Mercury in the Sediment of Pelotas River Basin, Brazil

Abstract

Many studies have determined the concentration of trace elements in river sediments in Brazil. Notwithstanding, mercury assessments are scarce, especially because of exclusive extraction techniques and expensive analysis techniques. Still, this element is known for its toxicity, persistence, and bioaccumulation, making its presence in the environment an important factor for biota and human health. For this reason, the objective of this study was to determine the mercury concentration in the sediment of the Pelotas River basin, located on the border of the states of Santa Catarina and Rio Grande do Sul. The sediment was collected at eight locations of the Pelotas basin and, after drying, the mercury was quantified by atomic absorption spectrometry based on the Zeeman-background correction, coupled to a pyrolysis reactor. The mercury concentrations in the sediments of the Pelotas River varied from 40.5 ng g-1 to 62.0 ng g-1 and presented a positive correlation with the fraction of silt and clay. The concentrations of mercury found in sediments of the Pelotas River basin have a low probability of negatively affecting the biota. Nonetheless, given the persistence and bioaccumulation potential of this element, the aforementioned region needs further studies to quantify the risks it may cause on the local biota and human health.

Mercury in the Sediment of the Upper Parnaíba River

“…2018 According to the PCA (Figure 3), Hg presented a negative correlation with Mn and is not correlated with the natural variables clay, silt, sand, TOC, Al, and Fe. When the concentration of a metal in the sediment is positively correlated with the variables clay, silt, TOC, Al, and Fe indicates that the concentration is of geogenic origin (Davutluoglu et al, 2010;Remor et al, 2018). In this fraction, the elements are bound to silicates (Favas et al, 2015) or complexed with organic matter (Strom et al, 2011) and hence unavailable for biota.…”

“…In addition, the highest concentration found in the basin (S1) is approximately 14 times higher when compared to the lowest concentration (S5) (Figure 4). In this context, detailed studies are essential in the region aiming at proving the bioaccumulative capacity and degree of Hg toxicity in order to quantify the risks to aquatic biota and human health (Remor et al, 2018).…”

“…However, due to the need for unique extraction techniques and the cost of analyses, studies involving mercury are in less number (Franklin et al, 2012). In this sense, the studies of Araujo et al (2015), Cabral et al (2016), Hu et al (2015), Remor et al (2015), Sahoo et al (2015), and Remor et al (2018) stand out. Thus, the aim of this study was to determine the total mercury concentrations in sediments of the Upper Parnaíba River basin because it is a new Brazilian agricultural frontier and does not yet have records related to mercury concentration in sediments in rivers of the region.…”

Chemical elements in the water of the São Pedro river basin, Faxinal - Paraná

“…In Brazil, the use of pesticides containing methylmercury and ethylmercury was banned by the Ministry of Agriculture in 1975 (Ministério do Meio Ambiente [MMA], 2011). However, mercury is a persistent chemical that has remained in the environment and living organisms for a long time (Remor, Sampaio, Model, Falco, & Prudente, 2018).…”