. Author manuscript; available in PMC: 2017 Mar 24.

Published in final edited form as: J Environ Occup Sci. 2015 Apr 7;4(2):62–69. doi: 10.5455/jeos.20150403060427

Table 1.

Number of observations and mean, standard deviation, and maximum (μg/L) for manganese, arsenic, and lead in well water in all counties combined in North Carolina from 1998 to 2011

	Arsenic	Lead	Manganese
Number of wells (excluding missing values)	72,290	82,195	73,220
Number above detection limit	8,362	11,309	22,400
Percent above detection limit	12	14	31
Mean concentration	1.55	162.91	82.02
Standard deviation	8.11	2,491.88	469.34
Maximum	806	300,000	46,300

Metal concentrations represent the means of all wells and are not separated by county