Heavy Metals in Oysters, Shrimps and Crabs from Lagoon Systems in the Southern Gulf of México

Lagoon systems in the southern Gulf of Mexico are highly productive. These aquatic systems have been severely negatively impacted by anthropogenic and industrial activities. The objective of this research was to estimate the concentration of heavy metals Pb, Cu, Cd and Zn in oysters, shrimp and crabs from the Carmen-Pajonal-Machona and Mecoacan lagoon systems in Tabasco, Mexico. Samples were collected from fishing zones within these lagoon systems and included oysters Crassostrea virginica, and crustaceans such as Litopenaeus setiferus (shrimp) and Callinectes sapidus (crab). Concentrations of Pb, Cu, Cd and Zn were determined by atomic absorption using flame spectrophotometry. The heavy metal concentration pattern in oysters, shrimp and crab in the Carmen-Pajonal-Machona system was Cu > Pb > Cd. The maximum average concentration of Cu was 259.12 plus or minus 12.312 in oyster; 0.516 plus or minus 0.154 in shrimp, and in crab 0.907 plus or minus 0.273 mu g g super( -1). Pb had a maximum concentration of 1.37 plus or minus 0.77 in oyster, in shrimp was 0.059 plus or minus 0.044, and for crab was 0.0055 mu g g super( -1) (p>0.05), while in the Mecoacan lagoon system the pattern showed Pb > Cd > Zn. The maximum average concentration of Pb was 321.15 plus or minus 28.828 mu g g super( -1), the minimum was 84.70 plus or minus 8.612 mu g g super( -1). The highest concentration of Cd was 63.74 plus or minus 8.446 mu g g super( -1), and the minimum 13.00 plus or minus 0.64 mu g g super( -1). For Zn the maximum average concentration obtained was 24.42 plus or minus 2.665 mu g g super( -1).