Bromine, iodine and sodium along the EAIIST traverse: Bulk and surface snow latitudinal variability

During the East Antarctic International Ice Sheet Traverse (Eaiist, december 2019), in an unexplored part of the East Antarctic Plateau, snow samples were collected to expand our knowledge of the latitudinal variability of iodine, bromine and sodium as well as their relation in connection with emission processes and photochemical activation in this unexplored area. A total of 32 surface (0-5 cm) and 32 bulk (average of 1 m depth) samples were taken and analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Our results show that there is no relevant latitudinal trend for bromine and sodium. For bromine they also show that it has no significant post-depositional mechanisms while its inland surface snow concentration is influenced by spring coastal bromine explosions. Iodine concentrations are several orders of magnitude lower than bromine and sodium and they show a decreasing trend in the surface samples concentration moving southward. This suggests that other processes affect its accumulation in surface snow, probably related to the radial reduction in the ozone layer moving towards central Antarctica. Even though all iodine, bromine and sodium present similar long-range transport from the dominant coastal Antarctic sources, the annual seasonal cycle of the ozone hole over Antarctica increases the amount of UV radiation (in the 280-320 nm range) reaching the surface, thereby affecting the surface snow photoactivation of iodine. A comparison between the bulk and surface samples supports the conclusion that iodine undergoes spring and summer snow recycling that increases its atmospheric lifetime, while it tends to accumulate during the winter months when photochemistry ceases.

Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene

The Northern Hemisphere experienced dramatic changes during the last glacial, featuring vast ice sheets and abrupt climate events, while high northern latitudes during the last interglacial (Eemian) were warmer than today. Here we use high-resolution aerosol records from the Greenland NEEM ice core to reconstruct the environmental alterations in aerosol source regions accompanying these changes. Separating source and transport effects, we find strongly reduced terrestrial biogenic emissions during glacial times reflecting net loss of vegetated area in North America. Rapid climate changes during the glacial have little effect on terrestrial biogenic aerosol emissions. A strong increase in terrestrial dust emissions during the coldest intervals indicates higher aridity and dust storm activity in East Asian deserts. Glacial sea salt aerosol emissions in the North Atlantic region increase only moderately (50%), likely due to sea ice expansion. Lower aerosol concentrations in Eemian ice compared to the Holocene are mainly due to shortened atmospheric residence time, while emissions changed little.

Past climate changes in Greenland ice were accompanied by large aerosol concentration changes. Here, the authors show that by correcting for transport effects, reliable source changes for biogenic aerosol from North America, sea salt aerosol from the North Atlantic, and dust from East Asian deserts can be derived.

Prominent features in isotopic, chemical and dust stratigraphies from coastal East Antarctic ice sheet (Eastern Wilkes Land)

In this work we present the isotopic, chemical and dust stratigraphies of two snow pits sampled in 2013/14 at GV7 (coastal East Antarctica: 70°41' S - 158°51' E, 1950 m a.s.l.). A large number of chemical species are measured aiming to study their potentiality as environmental changes markers. Seasonal cluster backward trajectories analysis was performed and compared with chemical marker stratigraphies. Sea spray aerosol is delivered to the sampling site together with snow precipitation especially in autumn-winter by air masses arising from Western Pacific Ocean sector. Dust show maximum concentration in spring when the air masses arising from Ross Sea sector mobilize mineral dust from ice-free areas of the Transantarctic mountains. The clear seasonal pattern of sulfur oxidized compounds allows the dating of the snow-pit and the calculation of the mean accumulation rate, which is 242 ± 71 mm w.e. for the period 2008-2013. Methanesulfonic acid and NO₃^- do not show any concentration decreasing trend as depth increases, also considering a 12 m firn core record. Therefore these two compounds are not affected by post-depositional processes at this site and can be considered reliable markers for past environmental changes reconstruction. The rBC snow-pit record shows the highest values in summer 2012 likely related to large biomass burning even occurred in Australia in this summer. The undisturbed accumulation rate for this site is demonstrated by the agreement between the chemical stratigraphies and the annual accumulation rate of the two snow-pits analysed in Italian and Korean laboratories.

Antibiotic prescribing patterns in Italian hospital inpatients with pneumonia, chronic obstructive pulmonary disease, and urinary tract infections

OBJECTIVE

The primary objective of this study was to describe the antibiotic prescribing patterns in hospital inpatients with pneumonia (PN), exacerbations of chronic obstructive pulmonary disease (COPD), and urinary tract infections (UTIs). A second objective was to verify if some selected variables (i.e., risk factors, patient age, size of hospitals) were affecting the therapeutic choice.

DESIGN

Survey was performed on 1609 patients. The data were collected by physicians using a special form, covering a six-month period.

SETTING

Twenty-six medical wards and 8 geriatric wards in 24 acute-care hospitals in the Veneto Region in Northern Italy.

PATIENTS

A consecutive sample of PN, COPD, and UTI patients treated with antibiotics.

MAIN OUTCOME MEASURES

The following information was collected: patient and hospital demographics, risk factors, diagnoses, and antibiotic regimens.

RESULTS

Sixty-three antimicrobial agents used, with 2115 administrations, 1227 of which were single-drug therapy. The most frequently used drugs were third-generation cephalosporins (24.6 percent), fluoroquinolones (15.4 percent), aminopenicillins (15.0 percent), and ureidopenicillins (9.7 percent). There is great variability of therapeutic regimens in the various hospitals for the same disease. However, this variability is not explained by the different types of hospitals or by the patients' characteristics (e.g., age, risk factors).

CONCLUSIONS

Our results show that the use of broad-spectrum antibiotics probably is excessive. Moreover, the treatment seems to be based more on the opinion of the treating physician and the local habits rather than objective criteria. These factors may have negative repercussions not only in economic terms, but also in terms of alteration of the bacterial ecology.

[Disulfiram-like effect of cefonicid: first observation]

The disulfiram-like reaction is linked to the assumption of ethyl alcohol during therapy with the cephalosporin latamoxef, cefamandole and cefoperazone. The reaction is commonly ascribed to the methyl-thiotetrazole group, resembling part of the disulfiram molecule. We describe the case of a patient who experienced on two different occasions a disulfiram-like effect during therapy with cefonicid. This cephalosporin contains the methylsulphothiotetrazole group in place of the methylthiotetrazole group. Our observation is the first related to cefonicid.