Mercury is an element with low abundance in the earth's crust and a heavy metal known for its high spread and persistence in the environment and for its potential toxicity in humans and wildlife that varies with its oxidation state, the dose and the rate of exposure. It is present in various environmental media in different forms such as inorganic mercury, which includes both metallic mercury (Hg 2+) and mercury vapor (Hg 0) and mercurous (Hg +), mercuric salts and in addition to organic compounds in which the mercury is bonded to a structures containing carbon atoms (methyl, ethyl or similar groups). Due to its volatility once emitted into the atmosphere from both natural and anthropogenic sources, it is transported to long distance and transferred to aquatic and terrestrial receptors mainly with precipitation. In order to protect human health and the environment as a whole from the adverse effects of mercury, the international community through the Minamata Convention on Mercury sets out a series of measures to regulate and reduce human activities that emit mercury into the atmosphere such as coal-fired power plants and waste incineration facilities or release it into waters and soils, such as manufacturing processes in which mercury or mercury compounds are used and artisanal and small-scale gold mining. The European Union through the Seventh Programme funded the research project "Global Mercury Observation System" (GMOS), whose purpose was to establish a network of scientific research stations for the measurement of mercury in the atmosphere and in precipitation (Vardè, et al., 2016). Sisal (SIS) hosted a Mexican Scientific Base were for a Global Mercury Observation System project (GMOS) scientists performed measurement of atmospheric mercury using automated instrument and sampling collection for wet deposition of Hg. In this area of the world, at the lower latitudes of North America, Hg in precipitation has been previously studied during a long-term record of Hg in wet deposition at two Mexican monitoring sites located respectively near the Gulf of Mexico and the Pacific coast of southern Mexico (Hansen & Gay, 2013) and in "Clean Air" site in Puerto Rico (Shanley, et al., 2015). Total Mercury (THg) concentrations in wet deposition and rainfall depth (THg) at this GMOS secondary site were determined for samples withdrawn between January 2013 and January 2015. Bi-Weekly to monthly based precipitation samples were collected using automated wet-only precipitation collection system. Samples were treated according to GMOS protocol and analyzed by cold vapor atomic fluorescence spectrometry (CVAFS). This report describes and discuss the first ever determination of THg concentrations in precipitation at Sisal (Mexico). The THg concentration in wet deposition samples ranged from the minimum value 1.8 ng/L (29/10-12/11/2013) to the maximum value 71.7 ng/L (29/01-12/02/2013), and the lowest and highest rainfall depth values were respectively 0.3 (March/April 2013) and 136.4 mm (September 2014) during the study period. The volume-weighted mean (VWM) concentrations and wet deposition fluxes of THg in precipitation from January 2013 to January 2015 were 10.1 ng L-1 and 13.9 micro g m-2 yr-1 respectively. Mean THg concentrations in only wet deposition at Sisal during the study was comparable to mercury values reported in scientific papers for rural and remote sites located at tropical latitudes.
Mercury in Wet-only Deposition: Concentration, Rainfall Depth and Fluxes in Sisàl, Yucatan, México. Global Mercury Observation System (GMOS) Project: Results 2013-2015
Alessandro Servidio;Franco Cofone;Annalisa Rosselli;
2016
Abstract
Mercury is an element with low abundance in the earth's crust and a heavy metal known for its high spread and persistence in the environment and for its potential toxicity in humans and wildlife that varies with its oxidation state, the dose and the rate of exposure. It is present in various environmental media in different forms such as inorganic mercury, which includes both metallic mercury (Hg 2+) and mercury vapor (Hg 0) and mercurous (Hg +), mercuric salts and in addition to organic compounds in which the mercury is bonded to a structures containing carbon atoms (methyl, ethyl or similar groups). Due to its volatility once emitted into the atmosphere from both natural and anthropogenic sources, it is transported to long distance and transferred to aquatic and terrestrial receptors mainly with precipitation. In order to protect human health and the environment as a whole from the adverse effects of mercury, the international community through the Minamata Convention on Mercury sets out a series of measures to regulate and reduce human activities that emit mercury into the atmosphere such as coal-fired power plants and waste incineration facilities or release it into waters and soils, such as manufacturing processes in which mercury or mercury compounds are used and artisanal and small-scale gold mining. The European Union through the Seventh Programme funded the research project "Global Mercury Observation System" (GMOS), whose purpose was to establish a network of scientific research stations for the measurement of mercury in the atmosphere and in precipitation (Vardè, et al., 2016). Sisal (SIS) hosted a Mexican Scientific Base were for a Global Mercury Observation System project (GMOS) scientists performed measurement of atmospheric mercury using automated instrument and sampling collection for wet deposition of Hg. In this area of the world, at the lower latitudes of North America, Hg in precipitation has been previously studied during a long-term record of Hg in wet deposition at two Mexican monitoring sites located respectively near the Gulf of Mexico and the Pacific coast of southern Mexico (Hansen & Gay, 2013) and in "Clean Air" site in Puerto Rico (Shanley, et al., 2015). Total Mercury (THg) concentrations in wet deposition and rainfall depth (THg) at this GMOS secondary site were determined for samples withdrawn between January 2013 and January 2015. Bi-Weekly to monthly based precipitation samples were collected using automated wet-only precipitation collection system. Samples were treated according to GMOS protocol and analyzed by cold vapor atomic fluorescence spectrometry (CVAFS). This report describes and discuss the first ever determination of THg concentrations in precipitation at Sisal (Mexico). The THg concentration in wet deposition samples ranged from the minimum value 1.8 ng/L (29/10-12/11/2013) to the maximum value 71.7 ng/L (29/01-12/02/2013), and the lowest and highest rainfall depth values were respectively 0.3 (March/April 2013) and 136.4 mm (September 2014) during the study period. The volume-weighted mean (VWM) concentrations and wet deposition fluxes of THg in precipitation from January 2013 to January 2015 were 10.1 ng L-1 and 13.9 micro g m-2 yr-1 respectively. Mean THg concentrations in only wet deposition at Sisal during the study was comparable to mercury values reported in scientific papers for rural and remote sites located at tropical latitudes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
