Non-circular Gas Kinematics and Star Formation in the Ringed Galaxy NGC 4736

We analyze the gas kinematics and star formation properties of the nearby RSab galaxy NGC 4736 using interferometric and single-dish CO(1-0) data and previously published Halpha and HI data. The CO morphology is dominated by a central molecular bar and tightly wound spiral arms associated with a bright ring of star formation. Strong HI emission is also found in the ring, but HI is absent from the central regions. Comparison of the HI and Halpha distributions suggests that HI in the ring is primarily dissociated H$_2$. Modeling of the CO kinematics reveals gas motion in elliptical orbits around the central bar, and we argue that the ring represents both the OLR of the bar and the ILR of a larger oval distortion. The HI kinematics show evidence for axisymmetric inflow towards the ring and are inconsistent with streaming in aligned elliptical orbits, but the highly supersonic (~40 km/s) inflow velocities required, corresponding to mass inflow rates of ~2 Msol/yr, suggest that more sophisticated models (e.g., gas orbiting in precessed elliptical orbits) should be considered. The radial CO and Halpha profiles are poorly correlated in the vicinity of the nuclear bar, but show a better correlation (in rough agreement with the Schmidt law) at the ring. Even along the ring, however, the azimuthal correspondence between CO and Halpha is poor, suggesting that massive stars form more efficiently at some (perhaps resonant) locations than at others. These results indicate that the star formation rate per unit gas mass exhibits strong spatial variations and is not solely a function of the available gas supply. The localization of star formation to the ring is broadly consistent with gravitational instability theory, although the instability parameter $Q \sim 3$ on average in the ring, only falling below 1 in localized regions.Comment: Revised version accepted by ApJ, with new section on p-v diagrams. 24 pages with 24 figures (emulateapj5). Full resolution and color versions are available at http://astro.berkeley.edu/~twong/preprint

First steps toward harmonized human biomonitoring in Europe : demonstration project to perform human biomonitoring on a European scale

'Reproduced with permission from Environmental Health Perspectives'Background: For Europe as a whole, data on internal exposure to environmental chemicals do not yet exist. Characterization of the internal individual chemical environment is expected to enhance understanding of the environmental threats to health. Objectives: We developed and applied a harmonized protocol to collect comparable human biomonitoring data all over Europe. Methods: In 17 European countries, we measured mercury in hair and cotinine, phthalate metabolites, and cadmium in urine of 1,844 children (5–11 years of age) and their mothers. Specimens were collected over a 5-month period in 2011–2012. We obtained information on personal characteristics, environment, and lifestyle. We used the resulting database to compare concentrations of exposure biomarkers within Europe, to identify determinants of exposure, and to compare exposure biomarkers with healthbased guidelines. Results: Biomarker concentrations showed a wide variability in the European population. However, levels in children and mothers were highly correlated. Most biomarker concentrations were below the health-based guidance values. Conclusions: We have taken the first steps to assess personal chemical exposures in Europe as a whole. Key success factors were the harmonized protocol development, intensive training and capacity building for field work, chemical analysis and communication, as well as stringent quality control programs for chemical and data analysis. Our project demonstrates the feasibility of a Europe-wide human biomonitoring framework to support the decision-making process of environmental measures to protect public health.The research leading to these results received funding for the COPHES project (COnsortium to Perform Human biomonitoring on a European Scale) from the European Community’s Seventh Framework Programme [FP7/2007–2013] under grant agreement 244237. DEMOCOPHES (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) was co-funded (50%:50%) by the European Commission LIFE+ Programme (LIFE09/ENV/BE/000410) and the partners. For information on both projects as well as on the national co-funding institutions, see http://www.eu-hbm.info/. The sponsors had no role in the study design, data collection, data analysis, data interpretation or writing of the report

