Open-pit coal-mining effects on rice paddy soil composition and metal bioavailability to Oryza sativa L. plants in Cam Pha, northeastern Vietnam

This study quantified Cd, Pb, and Cu content, and the soil–plant transfer factors of these elements in rice paddies within Cam Pha, Quang Ninh province, northeastern Vietnam. The rice paddies are located at a distance of 2 km from the large Coc Sau open-pit coal mine. Electron microprobe analysis combined with backscattered electron imaging and energy-dispersive spectroscopy revealed a relatively high proportion of carbon particles rimmed by an iron sulfide mineral (probably pyrite) in the quartz–clay matrix of rice paddy soils at 20–30 cm depth. Bulk chemical analysis of these soils revealed the presence of Cd, Cu, and Pb at concentrations of 0.146?±?0.004, 23.3?±?0.1, and 23.5?±?0.1 mg/kg which exceeded calculated background concentrations of 0.006?±?0.004, 1.9?±?0.5, and 2.4?±?1.5 mg/kg respectively at one of the sites. Metals and metalloids in Cam Pha rice paddy soils, including As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, were found in concentrations ranging from 0.2?±?0.1 to 140?±?3 mg/kg, which were in close agreement with toxic metal contents in mine tailings and Coc Sau coal samples, suggesting mining operations as a major cause of paddy soil contamination. Native and model Oryza sativa L. rice plants were grown in the laboratory in a growth medium to which up to 1.5 mg/kg of paddy soil from Cam Pha was added to investigate the effects on plant growth. A decrease in growth by up to 60 % with respect to a control sample was found for model plants, whereas a decrease of only 10 % was observed for native (Nep cai hoa vang variety) rice plants. This result suggests an adaptation of native Cam Pha rice plants to toxic metals in the agricultural lands. The Cd, Cu, and Pb contents of the native rice plants from Cam Pha paddies exceeded permitted levels in foods. Cadmium and Pb were highest in the rice plant roots with concentrations of 0.84?±?0.02 and 7.7?±?0.3 mg/kg, suggesting an intake of these metals into the rice plant as shown, for example, by Cd and Pb concentrations of 0.09?±?0.01 and 0.10?±?0.04 mg/kg respectively in the rice grain endosperm. The adaptation of native rice plants, combined with bioaccumulation ratios of 1?±?0.6 to 1.4?±?0.7 calculated for Cd transfer to the rice grain endosperm, and maximum Cd transfer factors of 4.3?±?2.1 to the plant roots, strongly suggest a continuous input of some toxic metals from coal-mining operations to agricultural lands in the region of Cam Pha. In addition, our results imply a sustained absorption of metals by native rice plant varieties, which may lead to metal accumulation (e.g., Cd) in human organs and in turn to severe disease.     

Weekly periodicities of meteorological variables and their possible association with aerosols in Korea

The weekly periodicities in meteorological variables and its association with aerosols in Korea are investigated using long-term surface measurements of meteorology (1975–2005) and aerosols (1999–2005). Through an analysis of the annual (and/or seasonal) values averaged over 10 stations, we identified distinct weekly periodicities in the daily minimum temperature (T_min), diurnal temperature range (DTR), cloud fraction, and solar insolation, although they have different characteristics from each other. The weekly association among variables is discussed in this study. Positive anomalies of the cloud fraction and T_min and negative anomalies of solar insolation and DTR are seen for the second half of the week and the reverse for the first half of the week, i.e., more cloudiness and less insolation for Wednesday?Thursday and less cloudiness and more insolation for Monday?Tuesday. Furthermore, seasonal dependence of weekly anomalies shows that the weekly periodicities are enhanced especially in autumn, more than 2–3 times as great as those of the annual mean. The weekly cycles in such variables are most likely driven by changes in cloud fraction, possibly through aerosol–cloud interactions induced by aerosol variations between working weekdays and Sunday, which are clearly identified in PM10 weekly cycles. This study also suggests that the weekly periodicities in meteorological variables are possibly associated with long-range transport of weekly periodicities, as well as aerosol–cloud-precipitation interactions over the region.     

