Acidity of twelve northern New England (U.S.A.) lakes in recent centuries

Studies of sediment cores from 12 acidic lakes in granitic, forested and uninhabited catchments in northern New England, U.S.A. produced diatom-inferred pH (IpH) 5.2 to 5.8 and alkalinity (Ialk) –12 to 31 µeq l^–1, with slowly declining values at some lakes, for one to four centuries prior to logging. Increases of IpH (0.05 to 0.60) and Ialk (5 to 40 µeq l^–1) correlate with logging in the catchments in the early-1800s to early-1900s. Recovery to pre-logging IpH and Ialk correlates with forest succession toward conifers, and is completed in the late-1800s to mid-1900s. Beginning at 1915–1920 (4 lakes), 1930–1950 (4 lakes) and 1965–1970 (4 lakes), IpH and Ialk start decreasing below pre-logging values due to atmospheric acidic deposition, leading to respective total decreases of 0.10 to 0.45 (X=0.25) and 5 to 25 µeq l^–1 (X=15). Inputs of anthropogenic Pb, Zn, V, polycyclic aromatic hydrocarbons, and soot from the atmosphere are first detectable in early- to late-1800s sediment, and Cu in late-1800s sediment, increase rapidly in the late-1800s to mid-1900s, and level off or decrease since the 1960s — partly due to emission controls. Decreasing Ca, Mn, and possibly Zn relative to other metals and normalized to organic content, and increasing flux of Fe to the lakes, indicate soil and water acidification after 1900.This is the fourteenth of a series of papers to be published by this journal which is a contribution of the Paleoecological Investigation of Recent Lake Acidification (PIRLA) project. Drs. D. F. Charles and D. R. Whitehead are guest editors for this series.     

广州不同季风期近地面大气气溶胶中7Be与持久性有机污染物的同步观测

2006年8月-2007年7月,在广州市天河区以每周采集2～3天的采样频率连续12个月采集近地面大气气溶胶样品,同步测定近地面气溶胶中7Be和有机氯农药(OCPs)、多氯联苯(PCBs)、多溴联苯醚(PBDEs)等持久性有机污染物的浓度值.7Be浓度全年平均值为2.59 mBq/m3,最高值出现在5月(8.5 mBq/...     

Distribution and sources of organochlorinated contaminants in sediments from Izmir Bay (Eastern Aegean Sea)

Eighteen surface sediment samples representative of the entire Izmir Bay were analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). This was in order to provide extensive information concerning the recent deposition of these compounds in this area, together with levels, distribution, possible sources and potential biological risk. Sites that were contaminated by high concentrations of organochlorine compounds were associated with dense population, such as the harbour and the Gediz River estuary. Relatively higher ΣDDT concentrations and high DDT/DDE + DDD ratios in the Gediz River estuary indicated DDT usage, probably linked to public health emergencies. According to the established guidelines for sediment quality, the risk of adverse biological effects from such levels of OCPs and PCBs as recorded at most of the study sites was insignificant. But the higher concentrations in Inner bay and in the Gediz River estuary could cause biological damage.     

不同季风时节北京近地面大气颗粒物中7Be和POPs的变化

2009年8月至2010年7月在东亚季风区中纬度城市北京连续一年以每周3天的时间尺度同步采集近地面大气中气溶胶样品并测定了宇宙射线成因核素7Be 和8种有机氯农药（OCPs）、7种多氯联苯（PCBs）的浓度。7Be浓度全年平均值为（8.39±0.49） mBq/m^3,显著高于欧洲地区具有相同纬度的城市。最高值出现在9月（15.64 mBq/m^3）,最低值出现在5月（1.35 mBq/m^3）。夏季7Be浓度值较低,春、秋季浓度值较高。对大气气溶胶中7Be进行不同季风时节的比较要比季节性的比较可更好地揭示7Be的变化规律及其来源。夏季的低值与东南季风导致的多降雨气象条件有关。秋季的高值为大气环流异常所致。OCPs和PCBs总浓度（∑OCPs和∑PCBs）呈现夏季低,秋、冬季高的现象。西风和西北风为北京市大气气溶胶中POPs浓度最高的季风时节。较高氯代PCBs （PCB153和PCB180）在冬季占主导优势。较高的PCB101和PCB118可能来自北京周边的污染源。在部分时期7Be与DDTs和δ-HCH有显著的相关性,而在春季和夏季PCB-101与7Be有很好的相关性。     

Dynamic changes of net anthropogenic nitrogen/phosphorus input and its riverine export in the Beijing's subcenter

