Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture

Ammonium (NH(4)(+)) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH(4)(+) correlated well with trends in particulate SO(4)(2-) over the 1988-2001 period. The NH(4)(+) trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO(4)(2-) may have a greater impact on concentrations of NH(4)(+) and subsequent deposition than local agricultural emissions of NH(3). Ammonium concentrations in precipitation correlated significantly with precipitation SO(4)(2-) concentrations for the 1984-2001 period although NH(4)(+) in precipitation increased after 1999 and SO(4)(2-) in precipitation continued to decline after 1999. The correlation between NH(4)(+) and SO(4)(2-) was stronger for particulates than for precipitation. Particulate NH(4)(+) concentrations were also correlated with particulate SO(4)(2-) concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH(4)(+) and SO(4)(2-) were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH(4)(+) dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH(4)(+) dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH(4)(+) and subsequent deposition may be more closely linked to SO(4)(2-) and thus SO(2) emissions than with NH(3) emissions. These results also suggest that reductions in S emissions have reduced NH(4)(+) transport to and NH(4)(+)-N deposition in the Northeast.     

Atmospheric concentrations of PCDDs/PCDFs in southern California.

A comprehensive air toxics measurements program designed to establish baseline concentrations of atmospheric polychlorinated dioxins and dibenzofurans (PCDDs/PCDFs) in the South Coast Air Basin has been completed. The program utilized state-of-the-art air sampling and laboratory analysis techniques (HRGC/HRMS) to quantify the fifteen 2,3,7,8-substituted PCDDs/PCDFs congeners of primary toxicological significance. This study, which included nine discrete sampling sessions between December 1987 and March 1989, provides the first systematic assessment of ambient PCDDs/PCDFs concentrations in the state of California. The highest PCDDs/PCDFs concentrations noted during this study occurred in December 1987. This period was dominated by off-shore air flows, suggesting a regional air mass and transport phenomena. Concentrations of the PCDDs/PCDFs were diminished markedly in subsequent sampling sessions where air flow patterns were primarily of on-shore or of coastal origin. Ambient PCDDs/PCDFs concentrations, expressed as toxic equivalents, were highest during the December 1987 sampling period. The El Toro monitoring site, located approximately 40 miles southeast of Los Angeles, consistently showed the lowest measured ambient PCDDs/PCDFs concentrations and toxic equivalents values. In the majority of the sessions and samples examined the PCDDs/PCDFs congener profiles strongly suggest combustion source influences. Typical of combustion source profiles, 1,2,3,4,6,7,8-HpCDD was the predominant 2,3,7,8-substituted species and most prevalent PCDD after OCDD. The congener of highest toxicological significance, 2,3,7,8-TCDD, was reported below the 10-20 fg/m3 detection limit for most of the ambient air samples selected for analysis.     

Evaluating peats for their capacities to remove odorous compounds from liquid swine manure using headspace "solid-phase microextraction".

This paper reports on research designed to investigate the capacities of different highly characterized peats to remove odorous compounds from liquid swine manure (LSM). Peat types representing a wide range of properties were tested in order to establish which chemical and physical properties might be most indicative of their capacities to remediate odors produced by LSM. Eight percent slurries (of peat/LSM) were measured for odor changes after 24 hours using odor panel and GC/MS-Solid-phase microextraction (GC/MS-SPME) analysis. The GC/MS-SPME and odor panel results indicated that, although all peats tested in this study were found to be effective at removing odor-causing compounds found in LSM, some peats tended to work better than others. Overall, the peats that were the most effective at removing odor-causing compounds tended to have lower bulk densities, ash contents, fulvic acids contents, and guaiacyl lignins contents, and higher water holding capacities, hydraulic conductivities, "total other lignins" contents, hydrogen contents, carbon contents, and total cellulose contents. GC/MS-SPME analysis was found to be a reasonably inexpensive and efficient way of conducting this type of research. It allows one to identify a large number of the odor-causing compounds found in LSM, and more importantly, to detect with some precision specific differences in the amounts of these compounds between peat types.     

