Photodegradation of the endocrine-disrupting chemical 4-nonylphenol in biosolids applied to soil

There is increasing concern about the environmental fate and impact of biosolids-associated anthropogenic organic chemicals, among which 4-nonylphenol (4-NP) is one of the most studied chemicals. This is primarily because 4-NP is an endocrine disruptor and has been frequently detected in environmental samples. Due to its high hydrophobicity, 4-NP has high affinity for biosolids. Land application of 4-NP-containing biosolids could potentially introduce large quantities of this chemical into the environment. A laboratory experiment was conducted to investigate the effect of artificial sunlight on 4-NP degradation in biosolids applied to soil. When exposed to artificial sunlight for 30 d, the top-5-mm layer of biosolids showed a 55% reduction of 4-NP, while less than 15% of the 4-NP was degraded when the biosolids were kept in the dark. Our results indicate that sensitized photolysis reaction plays an important role in reducing the levels of 4-NP in land-applied biosolids. Surface application rather than soil incorporation of biosolids could be effective in reducing biosolids-associated organic chemicals that can be degraded through photolysis reactions. However, the risks of animal ingestion, foliar deposition, and runoff should also be evaluated when biosolids are applied on the soil surface.     

Relationship between air pollution and daily mortality in a subtropical city: Taipei, Taiwan

Air pollution has been associated with daily mortality in numerous studies over the past decade. However most of these studies were conducted in the United States and Europe with relatively few done in Asia. In the current study, the association between ambient air pollution and daily mortality in Taipei, Taiwan's largest city which has a subtropical climate was undertaken, for the period 1994-1998 using a case-crossover analysis. This design is an alternative to Poisson time series regression for studying the short-term adverse health effects of air pollution. The air pollutants examined included particulate matter (PM(10)), sulfur dioxide (SO(2)), ozone (O(3)), nitrogen dioxide (NO(2)), and carbon monoxide (CO). The largest observed effect, which was without statistical significance, was seen for NO(2) and CO levels on deaths due to respiratory diseases (ORs=1.013 and 1.014, respectively). The well established link between air pollution levels and daily mortality may not be as strong in cities in subtropical areas, although other factors such as differences in pollutant mix or the underlying health of the population may explain the lack of a strong association in this study. Further studies of this type in cities with varying climates and cultures are needed.     

Potential source of asbestos in non-asbestos textile manufacturing company

Recently, a worker with lung carcinoma and a metastatic brain tumor was diagnosed as having a work-related disease. He had been employed in a non-asbestos textile company for 25 years. Consequently, to identify and explore possible causative agents for lung cancer in a non-asbestos textile manufacturing company and establish a causal relationship between exposure and lung cancer, an epidemiological investigative study was conducted and the work processes the worker was engaged in were examined. Air samples were taken from the workplace and during the drilling processes, and a suspected causative material was analyzed. The study revealed that the subject had been employed in the non-asbestos textile manufacturing company for 25 years from 1973 and his responsibilities included repairing spinning machines. In particular, the subject was involved in drilling B-bushings that were used to protect against gear abrasion in the spinning machines. An analysis of the B-bushings using a transmission electron microscope equipped with an energy dispersive X-ray analyzer indicated that they contained crocidolite asbestos fibers. Air samples obtained when drilling the B-bushings clearly indicated that the subject had most likely been exposed to crocidolite fibers when installing the B-bushings in the spinning machines. The frequency and duration of the work suggested that there would be a sufficient degree of exposure to crocidolite fibers to cause lung cancer. Except for smoking and asbestos exposure, no other chemical exposure was suspected for developing lung cancer in the workplace. Smoking appeared to be more of a potentiating risk factor in conjunction with the asbestos exposure. Accordingly, this case may provide significant evidence in identifying the cause of the mesothelioma or lung carcinoma found among workers in non-asbestos textile manufacturing companies elsewhere.     

