Bacterial community analysis of Tatsoi cultivated by hydroponics

Tatsoi (Brassica narinosa) is a popular Asian salad green that is mostly consumed as a source of fresh produce. The purpose of this study was to assess the microbial diversity of Tatsoi cultivated in a hydroponic system and of its ecosystem. Tatsoi leaves, nutrient solution, and perlite/earth samples from a trickle feed system (TFS) and an ebb-and-flow system (EFS) were collected and their microbial communities were analyzed by pyrosequencing analysis. The results showed that most bacteria in the leaves from the TFS contained genus Sporosarcina (99.6%), while Rhizobium (60.4%) was dominant in the leaves from the EFS. Genus Paucibacter (18.21%) and Pelomonas (12.37%) were the most abundant microbiota in the nutrient solution samples of the TFS. In the EFS, the nutrient solution samples contained mostly genus Rhodococcus and Acinetobacter. Potential microbial transfer between the leaves and the ecosystem was observed in the EFS, while samples in the TFS were found to share only one species between the leaves, nutrient solution, and earth. Together, these results show that the bacterial populations in Tatsoi and in its ecosystem are highly diverse based on the cultivation system.     

Evaluation of hazardous airborne carbonyls on a university campus in southern China

A comprehensive assessment of indoor carbonyl compounds for the academic staff, workers, and students was conducted on a university campus in Xiamen, China. A total of 15 representative environment categories, including 12 indoor workplaces and three residential units, were selected. The potential indoor pollution sources were identified based on the variability in the molar compositions and correlation analyses for the target carbonyls. Furnishing materials, cooking emissions, and electronic equipment, such as photocopiers, can generate various carbonyls in the workplace. Comparison studies were conducted in the clerical offices, demonstrating that off-gases from wooden furniture and lacquer coatings, environmental tobacco smoke (ETS), and the use of cleaning reagents elevated the indoor carbonyl levels. The measured concentrations of formaldehyde and acetaldehyde in most locations surpassed the exposure limit levels. The lifetime cancer hazard risk (R) associated with formaldehyde was above the concern risk level (1 × 10^?6) in all of the workplaces. The results indicate that formaldehyde exposure is a valid occupational health and safety concern. Wooden furniture and refurbishing materials can pose serious health threats to occupants. The information in this study could act as a basis for future indoor air quality monitoring in Mainland China.

Implications:A university campus represents a microscale city environment consisting of all the working, living, and commercial needs of staff and students. The scope of this investigation covers 21 hazardous carbonyl species based on samples collected from 15 categories of workplaces and residential building in a university campus in southern China. Findings of the study provide a comprehensive assessment of indoor air quality with regards to workers’ health and safety. No similar study has been carried out in China.     

Effects of droplet density and concentration on the efficacy of bacillus thuringiensis and carbaryl against gypsy moth larvae (Lymantria dispar L.)

Abstract

The feeding behavior of gypsy moth larvae exposed to two pesticide deposits (Bt and carbaryl) on oak leaf disks was monitored to determine the relationships between its efficacy and application parameters (droplet density and pesticide concentration). A range of pesticide concentrations and droplet densities (from 9 to 149 droplets/cm²) was used to simulate high and low application rates produced by different methods of application in the field.

The LD₅₀ and the LC₅₀, appeared to be affected by the spatial distribution of the deposit on the leaf surface. Both Bt and carbaryl showed a decreasing LD₅₀ at increasing time after spray. The LD₅₀ of Bt decreased from 14.1 BIU/liter to 3.1 BIU/Iiter between 48 and 144 hours after spray. The results show that feeding inhibition by Bt is more closely related to concentration than to droplet density and dose per unit area with the highest feeding inhibition occurring at 10 BIU/liter at 9 droplets/cm². With carbaryl, an increase in both concentration and droplet density was necessary to cause a decrease in leaf area eaten by larvae.     

Survey of Laboratory Performance Analysis of Simulated Ambient S02 Bubbler Samples

The Quality Control Branch of the Quality Assurance and Environmental Monitoring Laboratory, National Environmental Research Center, Research Triangle Park, N. C, coordinated a nationwide interlaboratory study which surveyed the ability of participating laboratories to analyze simulated ambient sulfur dioxide samples. The purposes of the study were (1) to provide participating laboratories with a means for self evaluation of their performance, and (2) to begin to acquire information which indicates the quality of ambient SO₂ data being reported.

Sample vials of sodium sulfite in mannitol were distributed to 134 laboratories throughout the country that routinely analyze for atmospheric SO₂. No restrictions were placed on the method of analysis other than that the normal absorbing solution used with the analysis be a tetrachloromercurate II solution. Each sample set contained five separate vials. Each vial, when mixed properly with absorbing reagent, simulated a 24 hour bubbler sample. The range of concentrations in each set extended from approximately the lower detectable limit of the pararosaniline method to approximately the alert level as described in Federal Regulations.     

