The M/V Cosco Busan spill: source identification and short-term fate

Understanding the fate of heavy fuel oils (HFOs) in the environment is critical for sound decisions regarding its usage and spill cleanup. To study weathering of HFOs, we examined the M/V CoscoBusan spill (November 2007; San Francisco Bay, CA, USA). In this baseline report, we identified which ruptured tank (port tank 3 or 4) was the source of the spilled oil and characterized changes in the oil composition across location and time. Samples from three impacted shorelines, collected within 80 days of the spill, were analyzed using one- and two-dimensional gas chromatography (GC and GC × GC, respectively). Weathering varied across sites, but compounds with GC retention times less than n-C₁₆ were generally lost by evaporation and dissolution. Changes in n-C₁₈/phytane and benz[a]anthracene/chrysene ratios indicated some biodegradation and photodegradation, respectively.     

Anthropogenic influence on the degradation of an urban lake - The Pampulha reservoir in Belo Horizonte, Minas Gerais, Brazil

The artificial reservoir Lagoa da Pampulha in central Brazil has been increasingly affected by sediment deposition and pollution from urban and industrial sources. This study investigates water chemistry and heavy metal concentrations and their fractionation in the lake sediment using ICP-OES, ICP-MS, and XRD analyses. Fractionation analysis was done by sequential extraction under inert gas as well as after oxidation. The lake exhibits a permanent stratification with an oxygen-free hypolimnion below 2 m depth. Nutrient concentrations are enriched for phosphorous components (SRP, PO₄). In the sediment it was not possible to detect oxygen. Carbon, sulfur, and most of the analyzed heavy metals are enriched in the top sediment layer with a pronounced downward decrease, indicating the presence of an anthropogenic influence. Statistical analysis, including correlations and a Principal Component Analysis (PCA) of depth-related total concentration data, helps to distinguish presumably anthropogenic heavy metals from geogenic components. Some samples with high element concentrations in the sediment also show elevated concentrations in their pore water. Analyses of element distribution between sediment and pore water suggest a strong bonding of heavy metals to the anoxic sediment. The trend towards elevated solubility in the pore water of oxidized samples is clear for most of the analyzed elements. Fractionation analysis reveals characteristic associations of selected elements to specific mineral bonding forms. In addition, it indicates that the behavior of heavy metals in the sediment is strongly influenced by organic substances. These substances provide buffering against oxidation, acidification, and metal release. The high nutrient loading causes reducing conditions in the lake sediment. These conditions trigger the accumulation of sediments rich in S²⁻, which stabilizes the fixation of heavy elements. In the future, care must be taken to reduce the supply of contaminants and to prevent the release of heavy metals from sediments dredged for remediation purposes.     

An example of application: The ecological “natural flow regime” paradigm in hydroclimatology

According to the concept of “natural flow regime,” introduced and developed in the 1990's in aquatic ecology, streamflow can be described using five basic characteristics: magnitude, frequency, duration, period of occurrence and variability. A sixth could be added to these, namely, distribution curve. Our study, which focused exclusively on the temporal variability of these six characteristics, had these objectives: (1) to compare their stationarity, (2) to determine the links among these characteristics and (3) to analyze, for the first time, their relationship to six climatic indices (Atlantic Multidecadal Oscillation, Artic Oscillation, North Atlantic Oscillation, Niño3.4, Pacific decadal Oscillation and Southern Oscillation Index). To do this, we used the Vermillon River (2670 km²) as an example, analyzing the streamflow of heavy spring floods (equal to or greater than the annual flood streamflow), as measured between 1934 and 2000.     

Regeneration and Reuse of a Seaweed‐Based Biosorbent in Single and Multi‐Metal Systems

A seaweed‐waste material resulting from the processing of Ascophyllum nodosum was previously shown to be very efficient at removing Zn(II), Ni(II) and Al(III) both in single and multi‐metal waste streams. In this study, the regeneration of the biosorbent using an acid wash resulted in the release of high metal concentrations during multiple desorption cycles. Maximum desorption efficiencies (DE) of 183, 122 and 91% were achieved for Zn(II), Ni(II) and Al(III), respectively, for subsequent metal loading cycles, significantly exceeding the desorption rates observed for conventional sorbents. The regeneration of the sorbent was accomplished with very little loss in metal removal efficiency (RE) for both single and multi‐metal systems. Values of 92, 96 and 94% RE were achieved for Zn(II), Ni(II) and Al(III), respectively, for the 5^th sorption cycle in single metal aqueous solutions. A slight decrease was observed for the same metals in multi‐metal systems with maximum REs of 85, 82 and 82% for Zn(II), Ni(II) and Al(III), respectively. This study showed that the novel sorbent derived from a seaweed industrial waste would be suitable for multiple metal sorption cycles without any significant loss in RE.     

2010年2月一次冬季黄海海雾的成因分析

利用青岛浮标观测、自动气象站观测、Micaps站点观测、L波段雷达等观测数据,New Generation SST,OI-SST和NCEP提供的FNL和CFSR再分析数据。并利用中尺度模式WRF对这次冬季海雾进行诊断分析。得到以下结论:(1)观测表明,这次海雾首先在黄海北部生成,是由于冷暖空气在黄海海域交汇,增大相对湿度,形成混合雾。在22日12:00时(UTC)之后,暖平流北上,冷平流消失。海雾逐渐转成平流冷却雾。青岛出现的海雾是从黄海发展过来的,并且为平流冷却雾。(2)在黄海,冷暖空气混合增大相对湿度,生成混合雾。与后期的平流冷却雾相比,混合雾的高度明显偏低。(3)海温异常偏低。在2010年2月渤海大面积结冰,海温偏低可能与融冰有关系。(4)模式结果表明,混合雾与冷水域的关系密切。平流冷却雾与冷水域的位置基本一致。混合雾和平流冷却雾都受海温影响较大。混合雾雾区变化很大,因为冷空气在移动过程中变性,不利于混合雾生成。冷海面对平流冷却雾起着很关键的作用。这次冬季海雾与春夏季黄海海雾的不同点在:这次海雾的发生机制不同于典型的春夏季黄海海雾。春夏季典型的黄海海雾主要是平流冷却雾,而这次冬季海雾在生成上首先是混合雾,后来转为平流冷却雾。