Automated solid phase extraction combined with gas chromatography-mass spectrometry methods for plastic and tire additives in surface waters: development, validation and greenness assessment

• Three methods based on automated SPE combined with GC–MS have been optimized. • Phthalates, bisphenols and tire additives were analysed in surface waters from Galicia. • The impact of analytical methodologies on the environment was assessed. Automated solid phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC–MS) methods were proposed for determination of plastic and tire additives in surface water. The plastic additives studied were phthalates (PAEs) and bisphenols (BPs), and the tire additives were diphenylamine derivatives (tire additives). These chemicals represent a serious hazard for the marine environment. BPs were derivatized prior to GC determination. The optimized and validated methods for seawater samples proved to be accurate (recoveries of 56–112 % for PAEs, 60–116 % for BPs and 60–110 % for tire additives), reproducible (relative standard deviation of 6–11 % for PAEs, 1–14 % for BPs and 4–13 % for tire additives) and sensitive for target analytes (detection limits of 0.015–0.142 μg/L for PAEs, 0.0010–0.0094 μg/L for BPs, 0.028–0.055 μg/L for tire additives). The methods were also validated for freshwater samples, showing satisfactory analytical parameters results. Finally, the validated methodologies were evaluated for environmental and occupational hazards using AGREE and successfully applied to the analysis of two types of surface water samples, influents and effluents from four sewage treatment plants (WWTPs) in Galicia. From the results obtained, a reduction of the compounds studied after passing through the WWTPs was observed. In fact, an influent surface water sample exceeded the MAC-EQS of Directive 2013/39/EU, this level was reduced when passing through the treatment plant.