A Geochemical, Isotopic, and Petrologic Study of a Watershed with Arsenic-enriched Ground Water in Northport, Maine

High mean arsenic concentrations up 26.6 ¹mol/L (1990 ¹g/L) occur in ground water within a watershed at Kelly\u27s Cove, Northport, Maine, USA. The Kelly\u27s Cove watershed is a fractured-bedrock system composed of sul¯dic schist with granitic to dioritic intrusions. Arsenic is enriched in these rocks up to 1050 mg kg¡1 (average: 68 mg kg¡1). The distribution of arsenic in the bedrock appears to be controlled by the presence of arsenopyrite and arsenian pyrite, that occur primarily in post-metamorphic, tourmaline + quartz § carbonate veins and the Kelly\u27s Cove granite. Based on the metamorphic signature of the tourmaline chemistry and the similarity in ±34S values of the sulfides, these veins probably derived from hydrothermal remobilization of surrounding metamorphic rock. Chemical analyses of water from 35 bedrock wells throughout the watershed reveal spatial clustering of wells with high arsenic concentrations. Stiff diagrams and box plots distinguish three distinct water types; calcium bicarbonate-dominated water with low arsenic concentrations (CaHCO3 type), sodium bicarbonate-dominated water with moderately high arsenic concentrations (NaHCO3 type), and calcium bicarbonate-dominated water with very high arsenic concentrations (High-As type). Di®erences in recharge area, ground-water evolution, and possibly bedrock composition contribute to the chemical distinctions within the watershed\u27s ground water. Lack of correlation of aqueous arsenic concentrations with pH indicates that desorption of arsenic is an insignificant control on arsenic concentration. Correlations of aqueous arsenic concentrations with increasing Fe(II)/Fe(III) and decreasing Eh indicates that reductive dissolution of ferric oxyhydroxides plays a role in the occurrence of high arsenic concentrations in the NaHCO3 and High-As type water. Ground water with high arsenic concentrations contains sulfate with enriched sulfur and oxygen isotopes. The range of ±34S[SO4] and ±18O[SO4] values at the Kelly\u27s Cove watershed (+3.4 to +4.9 ?? and -2.01 to +6.72 ?? , respectively) are strikingly similar to that of another Maine watershed (+3.7 to +4.6 ?? and -2.56 to +7.47 ?? , respectively), that has different oxidizing ground-water conditions. The association of high arsenic concentrations and high ±18O[SO4] is not due to oxidizing conditions or reduction of sulfate, but may be related to paleo-aeration of iron oxyhydroxides that are now reducing and releasing arsenic

A Geochemical, Isotopic, and Petrologic Study of a Watershed with Arsenic-enriched Ground Water in Northport, Maine

High mean arsenic concentrations up 26.6 ¹mol/L (1990 ¹g/L) occur in ground water within a watershed at Kelly\u27s Cove, Northport, Maine, USA. The Kelly\u27s Cove watershed is a fractured-bedrock system composed of sul¯dic schist with granitic to dioritic intrusions. Arsenic is enriched in these rocks up to 1050 mg kg¡1 (average: 68 mg kg¡1). The distribution of arsenic in the bedrock appears to be controlled by the presence of arsenopyrite and arsenian pyrite, that occur primarily in post-metamorphic, tourmaline + quartz § carbonate veins and the Kelly\u27s Cove granite. Based on the metamorphic signature of the tourmaline chemistry and the similarity in ±34S values of the sulfides, these veins probably derived from hydrothermal remobilization of surrounding metamorphic rock. Chemical analyses of water from 35 bedrock wells throughout the watershed reveal spatial clustering of wells with high arsenic concentrations. Stiff diagrams and box plots distinguish three distinct water types; calcium bicarbonate-dominated water with low arsenic concentrations (CaHCO3 type), sodium bicarbonate-dominated water with moderately high arsenic concentrations (NaHCO3 type), and calcium bicarbonate-dominated water with very high arsenic concentrations (High-As type). Di®erences in recharge area, ground-water evolution, and possibly bedrock composition contribute to the chemical distinctions within the watershed\u27s ground water. Lack of correlation of aqueous arsenic concentrations with pH indicates that desorption of arsenic is an insignificant control on arsenic concentration. Correlations of aqueous arsenic concentrations with increasing Fe(II)/Fe(III) and decreasing Eh indicates that reductive dissolution of ferric oxyhydroxides plays a role in the occurrence of high arsenic concentrations in the NaHCO3 and High-As type water. Ground water with high arsenic concentrations contains sulfate with enriched sulfur and oxygen isotopes. The range of ±34S[SO4] and ±18O[SO4] values at the Kelly\u27s Cove watershed (+3.4 to +4.9 ?? and -2.01 to +6.72 ?? , respectively) are strikingly similar to that of another Maine watershed (+3.7 to +4.6 ?? and -2.56 to +7.47 ?? , respectively), that has different oxidizing ground-water conditions. The association of high arsenic concentrations and high ±18O[SO4] is not due to oxidizing conditions or reduction of sulfate, but may be related to paleo-aeration of iron oxyhydroxides that are now reducing and releasing arsenic

