Mercury dynamics in macroinvertebrates in relation to environmental factors in a highly impacted tropical estuary: Buenaventura Bay, Colombian Pacific

Abstract

The environmental health of Buenaventura Bay, a highly impacted tropical estuary, is influenced by numerous human activities, including mining upstream. Large-and small-scale fishing plays an important role in the local economy, so we investigated the dynamic processes of bioaccumulation of mercury at basal trophic levels. Four samples were taken at each of the four locations in Buenaventura Bay during each of the four seasons of 2015. We measured the total mercury content (T-Hg, dry weight) in sediments and in muscle tissue across 17 macroinvertebrate species. The most abundant were the blue crab (C. arcuatus) and the mantis shrimp (S. aculeata aculeata). Blue crab showed an average muscle T-Hg value exceeding the limit of 0.2 g•g-1 , which is the maximum T-Hg level suggested for food consumption by vulnerable humans and populations: pregnant women, children, and the community that feeds from this source of protein on a daily basis. It was found that, 6.22% of individuals exceeded the 0.5 g•g-1 level, which is the maximum T-Hg level suggested for food consumption by the general population: the population that consumes it sporadically. Significantly high values of T-Hg in blue crab and mantis shrimp occurred during low salinity conditions in the estuary, suggesting that Hg mainly originates from river runoff during the rainy season. Nevertheless, the biota-sediment accumulation factor (BSAF) was favored in high salinity, which could mean greater availability of Hg for higher levels of the estuarine food web in the dry season and in marine waters. In general, the T-Hg levels in some samples exceeded 0.2 g•g −1. Therefore this pollutant must be monitored due to its biomagnification potential and as a threat to human health, especially that for the local population of fishermen and their families.

Effect of water quality variation on fish assemblages in an anthropogenically impacted tropical estuary, Colombian Pacific

“…In particular, the Colombian Pacific region is strongly socioeconomically dependent on the ecosystem services for the local fish consumption and the commercialization of fishery resources (Saavedra-Díaz et al 2016;Salas et al 2019;Villanueva and Flores-Nava 2019). However, previous studies from this region suggest that pollutant concentrations affect benthic communities (Martínez et al 2019) and that these pollutants are bioaccumulating in organisms of commercial interest (Duque and Cogua 2016;Gamboa-García et al 2020) as well as in organisms at higher trophic levels (Gamboa-García et al 2018b).…”

Spatial distribution and increase of microplastics over time in sediments of Buenaventura Bay, Colombian Pacific

“…Así mismo, los microplásticos pueden ser un vector de compuestos tóxicos (contaminantes orgánicos persistentes y metales pesados) en organismos marinos por los aditivos químicos añadidos al plástico durante su fabricación y tienden a absorber y acumular contaminantes del agua circundante, proceso que se ve favorecido por su forma y tamaño, que le dan una gran relación superficie/volumen. Los microplásticos presentan también una alta probabilidad de lixiviación de aditivos plásticos que pueden inducir efectos tóxicos en la biota acuática (Wang et al, 2019b;Zhang et al, 2020a;Gamboa-García et al, 2020). Debido a lo anterior, los microplásticos no solo causan daños mecánicos a los organismos, sino que también, pueden introducir compuestos contaminantes a través de la red trófica (Guo y Wang, 2019).…”

Assessment of ecological safety of fish from anthropogenically polluted freshwater reservoir

“…Their quantity can vary greatly between sampling sites even within one water reservoir since its water area contains various biotopes with a specific composition of hydrobionts and biological productivity [7]. The rivers are most highly affected by heavy metals contamination, they can circulate in their food chains for a long time [8]. Research [9] found that aquatic organisms are distributed in the following order for bioaccumulation capacity: phytoplankton < zooplankton < fish < shrimp < shellfish.…”

“…According to [11], in conditions of anthropogenically polluted reservoirs, fish body can accumulate a significant amount of heavy metals, which becomes dangerous not only for the fish themselves, but also for humans. Bioaccumulation of metals is facilitated by the fact that they are practically nonbiodegradable in biotic and abiotic components of aquatic ecosystems and accumulate in their composition [8]. Therefore, the fish body serves as a reliable bioindicator for monitoring metals accumulation in the environment [12][13][14].…”

“…Accumulating in the tissues of food fish, metals can have a negative effect on the human body when eating it up to acute and chronic poisoning [Castro-Gonzale M.I., 2008]. Especially dangerous is the presence of highly toxic heavy metals, such as lead, cadmium, mercury, arsenic in fish [8], which can accumulate in it even when ingested in microquantities due to low metabolic activity and long excretion period. In the fish body, metals are deposited not only in muscle, but also in fatty, bone, connective tissues, liver, bladder, intestines [15].…”