School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK.
Department F.-A. Forel, University of Geneva, Boulevard Carl-Vogt 66, CH-1205 Geneva, Switzerland.
Mar Pollut Bull. 2020 Sep;158:111352. doi: 10.1016/j.marpolbul.2020.111352. Epub 2020 Jun 18.
With an inherent density marginally below that of seawater, polyolefins (polyethylene-polypropylene) are predicted to float or undergo beaching in the marine environment. Polyolefins commonly observed on the seabed, therefore, require additional considerations that are usually based around increasing density through fouling or packaging into sinking faecal matter. Here, however, we propose that the presence of additives is of least equal significance to the behaviour of such plastics in marine systems. We compared barium, present largely as the filler, BaSO (density = 4.5 g cm), in consumer and beached plastics and established that the metal was more abundant and occurred at higher concentrations in the former samples, consistent with the environmental fractionation of plastics based on additive content. Significantly, the Ba content of polyolefins required to confer a density above seawater is about 13,000 mg kg, a value that was exceeded in many consumer plastics but never observed in beached samples.
由于密度略低于海水，聚烯烃（聚乙烯-聚丙烯）预计会在海洋环境中漂浮或搁浅。因此，在海底常见的聚烯烃需要额外考虑，通常通过污染或包装成下沉的粪便物质来增加密度。然而，在这里，我们提出添加剂的存在对这类塑料在海洋系统中的行为的重要性至少与密度相同。我们比较了在消费和搁浅塑料中大量存在的钡，即填充剂 BaSO（密度为 4.5gcm），并确定金属在前者样品中更为丰富，浓度更高，这与基于添加剂含量的塑料环境分馏一致。重要的是，赋予聚烯烃高于海水的密度所需的钡含量约为 13000mgkg，这一数值在许多消费塑料中都超过了，但在搁浅样本中从未观察到。
