Microplastic pollution is increasingly recognised as a threat to tropical aquatic ecosystems, yet exposure pathways in avian communities remain poorly documented, particularly in Africa. We assessed microplastic contamination in faecal samples from waterbirds inhabiting two contrasting wetland systems in Ghana: a sewage-influenced constructed wetland and a natural coastal Ramsar wetland. A total of 238 faecal samples from 12 species were analysed to quantify microplastic abundance, characterise particles, and identify ecological drivers of exposure. Microplastics were detected in birds from both wetlands, confirming widespread contamination. Contrary to expectations, birds from the natural wetland had significantly higher microfibre loads than those from the sewage-influenced wetland, suggesting that protected natural systems may act as sinks for dispersed plastic pollution. Fibres accounted for over 93% of recovered particles, with black and blue fibres and particles <100 µm dominating samples. Microplastic loads were associated with ecological traits, particularly guild identity and wingspan. Mixed foragers generally exhibited higher contamination, suggesting multiple exposure pathways, although this pattern varied between wetlands. A negative binomial model identified site, guild identity, and wingspan as predictors of fibre load. These findings highlight the vulnerability of tropical wetlands to microplastic contamination and the value of waterbirds as non-invasive indicators of exposure.

The present study aimed to elucidate the extent of microplastic (MP) contamination in the Guandu River basin. Samples were collected from surface waters using a Manta trawl at 11 sites in two seasonal periods. MPs abundance was 6.1 ± 4.9 particles m−3 in the cold-dry season, and 2.3 ± 1.1 particles m−3 in the warm-rainy season. Four shapes and 12 colors were identified, indicating a high degree of particle diversity. Fragments were the most common, followed by fibers. The frequent colors were black, blue and transparent. Eleven plastic polymers were identified using micro-Fourier transform infrared spectroscopy analysis; the dominant ones were polyethylene and polypropylene. Artificial cellulose particles (including the semisynthetic polymer rayon) were also detected in high relative abundance. No significant difference in MP abundance was found between seasons and limnic conditions. There was a significant trend toward higher abundance of MPs near areas with greater urban influence and lower abundance in reservoirs surrounded by less urbanized areas (upstream river). Therefore, MPs appeared to be influenced by land use and occupation, with higher abundance in more urbanized areas, suggesting an urban–rural effect.

We describe an improved experimental approach for characterizing the elastic modulus and hardness of single microfibers through instrumented indentation. A sample mounting technique on a curved surface is presented that ensures contact between an unmodified fiber and substrate. The indentation analysis considers three separate corrections to the well-known Oliver and Pharr method: (i) overestimation of the projected contact area due to sample curvature, (ii) overestimation of projected contact area due to substrate curvature, and (iii) underestimation of fiber stiffness due to the structural compliance of the sample. The method is applied to four types of high performance ballistic fibers: KM2 Plus, Twaron, AuTx, and Dyneema; the results are presented according to both the modified analyses as well as the standard Oliver and Pharr analysis. The modified analyses resulted in an increase in the elastic modulus and hardness of up to 35 and 60%, respectively, compared to the Oliver–Pharr method. The technique has the potential to be applied to single microfilaments under various environmental conditions that may otherwise be compromised by traditional fiber mounting methods.