Mercury Mass Budget Estimates and Cycling Seasonality in the Florida Everglades

Abstract

We estimated the mass budget for mercury (Hg) seasonally deposited into the Florida Everglades and investigated seasonality of Hg cycling by analyzing data obtained for water, soil, flocculent detrital material (floc), periphyton, and mosquitofish collected throughout the Everglades freshwater marshes in the 2005 dry and wet seasons. Higher wet season total Hg (THg) in soil, floc, and periphyton agreed with greater Hg amounts entering these compartments during the wet season, probably owing to substantially greater Hg deposition in the wet season than in the dry season. Seasonal differences were absent for THg in surface water. Methylmercury (MeHg) showed mixed seasonal patterns, with higher water and soil MeHg and lower periphyton MeHg in the dry season but no seasonality for floc MeHg. Seasonal variations in Hg deposition, MeHg production and transport, and mass of ecosystem compartments could be responsible for the seasonality of MeHg cycling. Higher mosquitofish THg, higher bioaccumulation factors, and higher biomagnification factors from periphyton to mosquitofish were observed in the wet season than in the dry season, indicating that the wet season is more favorable for Hg bioaccumulation. The mass budget estimation agreed with this result.

Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms

“…Lakes, rivers and coastal waters throughout the United States contain mercury at levels that harm wildlife and people who consume fish from these waters (Liu et al, 2008;KarounaRenier et al, 2008;EPA, 2011). Monitoring has established that atmospheric transport and deposition is a major source of mercury to many of these watersheds (Lindberg et al, 2007;Northeast Regional Mercury Total Maximum Daily Load, 2007).…”

Sulfetos volatilizáveis por acidificação e metais extraídos simultaneamente na avaliação de sedimentos de água doce

“…[75][76][77] As condições mais apropriadas para se formar os sulfetos e imobilizar o mercúrio são as mesmas capazes de promover a sua metilação, transformando-o em sua espécie mais tóxica, o metilmercúrio (CH 3 Hg + ). 78 Com relação ao cromo (Cr), não é possível a formação de um sulfeto de cromo no ambiente. 79 Tal espécie química é obtida apenas em condições especiais, associadas à manufatura do aço, como resultado da mistura de reagentes no estado sólido, em temperaturas elevadas.…”

Mercury characterization in soil collected nearby the Department of Energy Oak Ridge reservation

“…Natural mercury emissions include volcanoes, natural mercury deposits and volatilization from the ocean (Liu et al, 2008a;Liu et al, 2008b;Munthe et al, 2003;Murphy et al, 2006; U.S.E.P.A., 1997c; U.S.G.S., 1998), which was estimated by Mason (Mason, 1994) as 2000 tons per year. Naturally mercury-enriched material found associated with plate tectonic boundaries, areas of high crustal heat flow, precious and base metal mineralization, recent volcanism, and organic rich sedimentary rocks (Rasmussen, 1994).…”

“…Methylmercury is a highly toxic organomercury species, present in much lower concentrations and is readily accumulated by aquatic organisms (Cai et al, 1996;Liu et al, 2008a;Liu et al, 2008b;Mason, 1994;Mason and Benoit, 2003;Mason et al, 1993;Sanchez-Uria, 1998;Ullrich et al, 2007;Ullrich et al, 2001;USEPA, 2002) Methylmercury is neurotoxic, causes blockage of binding sites of enzymes, interferes with protein synthesis, impedes thymidine incorporation into DNA, among other factors (Clarkson, 1992;Halbach, 1995;National Institute of Environmental Health Science (NIEHS), 1998;National Research Council (NRC), 2000;Thayer, 1984). The short chain alkylmercury compounds are toxic and tend to bioaccumulate more readily than other species of mercury.…”

“…Investigations initiated in the late 1980s in the northern-tier states of the United States, Canada and the Nordic countries found that fish, mainly from oligotrophic lakes and often in very remote areas, commonly have high levels of mercury Cai, 2000;Cai et al, 1999;Krabbenhoft et al, 1998;Krabbenhoft et al, 2000;Kranzer, 2003;Lindberg et al, 2001;Lindberg and Zhang, 2000;Liu et al, 2008a;Liu et al, 2008b;Mason, 1994;Mason et al, 2005;Mason and Benoit, 2003;Mason et al, 2000;Mason and Sullivan, 1997;O'Driscoll and Evans, 2000;O'Driscoll et al, 2005). Fish sampling surveys in other regions of the United States have shown widespread mercury contamination in streams, wetlands, reservoirs and lakes (U.S.G.S., 1998).…”