Table 3.

Within- and between-worker variability of atrazine mercapturate for all farmers and controls and by season

Season	Urine collection timepoint	Na	Nb >LOD (%)	AMc	Percentiles		GMd	GSDe	GSDwwf	GSDbwg	R0.95wwh	R0.95bwi
					10	90
FARMERS (n=30)
All	1–10	313	181 (58)	2.2	<LOD	5.2	0.30	8.0	6.8	2.2	1881	21
Pre-planting/Off-season	1,10	60	8 (13)	0.12	<LOD	0.22	0.06	2.7	2.1	1.9	20	13
Planting	2–6	157	133 (85)	3.5	<LOD	9.7	1.0	6.5	4.0	3.6	223	156
Growing/Post-harvest	7–9	96	40 (42)	1.4	<LOD	1.0	0.10	5.0	4.6	1.7	397	7
CONTROLS (n=10)
All	1; 6–10	49	3 (6)	0.11	<LOD	0.17	0.06	2.4
Pre-planting/Off-season	1,10	19	1 (5)	0.08	<LOD	0.13	0.05	22
Planting	6	5	0 (0)	NAj	<LOD	<LOD	<LOD	<LOD
Growing/Post-harvest	7–9	25	2 (8)	0.13	<LOD	0.25	0.07	2.6

^aTotal number of samples

^bNumber of samples above the limit of detection (LOD)

^cArithmetic mean (μg/g creatinine), urinary concentrations below the LOD were replaced with LOD/2

^dGeometric mean (μg/g creatinine), urinary concentrations below the LOD were replaced with LOD/2. Due to left censoring the GM may be biased.

^eGeometric standard deviation. Due to left censoring the GSD may be biased.

^fWithin worker geometric standard deviation

^gBetween worker geometric standard deviation

^hR_0.95ww: The ratio between the 97.5^th and 2.5^th percentiles of the log-normal within-worker exposure distribution, was computed as exp[3.92*variance component^0.5] (Rappaport, 1991)

ⁱR_0.95bw: The ratio between the 97.5^th and 2.5^th percentiles of the log-normal between-worker exposure distribution, was computed as exp[3.92*variance component^0.5] (Rappaport, 1991)

^jNot applicable, all samples <LOD