American oyster (Crassostrea virginica) and sediments as a coastal zone pollution monitor by heavy metals

Abstract

Levels of barium, cadmium, chromium, copper, mercury and vanadium were determined by plasma emission spectroscopy in sediments and oysters (Crassostrea virginica) in the Palizada, Chumpán and Candelaria rivers, which flow into the Términos Lagoon, state of Campeche, Mexico. The relation between the condition index of the oyster and the detected elements were determined as well. Significant relations were observed between copper (r = -0.825, p \ 0.05) and chromium (r = -0.787, p \ 0.05), which indicates the oysters' affectation by ingesting both elements; concurrently, the results confirm that oysters present high tolerance to heavy metals. The average concentration of cadmium (2.05 lg/g), chromium (1.82 lg/g) and copper (115.55 lg/g) in rainy-season climate exceeded the limits for marine mollusks regarding different health standards. It was found that the rainy season, the sediment characteristics and organic matter content have a great influence on the transport and availability of heavy metals.

Effect of Mercury Transfer from Producer to Consumer in a Marine Environment

“…cell -1 Hg concentrations in the natural environment that were considerably lower than the phytoplankton subjected to Hg exposure in the laboratory, indicating the low assimilation of Hg by phytoplankton in nature. These results were in line with earlier studies [12,23,31].…”

“…BCF and BAF were determined by the following equation [18]: BCF = Hg concentration in phytoplankton Hg concentration in seawater (1) BAF = Hg concentration in secondary consumers Hg concentration in primary consumer (2) Results and Discussion ) during 2016-17. This was within the concentrations compared to the Hg levels observed by earlier investigators [23,[31][32]. This was also lower than 0.94 µg .…”

“…The high Hg concentrations in the sequence of sites V and IV indicated the past effect of salt chlor-alkali plants besides the present influence of discharges from desalination, thermal, power plants, industrial and domestic wastes, sedimentation, stagnation, and single-flow direction of Shatt Al-Arab River water mixing from the north to the south of Kuwait Bay. As the Bay water is characterized by restricted exchange with the open sea, the chances of coastal and catchment habitat destruction and biodiversity loss was observed with significant environmental damage from pollution, thus supporting the views of [20][21]23]. A gradual increase of Hg concentrations in seawater was observed during the winter compared to summer (Fig.…”

“…The density of zooplankton was constantly maintained. The cultured zooplankton were fed with Hg-exposed phytoplankton (2- [22][23] are schematically represented (Fig. 2).…”

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“…Most authors who determined the Hg 2+ content of wild or cultured oysters of Mexican Pacific lagoons found higher contents during the rainy than in the dry season (Osuna-Martínez, Páez-Osuna, & AlonsoRodríguez, 2010; Aguilar et al, 2012;Jara-Marin i et al, 2013;Páez-Osuna & Osuna-Martínez, 2015) and, although differences were not significant, the same tendency to higher values during the rainy season was found by Delgado-Alvarez et al (2015) in the oysters collected every three months during an annual cycle at 12 lagoons or coastal sites of the Mexican NW.…”