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	Annual Toxics Summary Chico-Manzanita Avenue FAQs Perchloroethylene parts per billion

Read About Estimated Risk

Year	Months Present	Minimum	Median	Mean	90th Percentile	Maximum	Standard Deviation	Number of Observations	Detection Limit	Estimated Risk
2023		*	*	*	*	*	*	0	*	*
2022		*	*	*	*	*	*	0	*	*
2021		*	*	*	*	*	*	0	*	*
2020		*	*	*	*	*	*	0	*	*
2019		*	*	*	*	*	*	0	*	*
2018		*	*	*	*	*	*	0	*	*
2017		*	*	*	*	*	*	0	*	*
2016		*	*	*	*	*	*	0	*	*
2015		*	*	*	*	*	*	0	*	*
2014		*	*	*	*	*	*	0	*	*
2013		*	*	*	*	*	*	0	*	*
2012		0.005	0.005	*	0.01	0.02	0.006	12	0.01	*
2011		0.005	0.005	0.006	0.01	0.02	0.004	30	0.01	0.7
2010		0.005	0.005	0.008	0.01	0.02	0.005	30	0.01	1
2009		0.005	0.005	0.010	0.02	0.05	0.010	31	0.01	1
2008		0.005	0.005	0.010	0.02	0.03	0.008	31	0.01	1
2007		0.005	0.005	0.011	0.02	0.04	0.010	29	0.01	1
2006		0.005	0.005	0.011	0.02	0.04	0.009	30	0.01	1
2005		0.005	0.01	0.028	0.02	0.67	0.119	31	0.01	3
2004		0.005	0.01	0.014	0.03	0.04	0.010	30	0.01	2
2003		0.005	0.01	0.015	0.03	0.03	0.008	31	0.01	2
2002		0.005	0.02	0.024	0.04	0.07	0.015	30	0.01	3
2001		0.005	0.02	0.024	0.05	0.08	0.017	31	0.01	3
2000		0.005	0.02	*	0.07	1.4	0.281	24	0.01	*
1999		0.005	0.02	*	0.03	0.04	0.010	16	0.01	*
1998		0.005	0.01	*	0.03	0.03	0.009	28	0.01	*
1997		0.005	0.02	*	0.10	0.29	0.057	28	0.01	*
1996		0.005	0.03	0.049	0.11	0.26	0.054	31	0.01	6
1995		0.01	0.03	0.047	0.10	0.21	0.051	30	0.01	5
1994		0.005	0.03	0.265	0.11	7.7	1.38	31	0.01	31
1993		0.005	0.04	0.057	0.12	0.19	0.046	30	0.01	7
1992		0.005	0.05	*	0.10	0.12	0.032	16	0.01	*
1991		*	*	*	*	*	*	0	*	*
1990		*	*	*	*	*	*	0	*	*
1989		*	*	*	*	*	*	0	*	*

	Notes:	Values below the Limit of Detection (LoD) assumed to be ½ LoD. Means and risks shown only for years with data in all 12 months. "*" means there was insufficient or no data available to determine the value.