Forty-nine 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 nondetectable to 8.03 ng g⁻¹, d.w. (mean = 2.16 ng g⁻¹, d.w.), and from nondetectable to 3.20 ng g⁻¹ (mean = 0.97 ng g⁻¹, d.w.) for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (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.

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Several phenolic compounds are present in tobacco smoke. They are formed from the pyrolysis of tobacco during the smoking process and all of them are toxic. Therefore, the determination of these compounds in air samples is important. A rapid, simple, and sensitive method using a synchronous spectrofluorimetry technique was developed to quantify hydroquinone and resorcinol simultaneously. One of the advantages of this method is the simple and rapid sampling technique, which uses water as the absorption solution of the analytes in the air sample. The precision of the method (%RSD) was 1.8% and the detection limits were 0.125 mg m(-3) and 0.292 mg m(-3) for hydroquinone and resorcinol, respectively.

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