"C1"	"C2"	"C3"	"C4"
"C1"	"C2"	"C3"	"C4"
			"SD"
	"Sample"	"Mean log"	"of log"
"Site"	"size"	"concentration"	"concentration"
"Steam plant"	"8"	"18"	"4.9"
"Clean"	"9"	"11"	"4.6"