Levels of heavy metals in zooplankton and suspended particulate matter in a in southwestern Atlantic temperate estuary (Argentina)

VILLAGRAN DIANA; FERNÁNDEZ SEVERINI M.D.; BIANCALANA F; MENÉNDEZ MC; SPETTER C.V.; GUINDER V. A.; BERASATEGUI A.; MARCOVECCHIO J. E.

Punta del Este

Congreso; XV Congreso Latinoamericano de Ciencias del Mar (COLACMAR); 2013

The concentrations of cadmium, chromium, copper, iron, manganese, nickel, lead and zinc were obtained in the suspended particulate matter (MPS) and in the mesozooplankton of the Bahía Blanca Estuary, one of the most important estuaries in Argentina. Water and zooplankton samples were collected monthly at four sampling stations, from April to October 2012. Twenty-four taxa were identified in the mesozooplankton and Acartia tonsa, Eurytemora americana, Balanus spp. (nauplii) and Cyrtograpsus altimanus (zoea) were the most important species. The total abundance showed maximum values in autumn (1220 ind m-3) and spring (1295.77 ind m-3) and lowest in winter (37.09 ind m-3). The heavy metals concentrations in the MPS (mg g-1 dry weight) were: Cd:0.11-7.53; Cu:7.34-85.67; Cr: 7.18-51.14; Fe: 8141- 41760; Mn: 221.1-1293; Ni: 4.89-31.05; Pb: 0.5-53.76; Zn: 30.18- 631.2. The highest concentrations were found in the stations near sewage or industrial discharges, indicating that those stations could be sources of these elements. Also, metals detectable levels were presented in the MPS during the sampling period, demonstrating the presence of continuous or quasi-continuous sources of these contaminants. Heavy metal levels in the mesozooplankton were highly variable (Cd: 0.26-3.77; Cu: 35.34-226.6; Cr: 2.19-57.9; Fe: 1060-39090; Mn: 17-963; Ni: 2.84-57.31; Pb: 6.06-66.68; Zn: 30.18-631.2). Similar levels of Cd, Cr and Ni were observed in all stations, while the levels of Cu, Pb and Zn were higher in the station next to sewage discharge and at the station farthest from the industrial area. The Fe and Mn levels were highest in an area near a former landfill. Finally, it was found that all metals biomagnified except Fe and Mn. These results reveal that strict monitoring control and management plans have to be considered to mitigate the anthropic impact on estuarine ecosystem.