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[en] A few studies have reported the occurrence of monoethylmercury (CH3CH2Hg+) in the natural environment, but further verification is needed due to the lack of direct evidence and/or uncertainty in analytical procedures. Various analytical techniques were employed to verify the occurrence of CH3CH2Hg+ in soil of the Florida Everglades. The identity of CH3CH2Hg+ in Everglades soil was clarified, for the first time, by GC/MS. The employment of the recently developed aqueous phenylation-purge-and-trap-GC coupled with ICPMS confirmed that the detected CH3CH2Hg+ was not a misidentification of CH3SHg+. Stable isotope-tracer experiments further indicated that the detected CH3CH2Hg+ indeed originated from Everglades soil and was not an analytical artifact. All these evidence clearly confirmed the occurrence of CH3CH2Hg+ in Everglades soil, presumably as a consequence of ethylation occurring in this wetland. The prevalence of CH3CH2Hg+ in Everglades soil suggests that ethylation could play an important role in the biogeochemical cycling of Hg. - A combination of various analytical techniques and stable isotope tracer experiments confirms monoethylmercury is present in Everglades soil.
[en] Models, widely used to estimate dust deposition to the oceans, have not been adequately tested because of the dearth of long-term measurements of dust deposition rates. Here we present the results of a three year deposition program in a nine-station network distributed throughout the State of Florida which is impacted by African dust every year. The deposition rates of soil-related elements (Al, Fe, Mn) were strongly correlated and exhibited an extremely strong summer maximum that closely matched concurrently-measured dust concentrations in Miami. The deposition rates of Al, Fe and Mn at all sites were remarkably uniform. The deposition rates of dust, based on Fe measurements, were compared with those from nine AEROCOM models. Dust models correctly characterized the seasonal cycle of deposition but most grossly underestimated summer deposition and they tended to produce latitudinal gradients that were not observed in the network. There is a clear need to better understand the treatment of deposition processes in models.
[en] The intrusive complex of Arroyo de la Virgen is as an intrusion zone which cover since granodioritic to leucogranitic terms. The petrography and geochemical zone is constant in all the massif, only interrupted by different phylum systems (acid and basic). The petrography and geochemical studies suggest an earlier and differential evolutive mechanism of crystals.
[en] This paper presents a critical view of Florida's photovoltaic (PV) subsidy system and proposes an econometric model of PV system installation and generation costs. Using information on currently installed systems, average installation cost relations for residential and commercial systems are estimated and cost-efficient scales of installation panel wattage are identified. Productive efficiency in annual generating capacity is also examined under flexible panel efficiency assumptions. We identify potential gains in efficiency and suggest changes in subsidy system constraints, providing important guidance for the implementation of future incentive programs. Specifically, we find that the subsidy system discouraged residential applicants from installing at the cost-efficient scale but over-incentivized commercial applicants, resulting in inefficiently sized installations. - Highlights: ► Describe a PV solar incentive system in the U.S. state of Florida. ► Combine geocoded installation site data with a detailed irradiance map. ► Estimate installation and production costs across a large sample. ► Identify inefficiencies in the incentive system. ► Suggest changes to policy that would improve economic efficiency.
[en] Vindicator of Florida, the nation's first commercial food irradiation facility is set to begin exposing foods to radioactive isotopes in November, 1991. Supporters and opponents agree that the success or failure of the plant will set the tone for the next decade of struggle over one of the most controversial food technologies ever developed