Long-term exposure to ambient ozone and mortality : A quantitative systematic review and meta-analysis of evidence from cohort studies

Objectives: While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Methods: Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. Results: 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Conclusions: Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted

Book Reviews

Reviews of the following books: Quiet Presence: Dramatic, First-Person Accounts - The True Stories of Franco-Americans in New England by Dyke Hendrickson; The Treasure of the Concepcion: The Wreck of the Almiranta by Peter Earle; In Search of Shipwrecks by Jim Jenney; Indian New England Before the Mayflower by Howard S. Russel

Does re-opening schools contribute to the spread of SARS-CoV-2?:Evidence from staggered summer breaks in Germany

This paper studies the effect of the end of school summer breaks on SARS-CoV-2 cases in Germany. The staggered timing of summer breaks across federal states allows us to implement an event study design. We base our analysis on official daily counts of confirmed coronavirus infections by age groups across all 401 German counties. We consider an event window of two weeks before and four weeks after the end of summer breaks. We do not find evidence of a positive effect of school re-openings on case numbers. For individuals aged between 5 and 59 years, comprising school-aged children and their parents, our pre- ferred specification indicates that the end of summer breaks had a negative but insignificant effect on the number of new confirmed cases. Our results are not explained by changes in mobility patterns around school re-openings arising from travel returnees. Analyses of Google Trends data suggest that behavioral changes of parents may have contributed to contain larger outbreaks after school re-openings. We conclude that school re-openings in Germany under strict hygiene measures combined with quarantine and containment measures have not increased the number of newly confirmed SARS-CoV-2 infections

Influence of Ibuprofen on Phospholipid Membranes

Basic understanding of biological membranes is of paramount importance as these membranes comprise the very building blocks of life itself. Cells depend in their function on a range of properties of the membrane, which are important for the stability and function of the cell, information and nutrient transport, waste disposal and finally the admission of drugs into the cell and also the deflection of bacteria and viruses. We have investigated the influence of ibuprofen on the structure and dynamics of L-alpha-phosphatidylcholine (SoyPC) membranes by means of grazing incidence small-angle neutron scattering (GISANS), neutron reflectometry and grazing incidence neutron spin echo spectroscopy (GINSES). From the results of these experiments we were able to determine that ibuprofen induces a two-step structuring behavior in the SoyPC films, where the structure evolves from the purely lamellar phase for pure SoyPC over a superposition of two hexagonal phases to a purely hexago- nal phase at high concentrations. Additionally, introduction of ibuprofen stiffens the membranes. This behavior may be instrumental in explaining the toxic behavior of ibuprofen in long-term application.Comment: -Improved indexing in Fig. 4e) -changed concentrations to mol% -improved arguments, however conclusions stay unchange

ModE-Sim – a medium-sized atmospheric general circulation model (AGCM) ensemble to study climate variability during the modern era (1420 to 2009)

We introduce ModE-Sim (Modern Era SIMulations), a medium-sized ensemble of simulations with the atmospheric general circulation model ECHAM6 in its LR (low-resolution) version (T63; approx. 1.8∘ horizontal grid width with 47 vertical levels). At the lower boundary we use prescribed sea surface temperatures and sea ice that reflect observed values while accounting for uncertainties in these. Furthermore we use radiative forcings that also reflect observed values while accounting for uncertainties in the timing and strength of volcanic eruptions. The simulations cover the period from 1420 to 2009. With 60 ensemble members between 1420 and 1850 and 36 ensemble members from 1850 to 2009, ModE-Sim consists of 31 620 simulated years in total. ModE-Sim is suitable for many applications as its various subsets can be used as initial-condition and boundary-condition ensembles to study climate variability. The main intention of this paper is to give a comprehensive description of the experimental setup of ModE-Sim and to provide an evaluation, mainly focusing on the two key variables, 2 m temperature and precipitation. We demonstrate ModE-Sim's ability to represent their mean state, to produce a reasonable response to external forcings, and to sample internal variability. Through the example of heat waves, we show that the ensemble is even capable of capturing certain types of extreme events.</p