Heavy Metals in a Coastal Lagoon of the Gulf of Mexico

Terminos lagoon is located in the south east Gulf of Mexico and is ecologically and economically important due to biological diversity, valuable fish, and wildlife resources. The hydrological parameters (salinity, temperature, turbidity, pH, dissolved oxygen, nitrate, nitrite, nitrite, ammonium, silicate, phosphate) and concentration of total metals (Cd, Cu, Ni, Zn, Fe, and Mn) were measured at 24 stations in the lagoon during six samplings (4 March 1994–28 January 1995). Salinities varied from freshwater to seawater and were a function of season. Concentrations of hydrological parameters and total metals were related to salinity by simple linear regression. The pH, turbidity, dissolved oxygen, nitrate, ammonium, and phosphate had no relationship with salinity. Iron and Mn concentrations were independent of salinity and the Cd, Cu, Ni, and Zn showed positive relationships with salinity. Possible causes of these relationships are briefly discussed.