NIVELES DE METALES PESADOS EN SEDIMENTOS SUPERFICIALES EN TRES ZONAS LITORALES DE VENEZUELA

To evaluate the water quality along the continental shores
of Venezuela, where fishing communities exploit the clam Tivela
mactroides, the concentration of heavy metals (Cu, Mn, Fe, Zn,
Cd, Ni, Pb y Cr) was determined in superficial sediments,
together with environmental factors (temperature, salinity,
dissolved O2, pH, phytoplanctonic biomass, seston, and total N
and P) of the litoral waters of Playa Güiria on the northeastern
coast (Sucre State), and of Río Chico and Boca de Paparo (Miranda
State), two localities on the central coast separated by
some 5km and influenced by the Tuy River. In Río Chico, and
mainly in Boca de Paparo, the concentration of heavy metals in
the sediments (>18μg·g-1 Cu, >3μg·g-1 Cd, >5μg·g-1 Cr, >0.9μg·g-1
Pb, >11μg·g-1 Ni) and the environmental factors (>28ºC,
<5.6ml·l-1 dissolved O2, >55μmol·l-1 total N, >17μmol·l-1 total P)
indicated the presence of polluted systems. This environmental
damage was linked to the influence of the Tuy River, which flows
into the sea at Boca de Paparo. The values for heavy metals
were higher than the values reported 14 year ago. In Playa
Güiria the values determinated did not show environmental
contamination (0.03μg·g-1 Cu; 0.5μg·g Cd and no Cr, Pb or Ni
were detected). Shore cleanup at Boca de Paparo and Río Chico
is recommended, as these locations have dangerous sanitary and
environmental conditions. Environmental conditions at Playa
Güiria allow for Tivela mactroides fishing.