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31.
Contaminants in fish tissue from US lakes and reservoirs: a national probabilistic study 总被引:1,自引:0,他引:1
Leanne L. Stahl Blaine D. Snyder Anthony R. Olsen Jennifer L. Pitt 《Environmental monitoring and assessment》2009,150(1-4):3-19
An unequal probability design was used to develop national estimates for 268 persistent, bioaccumulative, and toxic chemicals in fish tissue from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake). Predator (fillet) and bottom-dweller (whole body) composites were collected from 500 lakes selected randomly from the target population of 147,343 lakes in the lower 48 states. Each of these composite types comprised nationally representative samples whose results were extrapolated to the sampled population of an estimated 76,559 lakes for predators and 46,190 lakes for bottom dwellers. Mercury and PCBs were detected in all fish samples. Dioxins and furans were detected in 81% and 99% of predator and bottom-dweller samples, respectively. Cumulative frequency distributions showed that mercury concentrations exceeded the EPA 300 ppb mercury fish tissue criterion at nearly half of the lakes in the sampled population. Total PCB concentrations exceeded a 12 ppb human health risk-based consumption limit at nearly 17% of lakes, and dioxins and furans exceeded a 0.15 ppt (toxic equivalent or TEQ) risk-based threshold at nearly 8% of lakes in the sampled population. In contrast, 43 target chemicals were not detected in any samples. No detections were reported for nine organophosphate pesticides, one PCB congener, 16 polycyclic aromatic hydrocarbons, or 17 other semivolatile organic chemicals. 相似文献
32.
Fungiacyathus marenzelleri (Vaughan, 1906) is a deep-water solitary coral, cosmopolitan in distribution that is found at depths of 300–6,328 m. This
study examined gametogenesis, inter-annual variability and reproductive periodicity of F. marenzelleri collected from Station M (34°50′N, 123°00′W) in the northeast Pacific at a depth of 4,100 m. Samples were collected (May,
June, October 1996; August 1998; February, June 2001; and June 2002) and histologically processed with spermatogenic stage,
oocyte size and fecundity measured. Four stages of spermatogenesis were identified and all males contained multiple stages
of sperm development in each seasonal sample. Three stages of oocyte development were identified; previtellogenic (<28–150 μm),
vitellogenic (150–300 μm) and late vitellogenic (300–400 μm). Comparison of mean oocyte diameters among sampling dates showed
there were no inter-annual variations or seasonal differences. Overall, fecundity was 1,290 (±407) oocytes polyp−1, and with no significant differences between sample months. Fecundity was not polyp-size dependent. This study shows a similar
quasi-continuous mode of reproduction to this species examined from the Northeast Atlantic Ocean, but the fecundity is reduced
by 50%. The reproductive output may fluctuate in relation to the input of organic material at this site, as shown by non-significant
trends in the oocyte size-frequency and fecundity data. A quasi-continuous output of gametes would promote successful fertilisation
and wide dispersal of the lecithotrophic larvae. 相似文献
33.
Benavides-Lopez Jose Luis ter Hofstede Hannah Robillard Tony 《Die Naturwissenschaften》2020,107(1):1-11
The Science of Nature - The capability of producing sounds and vibrations is well known in insects and is thought to be a form of intra- and interspecific communication. Sounds and vibrations are... 相似文献
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To offset the detrimental effects of urbanization on groundwater recharge, stormwater managers are focusing on infiltrating much of the runoff from a site that was generated because of development. For this to be effective, tools are required to predict the potential for contamination resulting from this infiltration for many site conditions, because infiltration should be stressed in areas where the least potential for causing groundwater contamination exists. Factors that influence contamination potential include the pollutant concentration in the runoff directed to the infiltration device and the ability of the underlying soil to remove the pollutant. The groundwater contamination potential of some pollutants, even those with high concentrations and moderate-to-high mobilities, can be reduced with proper pretreatment before infiltration. This paper presents a methodology that can be used to evaluate infiltration as an management option and introduces two different levels of models that could be used to evaluate contamination potential. 相似文献
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High-resolution liquid chromatography is being applied to the characterization of refractory organic compounds present in coal conversion streams at concentrations as low as a few micrograms per liter. The chromatographic system, which was previously developed for the analysis of the molecular biochemical constituents in human body fluids, is capable of analyzing for compounds that are u.v.-absorbing and/or oxidizable with sulfatoceric acid. Aqueous samples from various coal-liquefaction experiments have been collected, concentrated when necessary, and chromatographed. The chromatographic fractions have then been subjected to a multiple-analytical identification procedure utilizing, in sequence, UV-spectrometry, gas chromatography, and mass spectrometry. With this procedure, 18 organics were identified and 15 were quantified in the effluent from the product scrubber of a bench-scale hydrocarbonization unit. In addition, numerous unknown constituents have been characterized with respect to gas chromatographic and mass spectrometric properties. 相似文献
38.
Sean T. Hannah 《组织行为杂志》2015,36(Z1):S104-S168
The role of the self in moral functioning has gained considerable theoretical and empirical attention over the last 25 years. A general consensus has emerged that the self plays a vital role in individuals' moral agency. This surge of research produced a proliferation of constructs related to the moral self, each grounded in diverse theoretical perspectives. Although this work has advanced our understanding of moral thought and behavior, there has also been a lack of clarity as to the nature and functioning of the moral self. We review and synthesize empirical research related to the moral self and provide an integrative framework to increase conceptual coherence among the various relevant constructs. We then discuss emerging opportunities and future directions for research on the moral self as well as implications for behavioral ethics in organizational contexts. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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