Multi-year monitoring of estuarine sediments as ultimate sink for DDT, HCH and other organochlorinated pesticides in Argentina

ARIAS, A.H.; PEREIRA, M.T.; MARCOVECCHIO, J.H.

ENVIRONMENTAL MONITORING AND ASSESSMENT

Springer

Año: 2011 vol. 172 p. 17 - 32

0167-6369

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Abstract 49 superficial sediment samples used in this study were collected from eight sites in the Bahia Blanca Estuary, located in the Buenos Aires Province southwest, Argentina, in a period between April 2005 and March 2009, to assess the concentration levels, spatial and seasonal distribution and putative input sources of 18 selected organochlorine pesticides (OCs), following UNEP-IAEA procedures. Average concentration levels in sediments ranged between 3.54 and 63.79 ng.g-1, d.w (mean = 15.99 ng.g-1, d.w), for ∑OCs, and from non detectable to 8.03 ng.g-1, d.w. (mean = 2.16 ng.g-1, d.w), and from non detectable to 3.20 ng.g-1 (mean = 0.97 ng.g-1, d.w) for HCHs and DDTs, respectively. Principal component analysis allowed the classification of sampling sites according to the main OCs inputs over the estuary. In comparison to other worldwide locations and to the world coastal sediment concentrations range, sediment DDTs and HCHs levels were in the low range; on the opposite, ∑OCs average was in the medium range. OCs seasonal distribution was found to be highly correlated with the precipitations seasonality and sowing seasons in the adjacent agriculture fields. In addition, an ecotoxicological risk assessment pointed industrial and agriculture catchment zones with intermediate probability of adverse effects to biota, while the city sewage outfall was classified with none indication of an immediate threat. Data indicated that the estuary sediments were functioning as a sink for persistent OC pesticides (either in use or banned), however, it was found a declining trend on their environmental burden.   Keywords: pesticides, principal component analysis, ecotoxicological risk, Argentina, 38º 40? S and 62º 09? W