In this study, surface seawater, sediment and zooplankton samples were collected from three different sampling stations in Marseille Bay (NW Mediterranean Sea) and were analyzed for both microplastics and organic plastic additives including seven phthalates (PAEs) and nine organophosphate esters (OPEs). PAE concentrations ranged from 100 to 527 ng L⁻¹ (mean 191 ± 123 ng L⁻¹) in seawater, 12–610 ng g⁻¹ dw (mean 194 ± 193 ng g⁻¹ dw) in sediment and 0.9–47 μg g⁻¹ dw (mean 7.2 ± 10 μg g⁻¹ dw) in zooplankton, whereas OPE concentrations varied between 9 and 1013 ng L⁻¹ (mean 243 ± 327 ng L⁻¹) in seawater, 13–49 ng g⁻¹ dw (mean 25 ± 11 ng g⁻¹ dw) in sediment and 0.4–4.6 μg g⁻¹ dw (mean 1.6 ± 1.0 μg g⁻¹ dw) in zooplankton. Microplastic counts in seawater ranged from 0 to 0.3 items m⁻³ (mean 0.05 ± 0.05 items m⁻³). We observed high fluctuations in contaminant concentrations in zooplankton between different sampling events. However, the smallest zooplankton size class generally exhibited the highest PAE and OPE concentrations. Field-derived bioconcentration factors (BCFs) showed that certain compounds are prone to bioaccumulate in zooplankton, including some of the most widely used chlorinated OPEs, but with different intensity depending on the zooplankton size-class. The concentration of plastic additives in surface waters and the abundance of microplastic particles were not correlated, implying that they are not necessarily good indicators for each other in this compartment. This is the first comprehensive study on the occurrence and temporal variability of PAEs and OPEs in the coastal Mediterranean based on the parallel collection of water, sediment and differently sized zooplankton samples.

This work presents, for the first time, a fast and highly sensitive electrochemical method for determination of three organophosphorus compounds (OPs), diazinon (DZN), malathion (MLT), and chlorpyrifos (CLPF), using a modified pyrolytic graphite electrode (PGE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA–MPA). The PGE was modified by a nanocomposite based on functionalized carbon nanotubes (CNTf) and silver nanoparticles (AgNPs). The OPs samples were directly analyzed on the modified working electrode surface by BIA-MPA system in Britton-Robinson (BR) buffer 0.15 mol L⁻¹ at pH 6.0. The MPA detection of DZN, MLT and CLPF was performed using two potential pulses, which were sequentially applied on modified PGE at −1.3 V (100 ms) and +0.8 V (100 ms) for selective determination of these three OPs and working electrode cleaning, respectively. Under optimized conditions, the sensor presented a linear range of 0.1–20 μmol L⁻¹ for DZN, 1.0–30 μmol L⁻¹ for MLT and from 0.25 to 50 μmol L⁻¹ for CLPF. The limits of detection (LOD) and quantification (LOQ) of 0.35 and 1.18 μmol L⁻¹ for DZN, 0.89 and 2.98 μmol L⁻¹ for MLT, and 0.53 and 1.78 μmol L⁻¹ for CLPF were obtained. The proposed method exhibited high sensitivity of 0.068, 0.030 and 0.043 mA L μmol⁻¹ for DZN, MLT and CLPF detection, respectively. Furthermore, the BIA-MPA system provided an analytical frequency of 71 determinations per hour for direct determination of these OPs in water and food samples. The modified PGE coupled to BIA-MPA system showed a high stability of electrochemical response for OPs detection with relative standard deviation (RSD) of 1.60% (n = 20). The addition-recovery studies of the proposed method were carried out in tap water, orange juice, and apple fruit real samples, which showed suitable recovery values between 77 and 124%. The analytical performance of the developed sensor provides an attractive alternative method for OPs determination with great potential for a fast and sensitive application in contaminated samples with these pesticides.