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131.
Chemical analyses were performed in nine fish species that are popular on the Polish market. These included Baltic fish (cod, herring, salmon), fish farmed in Poland (carp, trout), marine fish imported from China (Alaska pollock, sole), and farmed fish imported from Vietnam and China (sutchi catfish, tilapia). The nutritional composition (amino acid, micro- and macronutrients, fat-soluble vitamins - A1, D3, E) and certain contaminants (organochlorine pesticides, OCPs; indicator polychlorinated biphenyl, PCB6; polychlorinated dibenzo-paradioxins and polychlorinated dibenzofurans, PCDD/Fs; dioxin-like polychlorinated biphenyls, dl-PCBs; organotin compounds, OCTs; dyes, malachite green and crystal violet; veterinary drug residues, nitrofurans and chloramphenicol; toxic metals, Cd, Pb, Hg) in the muscle tissues of fish were determined. It was confirmed that the fish species analyzed were excellent sources of amino acids, and were rich in phosphorous and selenium. Baltic Sea fish (salmon, herring), fish farmed in Poland (carp and trout), and tilapia were also rich in vitamin D3.Traces of OCP, PCB6, OCT, dyes, veterinary drug residues, and heavy metals were detected in concentrations which do not pose a threat to consumers at the current rate of fish consumption in Poland. However, the problem might arise from the content of PCDD/Fs and dl-PCBs in fatty Baltic fish. The fish species analyzed, differed in their nutritional values and degrees of contamination. We suggest that for optimum health and safety, it is advisable that consumers include a variety of different fish species in their diets.  相似文献   
132.
This paper reports on the partitioning behaviour of 15 perfluorinated compounds (PFCs), including C4-C10 sulfonates and C5-C14 carboxylic acids, between water, sediment and fish (European chub, Leuciscus cephalus) in the Orge River (nearby Paris). Total PFC levels were 73.0 ± 3.0 ng L−1 in water and 8.4 ± 0.5 ng g−1 in sediment. They were in the range 43.1-4997.2 ng g−1 in fish, in which PFC tissue distribution followed the order plasma > liver > gills > gonads > muscle. Sediment-water distribution coefficients (log Kd) and bioaccumulation factors (log BAF) were in the range 0.8-4.3 and 0.9-6.7, respectively. Both distribution coefficients positively correlated with perfluoroalkyl chain length. Field-based biota-sediment accumulation factors (BSAFs) are also reported, for the first time for PFCs other than perfluorooctane sulfonate. log BSAF ranged between −1.3 and 1.5 and was negatively correlated with the perfluoroalkyl chain length in the case of carboxylic acids.  相似文献   
133.
对使用溶剂型油墨的凹版印刷设备和使用水性油墨的柔版印刷设备无组织排放的挥发性有机物(VOCs)浓度进行了实际监测,并采用计算流体动力学模拟无组织排放VOCs的收集效率。结果表明:(1)使用溶剂型油墨的凹版连续印刷过程非甲烷总烃(NMHC)最高均值达到5 975.67 mg/m3,约为使用水性油墨的柔版印刷(191.67 mg/m3)的31.2倍。虽然使用水性油墨可明显降低NMHC的排放,但其操作空间的浓度依然存在超过《工作场所有害因素职业接触限值第1部分:化学有害因素》(GBZ 2.1—2019)的现象。(2)印刷车间应该设置专门的调墨室,能缓解印刷车间内挥发性污染气体浓度的波动。(3)计算流体动力学模拟显示,设置合理的集气罩可有效降低VOCs的无组织排放,收集效率为70%~75%。  相似文献   
134.
Cadmium has been recognized as pollutant of the environment for many years and numerous studies on its toxic effects have been carried out. Little, however, is known about its metabolic behaviour e.g. why the metal is accumulated so extremely rapidly into the organs of men and animals. Since the study of the individual metabolic steps is very difficult in vivo cell cultures may be used to obtain first indications of what happens in the whole animal.

We used CHO cells in monolayer culture to study the conditions under which the uptake of cadmium occurs. From serumfree medium the metal is accumulated rapidly in the cells. The uptake is inhibited very strongly by the presence of serum or albumin. Accumulation occurs against a concentration gradient and is dependent on the incubation temperature. Below 10°C no cadmium uptake is seen. Several substances which are known to affect cell metabolism have been used to influence cadmium accumulation. Neither inhibitors of energy production nor microtubule or microfilament disruptors showed any substantial effect. In contrast SH‐group blocking agents markedly reduced cadmium uptake.

The results show that cadmium uptake does not occur by passive diffusion but by some active mechanism.  相似文献   
135.
