Contaminant concentrations in sport fish from San Francisco Bay, 1997

In 1997, seven sport fish species were sampled from seven popular fishing areas in San Francisco Bay. Mercury exceeded a human health screening value in 44 of 84 (52%) samples. All collected samples of leopard shark and striped bass exceeded the mercury screening value of 0.23 microg/g wet weight. PCBs exceeded the screening value in 51 of 72 (71%) samples. DDT, chlordane, and dieldrin, had lower numbers of samples above screening values: 16 of 72 (22%) for DDT, 11 of 72 (15%) for chlordanes, and 27 of 72 (37%) for dieldrin. Concentrations of PCBs and other trace organics were highest in white croaker and shiner surfperch, the two species with the highest fat content in their muscle tissue. Fish from one location, Oakland Harbor, had significantly elevated wet weight concentrations of mercury, PCBs, DDTs, and chlordanes compared to other locations. Removal of skin from white croaker fillets reduced lipid concentrations by 27-49% and concentrations of trace organics by 33-40%.     

Mercury concentrations in the fur of steller sea lions and northern fur seals from Alaska

We compared total mercury (THg) concentrations in the fur of northern fur seals (Callorhinus ursinus) from the depleted Pribilof Islands population with those of both declining and thriving populations of Steller sea lions (Eumetopias jubatus) from Prince William Sound (PWS) and Southeast Alaska (SEA), respectively. Relatively low wet weight concentrations (ranges) of THg were detected in the fur of Steller sea lion (SSL) pups (0.90-3.14 microg/g) and juveniles (0.56-6.75 microg/g) from both areas in 1998 and 2000 compared to northern fur seal (NFS) pups (3.15-8.14 microg/g) in 2000. The mean concentration +/- SD for SSLs sampled were 1.46 +/- 0.64 microg/g for pups (n = 22) and 2.74 +/- 2.89 microg/g for juveniles (n = 6). Analyses indicated higher THg concentrations from SSL pups from PWS compared to the SEA. Mean +/- SD. THg in the NFS pups was 4.90 +/- 1.42 microg/g (n = 34) and for post-partum dams was 7.84 +/- 1.78 microg/g (n = 12).     

Properties of the Hermean Regolith: II. Disk-Resolved Multicolor Photometry and Color Variations of the “Unknown” Hemisphere

Multicolor photometric observations of the “unknown” hemisphere of Mercury have been performed with the Swedish Vacuum Solar Telescope on La Palma at maximal elongations from the Sun in 1997 and 1998. A set of six interference filters with central wavelengths from 450 to 940 nm were used. Multicolor photometry of Mercury was performed on disk-resolved images of the unknown hemisphere (longitudes 160°-340°) with a highest resolution of ∼200 km (J. Warell and S. Limaye 2001, Planet. Space Sci.49, 1531-1552).Disk-integrated spectrophotometry shows that (1) the spectrum of Mercury displays a linear slope from 650 to 940 nm, indicating that the average mercurian regolith is considerably more mature than relatively immature pure anorthosite regions on the Moon; (2) there is negative evidence for the presence of the putative 1-μm absorption feature near 940 nm due to the presence of ferrous iron (Fe²⁺) in pyroxenes; and (3) no effect of phase reddening of the integrated disk is observed between phase angles of 63° and 84°.For the first time, disk-resolved spectrophotometry of Mercury's surface has been obtained, from which it is inferred that (4) the scattering properties of Mercury's regolith are more homogeneous than for the Moon and that there is no clear relation between reflectance and chemical properties at spatial scales of ∼300 km on the unknown hemisphere and (5) there exists an inverse relation of spectral slope with emission angle which is larger for Mercury than for the Moon, indicating that the average mercurian regolith is more backscattering and that this effect increases with wavelength.Finally, from filter ratio images of Mercury's disk it is found that (6) no color variations larger that 2% with respect to the surroundings are detected at a spatial resolution of ∼300 km.     

测汞用光纤传感器的初步研制

利用原子吸收原理初步研制了一种测示用光纤传感器,解决了光纤探头部分的技术难题。与传统的测汞仪器相比,该仪器的最大优点是可动的。中介绍了仪器的工作原理及主要技术性能。实验表明,可以利用光纤传感技术来实现汞测量。     

Mercury uptake by the estuarine species Palaemonetes pugio and Fundulus heteroclitus compared with their parasites,Probopyrus pandalicola and Eustrongylides sp

When exposed to methylmercury in the laboratory, grass shrimp, Palaemonetes pugio, parasitized by the isopod Probopyrus pandalicola, accumulated lower concentrations of mercury than their unparasitized counterparts. The parasitic isopod accumulated far less mercury than the grass shrimp. When exposed to mercury in a contaminated field site, mummichogs, Fundulus heteroclitus, parasitized with the nematode Eustrongylides, similarly accumulated lower concentrations of mercury than unparasitized fish, and the parasite similarly accumulated less than the host. The lower uptake by the parasites compared to their hosts is counter to the general view of biomagnification of methylmercury, since parasites are a trophic level above their hosts. The mechanism whereby parasitized animals accumulate less toxicant than unparasitized ones is unknown, but may be partially due to lower metabolic rate.     

从PM10的测量推测成都市区汞污染的来源

通过2007年5—6月期间测量成都市若干条剖面上大气可吸入颗粒物（PM10）中的汞含量，来推测成都市大气中汞的来源。结果表明：在12个点的测量范围内，成都市PM10的质量平均浓度为210．8μg／m^3；PM10中汞的质量平均浓度为0．36ng／m^3。公园和郊区PM10浓度和其中汞浓度均较少，可能与植被茂盛有关。由PM10中汞的分布可知，在热电厂、停用的生活垃圾堆放场和寺庙附近出现最高值。说明热电厂和生活垃圾堆放场是大气汞污染的重要次生来源。寺庙附近出现的高汞值，推测与寺庙的礼仪活动如香烛燃烧有关。     

云南水汞群体非均匀度异常与成组强震活动关系

阐述了一种前兆群体异常信息提取新方法前兆群体非均匀度的数学原理,并以云南水汞群体异常信息为例进行了具体计算。结果表明该方法以群体异常分布特征的变化为异常标准(ID≥1),达到异常即自动识别报警。该方法能克服个人经验的局限,易为他人进行检验,可成为本地区成组强震预测对应概率较高的新指标。     

水（金）星凌日的程序化预报方法

本文介绍了预报水(金)星凌日的计算方法和凌日图的绘制方法,建立了一套完整的预报程序。作为该程序的一个简单应用,我们结合DE200历表及美国海军天文台提供的岁差章动程序,给出了1999年水星凌日的预报结果。     

Global distribution of gaseous mercury in the troposphere

Atmospheric mercury concentrations were measured during a nautical expedition on the Atlantic Ocean between Hamburg (54°N, 10°E) and Santo Domingo (20°N, 67°W). In addition, samples were taken during flights on a commerical aircraft in the upper and middle troposphere between 60°N and 55°S, mostly over the Pacific Ocean. The data obtained in the lower troposphere over the Northern Atlantic show considerable variation in the Hg concentrations, with values ranging between 1 and 11 ng/m³; the average concentration was found to be 2.8 ng/m³. The upper tropospheric data show an interhemispheric difference with average values of 1.45 ng/m³ and 1.08 ng/m³ in the Northern and Southern Hemisphere, respectively. This suggests that mercury production occurs predominantly over the continents both by natural and anthropogenic processes. The mercury content in aerosols was found to be 0.3 ng/m³, or one-tenth of the atmospheric concentration. The data indicate a mean residence time of mercury in the atmosphere of a few months to one year.