Effects of Fuel Type,Driving Cycle,and Emission Status on In-Use Vehicle Exhaust Reactivity

ABSTRACT

The introduction of reformulated gasolines significantly reduced exhaust hydrocarbon (HC) mass emissions, but few data are available concerning how these new fuels affect exhaust reactivity. Similarly, while it is well established that high-emitting vehicles contribute a significant portion of total mobile source HC mass emissions, it is also important to evaluate the exhaust reactivity from these vehicles. The objective of this study was to evaluate the relative influence on in-use vehicle exhaust reactivity of three critical factors: fuel, driving cycle, and vehicle emission status. Nineteen in-use vehicles were tested with seven randomly assigned fuel types and two driving cycles: the Federal Test Procedure (FTP) and the Unified Cycle (UC). Total exhaust reactivity was not statistically different between the FTP and UC cycles but was significantly affected by fuel type. On average, the exhaust reactivity for California Phase 2 fuel was the lowest (16 % below the highest fuel type) among the seven fuels tested for cold start emissions. The average exhaust reactivity for high-emitting vehicles was significantly higher for hot stabilized (11%) and hot start (15%) emissions than for low-emitting vehicles. The exhaust reactivities for the FTP and UC cycles for light-end HCs and carbonyls were significantly different for the hot stabilized mode. There was a significant fuel effect on the mean specific reactivity (SR) for the mid-range HCs, but not for light-end HCs or carbonyls, while vehicle emission status affected the mean SR for all three HC compound classes.     

Atmospheric Aerosol over a Southeastern Region of Texas: Chemical Composition and Possible Sources

Speciated samples of PM_2.5 were collected at a site in Jefferson County, Texas by US EPA (Environmental Protection Agency) from July of 2003 to August of 2005. A total of 269 samples with 52 species were measured; however, 22 species were excluded in this study because of too many below-detection-limit data. The data set was analyzed by positive matrix factorization (PMF) to infer the sources of PM observed at the site. The analysis identified ten sources: sulfate-rich secondary aerosol I (35.9%), sulfate-rich secondary aerosol II (21.0%), cement/carbon-rich (11.7%), wood smoke (8.8%), metal processing (6.3%), motor vehicle/road dust (5.7%), nitrate-rich secondary aerosol (3.3%), soil (3.2%), sea salt (2.6%), and chloride depleted marine aerosol (1.6%). Sulfate and nitrate mainly exist as salts. The two sulfate-rich secondary aerosols account for almost 57% of the PM_2.5 mass concentration. The factor containing highest concentrations of Cl and Na was attributed to sea salt due to the proximity of the monitoring site to the Gulf of Mexico. The chloride depleted marine aerosol was related to the sea salt aerosol. Cement/carbon-rich, wood smoke, metal processing, and motor vehicle/road dust factor were likely to be the local sources.     

Gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) emissions from commercial restaurants in Hong Kong

Commercial cooking emissions are important air pollution sources in a heavily urbanized city. Exhaust samples were collected in six representative commercial kitchens including Chinese restaurants, Western restaurants, and Western fast-food restaurants in Hong Kong during peak lunch hours. Both gaseous and particulate emissions were evaluated. Eight gaseous and twenty-two particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in this study. In the gaseous phase, naphthalene (67-89%) was the most abundant PAH in all of the exhaust samples. The contribution of acenaphthylene in the gaseous phase was significantly higher in emissions from the Chinese restaurants, whereas fluorene was higher in emissions from the Western cooking style restaurants (i.e., Western restaurants and Western fast-food restaurants). Pyrene is the most abundant particulate PAH in the Chinese restaurants (14-49%) while its contribution was much lower in the Western cooking style restaurants (10-22%). Controlled cooking conditions were monitored in a staff canteen to compare the emissions from several different local cooking styles, including deep frying, steaming, and mixed cooking styles (combination of steaming and frying). Deep frying produced the highest amount of total gaseous PAHs, 6 times higher than the steaming. However, steaming produced the highest particulate emissions. The estimated annual gaseous PAH emissions for the Chinese restaurants, Western restaurants, and Western fast-food restaurants were 255, 173, and 20.2 t y(-1) whereas 252, 1.9, and 0.4 t y(-1) were estimated for particulate phase PAH emissions. The study provides useful information and estimates for PAH emissions from commercial cooking exhaust in Hong Kong.     

