Heavy metals pollution accessed from transplanted oysters (Crassostrea rhizophorae) in the Potengi estuary, RN / Brazil

Published: 17-08-2019| Version 3 | DOI: 10.17632/nmjxsrz9j8.3
Thaise Senez Mello,
carlos augusto ramos e silva,
Eduardo Teixeira da Silva,
Aecia Anjos


Concentrations of Cd, Cr, Cu, Pb, Ni and Zn were analyzed in total soft tissue from transplanted oysters between two sites in the Potengi estuary for almost six months to test the influence of environmental changes on accumulation and depuration of these metals. Native oysters were collected before and after transplantation to provide background for statistical analysis. The experimental design aims to test the following alternative hypotheses: H1- Significative difference on metal concentrations and biometrics between native oysters before transplantation and transplanted ones at the opposite site for 6 months. H2- Significative difference between heavy metal concentrations and biometrics achieved by transplanted oysters versus natives collected at the end of the experiment at the final site. H3- Significative correlation with biotic/abiotic variables. Description of spreadsheet columns: A: overall sample ordination. This numeration divides the dataset in 2 groups: the group named "Base Naval" containing 139 oysters, and "Quartel", with 157 oysters. The difference between sample sizes are due to mortality, loses during laboratorial procedures or data cleaning for outliers and doubtful data. B: categorical ordering of oysters within the same temporal sampling (collected at the same site and day). C: group name. For example, Nt0 is the group of natives collected before the transplantation. It was done on the July /17/2007. In this day, all oyster was taken to the lab, but only Nt0 were analyzed, While the others were carefully cleaned and housed in bag-shaped cages made of PVC mesh. These bags were taken back to the field and anchored at the opposite site. The following names in this column are referred to the chronological sampling order (T1, T2, T3 and so on) and the suffix (B or Q) indicates the location of the cage from which the oysters were taken. NtF stands for "final natives" and these oysters were collected at the same site where the last group from the transplant bag were removed. D: place where sample were collected, despite its s original site E: sampling date F: accumulated rainfall over the fourteen days preceding the sampling campaigns (mm/ per square meter) G: mean atmospheric temperature (Celsius degree) over the fourteen days preceding each sampling H: mean insolation over the fourteen days preceding each sampling (N per hour) I: mean wind intensity over the fourteen days preceding each sampling (meters per second) J: mean tide amplitude over the fourteen days preceding each sampling (meters) K: dry weight (grams) - Total soft tissue dry weight L: shell length (cm) - the largest length of the largest valve of each oyster M: Condition Index - C.I. = (soft tissue dry weight /shell volume) * 100. Results are expressed in (g/ cm³) N to S: Cd, Cr, Cu, Ni, Pb and Zn concentration from oyster's total soft tissue dry weight (µg/g-1) Ambiental variables were provided by CHM (Centro de Hidrografia da Marinha do Brasil)