Association between PAH and plastic fragments on Brazilian coast beaches: a baseline assessment.

Plastic materials have many destinies on the environment, and one of them is its continuous fragmentation, originating microplastics (MP). MP act as an adsorption surface for organic pollutants like polycyclic aromatic hydrocarbons (PAH). Due to its toxic and harmful properties, 16 PAH are defined as priorities in studies. Several works have evaluated the occurrence of MP and PAH individually in environmental matrices, but just a few have investigated their association. The present study aims to investigate PAH occurrence, sources, and concentration in MP from beach sediments of eight Brazilian coastal states. Sixteen PAH were analyzed by gas chromatography, in which 14 PAH were detected, and PAH total concentration (ΣPAH) ranged from 0.25 to 71.60 ng g-1. In the North and Northeast regions, the low PAH concentrations in MP appear to be related to the intense hydrodynamic processes. Naphthalene levels on the Styrofoam were above the threshold effect level in two samples and near it on one; therefore, effects in the organisms might occur due to these PAH. The Southeast and South regions are the only ones with previous studies relating PAH with MP, and ΣPAH ranged from 0.34 to 2.52 ng g-1. According to the diagnostic ratios, the PAH sources were associated with industrial and port activities, untreated effluent disposal, and urban runoff by pluvial waters. The highest ΣPAH level was found in the Styrofoam samples, suggesting that this MP type might contribute considerable to PAH dispersion on Brazilian coast beaches.

PAH Baselines for Amazonic Surficial Sediments: A Case of Study in Guajará Bay and Guamá River (Northern Brazil).

The 16 priority PAH were determined in sediment samples from the insular zone of Guajará Bay and Guamá River (Southern Amazon River mouth). Low hydrocarbon levels were observed and naphthalene was the most representative PAH. The low molecular weight PAH represented 51% of the total PAH. Statistical analysis showed that the sampling sites are not significantly different. Source analysis by PAH ratios and principal component analysis revealed that PAH are primary from a few rate of fossil fuel combustion, mainly related to the local small community activity. All samples presented no biological stress or damage potencial according to the sediment quality guidelines. This study discuss baselines for PAH in surface sediments from Amazonic aquatic systems based on source determination by PAH ratios and principal component analysis, sediment quality guidelines and through comparison with previous studies data.