In order to study the deposition on vegetation of plutonium arising from the testing of nuclear weapons and discharges from nuclear facilities, sheep faeces were collected from the South-west and North of England. The plutonium content of faeces has been shown to be a reproducible and sensitive indicator of deposition on herbage and, with this technique, plutonium discharged from the Sellafield Works of British Nuclear Fuels LImited can be detected 60 km from the site. On moorland pastures the concentration of 239+240Pu in faeces, expressed as activity per gram of ash, is roughly equal numerically to the deposit of plutonium on 1 m2 of vegetation.Some of the plutonium ingested by a grazing sheep is absorbed and the highest concentrations are found in liver. The liver of a sheep grazing on pasture where the 239+240Pu concentration in faeces was about 2 pCi (74 mBq) g−1 of ash, was found to contain <1% of the Generalised Derived Limit for mutton and offal, and the meat <0·001%. 相似文献
The purpose of this study is to evaluate the effect of reductions of reactive organic gases (ROG) and NOx emissions on short-term O3 and NO2 concentrations and annual average NO2 concentrations in the California South Coast Air Basin. Short-term air quality predictions were obtained by applying the Systems Applications Airshed Model to summer O3 and autumn NO2 episodes. Effects of emission controls on annual NO2 concentrations were estimated using CDM and a new parcel tracking model NOXTRAK. Results for the summer O3 episode indicate that ROG emission reduction in an effective means for reducing peak O3 concentrations. NOx emission reduction imposed in addition to ROG emission reductions are counterproductive in reducing peak O3 concentrations. The modeling results also suggest that attainment of the 1-h federal O3 standard requires ROG emission reductions on the order of 80% from 1987 levels. Results for the autumn NO2 episode indicate that NOx emission reductions approximating those recommended in a proposed Air Quality Management Plan (about 22%) will result in only small (about 5%) reductions in the peak NO2 concentrations. ROG emission reduction may be more effective than NOx emission reduction in reducing the peak NO2 concentration. For the episode studied, a reduction of 36% in ROG emissions is estimated to result in a reduction in peak NO2 concentrations commensurate with that required to attain the 1-h state NO2 standard. Model calculations also indicate that the federal NO2 standard may not be meet by 1987 at one or two stations, but may blosely approached. 相似文献
In the present paper, the optimum design of a PV system used to operate a water pumping system was determined for Oman. The system design focused on the environmental conditions of Sohar city. The implementation and measurement of the designed system are presented to prove the effectiveness of the proposed system. The results show that the system can provide the required power at peak hours, leading to a substantial reduction in the sizing of the PV system. Consequently, the investment capital costs 2400 USD, and the cost of energy is equal to 0.309 USD/kWh. Furthermore, the results indicate that the system annual yield factor is 2024.66 kWh/kWp and that the capacity factor is 23.05 %, which is encouraging since the latter is typically 21 %. The system capital cost and the cost of energy are worth comparing to a diesel generator. A comparison is made between the proposed system and several others in the literature. The comparison indicated that the system cost of energy is promising. 相似文献
Analysis of the concentrations of chemical elements and the composition of diatoms in the surface layer of bottom sediments has been performed in a small reservoir at the mouth of dammed river to evaluate the levels of pollution and the impact of toxicants on diatom communities of the river ecosystem. Data on interrelations between the concentrations of chemical elements and the relationship between inorganic pollution and accumulation of diatoms in bottom sediments as an indicator of development of the diatom assemblage have been obtained using linear correlation analysis and graphical plotting. 相似文献
Consideration is given to changes in the vegetation and climatic conditions on the eastern slope of the Northern Urals in the second half of the Holocene as reconstructed on the basis of integrated palynological, botanical, paleocarpological, and radiocarbon analysis of material from a peat bog section in the floodplain of the Loz’va River. The results show that the northern taiga zone of the study region in the period between approximately 5000 and 700 years BP was occupied by forests of southern taiga facies, as the climate was significantly warmer than it is today. 相似文献
Environmental Science and Pollution Research - This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if... 相似文献
Through administrative research and media records, this paper aims to examine and highlight the effects of the COVID-19 pandemic on Malaysian workers, property development, construction sites, and the national economy. The development of real estate and the construction industry can significantly impact socio-economic growth and infrastructure development. Adequate building and infrastructure construction can ensure national economic stability, job creation, community cohesion, and higher living standards. Since the COVID-19 pandemic began in 2019, many countries, including Malaysia, have reported an increased number of virus cases. According to the Ministry of Health, 9316 cases and 314 COVID-19 clusters were discovered in Malaysia, with a 38.55–48.06% prevalence for factories, a 12.55–15.29% prevalence for community spreading, an 8.6–11.56% prevalence for construction sites, a 5.53–7.96% prevalence for educational sites, and a 7.01% prevalence for shopping areas. Several governments-imposed lockdowns, movement, and proximity restrictions during the pandemic due to the high infection rates at property development sites. However, due to inactivity in various sectors such as the construction industry, these measures have significantly impacted the national economy. As a result, the pandemic has had an impact on workers, production costs, and project completion timelines, resulting in operational issues and policy concerns. Overall, the records reviewed revealed that the COVID-19 pandemic has significantly impacted real estate development, the housing market, and the construction industry. As a result, sustained and targeted policies are required to support Malaysia’s construction industry’s socio-economic growth and infrastructure development.
Environmental Science and Pollution Research - Exposure of geomaterials to acidic leachates may compromise their structure and functionality due to changes in physicochemical, mineralogical, and... 相似文献
The levels of toxaphene congeners, in addition to PCB congeners and organochlorine pesticides, were determined in various fish samples from different Danish waters. While PCB-153 and p,p'-DDE show different levels depending on the fishing area, with highest levels in fish from the Western Baltic Sea, toxaphene was detected in all the samples investigated at a more constant level. The distribution of the three toxaphene congeners Parlar #26, #50 and #62 depends on the fishing area, with the Western Baltic Sea being different from the other waters by having almost equal levels of toxaphene congeners #26 and #50. 相似文献