Organochlorine pesticidas and PCBs in sediments and bulrush from La Brava Lake, Argentina.

MENONE MIRTA; MIGLIORANZA KARINA SILVIA BEATRIZ; AIZPUN JULIA ELENA; MORENO VICTOR JORGE

AEHS, SAN Diego CA, USA

Conferencia; 18th Annual AEHS (Association for Environmental Health and Sciences) Meeting and West Coast Conference on Soils, Sediments and Water,; 2008

Association for Environmental Health and Sciences)

Poster Presentation The global occurrence of persistent organic pollutants is a concern for natural ecosystems and human heath. The use of aquatic plants in water quality assessment has been common for years as in-situ biomonitors. In this work, roots and stems of bulrush Schoenoplectus californicus as well as surface sediments and near root sediments (NRS)  were sampled in order to make a screening of the organochlorine pesticides (OCPs) and PCBs status in La Brava lake Argentina. Different sites of the lake including the affluent and effluent creeks were selected as sampling stations due to the agricultural activities developed in upstream areas. A particular emphasis was made on analysis of a representative plant species and its capacity for bioaccumulating organochlorines from sediments. The total OCPs concentrations ranged from 70 to 1710 ng/ g OC. The distribution pattern of OCPs in sediments showed a predominance of DDE, followed by HCHs (alfa- and gamma- isomers), cyclodienes (gamma- chlordane) and endosulfan (alfa- and beta- isomers). Bulrush tissues showed a mean total OCPs concentrations of 10 ng/g dry weight and similar distribution pattern than NRS. A predominance of endosulfan (alfa-, beta- and sulfate) was observed in roots and stems, followed by DDE. The relatively higher polarity among OCPs and the current use of endosulfan in the field could explain its higher levels in biota. Bioaccumulation of all groups of OCPs was observed in roots by using the factor: roots OCPs concentration/ NRS concentration. The concentrations of total PCBs in sediments ranged from 30 to 700 ng/g OC, while in bulrush tissues ranged between 0.6 and 4.2 ng/g dry weight. A predominance of tetra-, penta- and hexa- chlorobiphenyls was observed in both matrixes. Although low levels of total organochlorines were detected, the occurrence of DDE as the main pesticide found in sediments, highlights about its worldwide persistence.