. Author manuscript; available in PMC: 2019 Jan 1.

Published in final edited form as: Estuar Coast Shelf Sci. 2018;212:11–22. doi: 10.1016/j.ecss.2018.06.021

Table 3:

Summaries of flow-normalized trends in nitrite/nitrate and ammonium (mg L⁻¹) concentrations before and after WWTP upgrades upstream of station P8. Upgrades were completed in 2006 at the City of Stockton WWTP (San Joaquin County, Fig. 5). Summaries are medians and percent change per year in parentheses (increasing in bold). Changes and significance estimates are based on seasonal Kendall tests of flow-normalized results within each time period. Increasing values are in bold-italics. Months for each season are Spring: MAM, Summer: JJA, Fall: SON, Winter: DJF.

	Median	% change	Median	% change
Period	${NO}_{2}^{-} / {NO}_{3}^{2 -}$		${NH}_{4}^{+}$
Annual
1976–2006	1.3	(2.0)^*	0.2	(2.8)^*
2007–2013	1.4	(−1.9)^*	0.1	(−16.6)^*

Seasonal, pre
Spring	1.2	(1.6)^*	0.2	(1.4)^*
Summer	1.0	(2.4)^*	0.1	(3.3)^*
Fall	1.3	(2.2)^*	0.2	(4.9)^*
Winter	1.5	(2.1)^*	0.7	(4.8)^*

Seasonal, post
Spring	1.3	(−1.6)^*	0.1	(−16.2)^*
Summer	0.9	(−4.3)^*	0.1	(−15.7)^*
Fall	1.5	(−1.7)^*	0.1	(−19.3)^*
Winter	2.2	(−0.8)^*	0.2	(−26.7)^*

p < 0.05