Table 2).

Summary of statistical analyses performed on DI water and two environmental sediments as part of the subsampling component of this study. For these analyses, the dependent variable was the sum of all polymers detected.

Sample Type	Sample ID	Statistical Tests	Statistical Endpoint	Difference Among All Filter Fractions	Individual Differences between Filter Fractions
DI water	1	Multi-factor ANOVA followed by Dunnett’s Test (100% used as control)	Significant difference between means	No: F-test: 2.79; p = 0.057	No significant differences detected, not performed.
	2			No: F-test: 0.61; p = 0.691	No significant differences detected, not performed.
	3			Yes: F-test: 3.76; p = 0.021	Extrapolation of 6% filter wedge was greater than 100% counted
	4			Yes: F-test: 4.98; p = 0.007	Extrapolation of 6% filter wedge was greater than 100% counted
Sediment 1	Region 1; 4A-B1	Kruskal-Wallis followed by Dwass, Steel, Critchlow-Fligner pairwise comparisons	Relative accuracy	No: X2 = 5.02; p = 0.286	No significant differences detected
			Absolute bias	Yes: X2 = 12.3; p = 0.015	Extrapolation of 6% filter wedge was greater than the 75% filter wedge extrapolation
Sediment 2	Region 9; 5B-B1	Kruskal-Wallis followed by Dwass, Steel, Critchlow-Fligner pairwise comparisons	Relative accuracy	Yes: X2=10.0, p = 0.040	No significant differences detected.
			Absolute bias	Yes: X2=23.6, p < 0.001	Extrapolation of 6% filter wedge was greater than 12, 50 and 75% filter wedge extrapolations