Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA

We report results of air monitoring started due to the recent natural catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered the first arrival of the airborne fission products ¹³¹I, ¹³²I, ¹³²Te, ¹³⁴Cs, and ¹³⁷Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. We measured the evolution of the activities over a period of 23 days at the end of which the activities had mostly fallen below our detection limit. The highest detected activity from radionuclides attached to particulate matter amounted to 4.4 ± 1.3 mBq m⁻³ of ¹³¹I on 19-20 March.     

Field characterization of external grease abatement devices

This study characterized some of the physical and chemical features of large outside field grease abatement devices (GADs). 24-hour measurements of several food service establishments' (FSEs') influent GAD flowrates indicated highly intermittent conditions with hydraulic retention times (HRTs) that exceeded the common recommendation (30 minutes) by two to five times. Investigation into the chemical characteristics of GADs indicated highly variable influent and effluent fat, oil, and grease (FOG) concentrations. Low pH and dissolved oxygen values were measured throughout the GAD, indicating the likely occurrence of anaerobic microbial processes. Detailed spatial and temporal observations of the accumulation of FOG and food solids were also discussed. Though the FOG layer remained relatively constant for all GAD configurations investigated, results indicated that commonly-used GAD configurations with a straight submerged inlet tee or no-inlet tee configuration may result in the transport of food solids into the second compartment. The present research showed increased accumulation of food solids in the first compartment with a retro-fit flow distributive inlet. This retro-fit displays promise for potentially improving the separation characteristics of existing GADs.     

Report from the First International Symposium

The First International Symposium on Acid Precipitation and the Forest Ecosystem sponsored by the United States Department of Agriculture, Forest Service, Northeastern Forest Experiment Station, and by the Atmospheric Sciences Program of The Ohio State University was held in Columbus, Ohio, May 12-15, 1975. Approximately 300 people from 12 countries attended the Symposium.     

A comparison of PCDD/PCDFs exposure in infants via formula milk or breast milk feeding

Food is the major source for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulation in human body. In infant period, breast milk and formula milk are the major food sources. Congener-specific analyses of 17 PCDD/PCDFs were performed on 10 brands of formula milk samples which were milk-based and 37 breast milk samples collected from women living in southern Taiwan. The levels of 17 PCDD/PCDFs in 10 formula milk samples ranged from 0.468 to 0.962 pg WHO-TEQ/g lipid, with a mean value of 0.713+/-0.163 pg WHO-TEQ/g lipid. For the 37 breast milk samples, their PCDD/PCDF levels were 14.7+/-9.36 pg WHO-TEQ/g lipid, with a range between 4.21 and 52.8 pg WHO-TEQ/g lipid. At 12th month of age for infants, average daily intakes (ADI) of PCDD/PCDFs were 2.1 pg WHO-TEQ/kg/day for the formula-feeding infants, and 13 pg WHO-TEQ/kg/day for the breast-feeding infants. The present data may provide useful information for risk-benefit evaluation of formula- and breast-feeding.     

Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States

The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebraska, the Yakima watershed, Washington, and the Chester watershed, Maryland. Ground water analyses included major ion chemistry, dissolved gases, nitrogen and oxygen stable isotopes, and estimates of recharge date. Sediment analyses included potential electron donors and stable nitrogen and carbon isotopes. Within each site and among aquifer-based medians, dissolved oxygen decreases with ground water age, and excess N(2) from denitrification increases with age. Stable isotopes and excess N(2) imply minimal denitrifying activity at the Maryland and Washington sites, partial denitrification at the California site, and total denitrification across portions of the Nebraska site. At all sites, recharging electron donor concentrations are not sufficient to account for the losses of dissolved oxygen and nitrate, implying that relict, solid phase electron donors drive redox reactions. Zero-order rates of denitrification range from 0 to 0.14 micromol N L(-1)d(-1), comparable to observations of other studies using the same methods. Many values reported in the literature are, however, orders of magnitude higher, which is attributed to a combination of method limitations and bias for selection of sites with rapid denitrification. In the shallow aquifers below these agricultural fields, denitrification is limited in extent and will require residence times of decades or longer to mitigate modern nitrate contamination.     

Hydrodynamic modeling of Edmonton storm-water ponds

Environmental Fluid Mechanics - Computational models often are applied to simulate water quality for management of natural and constructed aquatic systems. As part of a larger study, a...     

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

Both eutrophication and SO₄ pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO₄ were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO₄ addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO₄ pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken.     

Responses of Hybrid Poplar Trees to Sulfur Dioxide Fumigation

This paper verifies the presence of significant interclonal variation in the tolerance of hybrid poplar (Populus deltoides Bartr. cv. Angulata × P. trichocarpa Torr. and Gray) to sulfur dioxide fumigation. Rooted stem cuttings of four hybrid poplar clones were exposed to 5 ppm sulfur dioxide for 0, 3, 6, 9, or 12 hours in controlled environment chambers. Multivariate analyses were made from the shoot growth measurements recorded for 4 weeks before and after fumigation and on the data of foliar injury induced by sulfur dioxide. The following factors were statistically significant in determining growth response and foliar injury: (1) genotype; (2) duration of treatment; and (3) interaction between genotype and hours of fumigation. All partial correlations between foliar injury and subsequent shoot growth were positive and significant. Sufficient genetic variation appears to exist in this Populus hybrid to encourage selection of clones tolerant to short-term exposures of high levels of sulfur dioxide.     

Beyond dichotomies: Gender and intersecting inequalities in climate change studies

Climate change and related adaptation strategies have gender-differentiated impacts. This paper reviews how gender is framed in 41 papers on climate change adaptation through an intersectionality lens. The main findings show that while intersectional analysis has demonstrated many advantages for a comprehensive study of gender, it has not yet entered the field of climate change and gender. In climate change studies, gender is mostly handled in a men-versus-women dichotomy and little or no attention has been paid to power and social and political relations. These gaps which are echoed in other domains of development and gender research depict a ‘feminization of vulnerability’ and reinforce a ‘victimization’ discourse within climate change studies. We argue that a critical intersectional assessment would contribute to unveil agency and emancipatory pathways in the adaptation process by providing a better understanding of how the differential impacts of climate change shape, and are shaped by, the complex power dynamics of existing social and political relations.     

A/O MBR处理生活污水效率与菌群多样性的关系

采用缺氧/好氧膜生物反应器（A/O MBR）工艺处理生活污水,试运行了5种不同的工况以确定最佳工艺参数,利用变性凝胶梯度电泳（DGGE）技术研究缺氧池和好氧池（MBR）中细菌群落结构,分析出水水质与细菌种群多样性的关系.结果表明A/O MBR在水力停留时间（HRT）为12 h,污泥停留时间（SRT）为10 d,硝化液回流比为300%,污泥回流比为100%的条件下,对COD、氨氮、总氮有稳定良好的去除,平均去除率分别为96.4%、99.1%、75.8%;系统运行过程中,缺氧池和好氧池中菌群结构发生较大变化,同一工况下两池菌群的相似性通常大于50%,但缺氧池菌群多样性随工况变换而波动较大,好氧池菌群多样性随运行时间而逐渐丰富;缺氧池菌群多样性指数与反硝化效率成正相关关系.