Heavy Metal Levels and Length-Weight Dynamics of Anodontia philippiana (Reeve, 1850) from Barobo and Hinatuan, Surigao del Sur, Philippines

Abstract

Anodontia philippiana is among the commercially valuable edible clams found in Brgy. Wakat, Municipality of Barobo, and Brgy.
Loyola, Municipality of Hinatuan, Surigao del Sur, Philippines. However, anthropogenic activities may pose a threat to the abundance and quality of this species. This study aimed to determine the levels of lead (Pb), nickel (Ni), chromium (Cr), and mercury (tHg) in both the sediments and flesh of A. philippiana using Atomic Absorption Spectrophotometry (AAS). Additionally, the length-weight relationship (LWR) of A. philippiana was assessed to determine the size structure of the species’ population. Among the heavy metals tested, only the concentration of Cr (59±0.38 ppm) in Hinatuan exceeded the prescribed tolerable limit of ≥50 ppm (FAO, 1993). Conversely, the heavy metal levels in the flesh of A. philippiana consistently remained below tolerable limits. Furthermore, A. philippiana from Barobo exhibited a positive allometry (B>3), while those from Hinatuan showed a negative allometry (B<3), suggesting the influence of environmental stressors on growth patterns. The LWR in A. philippiana exhibited significant differences (P<0.001) between the two stations. Despite heavy metal concentrations in A. philippiana flesh and sediments were mostly below standard limits, the observed negative allometric growth pattern in Hinatuan indicates the presence of ecological stressors in the sediments. This study underscores the potential impact of heavy metals on the growth patterns of A. philippiana. It is recommended that regular monitoring of heavy metal concentrations be conducted in these areas. Further studies can provide better insights into morphometric patterns in A. philippiana and other commercially significant bivalves.