Physicochemical properties of selected polybrominated diphenyl ethers and extension of the UNIFAC model to brominated aromatic compounds

The aqueous solubilities (S(w)) at various temperatures from 283 K to 308 K and 1-octanol/water partition coefficients (K(ow)) for four polybrominated diphenyl ethers (PBDEs: 4,4'-dibromodiphenyl ether (BDE-15), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153)) were measured by the generator column method. The S(w) and K(ow) data revealed the effect of bromine substitution and basic structure on S(w) and K(ow). To estimate the infinite dilution activity coefficients (gamma(i)(w,infinity)) of the PBDEs in water from the S(w) data, enthalpies of fusion and melting points for those compounds were measured with a differential scanning calorimeter. Henry's Law constants (H(w)) of the PBDEs were derived from the determined gamma(i)(w,infinity) and literature vapor pressure data. Some physicochemical characteristics of PBDEs were also suggested by comparing the present property data with that of polychlorinated dibenzo-p-dioxins, brominated phenols and brominated benzenes in past studies. Furthermore, in order to represent different phase equilibria including solubility and partition equilibrium for other brominated aromatic compounds using the UNIFAC model, a pair of UNIFAC group interaction parameters between the bromine and water group were determined from the S(w) and K(ow) data of PBDEs and brominated benzenes. The ability of the determined parameters to represent both properties of brominated aromatics was evaluated.     

EMF effects on microcirculatory system

Authors review the importance of studying the effects of electromagnetic fields (EMF) on microcirculatory system, especially in respect of possibility that vasculature may have direct and indirect role in interaction of static magnetic fields (SMF). We outline the physiological importance of microcirculation and relatively new methods of evaluation technique in vivo and explain in details the local and/or whole body exposure effects of SMF with␣range of 0.3–180 mT, power frequency EMF with range of 0.1–30 mT and microwaves at 1.5 GHz with range 0.08–8 W/kg brain average specific absorption rate (SAR) on microcirculatory systems in different tissues in experimental animals.     

Analyses of incinerated ash of paper sludge: comparison with incinerated ash of municipal solid waste

Fourteen paper sludge samples were collected at seven representative pulp and paper mills in Japan, and were analyzed to obtain fundamental data on the reuse of paper sludge-incinerated ash as papermaking material. For comparison, incinerated ashes of municipal solid waste (MSW) were collected at MSW incineration plants in Tokyo, and analyzed by similar methods. Elementary and X-ray diffraction analyses revealed that the predominant elements in paper sludge samples are calcium, silicon, aluminum, and magnesium, which are derived from paper fillers, coating pigments, and coagulants used in papermaking and process effluent treatments. Similar results were also obtained for the MSW-incinerated ashes, indicating that major components in the collected MSW are paper-related materials. Incineration of paper sludge around 800°C is recommended in terms of high brightness of the incinerated ash, which has about 60% brightness. Calcium, silicon, and aluminum components in the paper sludge are fused or sintered by heating. Although paper-sludge-incinerated ashes have irregular shape and large particle size distributions, they may be used as papermaking materials after pulverization using a ball mill. The MSW-incinerated ashes have 5%–30% water-soluble fractions and low brightness, and thus incineration conditions must be changed to reuse the MSW-incinerated ash as a papermaking material.Part of this paper was presented at the 68th Research Conference of Japan Tappi, Tokyo, 2001     

Biologically induced Po emission from fresh water

Behavior of Po in fresh waters was examined in laboratory culture experiments using fresh water collected from a small pool, Xi river and Xiqing lake, showing formation of volatile Po compounds followed by emission to air. Addition of tryptone to the fresh water cultures increased the emission of Po considerably along with a growth of microorganisms, suggesting a connection of chemoheterotrophs to Po emission. Participation of photoautotrophs was also considered because Po emission was increased when NaHCO3 was added to the fresh water cultures. The emission behavior of Po and S in these experiments appeared in different ways. The quantity of Po emitted was comparable to the previous culture experiments (Momoshima, Song, Osaki & Maeda, Environ. Sci. Technol., 35, 2956-2960, 2001) in which artificial culture medium containing 3% NaCl was used and inoculated with sea sediment extract. The biological support for Po emission, thus, would be a general phenomenon in fresh water as well as a seawater environment and is possibly a source for atmospheric Po.     

