Return of naturally sourced Pb to Atlantic surface waters

Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources during the past century, predominantly due to leaded petrol usage. Here, based on Pb isotope measurements, we reassess the importance of natural and anthropogenic Pb sources to the tropical North Atlantic following the nearly complete global cessation of leaded petrol use. Significant proportions of up to 30-50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters, reflecting the success of the global effort to reduce anthropogenic Pb emissions. The observation of mineral dust derived Pb in surface waters is governed by the elevated atmospheric mineral dust concentration of the North African dust plume and the dominance of dry deposition for the atmospheric aerosol flux to surface waters. Given these specific regional conditions, emissions from anthropogenic activities will remain the dominant global marine Pb source, even in the absence of leaded petrol combustion

April 2014 critical care case of the month: too much, too fast

No abstract available. Article truncated at 150 words. History of Present Illness A 69 year old man was admitted to the intensive care unit with shortness of breath and atrial fibrillation with a rapid ventricular response. PMH, FH, SH He has a history of peripheral vascular disease, end-stage renal disease and is receiving chronic hemodialysis. Physical Examination Afebrile. Pulse 135 and irregular. BP 105/65 mm Hg. SpO2 96% while receiving oxygen at 2L/min by nasal cannula. HEENT: Unremarkable. Neck: Jugular venous distention to the angle of the jaw while the head is elevated at 45 degrees. Lungs: Decreased breath sounds at the right base. Cardiovascular: Irregularly, irregular rhythm. 2-3+ pretibial edema. Abdomen: no hepatosplenomegaly. Radiography The admission chest x-ray is shown in figure 1. Which of the following is the best interpretation of the chest x-ray given the clinical situation? 1. Hepatomegaly elevating the right diaphragm 2. Large right pleural effusion 3. Paralyzed right diaphragm 4. Right lower ..