Improper environmental sampling design bias assessments of coastal contamination

Pollution of coastal areas play an important role in anthropocentric issues. Thus, several analytical tools were developed and optimized in recent years aiming to improve the acquisition of good quality chemical data. Despite these efforts, assessments of the environmental occurrence of hazardous chemicals in coastal regions are often biased by poorly planned sampling campaigns. In coastal zones, the influence of local contamination sources and environmental factors (such as coastal currents, tides, estuarine discharges, depth and luminosity) should be carefully considered before establishing a sampling grid. Moreover, the wrong selection of the environmental matrix to be analyzed, especially by multiresidue methods which include analytes with different physicochemical properties, has also been an important source of bias in many published papers. This critical review provides an overview of the key-factors to be considered during the planning and execution of sampling campaigns seeking to identify and quantify contaminants in environmental samples obtained in coastal areas. Further, a discussion on a more suitable and cost-effective sampling design, based in recent advances, is also presented.