Fig 2. Microparticles are rarer in waters of less disturbed catchments and with more potential for microbial decomposition.

Lines show mean model fit (±95% CI) at mean of all other variables for effects of (a) estimated plastic mass inputs integrated over the retention time of the lake prior to sampling, (b) load of wastewater collected by treatment plants in the surrounding catchment in p.e., (c) forest cover in the surrounding catchment, and (d) respiration measured in 24-hour laboratory incubations of lake water as an index of organic matter degradation [56]. Mean (95% CI) Bayesian R² = 0.37 (0.21 to 0.54). N = 67. Individual data points were derived by fitting the model given in S3 Data to raw data in S2 Data, with values used to generate lines and errors given in S2 Table. p.e., population equivalent; WwTWs, wastewater treatment works.