A multiresidue analytical procedure for legacy and emerging organic contaminants in marine sediments: Method development, validation, and application

Abstract

This study developed and validated a multiresidue analytical procedure for sediment samples, targeting both legacy contaminants regulated under the UN Stockholm Convention on Persistent Organic Pollutants (POPs) and emerging contaminants of concern to marine ecosystems. The focus was on emerging plastic additives and flame retardants, such as phthalate esters (PAEs) and organophosphate esters (OPEs), for which limited data exists regarding their global presence or fate in the marine environment.

The methodology targets 6 marker PCBs, 20 organochlorinated pesticides (OCPs), 14 PBDEs, 17 alternative halogenated flame retardants (aHFRs), 19 PAEs, and 17 OPEs. The optimized procedure involves microwave extraction with a mixture of n-hexane and dichloromethane, sulfur clean-up with copper, and silica SPE fractionation to separate legacy POPs and aHFRs from PAEs and OPEs. Gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) was used to measure the target analytes within two isolated fractions. Method validation included recovery yields in matrix-spiked sediments, reproducibility, repeatability, and blank optimization. Recoveries of PAEs and OPEs at 20-30 ng g⁻¹ ranged within 62–120% for the majority of analytes with RSD< 25%. Method detection limits for PAEs and OPEs ranged from 0.03 ng/g to 12 ng/g dw, influenced by background contamination variability.

The validated method was applied to marine sediment samples, including reference materials from the International Atomic Energy Agency (IAEA), providing preliminary data on the occurrence of these compounds in the marine environment. Integrating the analysis of PAEs and OPEs into existing procedures for legacy contaminants offers a cost-effective approach to expanding data availability for emerging organic pollutants.