Temporal variations of heavy metals levels in Perna viridis, on the Chacopata-Bocaripo lagoon axis, Sucre State, Venezuela

• Heavy metal concentrations were within levels allowed worldwide (FAO, BFL, FDA).
• The highest concentration of heavy metals was found during the drought period.
• Significant relationships amid size and metal concentration only found in drought.

Perna viridis was used as biomonitor to assess heavy metal levels in the Chacopata-Bocaripo lagoon axis, Venezuela, during rain and drought seasons. The mussels were weighed and measured. The metal concentrations were determined by atomic absorption spectrophotometry. For rain period, the order of bioavailability was: Cu > Ni > Mn > Co > Cd > Pb, and for drought: Cu > Mn > Ni > Co > Pb > Cd. The concentrations of Ni, Co, Cd and Pb showed significant differences (P < 0.05) in both periods. There was higher metal accumulation during drought season, possibly related to upwelling, since it produces an increase in primary productivity, which translates more food into organisms, making metals bioavailable for mussels. Only Cu and Mn showed significant relationships between the size and metal concentration, during drought period, it may be because of the organisms need for these essential metals in different physiological processes.