A Unique Monitoring Method for Fecal and Sewage-Derived Chemical Pollution Utilizing International Pellet Watch Approach.

This study established a unique approach to assess fecal contamination by measuring fecal sterols, especially coprostanol (5ß-cholestanol-3ß-ol, 5ß) and cholestanol (5α-cholestan-3ß-ol, 5α) and their ratio 5ß/(5ß + 5α) alongside triclosan (TCS) and methyl-triclosan (MTC) in beached plastic pellets across 40 countries. Coprostanol concentrations ranged from 3.6 to 8190 ng/g pellet with extremely high levels in densely populated areas in African countries. The 5ß/(5ß + 5α) ratio was not affected by the difference in residence time of pellets in aquatic environments, and their spatial pattern showed a positive correlation with that of sedimentary sterols, demonstrating its reliability as an indicator of fecal contamination. Pellets from populated areas of economically developing countries, i.e., Africa and Asia, with lower coverage of wastewater treatment exhibited higher 5ß/(5ß + 5α) ratios (∼0.7) corresponding to ∼1% sewage in seawater, while pellets from developed countries, i.e., the USA, Canada, Japan, and Europe, with higher coverage of modern wastewater treatment displayed lower ratios (∼0.5), corresponding to the first contact limit. Triclosan levels were higher in developing countries (0.4-1298 ng/g pellet), whereas developed countries showed higher methyl-triclosan levels (0.5-70 ng/g pellet) due to TCS conversion during secondary treatment. However, some samples from Japan and Europe displayed higher TCS levels, suggesting contributions from combined sewage overflow (CSO). Combination of 5ß/(5ß + 5α) and MTC/TCS ratios revealed extreme fecal contamination from direct input of raw sewage due to inadequate treatment facilities in some African and South and Southeast Asian countries.

Monitoring of polycyclic aromatic hydrocarbons, hopanes, and polychlorinated biphenyls in the Persian Gulf in plastic resin pellets.

Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and hopanes were analyzed in plastic resin pellets collected from 19 locations along the Persian Gulf coastline. PCBs were high at locations near industrial areas, where their concentrations (sum of 13 congeners, 54-624 ng/g-pellet) were higher than those in rural coastal towns, which were close to global background levels (<10 ng/g-pellet). PAH concentrations (sum of 27 PAH species) varied from 273 to 15,786 ng/g-pellet and were highest in industrial cities (Bushehr and Bandar Abbas), with a petrogenic signature at most locations, possibly due to the petroleum-based industries, refineries, and tankers. These levels were placed in the extremely polluted category on a global basis. The distribution of hopanes was relatively homogeneous, and their range of concentrations was 8048-59,778 ng/g-pellet. This range had a positive correlation with PAH concentrations. The PAH and hopane results emphasize the ubiquity of petroleum pollution in the Persian Gulf.