Table 4.

Limits of detection and summary statistics for detected OP pesticides in house dust from 15 Salinas agricultural homes and 13 Oakland urban homes by collection time point (ng/g).^a,^b

Precursor OP compound	Dialkylphosphate breakdown product(s)	LOD (ng/g)	Homes	Collection time point	No. of homes sampled	% DF	Concentration in dust (ng/g)
							p50	p75	p95	Max
Diazinon	DEP, DETP	4	Agricultural	1	14	86	15	19	56	56
				2	15	73	14	17	36	36
			Urban	1	13	54	9	16	139	139
				2	12	50	5	21	133	133
Chlorpyrifos	DEP, DETP	10	Agricultural	1	14	57	22	32	200	200
				2	15	53	20	26	135	135
			Urban	1	13	39	<LOD	35	56	56
				2	12	33	<LOD	33	43	43
Tetrachlorvinphos	DMP	10	Agricultural	1	14	14	<LOD	<LOD	252	252
				2	15	7	<LOD	<LOD	271	271
			Urban	1	13	8	<LOD	<LOD	16	16
				2	12	0	—	—	—	—
Malathion	DMP, DMTP, DMDTP	10	Agricultural	1	14	7	<LOD	<LOD	52	52
				2	15	7	<LOD	<LOD	71	71
			Urban	1	13	15	<LOD	<LOD	877	877
				2	12	8	<LOD	<LOD	1,158	1,158
Diazinon-oxonc	DEP	4	Agricultural	1	14	0	—	—	—	—
				2	15	0	—	—	—	—
			Urban	1	13	8	<LOD	<LOD	5	5
				2	12	0	—	—	—	—

Abbreviations: LOD, limit of detection; DF, detection frequency; “—”, statistic not reported when analyte was not detected.

^aOrganophosphate (OP) pesticides not detected in any samples included: methidathion, methyl parathion, and phorate.

^bNumber of samples analyzed for OP pesticides in each location was restricted to samples with adequate amount of dust volume remaining after initial analyses for DAPs: 29 samples from 15 Salinas agricultural homes and 25 samples from 13 urban homes. Summary statistics reported are for the number of samples at each collection.

^cOne molecule of the OP pesticide diazinon can either breakdown into DETP and the specific metabolite, isopropyl-methyl-hydroxypyrimidine (IMHP), or it may undergo activation into diazinon-oxon subsequently breaking down into DEP and IMHP.