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	Annual Toxics Summary Concord-2975 Treat Blvd 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
2025		*	*	*	*	*	*	0	*	*
2024		*	*	*	*	*	*	0	*	*
2023		*	*	*	*	*	*	0	*	*
2022		*	*	*	*	*	*	0	*	*
2021		*	*	*	*	*	*	0	*	*
2020		*	*	*	*	*	*	0	*	*
2019		*	*	*	*	*	*	0	*	*
2018		*	*	*	*	*	*	0	*	*
2017		*	*	*	*	*	*	0	*	*
2016		*	*	*	*	*	*	0	*	*
2015		*	*	*	*	*	*	0	*	*
2014		*	*	*	*	*	*	0	*	*
2013		*	*	*	*	*	*	0	*	*
2012		*	*	*	*	*	*	0	*	*
2011		*	*	*	*	*	*	0	*	*
2010		*	*	*	*	*	*	0	*	*
2009		*	*	*	*	*	*	0	*	*
2008		*	*	*	*	*	*	0	*	*
2007		*	*	*	*	*	*	0	*	*
2006		*	*	*	*	*	*	0	*	*
2005		*	*	*	*	*	*	0	*	*
2004		*	*	*	*	*	*	0	*	*
2003		*	*	*	*	*	*	0	*	*
2002		*	*	*	*	*	*	0	*	*
2001		*	*	*	*	*	*	0	*	*
2000		0.02	*	*	*	0.09	0.027	5	0.01	*
1999		0.005	0.03	*	0.06	0.07	0.018	19	0.01	*
1998		0.01	0.03	*	0.06	0.13	0.031	15	0.01	*
1997		0.01	0.04	0.102	0.31	0.42	0.127	29	0.01	12
1996		0.01	0.04	0.082	0.18	0.60	0.112	31	0.01	9
1995		0.02	0.07	0.147	0.37	1.1	0.242	30	0.01	17
1994		0.005	0.07	0.098	0.26	0.39	0.099	32	0.01	11
1993		0.01	0.12	0.204	0.51	1.1	0.254	30	0.01	24
1992		0.04	0.20	0.390	0.79	1.6	0.404	31	0.01	45
1991		0.03	0.21	0.419	1.3	1.7	0.450	29	0.01	49
1990		0.04	0.24	0.337	0.65	1.0	0.247	28	0.01	39
1989		0.06	0.34	0.436	0.95	1.7	0.418	22	0.01	51

	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.