A Study on the Distribution and Level of Cadmium in Scallop Bractechlamys vexillum (Reeve 1853) from the Visayan Sea, Philippines

Abstract

Bivalves such as scallop Bractechlamys vexillum are considered an essential resource for livelihood and revenues in the Visayan Sea, central Philippines. To date, there are several reports that the local marine ecosystems are contaminated with heavy metals like cadmium; hence, these species are also susceptible to bioaccumulation of cadmium because they feed mainly by filtering particles from contaminated water. In recent studies, scallops are suggested to be a potential bioindicator for cadmium contamination due to their ability to accumulate and tolerate the metal. This research aims to examine the anatomical distribution of cadmium in B. vexillum and measure the relationship between shell weight and cadmium concentration. The sites for this study include Carles, Iloilo, Madridejos, Cebu, and Cawayan, Masbate. Five organs were analyzed: adductor muscle, digestive gland, gonad, gill, and mantle. The analysis for quantification of cadmium in the different scallop parts was carried out by Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES Model ICPE-9820, Shimadzu, Kyoto, Japan). Results showed that cadmium preferentially accumulates in the digestive gland, accounting for 76.39% of the total metal concentration. Moreover, a significant positive correlation (r = 0.798, p < 0.01) between the cadmium content in the whole digestive gland and shell weight were observed. Thus, this tissue tends to have a potential marker of metal contamination in the environment.