6 research outputs found
Chemical contamination assessment in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as biomonitor species
This paper aims to contribute to the use of mangrove
cupped oyster, Crassostrea rhizophorae, as a biomonitor
species for chemical contamination assessment in
mangrove-lined Caribbean coastal systems. Sampling was
carried out in eight localities (three in Nicaragua and five in
Colombia) with different types and levels of contamination.
Oysters were collected during the rainy and dry seasons of
2012â2013 and the tissue concentrations of metals, polycyclic
aromatic hydrocarbons (PAHs), and persistent organic pollutants
(POPs) were determined. Low tissue concentrations of
metals (except Hg) and PAHs; moderate-to-high tissue concentrations
of Hg, hexachlorocyclohexanes (HCHs), and
dichlorodiphenyl-trichloroethanes (DDTs); detectable levels
of chlorpyrifos, polychlorinated biphenyls (PCBs) (mainly
CB28, CB118, CB138 and CB 153) and brominated diphenyl
ethers 85 (BDE85); and negligible levels of musks were recorded
in Nicaraguan oysters. A distinct profile of POPs was
identified in Colombia, where the tissue concentrations of
PCBs and synthetic musk fragrances were low to moderate,
and Ag, As, Cd, Pb, and PAHs ranged from moderate to extremely
high. Overall, the values recorded for HCHs, DDTs
and PCBs in Nicaraguan mangrove cupped oysters greatly
exceeded the reference values in tissues of C. rhizophorae
from the Wider Caribbean Region, whereas only the levels
of PCBs were occasionally surpassed in Colombia. Different
contaminant profiles were distinguished between oysters from
Nicaragua and Colombia in radar plots constructed using the
main groups of contaminants (metals, PAHs, musks, PCBs,
and organochlorine pesticides (OCPs)). Likewise, integrated
pollution indices revealed differences in the levels of contaminants.
Moreover, the profiles and levels in oyster tissues also
varied with season. Thus, principal component analysis clearly
discriminated Nicaraguan and Colombian localities and, especially
in Colombia, seasonal trends in chemical contamination
and differences amongst localities were evidenced. The geographical
and environmental disparity of the studied scenarios
may represent to a large extent the diversity of mangrove-lined
Caribbean coastal systems and therefore the present results
support the use of C. rhizophorae as suitable biomonitor species
at Caribbean regional scale, where seasonal variability
is a major factor controlling pollutant mobility and
bioavailability