Table 2.

Predicted release rate constants and equilibrium concentrations of copper from five types of pressure treated lumber blocks as a function of salinity based on a non-linear first-order model. Salinity is expressed as parts per thousand (‰).

Treatment	Salinity (‰)	Copper release rate constant (1/d)	Significance groupinga	Equilibrium concentration (mg/L)	Significance groupinga
MCA low	0	2.71 ± 1.13	A	1.68 ± 0.76	NS
	1	0.79 ± 0.15	B	3.15 ± 1.86
	10	0.29 ± 0.09	B	4.25 ±1.10
	30	0.44 ± 0.12	B	3.94 ± 0.83
MCA high	0	1.82 ± 1.49	NS	4.47 ± 1.96	B
	1	0.57 ± 0.07		9.48 ± 1.25	A
	10	0.32 ± 0.11		8.31 ± 0.97	AB
	30	0.58 ± 0.17		5.22 ± 2.49	AB
CCA	0	1.66 ± 0.27	A	4.12 ± 0.50	A
	1	0.33 ± 0.05	B	12.0 ± 0.15	A
	10	0.09 ± 0.04	B	16.0 ± 2.62	A
	30	0.03 ± 0.03	B	1400 ± 2400b	A
ACQ low	0	0.57 ± 0.24	NS	1.00 ± 0.25	B
	1	0.49 ± 0.43		1.24 ± 0.72	B
	10	0.49 ± 0.12		2.31 ± 0.13	A
	30	0.53 ± 0.06		0.59 ± 0.04	B
ACQ high	0	0.78 ± 0.29	NS	9.09 ± 6.17	A
	1	0.73 ± 0.31		11.6 ± 5.22	A
	10	0.37 ± 0.02		19.2 ± 5.44	A
	30	0.28 ± 0.10		14.4 ± 2.24	A

NS = not a statistically significant difference between salinities within a treatment.

^a Different letters denote significant differences between salinities with a treatment. Treatments sharing two letters (e.g., ‘AB’) are not different from either salinities ‘A’ or ‘B’.

^b Poor model fitting.