Formation of cyanide ion or cyanogen chloride through the cleavage of aromatic rings by nitrous acid or chlorine. IX. On the reactions of chlorinated, nitrated, carboxylated or methylated benzene derivatives with hypochlorous acid in the presence of ammonium ion

Chlorinated, nitrated, carboxylated or methylated benzenes, phenols and anilines reacted with chloramine to give cyanogen chloride, independently of the positions and the numbers of the substituents. Among these compounds, 2,4,6-trichlorophenol afforded cyanogen chloride in a relatively high yield of 13.3%, and the intermediates in the reaction were 2,6-dichloro-1,4-benzoquinone-4-(N-chloro)imine and 4,6-dichloro-1,2-benzoquinone-2-(N-chloro)-imine, of which the latter was the main intermediate.     

Personal exposure monitoring to nitrogen dioxide

Measurement of personal exposure to nitrogen dioxide for short and long term was made with a sensitive NO₂ passive sampler by volunteer housewives and office workers in different seasons. These measurements were compared with the simultaneous measurement of outdoor and indoor concentration of the participants. A common result over all the measurements is the potential effect of using an unvented space heater to increase personal exposure. Mean personal exposure and indoor concentration are higher than outdoor levels elevated by the samples exposed to pollutant produced from the heater. Without an NO₂ source indoors, the mean outdoor concentrations are always highest among the data of measurement. A time-weighted indoor/outdoor activity model gives modestly improved estimates of personal exposure over those predicted from measured indoor concentrations alone.     

复合菌群产絮凝剂MAC37的特征及其在黏合剂废水中的应用

以利用复活促进因子(Rpf)从土壤和污水处理系统中分离得到的菌种作为筛选絮凝剂产生菌的菌源,采用高岭土悬浊液为活性评价体系,筛选出4株絮凝率高于50%的菌株.经两两菌株复配,构建出产高效絮凝剂的复合菌群M3+M7,该菌群经优化培养后,絮凝率达96.27%.将其产生的絮凝剂进行提纯固化得絮凝剂粗品MAC37,对其主要成分进行定性和定量分析,并将复合菌群的发酵液应用于黏合剂废水的处理.结果表明:MAC37的主要成分为多糖和蛋白质,含量分别为74.5%和20.4%;黏合剂废水经复合菌群发酵液絮凝处理后,浊度、色度及CODCr的去除率分别为92.57%、94.73%和92.12%.      

Chemical investigations of defensive steroid sequestration by the Asian snake Rhabdophis tigrinus

Rhabdophis tigrinus is an Asian natricine snake that possesses unusual defensive glands on the dorsal surface of its neck. These nuchal glands typically contain cardiotonic steroidal toxins known as bufadienolides, which are also abundant in the skin of toads. Feeding experiments demonstrated that toads consumed as prey are the ultimate sources of the bufadienolides in nuchal glands of R. tigrinus. Indeed, snakes on a toad-free Japanese island (Kinkasan, Miyagi Prefecture) lack these compounds in their nuchal glands, confirming that these snakes are unable to synthesize defensive bufadienolides. However, when snakes from Kinkasan are fed toads in the laboratory, they accumulate bufadienolides in their nuchal glands, indicating that they have not lost the ability to sequester defensive compounds from prey. In contrast, R. tigrinus from a toad-rich island (Ishima, Tokushima Prefecture) possess large quantities of bufadienolides, reflecting the abundance of toads from which these compounds can be sequestered. Feeding experiments involving gravid R. tigrinus demonstrated that bufadienolides can be provisioned to offspring so that hatchlings are chemically defended before their first toad meal. Maternal provisioning of bufadienolides can take place through two routes: by deposition in yolk and by diffusion in utero, even late in gestation. We applied bufadienolides to the surface of eggs from Kinkasan and found that the embryos are able to take up these compounds into their nuchal glands, demonstrating the feasibility of uptake across the eggshell. Female R. tigrinus provision bufadienolides to their offspring in direct proportion to their own level of chemical defense. By feeding toad-derived bufotoxins to R. tigrinus hatchlings, we determined that the sequestration of these compounds involves at least three types of modification: hydrolytic cleavage of suberylarginine side chains, hydroxylation, and epimerization.