A dynamic flux chamber has been used to estimate fluxes of mercury over different types of surfaces in an abandoned open‐cut mine of Tongren prefecture, Guizhou province, China during spring and summer of 1996. The highest fluxes were obtained over cinnabar slag and contaminated soils, whereas the emissions above cinnabar ore were substantially lower. These fluxes was scaled up to estimate the contribution of mercury emissions to air from mercury wastes, compared to anthropogenic activities in the province of Guizhou, China. Atmospheric mercury concentrations measured were enhanced in the mining area (<1.3 μg m‐3) compared to regional background sites (1.8–5.1 ng m‐3). The spreading of mercury was estimated by using biological and geological samples. Moss bags have been employed to estimate long‐time dry‐ and wet‐deposition to this area.  相似文献   
136.
ABSTRACT: Contamination of ground water supplies with volatile organic compounds is a new and significant problem. Municipalities and their community water systems are often the first to discover ground water contamination because of the monitoring programs they are required to carry out. When contamination exceeds standards, some action is required. The responses of Wisconsin municipalities to volatile organic compounds that exceed standards in their ground water sources is described. Actions to protect human health are prompt, but the survey results indicate plumes of contaminated ground water are usually not treated. They may continue to migrate and contaminate other private and public wells.  相似文献   
137.
贵州喀斯特地区旅游资源的变异与可持续利用   总被引:6,自引:0,他引:6  
喀斯特景观与民族文化是不可再生的旅游资源,其开发在促进喀斯特地区经济、文化发展的同时,也加剧了环境的损耗和地方特色的消失,旅游资源变异现象普遍发生。文中分析了资源变异的几种情况,并指出控制资源变异,实现可持续利用的途径  相似文献   
138.
Q1, an organochlorine component with the molecular formula C(9)H(3)Cl(7)N(2) and of unknown origin was recently identified in seal blubber samples from the Namibian coast (southwest of Africa) and the Antarctic. In these samples, Q1 was more abundant than PCBs and on the level of DDT residues. Furthermore, Q1 was more abundant in seals from the Antarctic than the Arctic. To prove this assumption, gas chromatography-electron-capture negative ion mass spectrometry (GC/ECNI-MS), which is sensitive and selective for Q1, allowed for screening of traces of Q1 even in samples with particularly high levels of other organochlorine contaminants. Q1 was isolated by high-performance liquid chromatography (HPLC) from a skua liver sample. A 1:1 mixture with trans-nonachlor in electron-capture detectors (ECDs) was used to determine the relative response factor with ECNI-MS. The ECNI-MS response of Q1 turned out to be 4.5 times higher than that of trans-nonachlor in an ECD. With GC/ECNI-MS in the selected ion-monitoring mode, four Antarctic and four Arctic air samples were investigated for the presence of Q1. In the Antarctic air samples, Q1 levels ranged from 0.7 to 0.9 fg/m(3). In Arctic air samples, however, Q1 was below the detection limit (<0.06 fg/m(3) or 60 ag/m(3)). We also report on high Q1 levels in selected human milk samples (12-230 microg/kg lipid) and, therefore, suggested that the unknown Q1 is an environmental compound whose origin and distribution should be investigated in detail. Our data confirm that Q1 is a bioaccumulative natural organochlorine product. Detection of a highly chlorinated natural organochlorine compound in air and human milk is novel.  相似文献   
139.
The photodegradation of tetraphenyltin (TePT) contained in polychlorinated biphenyl (PCB)-based transformer oil simulants by ultraviolet (UV) irradiation in alkaline 2-propanol solutions was examined. In the absence of PCBs, the TePT level fell to below 1% of the initial concentration within 30 min. In the absence of both PCBs and an alkali, the concentrations of tri-, di-, and monophenyltins initially increased to a few milligrams per liter, and then reduced to below the detection limits within 90 min. The addition of an alkali to the reaction solution slightly accelerated the photodecomposition of TePT. The decomposition of other phenyltins (PTs) was also accelerated. When PCBs with concentrations of approximately 80 times the initial TePT concentration were added, only a small fraction of the TePT decomposed within 100 min. Moreover, the levels of PTs did not change during irradiation. TePT and other PTs did decompose when the level of PCBs was reduced to the same concentration as that of TePT; however, the decomposition rates were slower than those in the absence of PCBs. In the actual treatment process, TePT and other PTs in PCB-based transformer oil are decomposed by catalytic reduction, which is used after UV irradiation. Therefore, in the actual treatment of PCB-based transformer oil wastes, pollution due to PTs can be prevented.  相似文献   
140.
In the present research, the effects of static magnetic field, with or without iron on the growth, the activity of certain enzymes (like polyphenol oxidase and phenyle alanine ammonialyase), the content of phenolic compounds and the essential oil composition of sweet basil (Ocimum basilicum) were studied. Treatment of plants with static magnetic field with or without iron led to decrease of the growth of plants as well as decrease in the activity of phenyle alanine ammonialyase and of phenolic compounds content. In addition in those plants exposed to magnetic field the amount of essential oils, notably of methyl chavicol, was increased. Exposure of plants to the magnetic field decreased the activity of polyphenol oxidase, whereas treatment of plants with iron when exposed to magnetic field increased polyphenol oxidase activity. In this group the content of essential oil was reduced.  相似文献   
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