Mercury and Organic Matter Concentrations in Lake and Stream Sediments in relation to One Another and to Atmospheric Mercury Deposition and Climate Variations across Canada

Table 4

Trend analysis for the organic matter contributions to lake and stream sediment THg (10th and 90th percentiles) from low to high mean annual precipitation rate and atmospheric Hg deposition rates.

(a)

Medium	Percentile	[ (ng g^−1)]			⁢ [ (ng g^−1)]		Gain of THg in sediment organic matter (2)
					⁢at precipitation (m a^−1)
		Intercept	Slope		0	1.4
Lakes	90th	2.00	0.664	0.484	100.0	597.0	5.97
	10th	1.61	0.570	0.498	40.7	188.8	4.64
Streams	90th	2.34	0.570	0.202	218.8	1014.4	4.64
	10th	1.79	0.550	0.234	61.7	270.8	4.39

(b)

Medium	Percentile	[ (ng g^−1)]			⁢ [  (ng g^−1)]		Gain of THg in sediment organic matter (2)
					⁢at atm.Hg (μg m^−2 a^−1)
		Intercept	Slope		0	26
Lakes	90th	1.76	0.047	0.465	57.6	602.6	10.46
	10th	1.40	0.041	0.491	25.1	194.9	7.76
Streams	90th	2.31	0.030	0.200	204.2	914.3	4.48
	10th	1.90	0.021	0.121	79.4	226.9	2.86

Based on the trend lines in Figure 10; mean annual precipitation rate; GRAHM2005 mean annual atmospheric Hg deposition rate.