Abstract
Dragonflies (Order Odonata) often are considered to be biosentinels of environmental contamination, e.g., heavy metals and/or persistent organic pollutants (POPs). Dragonflies (n = 439) belonging to 15 species of 8 genera were collected from an abandoned mercury (Hg) mining region in China to investigate the bioaccumulation of total Hg (THg) and methylmercury (MeHg). THg and MeHg concentrations in dragonflies varied widely within ranges of 0.06-19mg/kg (average: 1.5 ± 2.2mg/kg) and 0.02-5.7mg/kg (average: 0.75 ± 0.65mg/kg), respectively. THg and MeHg were positively correlated with bodyweight (THg: r2 = 0.10, P = 0.000; MeHg: r2 = 0.09, P = 0.000). Significant variations were observed among species, with the highest MeHg value (in Orthetrum triangulare) was fivefold higher than the lowest (in Pantala flavescens). These variations were consistent with those of nitrogen isotope (δ15N) values, indicating that increased δ15N, i.e., trophic levels, may reflect increased exposure and uptake of biomagnifying MeHg in dragonflies. A toxicologicalrisk assessment found hazard quotients for specialist dragonfly-consuming birds of up to 7.2, which is 2.4 times greater than the permissible limit of 3, suggesting a potential toxicological risk of exposure.
Highlights
Mercury (Hg) is a globally distributed pollutant that can cause severe health-exposure risks to the biota of both aquatic and terrestrial ecosystems (Cristol et al, 2008; Walters et al, 2010)
Dragonflies (n = 439) belonging to 15 species of eight genera were collected from an abandoned mercury (Hg) mining region in China to investigate the bioaccumulation of total Hg (THg) and methylmercury (MeHg)
Dragonflies in WK had extremely high THg levels, while dragonflies from other sites showed slightly decreasing or comparable levels of both THg and MeHg with distance from upstream pollutant Hg sources. This was coincident with the THg concentrations of surface water (Figures 4 a, b); both THg (r = 0.894, P = 0.000) and MeHg (r = 0.684, P = 0.020) in dragonflies were positively correlated to surface water THg, suggesting that they are a good indicator of aquatic Hg concentrations
Summary
Mercury (Hg) is a globally distributed pollutant that can cause severe health-exposure risks to the biota of both aquatic and terrestrial ecosystems (Cristol et al, 2008; Walters et al, 2010). Apart from unintentional accidents, the dominant pathway of Hg poisoning is through the consumption of foodstuffs contaminated with Hg, methylmercury (MeHg). As an organic form of Hg, MeHg has extremely neurotoxic effects and is readily accumulated in biota due to its lipophilic and protein-binding properties (Ullrich et al, 2001). Consumption of fish and rice is considered the major pathway for human exposure to MeHg (Clarkson and Magos, 2006; Feng et al, 2008; Qiu et al, 2008; Kathryn et al, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Archives of Environmental Contamination and Toxicology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
