Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China

Abstract

a b s t r a c tTieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m À2 and averaged 14.5 mg m À2, indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils.

Investigation of factors affecting mercury emission from subtropical forest soil: A field controlled study in southwestern China

“…The forest stand in TNFP is a Masson Pine dominated, coniferous-broad leave mixed subtropical forest and trees were planted in the 1960s. The soil is typically mountain yellow earth and its texture is haplic acrisol/alisol, which is severely acidified with an acidic pH 3.79 and TOM 12.7% in the organic horizon (Zhou et al, 2015). Based on our precious study, atmospheric deposition and soil pools of mercury were significantly elevated in TNFP area, which was several or even dozens of times compared to estimates obtained in North America and Europe (Wang et al, 2009;Zhou et al, 2015).…”

“…Some recent studies and models of its cycle in the environment suggested that mercury emissions and re-emissions from soil and vegetation were estimated up to 5500-8900 tons, accounting for 19-51% of the current release to the atmosphere from all sources (UNEP, 2013). Furthermore, studies have also reported that mercury evasion from forest and grassland was an important source of total gaseous mercury (TGM) in the atmosphere in the background area (Zhou et al, 2015;Ericksen et al, 2006;Choi and Holsen, 2009a;Almeida et al, 2009). Therefore, soil/air exchange flux is an important component of the mercury global biogeochemical cycle.…”

“…In addition, flux between soil and air is the relationship of dynamic diffusion between mercury concentrations of soil gas in soil column underneath the soil surface layer (0-5 cm, our unpublished data) and TGM in atmosphere, indicating that mercury concentrations variation in atmosphere or soil gas seriously influences the flux (Zhang et al, 2002). Subtropical forest in China is considered as a large pool of atmospheric mercury (Zhou et al, 2013(Zhou et al, , 2015Wang et al, 2009), while soils of forested watershed is a large reservoir of atmospherically deposited mercury, accounting for up to 90% of mercury in forests (Grigal, 2003). Forest ecosystems not only act as sinks but also as sources of previously deposited mercury emitted back to the atmosphere.…”

Presencia de bacterias rizosféricas resistentes a mercurio en suelos del sur de Bolívar, Colombia

“…Estudios recientes y los modelos del ciclo en el medio ambiente, estima que las emisiones de mercurio y las reemisiones desde el suelo y la vegetación es de aproximadamente 5500 -8900 toneladas, incluyendo además un 19-51% de emisión a la atmósfera a través de otras las fuentes (UNEP, 2013). ZHOU et al, (2015), han señalado que la emisión del mercurio a partir de los bosques y las praderas se han convertido en una fuente importante del total del mercurio gaseoso que se encuentra en la atmósfera, por lo que, el flujo de intercambio suelo/ aire es un componente importante dentro del ciclo biogeoquímicos del mercurio total. La toxicidad y los efectos adversos del mercurio en la salud humana y en los ecosistemas han sido dados a conocen desde hace mucho tiempo atrás.…”

Litterfall and nutrient return in moist evergreen broad-leaved primary forest and mixed subtropical secondary deciduous broad-leaved forest in China

“…Due to the massive deforestation in the 1950s, most of the subtropical primary forest in eastern and southeastern China disappeared and only small portion was reserved in southwestern China (Wu 1995). Number of secondary forests have been developed in eastern and southern China after 1960s with a view to sustainable development (Zhou et al 2015), which has improved the soil fertility levels. In China most of the soil in subtropical secondary forest is highly weathered, leached and poor nutrient (Li et al 2015;Wei et al 2012).…”