Our results indicate that microplastics in the size range analysed (∼25–1000 μm) may not be a good predictor of the spatial distribution of plasticisers in estuaries. This could result from release of plasticisers prior to plastic fragmentation and deposition and differences in transport and fate.

There was strong evidence that concentrations of microplastics and plasticisers were significantly lower in the outer estuary. However, we found no evidence for a spatial relationship between the concentration of microplastics and plasticisers at an individual site level.

We investigated spatial trends and relationships between microplastics and plasticisers in sediments of an urbanized estuary subject to contemporary and historic sources of contamination (Forth estuary, Scotland, UK).

We know that there is a theoretical link between microplastics and plastic additives (such as plasticisers). However, there has been little empirical data gathered about their relationships in the environment.