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171.
Although satellite radar altimetry was developed and optimized for open oceans, it has been used to monitor variations in the level of inland water-bodies such as lakes and rivers. Here, for the first time, we have further used the altimetry-derived variation of water level for estimating the fluctuation of water storage as an addition to the present in situ water storage estimation systems to be used in remote areas and in emergency situation such as in the events flooding monitoring and for studying the effect of climate change. Lake Dongting, the second largest lake in China, influenced frequently by flooding, was, therefore, chosen to demonstrate the potential of the technique. By using the concept of an “assumed reference point”, we converted Topex/Poseidon satellite altimetry data on water level variations in Lake Dongting to “water level” data. The “water level” time-series data and in situ water storage were used to establish a rating curve. From the rating curve, we converted data on “water level” derived from seven years (1993–1999) of Topex/Poseidon data to actual water storage in Lake Dongting. The result reveals that the seasonal and annual fluctuations of water storage occurred during the 1990s with a more frequent flooding at the late 1990s' especially the flooding in whole catchment level in 1998 and 1999. The study supports the usefulness of satellite altimetry for dense and continuous monitoring of the temporal variations in water dynamic in moderate to large lakes.  相似文献   
172.
Environmental release and behavior of brominated flame retardants   总被引:34,自引:0,他引:34  
Recently, environmental problems relating to brominated flame retardants (BFRs) have become a matter of greater concern than ever before, because of the recent marked increase in levels of polybrominated diphenyl ethers (PBDEs) found in human milk in Sweden and North America. The question that arises is whether environmental levels of PBDEs and other BFRs will continue to increase, causing toxic effects to humans. In an attempt to elucidate the current state of the science of BFRs, we review the consumer demand for BFRs (mainly in Japan), the characteristics of waste flame-retarded products, sources of emission, environmental behavior, routes of exposure of humans, temporal trends, and thermal-breakdown products of BFRs. At present, flame-retarded consumer products manufactured 10-20 years ago, when PBDEs were frequently used, are being dumped. The possible major sources of emission of BFRs into the environment are effluent and flue gases from BFR factories and other facilities processing BFRs. With respect to the environmental behavior of BFRs, the lower brominated compounds are, on the whole, predicted to be more volatile, more water soluble, and more bioaccumulative than the higher brominated compounds. The most probable route for exposure of the general human population to PBDEs, especially the lower brominated congeners, is through the diet. The release of BFRs from consumer products treated with these compounds could also lead to human exposure. Temporal trends in PBDE levels in the environment and in humans worldwide seem to vary considerably, depending on the regions or country, with possible reflections of the historic and current use of PBDEs. The environment and the general human population are also exposed to the thermal-breakdown products of PBDEs, such as polybrominated and mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs and mixed PXDDs/DFs).  相似文献   
173.
The relationship between somatic growth and incremental growth of otoliths of Pacific saury, Cololabis saira (Brevoort), larvae under different temperature conditions was studied in the laboratory for three age groups (0 to 9, 10 to 20 and 20 to 30 d posthatch). Larvae were incubated from hatching to 9 d at 24, 20, and 16 °C. Further, larvae initially reared at an ambient temperature of 21.7 °C were transferred to experimental temperatures of 22, 18, and 14 °C on Day 10 and reared to Day 20 and similarly from Day 20 and reared to Day 30 posthatch. Growth trajectories of larvae sampled at the end of the three experiments were back-calculated using the biological intercept method and compared to the measured values 0 and 5 d after the start of each experiment. Back-calculated knob length at the different temperatures indicated no significant difference to the measured knob lengths except for the cases at 20 °C from hatching to 9-d-old larvae and at 14 °C from 20- to 30-d-old larvae. The close correlation between somatic and otolith growth shown in this study indicated the feasibility of estimating the growth history of Pacific saury larvae using otolith readings. Received: 14 April 1999 / Accepted: 27 October 1999  相似文献   
174.
