A chemo-metric approach to assess heavy metal pollution status in a human impacted coastal system

TRUCHET, D.M.; NEGRO, C.L; BUZZI, N.S.; MORA, C; ARDUSSO, M.G.; MARCOVECCHIO, J. E.

Encuentro; SETAC Latin America 14th Biennial Meeting. Latin America, Diversity of Knowledge for a sustainable future; 2021

Estuaries are among the most threatened coastal environments since they receive several pollutants from riverine discharges, large urban settlements, industries and ports. Human pressures are enhanced in developing countries of South America, such as Argentina, where the biota is at risk due to several pollutants (metals, POPs and microplastics), and therefore, biomonitoring of these areas is highly recommended. However, few studies have achieved this concern and the scientific tools displayed in an integrative way where abiotic and biotic matrices are combined using multiple indices were even less studied. The current study compared metal concentrations (Cd, Cu, Pb, Zn, Mn, Ni, Cr, Fe) in sediments and a resident benthic crab species, Neohelice granulata and the biochemical biomarkers (CAT, GST, H2O2, MT) in this organisms in a salt marsh (SM) and a mudflat (M) in different stations (autumn and spring) of a SW Atlantic estuary (Bahía Blanca estuary, BBE) in Argentina. This area is currently influenced by several industrial and domestic discharges, ports and large scale fisheries. Metals in sediments did not exhibit significant differences between sites and seasons, except for Mn that was higher in SM during spring. Crabs bioaccumulated more Cu from sediments during autumn than spring for both sites. Except for Cd in M, Mn, Ni and Fe in SM, metals did not exhibit significant differences between sites, but tended to increase in autumn at both sites. Through geochemical indices, it was observed that sediments were low to medium polluted with probable adverse biological effects to the biota. Some of the biochemical analyses applied (i.e., IBR) demonstrated high values in the SM during spring with a great contribution of H2O2 and GST. By multivariate analyses (Pearson correlations and PCA), it was possible to observe that the biomarkers induction might be due to natural intrinsic factors such as energetic costs for reproduction and not strictly metallic pollution. But also, it should be considered that during spring, the available organic matter in the estuary is higher and specifically in the SM that also uptakes metals coming from plants. These metals are ultimately incorporated into the body burden of organisms and some correlated metals like Zn, Cu, Mn and Cd can cause biomarkers induction.