In a recent report by the Xunta de Galicia on January 9, details regarding the pellets discovered on December 8 from the Toconao ship spill have come to light. These pellets, found in bags labeled “UV9000 light stabilizer,” imported by Bedeko Europa and manufactured in India by Coraplast, reveal a composition worth understanding.
The primary component is the ubiquitous polymer, polyethylene, innocuous on its own. However, these pellets contain 10-13% of a chemical additive known as UV622 (CAS number 65447-77-0), serving as a UV light stabilizer, in line with the bag labels. UV622, a non-biodegradable polymer, consists of succinic acid (a non-toxic organic acid) and a synthetic substance from the aromatic amine family, lending its antioxidant properties (CAS number 52722-86-8).
As per the European Chemicals Agency, UV622 is classified as chronically toxic (effective in prolonged exposure) and eye irritant during cleaning activities. Daphnia toxicity testing, an aquatic invertebrate used for substance toxicity evaluation, indicates a relatively low toxicity level with a CE50 (concentration causing 50% mortality) of 160 mg/L.
However, the safety data sheet for UV622 reveals a higher toxicity level for Daphnia (EC50=25 mg/L), categorizing it as moderately toxic to aquatic life. Yet, it’s crucial to note that these levels are not anticipated in open coastal environments.
Currently, the ECOTOX group is conducting toxicity tests on representative marine organisms like phytoplankton and zooplankton, aiming to fill the knowledge gap on marine organism toxicity.