Biomagnification of Mercury in Fish from Two Gold Mining-Impacted Tropical Marshes in Northern Colombia

Abstract

Total mercury concentrations (T-Hg) and stable isotope ratios (δN and δC) were analyzed in the muscle of fish, collected at two marshes impacted by gold mining in Northern Colombia, to evaluate the seasonal and spatial behavior of these variables and mercury biomagnification based on their relationship with δN ratios in the fish. There was not significant (p > 0.05) seasonal differences (dry and rainy season) in δN and δC values in none marsh, suggesting that these fish species keep a similar feed pattern within each marsh along the year. However, there were significant differences (p < 0.05) between marshes in δN, δC, and T-Hg, as well as significant seasonal differences (p < 0.05) in T-Hg values for some species, suggesting the possible influence of factors, such as differences in length of food chains between marshes and different degree of anthropogenic impact in relation to human settlements, farmland, livestock (higher in Ayapel marsh), and gold mining activity (higher in La Raya marsh). Correlations analysis showed significant (p < 0.05) relationships between T-Hg concentrations and δN values, as well as trophic level, evidencing a T-Hg biomagnification process in the fish food chain from both marshes and consequently a potential health risk for human riverside inhabitants who eat these fish.

Water quality in the municipalities of Sincerín and Gambote, Bolívar, Colombia (2017-2018

“…In the case of mercury, the ingestion of high concentrations leads to higher risks since it tends to bioaccumulate through the food chain and can cause mutations (teratogenicity) [25]. It has been reported that up to 90% of the bioaccumulated mercury is incorporated into the digestive system through food [26].…”

Foraging habits and levels of mercury in a resident population of bottlenose dolphins (Tursiops truncatus) in Bocas del Toro Archipelago, Caribbean Sea, Panama

“…The isotopic measurements were expressed in parts per thousand (‰), using the delta (δ) unit relative to the deviation from international standard values PeeDee Belemnite Carbonate for δ 13 C and atmospheric N2 for δ 15 N (Méndez-Fernandez et al, 2012;Marrugo-Negrete et al, 2018). Based on replicate measurements of internal laboratory standards, experimental precision (SD) was < 0.09 for δ 13 C and < 0.36 for δ 15 N.…”

“…The Hg low concentrations could be also related to the dominance of juvenile fish in the Archipelago, which reflect lower Hg concentrations compare to bigger ones as a consequence of bioaccumulation of Hg with age (Boush and Thieleke, 1983;Marrugo-Negrete et al, 2018). The abundance of juvenile fish in areas such as Almirante Bay is a result of dramatic decrease of larger predatory fish due to overfishing (Seemann et al, 2013).…”

“…Top predators such as bottlenose dolphins have shown high mercury (Hg) concentrations as the result of bioaccumulation with individual age and biomagnification processes in the food webs (Fossi et al, 2012). Therefore, Hg can be used as ecological tracer to assess the trophic position in the food chain, since Hg variations have been associated to age, individual size, and trophic level (Boush and Thieleke, 1983;Power et al, 2002;Cai et al, 2007;Newsome et al, 2010;Kehrig et al, 2013;Marrugo-Negrete et al, 2018). Hg concentration also varies with location, depth, and distance to the shore (Rivers et al, 1972;Colaco et al, 2006, Choy et al, 2009, with higher Hg values found in coastal ecosystems largely due to the influence of freshwater inputs and coastal development (Strom and Graves, 2001).…”

Concentraciones de metilmercurio en Prochilodus magdalenae (Teleostei: Curimatidae) y Hoplias malabaricus (Teleostei: Erythrinidae) en la cuenca baja del río Cauca-Magdalena, norte de Colombia

“…Dentro de los elementos nocivos se encuentran metales como el Hg, los cuales han sido reportados de alto riesgo para la salud humana, debido a que en los tejidos de los peces de consumo se pueden llegar a encontrar en altas concentraciones (Olivero-Verbel et al, 2015;Vargas y Marrugo, 2019). ACTA BIOLÓGICA COLOMBIANA El MeHg puede ser bioacumulado en tejidos de peces como Prochilodus magdaleneae (bocachico) y Hoplias malabaricus (moncholo) (Marrugo-Negrete et al, 2018;Vargas y Marrugo, 2019), peces de alta importancia económica, gastronómica, cultural y comercial en las zonas de estudio. En Colombia, el bocachico habita las cuencas hidrográficas de los ríos Magdalena, Sinú y Atrato (Mojica et al, 2002;Maldonado-Ocampo et al, 2005;Román-Valencia, 1993).…”