AUTOMATIC BOTTLE SEALING MECHANISM FOR SEQUENTIAL SAMPLING OF VOLATILE ORGANICS IN WATER1

ABSTRACT: The design, construction, and evaluation of two automatic bottle sealing mechanisms for the collection of volatile organic compounds in water are described. Manually collected samples were either stored in uncapped bottles or in bottles capped with the automatic bottle sealing mechanisms. After 24 hours' storage, significant losses of volatile compounds from uncapped samples occurred even if the samples were stored at 4°C, but not for the samples capped with the automatic bottle sealing mechanisms. The mechanism for sealing the sample bottles was integrated into a commercial sampler with minor modifications to the sampler. The sampling system was then evaluated under controlled conditions to simulate actual field sampling. The results showed that the system was suitable for taking sequential discrete water samples automatically for 24 hours without significant losses of volatile organic compounds.     

Field Exposure Study of Polylactic Acid (PLA) Plastic Films in the Banana Fields of Costa Rica

For use by the banana industry of Costa Rica, polylactic acid (PLA) plastic ropes and banana finger shrouds must remain operational for 14 to 16 weeks, and they also must be able to break down in the soil after serving their purposes. The banana field at La Rebusca Farm (Costa Rica) and the experiment station at University of Costa Rica were selected for a field exposure study of Cargill EcoPla Generation II (GII) and Cargill EcoPla monolayer (Ca-I) PLA films. The average monthly temperature, relative humidity, and cumulative rainfall of the La Rebusca Farm and the University of Costa Rica site were 26 and 22°C, 92 and 84%, and 352 and 177 in., respectively. The PLA plastic films at the La Rebusca Farm lost their mechanical properties earlier than at the University of Costa Rica site because of the higher temperature and relative humidity of the banana farm. The Ca-I film meets the 14-week operational time frame and it is recommended for further studies as ropes and banana shrouds.     

Popular Cognition of National Monuments in Singapore

Monumental features or landmarks in the urban built environment are distinguished by clear form, prominent location, a high degree of visibility and in Lefebvres (1991:143) words, "impose a clearly intelligible message". In Singapore, the gazetting and preservation of national monuments come under the ambit of the Preservation of Monuments Board. From the states perspective, national monuments embody historical value: as enduring landmarks of the city which link the present to the past, they give "lithic memory to the life of a nation" and are integral to the process of building national solidarity, identity and pride. This paper examines popular cognition of Singapores national monuments, that is, the extent to which the general public are able to identify gazetted monuments in visual and nomenclatural terms. A questionnaire survey of 284 respondents selected from a public housing estate as well as in-depth interviews with a smaller sample yielded information on Singaporeans visual recognition, nomenclatural accuracy and historical knowledge with respect to national monuments. The results showed that while visual identification of monuments was strong and the public could clearly identify the main attributes and general forms which national monuments take, the specific names of these monuments were often overlooked and historical knowledge of them rather shallow. In the conclusion, it is argued that if monuments are to serve their purpose as the countrys "psyche" annd "memory", deeper knowledge of the history and meaning behind these monuments must be inculcated in the Singaporean consciousness.     

Sustainable green technology on wastewater treatment: The evaluation of enhanced single chambered up-flow membrane-less microbial fuel cell

This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell(UFML-MFC) in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand(COD) reduction and power generation,including the increase of KCl concentration(MFC1) and COD concentration(MFC2). The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC.Despite the COD reduction was up to 96%, the power output remained constrained.     

DECISION SUPPORT FOR ALLOCATION OF WATERSHED POLLUTION LOAD USING GREY FUZZY MULTIOBJECTIVE PROGRAMMING1

ABSTRACT: This paper uses the grey fuzzy multiobjective programming to aid in decision making for the allocation of waste load in a river system under versatile uncertainties and risks. It differs from previous studies by considering a multicriteria objective function with combined grey and fuzzy messages under a cost benefit analysis framework. Such analysis technically integrates the prior information of water quality models, water quality standards, wastewater treatment costs, and potential benefits gained via in‐stream water quality improvement. While fuzzy sets are characterized based on semantic and cognitive vagueness in decision making, grey numbers can delineate measurement errors in data collection. By employing three distinct set theoretic fuzzy operators, the synergy of grey and fuzzy implications may smoothly characterize the prescribed management complexity. With the aid of genetic algorithm in the solution procedure, the modeling outputs contribute to the development of an effective waste load allocation and reduction scheme for tributaries in this subwatershed located in the lower Tseng‐Wen River Basin, South Taiwan. Research findings indicate that the inclusion of three fuzzy set theoretic operators in decision analysis may delineate different tradeoffs in decision making due to varying changes, transformations, and movements of waste load in association with land use pattern within the watershed.