Pollution Abatement Energy Usage of Gas Treating and Processing Plants

The body of information presented in this paper is directed to individuals dealing with energy distribution and environmental issues. Production of natural gas demands energy for abatement of air pollutants. Perspective of energy requirements for natural gas production is presented by analysis of a survey of about 20% of the operating gas plants in Texas. The variation of fuel requirements for production is determined for inlet gas streams with increasing concentrations of toxic contaminants. Then the energy requirements of specific abatement devices is presented and the resultant cost of preparing natural gas for distribution is outlined. The average abatement energy requirement is 1.5% of the total energy requirement for gas processing or consumption of less than 0.1 % of the marketed production of natural gas.     

Design and Performance of a Reliable Personal Monitoring System for Respirable Participates

Personal exposure to respirable particulates and sulfates is being measured as a part of a long term prospective epidemiological study of the respiratory health effects of air pollution, the Harvard Six City Study.¹ The purpose of this monitoring program is to develop better estimators of actual personal exposure from comparison of the direct measurements of personal exposure with simultaneous measurements of the normally measured outdoor air, the air inside each participant’s home, and records of the daily activities of each participant. Results are reported in a paper by Dockery and Spengler.²     

Reproducibility of the Pulmonary Function Response of Older Men and Women to a 2-Hour Ozone Exposure.

To test the reproducibility of the pulmonary function response to ozone exposure in older individuals, eight men and eight women, average age 62.8 years, participated in three 2-hour exposures to 0.45 ppm ozone at 23.3 C and 62.5 percent relative humidity. The first and second exposures were separated by an average time of 17.2 days, and 27.3 days separated the second and third exposures. Subjects alternated riding a bicycle ergometer for 20 minutes at an average minute ventilation of 26 liters BTPS (body temperature pressure, saturated), with 20-minute rest periods. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV-1), and forced expiratory flow between 25 and 75% of FVC (FEF 25- 75%) were measured pre and post exposure. The reproducibility of individual pre-post changes were assessed by calculation of the best linear fit and correlation coefficients between exposures. For FVC and FEV-1, the slopes were significantly different from 1, and correlation coefficients not significantly different from zero, implying that older individuals may not respond consistently to similar ozone exposures.     

Alteration in Carboxyhemoglobin Concentrations During Exposure to 9 ppm Carbon Monoxide for 8 Hours at Sea Level and 2134 m Altitude in a Hypobaric Chamber

Seventeen non-smoking young men served as subjects to determine the alteration in carboxyhemoglobin (COHb) concentrations during exposure to 0 or 9 ppm carbon monoxide for 8 hours (CO) at sea level or an altitude of 2134 meters (7000 feet) in a hypobaric chamber. Nine subjects rested during the exposure and 8 exercised for 10 minutes of each exposure hour at a mean ventilation of 25 L (BTPS). All subjects performed a maximal aerobic capacity test at the completion of their respective exposures. Carboxyhemoglobin concentrations fell in all subjects during their exposures to 0 ppm CO at sea level or 2134 m. During the 8-h exposures to 9 ppm CO, COHb rose linearly from approximately 0.2 percent to 0.7 percent. No significant differences in uptake were found whether the subjects were resting or intermittently exercising during their 8-h exposures. COHb levels attained were similar at both sea level and 2134 m. Maximal aerobic capacity was reduced approximately 7-10 percent consequent to altitude exposure during 0 ppm CO exposures. These values were not altered following exposure for 8 h to 9 ppm CO in either the resting or exercising subjects.     

In Situ Measurement of Hydrochloric Acid in Rocket Exhaust Clouds Using a Remotely Piloted Aircraft

Abstract

An instrumentation system employing an RPV (remotely piloted vehicle) platform was developed for temporally and spatially resolved air pollution measurements, and was used to measure the evolution of gas-phase HC1 in exhaust clouds from a solid rocket motor firing and fuel pit burns. A thermistor and a sensitive (ppmv-level), rapid-response (<0.1 sec) infrared absorption sensor for HC1 were mounted in a flow channel in the RPV, permitting concentration and temperature measurements to be made in the cloud on a several-meter scale. The RPV system was flown in a series of field tests at Thiokol Corporation’s Elkton, MD division to evaluate the HC1 content of the exhaust products of a new Mg-based fuel formulation. Measurements were made in the clouds from Al-based and Mg-based solid fuel pit burns and a Mg-fueled motor firing over periods of several minutes. Elevated temperatures and HC1 concentrations were found to be temporally correlated with video images of the particulate cloud. Cl originating from the ammonium perchlorate oxidizer appeared in the exhaust as HC1 in each of the tests. Both the macroscopic and local cloud parameters indicate that the Mg-based fuel may provide some reduction in HC1 concentration compared to the standard Al-based fuel.