Due to human activities, the overabundance of regional nitrogen/phosphorus (N/P) has a huge impact on ecological environment worldwide. It is necessary to comprehensively understand the human-induced N/P input and spatiotemporal variations of nutrients in a river. As the adjustment to the spatial structure of Beijing, the Beijing's subcenter is an important strategic position in promoting the coordinated development of Beijing–Tianjin–Hebei. In this study, the dynamic changes of ammonia nitrogen (NH₃-N) and total phosphorus (TP) from 2012 to 2022 were analyzed, then the net anthropogenic N input (NANI) and net anthropogenic P input (NAPI) was estimated in the Beijing's subcenter. The results showed that both NH₃-N and TP had an overall downward trend with a three-stage pattern. The NANI and NAPI declined from 5.68 × 10⁴ and 0.95 × 10⁴ to 0.78 × 10⁴ and 0.15 × 10⁴ kg km⁻² per year, respectively. The chemical fertilizers input accounted for the largest part at 53–81% of NANI and 49–80% of NAPI. There were high values of N and P input in the southeast of Tongzhou, and the fluxes of N and P were positively correlated with the input of anthropogenic N and P in the Chaobai River Basin (Tongzhou District) and the Beiyun River Basin (Tongzhou District). This study would provide the foundation for setting priorities and enacting more targeted N/P management strategies in the Beijing's subcenter.     

ISENTROPIC TRAJECTORY ANALYSES OF POLLUTANT TRANSPORT IN NORTHEAST ASIA-INFLUENCE ON CHINA FROM NEIGHBORING COUNTRIES

The transport of air pollutants from several big cities in the north of China and theneighboring countries is researched by using the isentropic trajectory model. The trajectories arecalculated twice daily for the cities in January, April. July and October for the period of 1992-1994. The statistical method has been used to deal with trajectory dots at intervals of 30 min forthe forward and backward trajectories during 0-24 h and 24-48 h. The probability distributiondiagrams of trajectory show clearly the ensemble properties of isentropic trajectories for each cityand the dominant transport directions of pollutants. They possess notable seasonal variations. Theforward trajectory areas of the Ulaan Baatar in Mongolia can spread over North China. and thoseof the Chita in Russia can influence Northeast China except in summer. In July the forwardtrajectory of Pyongyang and Seoul can extend northward to the boundaries of China.     

Assessment of the anthropogenic influx of metallic pollutants in Yarmouk River, Jordan

 Chemical data for 15 elements at depths at 10-cm intervals in 6 cores at two locations along the Yarmouk River as well as the heavy-metal enrichment factors (EFs) and anthropogenic factors (AFs) show that Cd and Ni for all the cores, and Mn, Zn, Cr, Co and Pb for core 3 at location A are anthropogenically enriched. The contents of these elements decrease clearly with depth in the sediment column. The sequence of element enrichment depends on whether the EF and the AF are used to calculate the elements which show no systematic decrease in enrichment with depth in all cores, especially for location A, probably due mainly to a higher sedimentation rate. The results of the present study show that the sediments of the Yarmouk River are uncontaminated with Fe, Cr, and Mn, whereas they are uncontaminated to moderately contaminated with Ni, Co, and Zn, moderately contaminated with Pb, and strongly to extremely contaminated with respect to Cd. Also, the study shows that the EF and AF values are higher than 1, which indicates that all the metals measured in the sediments of the Yarmouk River were enriched by various anthropogenic sources in the catchment area of this river. Heavy metal enrichment reflects the combined effects of agricultural activities, a treatment plant, a landfill site at El-Akader, and small industries in the region. Received: 16 March 2000 · Accepted: 12 August 2000     

A multi-generation Schmakeria poplesia culturing system for use in ecotoxicological study

Crustacean zooplankton form the keystone link between primary producers and fish stocks in marine and estuary ecosystems. We have established a multi-generation cultivation system for zooplankton with which future experiments on the biological effects of pollutants in marine and estuary environments can be better performed. A population of calanoid copepod, Schmakeria poplesia, was collected in December 2003 and maintained in a static system through all stages (eggs to adults). The population exhibited an average developmental time of 13.6 d in conditions corresponding to the natural environment (water temperature 20°C, salinity 15). A series of experiments were performed to examine copepod egg production and hatching success as functions of food type and feeding concentration. Results in our study showed that Isochrysis galbana was more favored for the reproduction of copepods than Phaeodactylum tricornutum, and 10×10⁴cells mL⁻¹ was the most practical algae concentration. We have demonstrated that the Schmakeria poplesia population can be maintained in the laboratory through multiple generations. In addition, methods to control egg production through changes in food concentration have been established, making it feasible to control the start date of exposure experiments or the timing of the collection of offspring to initiate a new generation.     

考虑泥沙影响的污染物输运年龄数值模拟

自然水体中污染物的迁移、转化规律与经泥沙吸附后的沉降、再悬浮等泥沙过程密切相关,其机制尚不明确。采用污染物输运年龄对泥沙影响进行了量化分析,并应用于南黄海辐射沙脊群西洋海域。基于水体中泥沙-污染物模型,推导了考虑泥沙影响的污染物输运年龄的计算方程,通过数值模拟分析了污染物分配系数KD对污染物输运年龄空间分布的影响。研究成果表明:计入泥沙影响后,污染物浓度显著减小,污染物输运年龄随之增大,表明泥沙对污染物扩散起阻碍作用;污染物分配系数KD表征泥沙吸附能力,污染物输运年龄与其呈一定的正相关性,当该系数达到一定值(KD=10^3L/g)时,泥沙吸附能力趋于饱和,污染物输运年龄不再发生显著改变。