highly significantp < 0.0001
Moreover, when plastic particles used in toxicity testing were classified into 4 size classes, the effect of particle size on toxicity was highly significant (ANOVA, p < 0.0001), and the dependence of safe concentration (HC 5 ) on particle size was even more remarkable, with a slope b = 1.21 according to the equation: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\log \;{\text{HC}}_{5} = 1.21\;\log \;{\text{S}}{-}2.10$$\end{document} log HC 5 = 1.21 log S - 2.10 where S is the mean particle size (μm) for each size class (r 2 = 0.92, n = 4).