The nonlinearity and related band strength of carbon monoxide when applied in ambient air measurement using open long-path Fourier transform infrared spectrometry

The accuracy of CO concentration determination by open-path Fourier transform infrared (FTIR) spectrometry has been re-evaluated in detail. The evaluation focuses on the correction of the calibration curve--the integrated intensity of a standard spectrum--that is used as a comparison spectrum when doing quantitative analysis of CO. Results show that the calibration curve (with 0.5 cm(-1) or 1 cm(-1) resolution) is apparently inclined to be nonlinear under standard conditions, and that the threshold point of nonlinearity is approximately 0.1 atm-cm. Two commercial FTIR field monitoring systems have been used to investigate the nonlinearity trend. The experimental method consists of using open-path FTIR systems in combination with nondispersive infrared (NDIR) monitors to establish the calibration curve in a semi-closed corridor The results have been double-checked using closed-cell dynamic equilibrium systems. When the optical density is larger than a certain value, the curves begin to bend, and when the optical density approaches zero, the band strength is around 178 +/- 3 atm(-1) cm(-2) and 173 +/- 2 atm(-1) cm(-2), respectively, for 0.5 and 1 cm(-1) resolution at standard temperature and pressure (STP). These values are quite different from other published data that have been acquired by the pressurized method or by high-resolution (<0.006 cm(-1)) spectrometers. It is thought that a higher accuracy is achieved when these new calibration results are used to quantify the CO concentration. The error in concentration determination within 0.1 optical density is less than 2%, and that in the higher optical density region is less than 5%.     

Phosphorus accumulation in cultivated soils from long-term annual applications of cattle feedlot manure

Historically, manure has been recognized as an excellent soil amendment that can improve soil quality and provide nutrients for crop production. In areas of high animal density, however, the potential for water pollution resulting from improper storage or disposal of manure may be significant. The objective of this study was to determine the P balance of cultivated soils under barley (Hordeum vulgare L.) production that have received long-term annual manure amendments. Nonirrigated soils at the study site in Lethbridge, AB, Canada, have received 0, 30, 60, or 90 Mg manure ha(-1) (wet wt. basis) while irrigated plots received 0, 60, 120, and 180 Mg ha(-1) annually for 16 yr. The amount of P removed in barley grain and straw during the 16-yr period was between 5 and 18% of the cumulative manure P applied. There was a balance between P applied in manure and P recovered in crops and soils (to the 150-cm depth) of nonirrigated plots during the 16-yr study. In irrigated plots, as much as 1.4 Mg P ha(-1) added (180 Mg ha(-1) yr(-1) treatment) was not recovered over 16 yr, and was probably lost through leaching. The risk of ground water contamination with P from manure was greater in irrigated than nonirrigated plots that have received long-term annual manure amendments. Manure application rates should be reduced in nonirrigated and irrigated plots to more closely match manure P inputs to crop P requirements.     

Distribution of 137Cs in soil along Ta-han River Valley in Tau-Yuan County in Taiwan

Environmental 137Cs contamination was suspected from accidents at spent fuel storage pits of a research reactor site in the Ta-han River valley in Taiwan. In order to further characterize this contamination, soil samples were collected and measured by a gamma-spectroscopy system in 1999. It was found that 137Cs contamination is distributed up to 4 km from the reactor in an area covered mostly by rice and plant fields. 137Cs concentration in the topsoil ranged up to about 1000 Bq kg-1, as compared with soil beyond the contaminated area, which does not exceed 15 Bq kg-1. Spatial distribution of 137Cs was characterized by strong non-uniformity, which complicated our understanding of the distribution pathway of the radionuclides. The highest concentrations of 137Cs, up to more than 1000 Bq kg-1, were found within a few rice fields. The relative location of these rice fields and the water supplies from local streams suggested that the 137Cs was distributed along water pathways in the valley.     

“两控区”内燃煤火电厂烟气脱硫成本的转移

运用环境经济学、环境法学方面的知识研究了如何解决“两控区”内燃煤火电厂的烟气脱硫成本问题．结果表明,只要电能消费者消费了酸雨和SO₂污染控制区内燃煤火电厂的火电,就应最终承担燃煤火电厂的烟气脱硫成本电能消费者的负担标准为火电厂依靠经济上可实现的最佳可得控制技术生产单位电能所耗费的平均脱硫成本费用;烟气脱硫成本转移的最佳时间和方式为电网经营者把平均脱硫成本分摊给电能消费者,收取电费后再补贴给火电厂．     

依靠科技进步，实现跨越式发展

结合西部地区的科技现状,分析了科技创新的内在要求,探讨了实现跨越式发展的途径和对策。     

整装反应器无反应条件下的传热

研究整装反应器在反应点火之前的传热行为以及反应器参数对基体热响应的影响。建立了起燃阶段反应器的传热模型,通过数值计算,分析和讨论了固相轴向热传导性能及各种设计参数对基体热响应的影响。比较了基体采用金属体或陶瓷体时热响应的不同。结果表明,当无量纲导热系数∧＜1时,固相轴向导热性能对基体热响应无明显影响,金属体具有好的热响应性能,参数分析有助于反应器的设计和建模。