Trace Metals in Sediments of Seven Coastal Lagoons of the Sabana – Camagüey Archipelago, Cuba

Abstract

ABSTRACT Coastal lagoons are highly sensitive ecosystems from the ecological point of view. Water samples to assess physicochemical parameters, as well as sediments to measure trace metals (Cd, Cr, Cu, Ni, Pb, Zn and Hg) were collected in seven coastal lagoons of the Sabana-Camagüey Archipelago. Los Caimanes, Tortuguilla and La Salina lagoons showed high salinity levels (>100.0 PSU). High concentrations of Total Nitrogen (TN, up to 819.3 mmol/L) and Total Phosphorus (TP, up to 7.8 mmol/L) were recorded in the lagoons with more impact from tourism development, such as Las Coloradas, Larga, Los Caimanes and La Salina lagoons. Regarding their relative abundance, metals ranked as follows: Ni > Zn > Cu > Cd > Hg > Cr >Pb. Metal concentrations ranged within the following intervals: Pb: < 50 mg/kg (all values below the quantification limit); Ni: <12.5–115.7 mg/kg; Cd: <2.0–3.4 mg/kg; Zn: 5.2–81.4 mg/kg; Cu: <5.0–45.2 mg/kg; Cr: <25.0–156.4 mg/kg and Hg: <0.1–0.30 mg/kg. The concentrations of trace metals were similar to those recorded in uncontaminated coastal systems of Cuba and other parts of the world. Nevertheless, most trace metals, except Hg, showed high concentrations at Site 1 of Laguna Las Coloradas. Laguna Tortuguilla was the lagoon with the highest ecological risk. Cd must be carefully monitored there, as concentrations detected were high (up to 3.4 mg/kg), which poses an ecological risk for all the lagoons.