Distribuição de agentes anti-incrustantes de 3ª geração em distintos compartimentos ambientais da região portuária de São Luís, Maranhão

Abstract

Substances used in antifouling paints are important contaminants into the aquatic environment. Due to the high traffic of vessels, São Luís Island is subject to the presence of this type of contaminant. So, the aim of this work was to evaluate the presence and distribution of the antifouling biocides irgarol, diuron, DCPMU (diuron degradation product) and DMSA in marine water, sediment and interstitial water samples from coastal areas of São Luís, where vessel traffic take place. The analyses were performed by high-performance liquid chromatography coupled to mass spectrometry with electrospray ionization and single quadrupole mass analyzer (HPLC-ESI-SQ-MS). The analytes were extracted from sediment samples by vortex-assisted matrix solid-phase dispersion (VA-MSPD), in marine water a SPE protocol was applied and in interstitial waters, the methodology used was vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME). The analytical parameters evaluated were suitable for trace analysis of these substances in the matrices studied, except for DMSA in marine water. Diuron, DCPMU and irgarol were detected in all matrices studied, while DMSA was detected only in interstitial waters. Diuron was the predominant biocide in sediments, but it was detected in only one marine water sampling site and in three interstitial water sampling sites. DCPMU, on the other hand, was the most detected analyte in interstitial water samples, despite having a low detection frequency in the other matrices studied. The predominance of irgarol was observed in marine water, where it showed a 100% detection frequency, but its levels in sediment samples were much higher. Distribution coefficients (Kd) and organic carbon/water partitioning coefficients (Koc) between sea water/sediment and interstitial water/sediment showed that irgarol and diuron had preferential partitioning in sediments, whereas DCPMU and DMSA had partitioning in water interstitial. In all cases, the partitioning in marine water was low. The levels of irgarol and diuron represented a risk for marine biota, according to environmental risk limits and ecotoxicological tests present in the literature.