Phthalates are esters of the phthalic acid and are a group of chemicals of high environmental relevance due to their production rates and ecotoxicological potential. Phthalates are mainly used as plasticizers in PVC plastics. Therefore, many consumer products contain specific members of this family of chemicals, including building materials, household furnishings, clothing, cosmetics, pharmaceuticals, nutritional supplements, medical devices, dentures, children's toys, glow sticks, modelling clay, food packaging, automobiles, lubricants, waxes, cleaning materials and insecticides. Di-(2-ethylhexyl) phthalate (DEHP) is one of the most widespread phthalate plasticizer, used in numerous consumer products, commodities, and building materials. Due to its classification as toxic to reproduction, the corresponding labelling (skull and crossbones) and several restrictions on marketing and use (2003/36/EC) DEHP is replaced with other phthalate plasticizers as di-isodecyl phthalate (DIDP) and di-isononyl phthalate (DINP). With the total amount of plasticizer consumption remaining unchanged in Europe, the consumption of DEHP dropped from 42% in 1999 to 21% in 2006, whereas the share of DIDP and DINP increased from 35% to 60% within the same time period (Cardogan, 2007). Also other phthalates such as di-ethyl-phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), and di-n-octyl phthalate (DnOP) are widely used. As the phthalate plasticizers are not chemically bound to PVC, they can leach, migrate or evaporate into indoor air and atmosphere, foodstuff, other materials, etc. Once released to the environment they tend to adsorb on particles and, in this way, have been detected in different estuarine compartments as sediment, water or biota. The effects of phthalates on aquatic wildlife have been extensively studied. Phthalate compounds are weak xenoestrogenic compounds to aquatic organisms and can alter the reproduction of exposed organism. Furthermore, they can also modulate cellular pathways such as lipid metabolism leading to oxidative stress processes. Proliferation of peroxisomes and induction of peroxisomal enzymes such as catalase and acyl-CoA oxidase have been reported on fish and molluscs. Our work was developed in two selected estuaries from Bay of Biscay, the estuary of Bilbao and Urdaibai, showing different pollution loads. The estuary of Bilbao is one of the most industrialised and populated areas of the Bay of Biscay. Due to its geographic location, the area has been subjected to intense industrial pressure. For many years, urban and industrial effluents were discharged into the estuary without further treatment. In 1979, an Integral Plan for the Drainage of the estuary was approved and new environmental protection policies resulted in improved wastewater treatment systems. This, together with the closure of several industries, has produced a gradual recovery of the estuarine environment, with a continuing decrease in heavy metal concentrations and an increase in oxygenation. The tidal zone of the Ibaizabal River forms the estuary, although four tributaries (Kadagua, Asua, Galindo and Gobela) also discharge in the estuary.The docks and secondary channels are the most affected by urban and industrial wastes. The estuary of Urdaibai and its surroundings have been a Biosphere Reserve by UNESCO since 1984, and are located in a rural environment about 50 km east from the Ibaizabal estuary. The Urdaibai region is characterised by the basin of the Oka River, and by some shorter rivers, including the Golako, Mape, Artike and Laga. The estuary, some 13 km long and 500 m wide, is located in relatively close proximity to several industries (metallurgic, shipyards, dyes, cutlery manufacture) located in the surroundings of Gernika (population ~20,000) upstream the Oka River. The present chapter would report: i. Levels and spatial distribution of phthalate esters PEs in sediments and biota samples along the both estuaries since 2002 to 2005 in different sampling campaigns. Comparison between estuaries. ii. Bio vailability and bioaccumulation studies in both estuaries. iii. Toxicological effects in aquatic organisms inhabiting both estuaries based on biomarker responses. © 2012 by Nova Science Publishers, Inc. All rights reserved.
