BOTTE Sandra Elizabeth
congresos y reuniones científicas
Lead concentrations in a southwestern Atlantic temperate estuary (Bahía Blanca, Argentina)
Santa Fe
Congreso; III Congreso Argentino de la Sociedad de Toxicología y Química Ambiental SETAC; 2010
Institución organizadora:
The present work constitutes the first study of lead concentrations in the zooplankton from one of the most important and industrialized estuaries of Argentina, the Bahía Blanca estuary. The main objective of the present study was to analyze the spatial and temporal distribution of lead, focusing on the zooplankton as well as the dissolved and particulate fraction due to their importance in the biogeochemical cycles of heavy metals. The major physicochemical variables (pH, temperature, salinity, dissolved oxygen, pigments, particulate organic matter and nutrients) and the zooplankton composition and abundance were also analyzed. Samplings were carried out from March to December 2005 with a bimonthly frequency and considering a study area with stations located near industrial settlements and other stations far from these points. Lead concentrations were measured with a Perkin–Elmer AA-2380 atomic absorption spectrophotometer with an air/acetylene flame. The physicochemical variables agreed with historical values for the estuary, and did not present any evidence of abnormality in their temporal and spatial distribution. Moreover, the zooplankton composition and abundance did not show any unusual pattern, since both the temporal and spatial distribution presented the normal behavior for this estuary. Dissolved Pb presented a mean concentration of 2.15 ± 0.46 µg L-1, while particulate Pb, 13.52 ± 3.07 µg g-1d.w. In the mesozooplankton (200 µm-2 mm) the mean concentration was 13.38 ± 4.41 µg g-1 d.w. and in the macrozooplankton (2-20 mm): 9.81 ± 1.89 µg g-1 d.w. The concentrations of lead in all the fractions fluctuated throughout the study time and the sampling stations did not present pronounced differences (Blocked Nested ANOVA, p>0.25). Lead concentrations were relatively high in the particulate phase and in some months zooplankton accumulated important concentrations of this metal. The enrichment of lead in all these fractions could be related to the discharges of the industries as well as of the domestic sewage located near the estuary. However, futures studies are needed in order to corroborate these sources of lead and develop appropriate management strategies to regulate these sources