Groundwater flow at Kharga Oasis, located in the western desert of Egypt, was previously analyzed using numerical models; however, the lack of basic data often limits the implementation of these models, as well as introducing a problem for model calibration and validation. The Grey Model (GM) was used to overcome these difficulties of data limitation and uncertainty of hydrogeological conditions. However, no clear theories exist for selecting the number of input model trends and the most suitable values of input parameters. Therefore, in the current study, a modification of the GM is newly proposed and called the Modified Grey Model (MGM) in an attempt to determine a process for selecting the best input models' trends with the appropriate values of input parameters to achieve acceptable fitting to observations. The sensitivity analysis results showed that the MGM produced more stable results than the GM using a wide range of values for input parameters. Moreover, the MGM reduced the calculation time required for fitting the measured piezometric level trends by 99.8 %. Three development scenarios of groundwater withdrawal were proposed that involved either expanding the present extraction rate or redistributing the groundwater withdrawal over the recent working production wells (RWPWs). The results concluded that the groundwater table in the northern part of the oasis could be temporally recovered to an economical piezometric level; however, the table in the southern part is severely decreased. Therefore, new production wells are recommended to be constructed in the southern part far enough from the RWPWs.  相似文献   
175.
Generic Escherichia coli was isolated from surface water and groundwater samples from two dairies in Northern California and tested for susceptibility to antibiotics. Surface samples were collected from flush water, lagoon water, and manure solids, and groundwater samples were collected from monitoring wells. Although E. coli was ubiquitous in surface samples with concentrations ranging from several hundred thousand to over a million colony-forming units per 100 mL of surface water or per gram of surface solids, groundwater under the influence of these high surface microbial loadings had substantially fewer bacteria (3- to 7-log10 reduction). Among 80 isolates of E. coli tested, 34 (42.5 %) were resistant to one or more antibiotics and 22 (27.5 %) were multi-antibiotic resistant (resistant to ≥3 antibiotics), with resistance to tetracycline, cefoxitin, amoxicillin/clavulanic acid, and ampicillin being the most common. E. coli isolates from the calf hutch area exhibited the highest levels of multi-antibiotic resistance, much higher than isolates in surface soil solids from heifer and cow pens, flush alleys, manure storage lagoons, and irrigated fields. Among E. coli isolates from four groundwater samples, only one sample exhibited resistance to ceftriaxone, chloramphenicol, and tetracycline, indicating the potential of groundwater contamination with antibiotic-resistant bacteria from dairy operations.  相似文献   
176.
We have achieved major improvements in the efficient chemical recycling of waste fiber-reinforced plastics (FRPs). The effects of reduction in the amounts of dimethylaminopyridine (DMAP) used for depolymerization were examined. The treatment of waste FRP in the presence of 1 or 2 wt% DMAP resulted in the successful recovery of monomeric materials that could be employed in the polymerization process to produce recycled plastic. The separation of linker units from glass fiber, however, was unsuccessful. The purity of the recovered monomeric material, when treated with activated charcoal, was improved to about 70%. This resulted in effective decoloration of the recovered monomer. Finally, the purified material, after undergoing repolymerization, provided high-quality recycled plastic comparable to new plastics produced from new monomers.  相似文献   
177.
Derivation of effect benchmark values for each taxonomic group, which has been difficult due to lack of experimental effects data, is required for more adequate protection of the environment from ionising radiation. Estimation of effects doses from nuclear DNA mass and subsequent species sensitivity distribution (SSD) analysis were proposed as a method for such a derivation in acute irradiation situations for assumed nuclear accident scenarios. As a case study, 5% hazardous doses (HD5s), at which only 5% of species are acutely affected at 50% or higher lethality, were estimated on a global scale. After nuclear DNA mass data were obtained from a database, 50% lethal doses (LD50s) for 4.8 and 36% of the global Anura and Caudata species, respectively, were estimated by correlative equations between nuclear DNA mass and LD50s. Differences between estimated and experimental LD50s were within a factor of three. The HD5s obtained by the SSD analysis of these estimated LD50s data were 5.0 and 3.1 Gy for Anura and Caudata, respectively. This approach was also applied to the derivation of regional HD5s. The respective HD5s were 6.5 and 3.2 Gy for Anura and Caudata inhabiting Japan. This HD5 value for the Japanese Anura was significantly higher than the global value, while Caudata had no significant difference in global and Japanese HD5s. These results suggest that this approach is also useful for derivation of regional benchmark values, some of which are likely different from the global values.  相似文献   
178.