Prenatal diagnosis of tetrasomy 12p by in situ hybridization: Varying levels of mosaicism in different fetal tissues

Prenatal diagnosis of tetrasomy 12p is complicated by the discrimination of the 12p isochromosome from the duplication 21q as well as the level of mosaicism demonstrated in the particular tissue sampled. In this disease, a high percentage of chromosomally abnormal cells are generally found in fibroblastic cells, but lymphocyte karyotypes from the same individual may be normal. We report on the pregnancy of a 37-year-old female who presented to our centre at 16 weeks' gestation for genetic amniocentesis. Sonography of the fetus revealed dextrocardia and diaphragmatic hernia. Chromosome analysis of amniocytes demonstrated mosaicism of a 47,XY,+i(12p) line in 80 per cent of cells and a normal male line (20 per cent), consistent with the Pallister-Killian syndrome. Following termination, a 220 g male fetus of 18 weeks was examined. A flattened nose and low-set ears were noted. In situ hybridization with a chromosome 12 centromeric probe in lymphocytes and skin cells unequivocally confirmed the karyotype and showed the presence of a single centromere in the abnormal chromosome, suggesting a true isochromosome. Chromosome analysis of various fetal tissues was performed and the following percentages of abnormal cells were found: skin 100 per cent, chorion 50 per cent, placenta 30 per cent, and blood 80 per cent. The high frequency of tetrasomic cells in fetal blood at this early gestational age is noteworthy, since most reports of this syndrome show a very low percentage of abnormal cells postnatally.     

Prevention of neural tube defects in curly-tail mice by maternal administration of vitamin A

Various doses of vitamin A were administered on day 9 of pregnancy to the pregnant curly-tail mouse, a mutant, 60 per cent of which have neural tube defects (NTD). There was a reduction in the incidence of NTD in the fetuses with all doses used. The effect was maximal with 5 mg/kg; it was also marked, but to a lesser degree, with 10 and 20 mg/kg and minimal with 1 mg/kg. The implications of these findings in the mouse to the prevention of NTD in humans by preconception vitamin supplementation are discussed.     

Rating child passenger safety laws relative to best practice recommendations for occupant protection

Background: State laws regarding child passenger protection vary substantially.

Objectives: The objective of this study was to develop a scoring system to rate child passenger safety laws relative to best practice recommendations for each age of child.

Methods: State child passenger safety and seat belt laws were retrieved from the LexisNexis database for the years 2002–2015. Text of the laws was reviewed and compared to current best practice recommendations for child occupant protection for each age of child.

Results: A 0–4 scale was developed to rate the strength of the state law relative to current best practice recommendations. A rating of 3 corresponds to a law that requires a restraint that is sufficient to meet best practice, and a rating of 4 is given to a law that specifies several options that would meet best practice. Scores of 0, 1, or 2 are given to laws requiring less than best practice to different degrees. The same scale is used for each age of child despite different restraint recommendations for each age. Legislation that receives a score of 3 requires rear-facing child restraints for children under age 2, forward-facing harnessed child restraints for children aged 2 to 4, booster seats for children 5 to 10, and primary enforcement of seat belt use in all positions for children aged 11–13. Legislation requiring use of a “child restraint system according to instructions” would receive a score of 1 for children under age 2 and a 2 for children aged 2–4 because it would allow premature use of a booster for children weighing more than 13.6 kg (30 lb).

Conclusions: The scoring system developed in this study can be used in mathematical models to predict how child passenger safety legislation affects child restraint practices.     

