Table 5.

Results of post-hoc Dunnett T3 tests used to determine differences in sector-specific mean enrichment (mean EFs) among 2017 surface sediment (Peace sector d.f. = 26; Athabasca sector d.f. = 33), 2018 surface sediment (Peace sector d.f. = 7; Athabasca sector d.f. = 11) and pre-1920 baseline sediment samples (Peace sector d.f. = 63; Athabasca sector d.f. = 63). Table presents the sample means and P values. Statistically significant P values (at alpha = 0.05) are identified in italics

Sector	Metal	Comparison		Mean EF		P value
		Sample 1	Sample 2	Sample 1	Sample 2
Peace sector	Be	Baseline	2017	1.00	1.04	0.076
		Baseline	2018	1.00	0.93	0.004
		2017	2018	1.04	0.93	9.94 × 10−5
	Cd	Baseline	2017	1.00	0.96	0.526
		Baseline	2018	1.00	1.01	0.998
		2017	2018	0.96	1.01	0.895
	Cr	Baseline	2017	1.00	0.95	2.53 × 10−7
		Baseline	2018	1.00	0.98	0.311
		2017	2018	0.95	0.98	0.306
	Cu	Baseline	2017	1.00	0.97	0.282
		Baseline	2018	1.00	0.96	0.075
		2017	2018	0.97	0.96	0.936
	Ni	Baseline	2017	1.00	0.92	2.28 × 10−5
		Baseline	2018	1.00	0.88	1.65 × 10−12
		2017	2018	0.92	0.88	0.013
	Pb	Baseline	2017	1.00	0.92	0.001
		Baseline	2018	1.00	1.00	0.999
		2017	2018	0.92	1.00	0.021
	V	Baseline	2017	1.00	0.99	0.841
		Baseline	2018	1.00	0.97	0.006
		2017	2018	0.99	0.97	0.114
	Zn	Baseline	2017	1.00	1.03	0.564
		Baseline	2018	1.00	0.95	0.377
		2017	2018	1.03	0.95	0.168
Athabasca sector	Be	Baseline	2017	1.00	1.07	1.663 × 10−4
		Baseline	2018	1.00	0.96	0.198
		2017	2018	1.07	0.96	1.893 × 10−4
	Cr	Baseline	2017	1.00	0.98	0.072
		Baseline	2018	1.00	0.98	0.294
		2017	2018	0.98	0.98	0.998
	Pb	Baseline	2017	1.00	0.98	0.579
		Baseline	2018	1.00	1.05	0.046
		2017	2018	0.98	1.05	0.012
	V	Baseline	2017	1.00	1.01	0.754
		Baseline	2018	1.00	1.01	0.840
		2017	2018	1.01	1.01	1.00
	Zn	Baseline	2017	1.00	1.13	2.329 × 10−5
		Baseline	2018	1.00	1.08	0.029
		2017	2018	1.13	1.08	0.272