TNT in Komposten und Flüssigkultur

The formation of aromatic amines was investigated using a summarized test (NEDA-test) during the composting of 2,4,6-trinitrotoluene (TNT) contaminated soil. In this test, the aromatic amines were diazolated and then coupled to N-1-Naphthyl-ethylenediamine-dihydrochloride (NEDA) to yield an azo dye which can be monitored photometrically. The test was calibrated for known TNT-metabolites with an active amine-group. Liquid samples from composting- and liquid-culture-experiments were analyzed by HPLC for these known metabolites. Moreover, the samples were monitored by the NEDA-test and the expected extinction of the TNT-metabolites found with amine function were extrapolated with the help of calibration curves. It was shown that substantial differences are obvious between the monitored and extrapolated values. After separation into polar and non-polar aromatic amines, it became clear that these differences are made by the polar aromatic amines. Polar aromatic amines, which are not detectable by presently available analytical tests, were generated during the composting of TNT-contaminated soils. Contaminated stagnant water, which was generated during anaerobization of a compost prephase, was treated aerobically for 70 days in a biofermenter. During this treatment TNT and its known metabolites were eliminated almost entirely. Simultaneously, the toxicity in the Lumis Tox-test decreased drastically. In striking contrast, the sum of aromatic amines decreased only to a minor extent. Moreover, the percentage of polar compounds from total amount of aromatic amines increased drastically from 48% to more than 95%. At present, the chemical identification of these polar compounds is still missing and is the object for further research.     

Filtering rates of the juvenile Atlantic menhaden Brevoortia tyrannus (Pisces: Clupeidae), with consideration of the effects of detritus and swimming speed

From July to September 1982 feeding experiments were conducted with 138-mm fork length Atlantic menhaden Brevoortia tyrannus (Latrobe) (Pisces: Clupeidae) to determine their particle size-specific feeding abilities. Monoculture clearing-rate experiments showed that the minimum size of particles filtered, the minimum size threshold, for 138-mm fish is 7 to 9 m. Filtration efficiency for three species of phytoplankton below the minimum size threshold. Pseudoisochrysis paradoxa, Monochrysis lutheri, and Isochrysis galbana, averaged 1.0% (n=14). Tetraselmis suecica, Prorocentrum minimum, and 2-celled Skeleionema costatum, phytoplankton which are larger than the minimum size threshold and smaller than the 20-m upper limit for nanoplankton, were filtered at efficiencies averaging 21% (n=24). S. costatum chains of 3 to 6 cells, prey particles exceeding the size limits of nanoplankton, were filtered at average efficiencies ranging from 22 to 84%. The mean filtration efficiency for Artemia sp. nauplii (San Francisco Bay Brand) of 36% (n=7) was lower than for smaller phytoplankton prey. The presence of detritus at concentrations usually encountered in nature enhanced filtering efficiency and lowered minimum size thresholds at which phytoplankton were retained. For small food particles, filtering efficiency decreased as swimming speed of the menhaden increased. As menhaden grow, their feeding tepertoire shifts to larger planktonic organisms.Contribution No. 1201 Virginia Institute of Marine Science     

Analysis of Daily Peaking and Run‐of‐River Operations with Flow Variability Metrics,Considering Subdaily to Seasonal Time Scales

Environmental flows are an important consideration in licensing hydropower projects as operational flow releases can result in adverse conditions for downstream ecological communities. Flow variability assessments have typically focused on pre‐ and post‐dam conditions using metrics based on daily averaged flow values. This study used subdaily and daily flow data to assess environmental flow response to changes in hydropower operations from daily peaking to run‐of‐river. An analysis tool was developed to quantify flow variability metrics and was applied to four hydropower projects. Significant differences were observed between operations at the 99% confidence level in the median flow values using hourly averaged flow datasets. Median daily rise and fall rates decreased on average 34.5 and 27.9%, respectively, whereas median hourly rise and fall rates decreased on average 50.1 and 50.6%, respectively. Differences in operational flow regimes were more pronounced in the hourly averaged flow datasets and less pronounced or nonexistent in the daily averaged flow datasets. These outcomes have implications for the development of ecology‐flow relationships that quantify effects of flow on processes such as fish stranding and displacement, along with habitat stability. Results indicate that flow variability statistics should be quantified using subdaily datasets to accurately represent the nature of hydropower operations, especially for daily peaking facilities.     

Imprägnierte Filterpapiere für die Wasserreinigung

With special filter materials it is possible to eliminate the heavy metals lead, copper and nickel and arsenic from water by sorption resp. chemical bounding. After a reaction time of 24 hours the reduction rates were between 97% and >99,9%.     

Spatial and temporal variation of resource limitation in Chesapeake Bay

We report nutrient addition bioassays at 18 stations in Chesapeake Bay (USA) to assess resources limiting phytoplankton growth. Data were pooled from several sampling programs conducted from 1989 to 1994. Spatially, light and P limitation declined from low salinity regions to high salinity regions, as N limitation increased. This spatial pattern was driven primarily by freshwater inflows with high N/P and seawater inflows with low N/P. Seasonally, there was a marked progression of winter light limitation, spring P limitation, and summer N limitation at mesohaline and polyhaline stations. The seasonal pattern appeared to be caused by temperature, mixing, river discharge, and sediment P fluxes. At high salinity stations, we also observed winter N limitation (caused by DIN depletion prior to spring nitrate delivery), and at lower salinity stations there was fall P limitation (caused by reaeration of bottom sediments). At tidal fresh stations, turbidity and nutrient concentrations resulted in continuous light limitation, except at some stations in summer. Interannual decreases in light limitation and increases in N and P limitation appear to represent improvements in water quality. Received: 31 October 1997 / Accepted: 18 December 1998     

Chemische Reaktionen von Chlorvinylarsinverbindungen (Lewisite)

2-Chlorovinylarsine dichloride (Lewisite I) react by room temperature quickly with alcohols in an equilibrium reaction to yield 2-Chlorovinylarsine chloride ether and 2-Chlorovinylarsine bisether. The reactions are not quantitative. The ethyl- and propylether are not stable. The ether were identified with mass spectrometry.     

南极春季海冰物理对叶绿素控制作用的统计分析

利用2006年南极威德尔海西北海域冬末春初的冰芯晶体结构,和302组冰芯温度、盐度、密度、叶绿素-a、脱镁叶绿素数据,以及冰底面叶绿素a垂直分布数据,进一步确定积雪/海冰厚度、冰内温度、盐度、密度对冰内和冰下叶绿素a的贡献.利用环境制约与生态平衡原理,阐明积雪/海冰厚度通过阻碍光通量对冰底叶绿素的效应,以及卤水体积通过冰温度和盐度体现对冰藻细胞活性的抑制作用.统计分析不仅确立了南极海冰冰内卤水体积-内叶绿素a的逻辑斯蒂上限含量曲线,并体现出粒状冰同柱状冰卤水排泄方式的差异及其对冰底春季叶绿素a快速增长的冰物理贡献.冰藻细胞活性指标小于0.5的仅占4.3%,该数据为南极冰藻是维持南极冰区浮游植物旺发的主导因子提供了重要依据.