant increasing in water and soil loss areas were the primary reasons of agricultural nonpoint source P losses. How to decrease the agricultural nonpoint source P loss from the catchment scale is a key controlling P concentration in the Changjiang River and its mouth. The point source industrial waste P discharge has been primarily treated in the river catchment, but the residential sewage P discharge needs further control.