Individuals’ exposure to various persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), and its adverse health effects have been a cause of concern. We measured blood PCB concentrations from samples taken from 507 Japanese individuals ranging from infants to those over 80 years of age. The blood PCB levels increased with age for both male (Spearman’s r?=?0.69, p?<?0.001) and female (Spearman’s r?=?0.70, p?<?0.001) participants. Adult men and nulliparous women showed similar increases with age. However, the PCB levels of multiparous women were lower than those of nulliparous women in their thirties (p?=?0.005), probably because the PCBs were transferred from the mothers to their children during pregnancy and lactation. Among infants (<2 years of age), some had as high levels of accumulated PCB levels as those in adults >30 years of age. In some cases, the PCB levels were over 0.8 ng/g wet weight, similar to levels observed in adults over 50 years of age. In the future, it will be necessary to do research on the health of the children who are exposed by high concentration level of POPs.  相似文献   
179.
Shortly after the March 11th earthquake and tsunami in eastern Japan, a Task Team for Disaster Waste Management and Reconstruction was established within the Japan Society of Material Cycles and Waste Management (JSMCWM). One of the major tasks undertaken by the team was to create a manual entitled, Strategies for Separation and Treatment of Disaster Waste. In this paper, this JSMCWM manual is introduced, followed by a review of existing guidelines for disaster waste management in various countries. We identify useful guidelines created by international agencies, national and local governments. The JSMCWM manual adds our new experiences, especially characterized by a huge scale of disaster and tsunami information, to the existing knowledge with an emphasis on separation and subsequent treatment options. It should be desirable to share our knowledge and experiences, not only domestically but also with other countries in the world, especially regions that could be affected by large earthquake and tsunami events.  相似文献   
180.
A total 23 of organochlorine pesticides (OCPs) residues were determined in five groups of foodstuffs, i.e.: vegetables (carrot, potato, cucumber, corn, and onion), rice, pulses (green bean and soybean), nuts (peanut), and fish (milkfish), which collected from traditional markets in three big cities of Indonesia; Jakarta, Bogor, and Yogyakarta. OCPs were only detected in fatty foodstuffs, such as soybean, peanut, and milkfish. The concentration of HCB (expressed as ng g?1 on a whole basis), ΣDrins, ΣDDTs, ΣHeptachlors, and ΣHCHs were in the range of <0.3–0.74 ng g?1, <0.03–0.42 ng g?1, <0.02–0.41 ng g?1, <0.03–0.14 ng g?1, and <0.03–0.06 ng g?1, respectively, which were far below the maximum residue limits (MRLs) as established by FAO/WHO. These very low concentrations of OCPs residues in foodstuffs indicated that OCPs were used only in past time and no recent input into the environment. Furthermore, the estimated daily intake (EDI) of HCB, ΣDDTs, ΣDrins, ΣHeptachlors, and ΣHCHs in five group foodstuffs, which were 60% of total daily diet of Indonesian, were 0.09 ng kg?1 bw d?1, 0.04 ng kg?1 bw d?1, 0.01 ng kg?1 bw d?1, 0.003 ng kg?1 bw d?1, and 0.002 ng kg?1 bw d?1, respectively. These results were far below the acceptable daily intake (ADI) as established by FAO/WHO, which indicated that consumption of foodstuffs from Indonesia were at little risk to human health in term of OCPs at present.  相似文献   
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