Incidence of thyroid disease following exposure to polybrominated biphenyls and polychlorinated biphenyls, Michigan, 1974-2006

Thyroid hormones, which influence body metabolism and development, could be affected by persistent organic pollutants. We sought to examine the relationship between polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) and thyroid disease. We employed incidence density sampling to perform a nested case control analysis of the Michigan Long-Term PBB Cohort. Cohort members (n = 3333) were exposed to PBBs through contaminated cattle feed in 1973-1974 and to PCBs through daily life. Those with detectable serum PBB and PCB concentrations at enrollment were categorized into tertiles of PBB and PCB exposure. Case-patients were cohort members answering “Yes” to “Has a healthcare provider ever told you that you had a thyroid problem?” during follow-up interviews; control-patients were cohort members answering “No”. We used odds ratios (OR) with 95% confidence intervals (CI) to compare odds of thyroid disease by PBB and PCB exposure and by various risk factors. Total cumulative thyroid disease incidence after 33 years was 13.9% among women and 2.6% among men. After adjusting for body mass index, we found no statistically significant differences in odds of any type of thyroid disease among women or men with elevated PBB or PCB exposure. Compared to control-patients, women with thyroid disease had increased odds of being overweight/obese (OR = 2.82, 95% CI: 1.94-4.11) and developing infertility (OR = 1.71, 95% CI: 1.08-2.69), diabetes (OR = 1.61, 95% CI: 1.04-2.51), or arthritis (OR = 1.71, 95% CI: 1.18-2.50) during follow-up. Additional research should explore potential associations between PBBs/PCBs and thyroid disease among children exposed in utero.     

Effects of Heating Season on Residential Indoor and Outdoor Polycyclic Aromatic Hydrocarbons, Black Carbon, and Particulate Matter in an Urban Birth Cohort

Exposure to air pollutants has been associated with adverse health effects. However, analyses of the effects of season and ambient parameters such as ozone have not been fully conducted. Residential indoor and outdoor air levels of polycyclic aromatic hydrocarbons (PAH), black carbon (measured as absorption coefficient [Abs]), and fine particulate matter <2.5 μm (PM)(2.5) were measured over two-weeks in a cohort of 5-6 year old children (n=334) living in New York City's Northern Manhattan and the Bronx between October 2005 and April 2010. The objectives were to: 1) characterize seasonal changes in indoor and outdoor levels and indoor/outdoor (I/O) ratios of PAH (gas + particulate phase; dichotomized into Σ(8)PAH(semivolatile) (MW 178-206), and Σ(8)PAH(nonvolatile) (MW 228-278)), Abs, and PM(2.5); and 2) assess the relationship between PAH and ozone. Results showed that heating compared to nonheating season was associated with greater Σ(8)PAH(nonvolatile) (p<0.001) and Abs (p<0.05), and lower levels of Σ(8)PAH(semivolatile) (p<0.001). In addition, the heating season was associated with lower I/O ratios of Σ(8)PAH(nonvolatile) and higher I/O ratios of Σ(8)PAH(semivolatile) (p<0.001) compared to the nonheating season. In outdoor air, Σ(8)PAH(nonvolatile) was correlated negatively with community-wide ozone concentration (p<0.001). Seasonal changes in emission sources, air exchanges, meteorological conditions and photochemical/chemical degradation reactions are discussed in relationship to the observed seasonal trends.     

How interdisciplinary is sustainability research? Analyzing the structure of an emerging scientific field

Sustainability research is expected to incorporate concepts, methods, and data from a diverse array of academic disciplines. We investigate the extent to which sustainability research lives up to this ideal of an interdisciplinary field. Using bibliometric data, we orient our study around the “tripartite model” of sustainability, which suggests that sustainability research should draw from the three “pillars” of the environmental, economic, and social sciences. We ask three questions: (i) is sustainability research truly more interdisciplinary than research generally, (ii) to what extent does research grounded in one pillar draw on research from the other two, and (iii) if certain disciplines or pillars are more interdisciplinary than others, then what explains this variation? Our results indicate that sustainability science, while more interdisciplinary than other scientific fields, falls short of the expectations inherent in the tripartite model. The pillar with the fewest articles published on sustainability—economics—is also the most integrative, while the pillar with the most articles—environmental sciences—draws the least from outside disciplines. But interdisciplinarity comes at a cost: sustainability research in economics and the social sciences is centered around a relatively small number of interdisciplinary journals, which may be becoming less valued over time. These findings suggest that, if sustainability research is to live up to its interdisciplinary ideals, researchers must be provided with greater incentives to draw from fields other than their own.