环境中的药物——LC-MS/MS分析地表水和地下水

成百上千的活性物质正被用于人药和兽药处方中.由于药物的广泛应用,它们的残留物可通过多种途径进入环境.虽然主要通过尿和粪便的排泄,但是药品生产中的排放也应被考虑.当抗生素用于水产业,就会产生更直接的影响.污水处理设备不能完全除去药物,因此药物会出现在地表和地下水样品中.近年来,人们对环境中药物的兴趣正在增加,需要建立一种快速、灵敏、有选择性的方法来分析水样.     

Juvenile–adult associations in sea urchins ( Strongylocentrotus franciscanus and S. droebachiensis ): protection from predation and hydrodynamics in S. franciscanus

Juvenile red sea urchins, Strongylocentrotus franciscanus, aggregate under adult conspecifics, whereas sympatric juvenile green sea urchins, Strongylocentrotus droebachiensis, are typically more solitary and dispersed. Neither the potential advantage of juvenile sheltering nor the differences in post-settlement behavior between the two species has been demonstrated experimentally, but may be related to protection from predators and/or hydrodynamics. In predation experiments, juvenile vulnerability differed in the two species as the seastar Pycnopodia helianthoides consistently chose juvenile S. franciscanus over S. droebachiensis (100% vs. 0%). When associated with adults, juvenile mortality decreased dramatically in S. franciscanus (90% alone vs. 5% with adults), but very little in S. droebachiensis (85% vs. 75%). Not surprisingly, juvenile behavioral responses in the two species reflect this difference in vulnerability. Juvenile S. franciscanus sheltered under adults when predation risk was high, but not when risk was low (44% vs. 13%), whereas sheltering in S. droebachiensis was infrequent and not related to predation risk (7% for high risk versus 5% for low risk). From a hydrodynamic perspective, the presence of an adult led to the creation of a hydrodynamic refuge for juveniles, where average water velocities were reduced by > 60% around the adult urchin. Again, striking differences in sheltering rate were apparent in S. franciscanus (52% vs. 13% for high flow and low flow, respectively), but not S. droebachiensis (5% for high flow versus 4% for low flow). Sheltering behavior was also species-specific as juveniles did not shelter at high rates under adults of the opposite species (≤ 16%). A field survey confirmed these finding in that juvenile S. franciscanus abundance was associated with both adults and water motion (R ² = 0.80, P = 0.008, best-subsets regression). These results suggest that sheltering confers juvenile S. franciscanus with a degree of protection from predators and water motion, and that species-specific differences in this post-settlement behavior may be related to the differences in the protection afforded by adults.     

Cycads: their evolution,toxins, herbivores and insect pollinators

Palaeobiological evidence indicates that gymnosperms were wind-pollinated and that insect pollination began in angiosperms in the Lower Cretaceous (ca. 135 mya) leading to close associations between higher plants and their pollinators. Cycads, which were widespread and pervasive throughout the Mesozoic (250-65 mya) are among the most primitive living seed-plants found today. Because pollination by beetles and by thrips has now been detected in several modern cycads, it is attractive to speculate that some insects and cycads had already developed similar mutualistic interactions in the Triassic (250-205 mya), long before the advent of angiosperms. We also draw attention to another key factor in this insect-plant relationship, namely secondary, defensive plant substances which must always have controlled interspecific interactions. Cycads mainly produce toxic azoglucosides and neurotoxic non-protein amino acids (e.g. BMAA), which apparently are crucial elements in the development and maintenance of mutualism (pollination) and parasitism (herbivory) by cycad-linked herbivores. We now add new results on the uptake and storage of the main toxin, cycasin, of the Mexican cycad Zamia furfuracea by its pollinator, the weevil Rhopalotria mollis, and by a specialist herbivore of Zamia integrifolia, the aposematic Atala butterfly Eumaeus atala.     

Historical record of polychlorinated dibenzo-p-dioxins and dibenzofurans in Swiss lake sediments

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were found in annually laminated sediments from Lakes Zurich, Baldegg, and Lugano in Switzerland. Octachlorodibenzo-p-diox in (OCDD) predominated, averaging approximately 1.3 ppb. The congener distribution indicated that combustion was the source of PCDD and PCDF in these sediments. In these dated sediment cores, we found that PCDD and PCDF were absent from the sediments before about 1945, but increased thereafter.     

Biodegradation of chlorinated solvents in a water unsaturated topsoil

In order to investigate topsoils as potential sinks for chlorinated solvents from the atmosphere, the degradation of trichloromethane (CHCl(3)), 1,1,1-trichloroethane (CH(3)CCl(3)), tetrachloromethane (CCl(4)), trichloroethene (C(2)HCl(3)) and tetrachloroethene (C(2)Cl(4)) was studied in anoxic laboratory experiments designed to simulate denitrifying conditions in water unsaturated topsoil. Active denitrification was demonstrated by measuring the release of 15N in N(2) to the headspace from added 15N labeled nitrate. The degradation of chlorinated aliphatic compounds was followed by measuring their concentrations in the headspace above the soil.The headspace concentrations of all the chlorinated solvents except CH(3)CCl(3) were significantly (P相似文献   

Concentration of LAS and boron in the Itter. Comparison of measured data with results obtained by simulation with the GREAT-ER software

The GREAT-ER software was used to calculate linear alkylbenzene sulphonate [LAS] and boron concentrations in the Itter stream in North Rhine-Westfalia, Germany. The aim was to investigate the predictive strength of this newly developed tool and to compare its results to measured data. Substance-specific input data which were used in this scenario were partly generic (e.g. LAS and sodium perborate tetrahydrate consumption figures for Germany) and partly (site-)specific data (e.g. half-life time for LAS elimination). The comparison with the measured data reveals that the model predictions for LAS and boron are correct at least within a factor of two, only if generic German consumption data is applied. By using refined input data, the accuracy can be increased further.     

Secondary air pollutants

The study has been performed in a supposedly clean-air region of a Northern Finnish forest with a homogeneous stand of Scots pine. Stomatal epicuticular wax layer erosion is described using a classification system of five erosion stages. The percentage of stomatal wax within each erosion stage is calculated and the results are treated statistically, which makes the morphological study of the needle surface semi-quantitative. Severe wax degradation has already been found in the current year, increasing with the age of the needles. In this area, the wax layer erosion is correlated with secondary air pollutants, as analyses have shown high trichloroacetate (TCA) levels in needles from the same trees. The wax layer analyses are in accordance with earlier findings which have demonstrated differences in tolerance to TCA.     

Studies on metal content in the brown seaweed, Fucus vesiculosus, from the Archipelago of Stockholm

Concentrations of eleven metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) were determined in the brown seaweed Fucus vesiculosus collected from the Archipelago of Stockholm. Several factors which influence the metal content in the seaweed have been studied, including errors caused by epiphytes, sea exposure and differences depending on which part of the seaweed is analysed. It is concluded that, if all these factors are considered, Fucus vesiculosus plants are excellent bio-indicators of metal pollution. This is also demonstrated by a significant increase in metal content in transplanted Fucus vesiculosus near the city of Stockholm. The results from this investigation also indicate increasing metal concentrations, especially Cd, in samples from the northern parts of the Archipelago and the reason for this is discussed.