A long-term study programme has evaluated heavy metals in the Bahı ´a Blanca estuary, considering occurrence, concentration and distribution in the estuarine sediments, as well as their corresponding geochemical partitioning in the Ͻ62 m grain size fraction of the sediment. Total concentrations of heavy metals (Cd, Zn, Cu, Cr, Pb, Fe) have been determined through flameless atomic absorption spectrophotometry (AAS). Geochemical partitioning of these metals was determined following a sequential extraction technique. Furthermore, heavy metal distribution was studied against organic matter concentration within the sediments.The results allow the characterization of the spatial distribution of the metals, together with their accumulation areas and potential sources. Bahı ´a Blanca estuarine sediments have low to medium heavy metal concentrations. The geochemical partitioning indicated that many bioavailable species occur within the system, including those of highly toxic elements such as cadmium. Moreover, a theoretical scheme of transference of these metals to other compartments within the system was proposed. Finally, the environmental status of the estuary was addressed within the described framework.

1. The concentration and distribution of several hydrographical variables from Mar Chiquita coastal lagoon, Argentina, were measured monthly over a year in order to quantify their seasonal variations. Temperature, salinity, inorganic nutrient concentrations (nitrate, nitrite, phosphate, silicate) in the water column, and photosynthetic pigments (chlorophyll a and phaeopigments) in suspended particulate matter (SPM), were measured using internationally standardized analytical methods.2. Agricultural use of land surrounding the coastal lagoon has been shown to be the main nutrient source, owing to the use of fertilizers for farming and the consequent leaching of the soils by freshwater runoff.3. Two different hydrographical areas were identified within the coastal lagoon, one showing marine influence and the other dominated by inland influence (due to catchment and freshwater inputs), both with different characteristics and ecological behaviour.4. The frequent occurrence of phytoplankton blooms has also been identified within the coastal lagoon. There was significant biological production (in terms of chlorophyll a) within the lagoon throughout the year. The lagoon appears to function as a transitional system, opportunistically benefiting from extra nutrient inputs which, together with other environmental conditions, results in a continuous food supply, useful to both marine and estuarine organisms. Consequently the system is important for numerous fish and shellfish species as a nursery area.

An on-line solid-phase extraction method linked to inductively coupled mass spectrometry (ICP-MS) has been developed for the determination of low levels of uranium and thorium in environmental samples. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to an ICP-MS, allows the simultaneous determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. On-line separation and preconcentration of thorium and uranium are carried out by means of UTEVA resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the on-line regeneration of the column. The limits of detection reached are 0.4 ng L À1 of uranium and 2.8 ng L À1 of thorium. The reproducibility of the LOV-MSFIA-ICP-MS is 1.7% of RSD. Moreover, a high sensitivity, a wide working range (0-200 mg L À1 for uranium and thorium) and an injection frequency up to 9 h À1 (depending on the sample volume) should be highlighted. Different water sample matrices (seawater, well water, freshwater, tap water and mineral water), a phosphogypsum sample with natural uranium and thorium content and a channel sediment reference material were satisfactorily analyzed with the proposed method.

The use of functional fillers can be advantageous in terms of cost reduction and improved properties in plastics. There are many types of fillers used in industry, organic and inorganic, with a wide application area. As a response to the growing concerns about environmental damage that plastics cause, recently fillers have started to be considered as a way to reduce it by decreasing the need for petrochemical resources. Life cycle assessment (LCA) is identified as a proper tool to evaluate potential environmental impacts of products or systems. Therefore, in this study, the literature regarding LCA of plastics with functional fillers was reviewed in order to see if the use of fillers in plastics could be environmentally helpful. It was interesting to find out that environmental impacts of functional fillers in plastics had not been studied too often, especially in the case of inorganic fillers. Therefore, a gap in the literature was identified for the future works. Results of the study showed that, although there were not many and some differences exist among the LCA studies, the use of fillers in plastics industry may help to reduce environmental emissions. In addition, how LCA methodology was applied to these materials was also investigated.

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