Loaiza I.1,2,3, De Boeck G.2 and De Troch M.1
1 Ghent University, Department of Biology, Marine Biology, Krijgslaan 281/S8, 9000 Ghent, Belgium
2 University of Antwerp, SPHERE – Systematic Physiological and Ecotoxicological Research, Groenenborgerlaan 171, 2020 Antwerp, Belgium
3 Facultad de Biología Marina. Universidad Científica del Sur. Av. Antigua Carretera Panamericana Sur km 19 Villa El Salvador. – Lima 42, Perú.
An integrated approach was developed in order to determine different environmental status in Sechura Bay (SB) and front the Illescas Reserved Zone (IRZ) – Piura. Metals, stable isotopes, fatty acids and sediment quality parameters were analyzed in samples from southern and northern of SB and IRZ (summer ENSO-2016 sampling). Subsequently, a non-metric multidimensional scaling method (nMDS) (Bray Curtis similarity) and one-way analysis of similarity test (ANOSIM, the biochemicals: non-essential metals and biomarkers (fatty acids) in scallop Argopecten purpuratus, snail B. ventricosa and food sources (seston, POM and sediment) showed no differences between locations (one way ANOSIM; p>0.005). The only significant differences (p=0.001) were found between the trophic position components (primary consumer, carnivorous consumer and food sources) without any spatial variation. Based on δ15N and δ13C, crabs Hepatus chilensis and Romaleon polyodon showed the highest trophic level with δ15N values of 12.68 ‰ and 12.29 ‰, respectively. The lowest values (down to 1.10 ‰) were measured for the food sources. A. purpuratus was more δ15N-depleted (6.96 – 8.45 ‰) than its potential predators. This points at its role as intermediate consumer and main food item for the predators in the benthic food webs of SB and IRZ. Mean δ13C values for predators of A. purpuratus were between -12.25 and -15.26 ‰, while the food sources showed high variations because the fresh and brackish-water input. For metals, around 20 and 30% of molluscans and crustaceans exceeded the maximum residue levels (MRLs) for inorganic As, while 10 and 40% for Cd. Other metals such as Cr, Ni, Cu, Zn and Pb exhibited generally concentrations below the MRLs. Integrated risk indexes were estimated to determine if there is a health risk for consumption. Provisional tolerable weekly intake (PTWI) for Cd was exceeded in Bursa ventricosa at IRZ. Target cancer risks (TRs) for inorganic As were always higher than the threshold (1×10-6), therefore a cancer risk could be posed.