Bioconcentration Factors for Volatile Organic Compounds in Vegetation

Table 1. Analytes and surrogates
	retention time^a	quantitation ion	secondary ion(s)	relative volatility (aK_oa)^b
	surrogates		-	-
benzene-d₆	9.45	84	82,85	500
fluorobenzene	9.91	96	70	690
1,4-difluorobenzene	10.06	114	63	860
1,2-dichloropropane	10.78	67	69	98
toluene-d₈	13.02	98	100,99	2200
1,1,2-trichloroethane-d₃	13.90	100	98	3800
1,2-dibromoethane-d₄	15.44	111	113	5000
chlorobenzene-d₅	16.55	117	119,82	5800
o-xylene-d₁₀	17.81	98	116	8400
4-bromofluorobenzene	19.72	174	176	13000
bromobenzene-d₅	20.05	161	163,82	12000
1,2-dichlorobenzene	22.65	152	150	22000
1,2,4-trichlorobenzene	24.75	183	185	41000
naphthalene-d₈	25.03	136	108	57000
	analytes		-	-
benzene	9.45	78	77	460
trichloroethene	10.61	130	132	2600
toluene	13.18	91	92	2100
tetrachloroethene	14.6	166	164	6100
ethylbenzene	16.79	106	91	5000
m,p-xylene	16.97	106	91	4500
o-xylene	18.15	106	91	8200
1,2,4-trimethylbenzene	21.24	120	105	16000
1,4-dichlorobenzene	22.14	146	148	20000
naphthalene	25.07	128	108	41000
	monoterpenes		-	-
tricyclene	18.15	93	91,136	7400
a-pinene	18.58	93	91,136	5600
camphene	19.45	93	91,136	11000
b-pinene	20.49	93	91,136	4800
3-carene	21.23	93	91,136	6300
a-terpinene	21.39	93	91,136	8000
limonene	21.67	93	91,136	11000
g-terpinene	22.33	93	91,136	19000

^a Retention times were determined using 60-m x 0.53-mm i.d., 3.0-µm film thickness. Temperature program was: 3 min at 10 °C, 50 C/min ramp to 40 °C; 5 C/min ramp to 120 °C; 20 C/min to 220 °C and held at 220 °C to end of run.^b Relative volatility values from reference 7. Relative volatilities for monoterpenes were experimentally determined as part of this study.

Table 2. Bioconcentration factors for selected leaves.
	dry wt (%) avg	Total^amonoter- penes µg/g^a avg	toluene		tetrachloro- ethene		ethyl- benzene		m,r-xylene		1,2,4-trimethyl- benzene		1,4-dichloro- benzene		naphthalene
plant	dry wt (%) avg	Total^amonoter- penes µg/g^a avg	avg	dev	avg	dev	avg	dev	avg	dev	avg	dev	avg	dev	avg	dev
juniper	40	1070.	900	400	420	590	100000	54000	76000	47000	NA^b		NA		280000	100000
rosemary	23	1000.	14000	6000	5400	8100	1100	7000	10000	7000	NA		NA		66000	34000
pine	48	190.	2300	1800	440	80	1800	1300	1300	1100	53000	29000	6200	c	13000	10000
mock orange	42	53.	590	230	350	320	1600	900	2200	1500	110000	80000	5200	3100	39000	22000
ivy	37	3.9	190	-	NA		NA		290	-	9000	-	4000	-	8000	-
holly	43	3.1	220	180	210	210	260	290	230	160	1500	800	2300	1600	2900	1300
grass	20	0.6	200	70	220	190	350	240	420	200	1800	900	2700	300	5800	2600
olive	52	0.1	180	70	350	180	330	100	230	160	800	430	800	-	1400	600

^a Concentrations determined as described in this study
^b Concentration of analyte in leaves could not be determined.
^c Only one determination

Table 3. The ratios of BCF to K_oa and P values for VOCs in leaves
	BCF/K_oa									R
	toluene	PCE	ethyl- benzene	m,r-xylene	1,2,4-trimethyl- benzene	1,4-dichloro- benzene	naphtha lene	avg	dev	avg	dev
juniper	.47	.87	19.8	13.1	NA^b	NA	10.6	9.0	8.3	6.3	8.0
rosemary	7.64	16.8	2.1	1.8	NA	NA	2.55	6.2	6.4	4.3	6.0
pine	1.2	.91	.35	.22	NA	.41	.50	.60	.38	.43	.39
mock orange	.31	.72	.30	.37	NA	.35	.85	.48	.24	.35	.28
ivy	.10	NA	NA	.05	.49	.25	.32	.24	.18	.15	.16
holly	.12	.45	.05	.04	.08	.15	.11	.14	.14	.06	.13
grass	.11	.46	.07	.07	.09	.18	.22	.17	.14	.08	.13
olive	.09	.73	.06	.05	.04	.05	.05	.15	.25	.09	.24
K_oa^a	1900	480	5100	5800	19000	15000	26000

^a K_oa values taken from reference 7.^b concentration of analyte in leaves could not be determined.

Figure 1. Concentrations of toluene in morning and afternoon air samples.

Figure 2. Comparison of VOC concentrations in leaves varying with daily changes in air concentration as a function of analyte vapor pressure during sampling.

Figure 3. Concentration of naphthalene in mock orange and air with calculated BCEs.

National Exposure Research Laboratory
Author: Mike Hiatt / Email: Hiatt.Mike@epa.gov
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Bioconcentration Factors for Volatile Organic Compounds in Vegetation

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