Harmonised human biomonitoring in Europe: Activities towards an EU HBM framework

Human biomonitoring (HBM) can be an effective tool to assess human exposure to environmental pollutants and potential health effects and is increasingly seen as an essential element in a strategy when integrating health and environment. HBM can be used (i) to prioritise actions and measures for policy making; (ii) to evaluate policy actions aimed at reducing exposure to potentially hazardous environmental stressors; and (iii) to promote more comprehensive health impact assessments of policy options. In support of the European Environment and Health Action Plan 2004-2010, European scientists, experts from authorities and other stakeholders joined forces to work towards developing a functional framework and standards for a coherent HBM in Europe. Within the European coordination action on human biomonitoring, 35 partners from 27 European countries in the COPHES consortium aggregated their experiences and expertise and developed harmonized approaches and recommendations for better comparability of HBM data in Europe via the elaboration of a harmonized study protocol. This protocol is the product of discussion and compromises on the selection of environmental exposures, national environmental health concerns, and political and health priorities. The harmonised approach includes sampling recruitment, and analytical procedures, communication strategies and biobanking initiatives. The protocols and the harmonised approach are a means to increase acceptance and policy support and to in the future to enable determination of time trends. The common pilot study protocol will shortly be tested, adapted and assessed in the framework of the DEMOCOPHES in 17 European countries, including 16 EU Member States. COPHES and DEMOCOPHES constitute important steps towards establishing human biomonitoring as a tool for EU environmental and health policy and to improve quantification of exposure of the general European population to existing and emerging pollutants.status: publishe

Mercury analysis in hair: Comparability and quality assessment within the transnational COPHES/DEMOCOPHES project

Human biomonitoring (HBM) is an effective tool for assessing actual exposure to chemicals that takes into account all routes of intake. Although hair analysis is considered to be an optimal biomarker for assessing mercury exposure, the lack of harmonization as regards sampling and analytical procedures has often limited the comparison of data at national and international level. The European-funded projects COPHES and DEMOCOPHES developed and tested a harmonized European approach to Human Biomonitoring in response to the European Environment and Health Action Plan. Herein we describe the quality assurance program (QAP) for assessing mercury levels in hair samples from more than 1800 mother–child pairs recruited in 17 European countries. To ensure the comparability of the results, standard operating procedures (SOPs) for sampling and for mercury analysis were drafted and distributed to participating laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0.20–0.71 and 0.80–1.63) per exercise. The results revealed relative standard deviations of 7.87–13.55% and 4.04–11.31% for the low and high mercury concentration ranges, respectively. A total of 16 out of 18 participating laboratories the QAP requirements and were allowed to analyze samples from the DEMOCOPHES pilot study. Web conferences after each ICI/EQUAS revealed this to be a new and effective tool for improving analytical performance and increasing capacity building. The procedure developed and tested in COPHES/DEMOCOPHES would be optimal for application on a global scale as regards implementation of the Minamata Convention on Mercury

Pilot study testing a European human biomonitoring framework for biomarkers of chemical exposure in children and their mothers: experiences in the UK

Exposure to a number of environmental chemicals in UK mothers and children has been assessed as part of the European biomonitoring pilot study, Demonstration of a Study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES). For the European-funded project, 17 countries tested the biomonitoring guidelines and protocols developed by COPHES. The results from the pilot study in the UK are presented; 21 school children aged 6-11 years old and their mothers provided hair samples to measure mercury and urine samples, to measure cadmium, cotinine and several phthalate metabolites: mono(2-ethyl-5-hydroxyhexyl)phthalate (5OH-MEHP), mono(2-ethyl-5-oxo-hexyl)phthalate (5oxo-MEHP) and mono(2-ethylhexyl)phthalate (MEHP), mono-ethyl phthalate (MEP), mono-iso-butyl phthalate (MiBP), mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP). Questionnaire data was collected on environment, health and lifestyle. Mercury in hair was higher in children who reported frequent consumption of fish (geometric mean 0.35 μg/g) compared to those that ate fish less frequently (0.13 μg/g, p = 0.002). Cadmium accumulates with age as demonstrated by higher levels of urinary cadmium in the mothers (geometric mean 0.24 μg/L) than in the children(0.14 μg/L). None of the mothers reported being regular smokers, and this was evident with extremely low levels of cotinine measured (maximum value 3.6 μg/L in mothers, 2.4 μg/L in children). Very low levels of the phthalate metabolites were also measured in both mothers and children (geometric means in mothers: 5OH-MEHP 8.6 μg/L, 5oxo-MEHP 5.1 μg/L, MEHP 1.2 μg/L, MEP 26.8 μg/L, MiBP 17.0 μg/L, MBzP 1.6 μg/L and MnBP 13.5 μg/L; and in children: 5OH-MEHP 18.4 μg/L, 5oxo-MEHP 11.4 μg/L, MEHP 1.4 μg/L, MEP 14.3 μg/L, MiBP 25.8 μg/L, MBzP 3.5 μg/L and MnBP 22.6 μg/L). All measured biomarker levels were similar to or below population-based reference values published by the US National Health and Nutrition Examination Survey (NHANES) and Germany's GerES surveys. No results were above available health guidance values and were of no concern with regards to health. The framework and techniques learnt here will assist with future work on biomonitoring in the UK.status: publishe