In 2016 and 2017 the Department of Environmental Affairs conducted sampling at more than 150 sandy beach sites along the South African coastline, to quantify the extent of micro-plastic pollution at an average spatial sampling scale of about 15 km. Most of the sites along the west coast were sampled 3 times, to investigate seasonal variability. The east and south coasts were sampled twice, during low and higher river runoff conditions, respectively. At all sites, plastic micro-fibres were found to be the dominant micro-plastic constituents present, and the quantitative data for that is presented in this dataset. One of the problematic issues related to comparison of global micro-plastic pollutant levels, presently, is the lack of agreed to measurement methodologies and reporting units. This dataset represents results for samples taken along the high-level water mark, as a composite sample of about 1 L consisting of aliquots taken from at least 3 different sampling spots, sampled to a depth of 5 cm. The micro-fibre count is reported as the number of fibres per liter (or #F/dm3). In order to convert this to other units for comparison with other studies, sediment dry bulk density measurements are included. Data is also provided for the dominant sediment grain size (fine sand is 63 to 250 µm, and medium-coarse sand 250 µm to 1 mm) , and the temperature and salinity of surf-zone water at the time of sampling.

Supplement to: de Villiers, Stephanie (2018): Quantification of microfibre levels in South Africa's beach sediments, and evaluation of spatial and temporal variability from 2016 to 2017. Marine Pollution Bulletin, 135, 481-489