Study of polycyclic aromatic hydrocarbons (PAHs) in soil samples from Al-Ahdab oil field in Waset Region, Iraq

Figures & data

Figure 1. Locations of soil samples from Al-Ahdab oil field.

Table 1. PAHs quantitation masses, according to Peters and Harlin (1995).

PAH	m/z	PAH	m/z
1-Fluoronaphthalene	146	Chrysene	228
Acenaphthylene	152	Benzo(b)fluoranthene	252
Fluorene	166	Benzo(k)fluoranthene	252
Phenanthrene	178	Benzo(a)pyrene	252
Anthracene	178	Ineno(1,2,3-cd)pyrene	276
Pyrene	202	Dibenzo(a,h)anthracene	278
Benzo(a)anthracene	228	Benzo(g,h,i)perylene	276

Table 2. Instrument and method limits of detection (LOD) and lower limit of quantitation for PAHs.

Standard of PAHs	LOD (ng/ml)	LLOQ (ng/ml)	MLOD (ng/g)	MLLOQ (ng/g)
Fluorene	0.01	0.05	0.03	0.11
Phenanthrene	0.07	0.23	0.05	0.13
Anthracene	0.01	0.05	0.06	0.19
Fluoranthrene	0.01	0.05	0.02	0.07
Pyrene	0.01	0.04	0.02	0.07
Benzo(a)anthracene	0.06	0.19	0.02	0.07
Chrysene	0.04	0.14	0.02	0.08
Benzo(b)fluoranthene	0.02	0.07	0.01	0.04
Benzo(k)fluoranthene	0.21	0.63	0.01	0.03
Benzo(a)pyrene	0.05	0.17	0.07	0.22
Indeno(1,2,3 cd)pyrene	0.04	0.11	0.04	0.13
Dibenzo(a,h)anthracene	0.04	0.13	0.04	0.13
Dibenzo(g,h,i)perylene	0.05	0.17	0.05	0.16

Table 3. Results of recovery studies using blank sand samples spiked with standard solution of PAHs mixture at 1000 μg/kg and 100 μg/kg levels.

Standard of PAHs	Average recovery X± S (n = 3)For the concentration1000 μg/kg	Average recoveryX± S (n = 3)For the concentration100 μg/kg
Fluorene	90 ± 4	99 ± 2
Phenanthrene	98 ± 4	100 ± 2
Anthracene	99 ± 4	88 ± 5
Fluoranthrene	100 ± 3	96 ± 4
Pyrene	92 ± 3	98 ± 3
Benzo(a)anthracene	97 ± 2	95 ± 4
Chrysene	100 ± 4	81 ± 2
Benzo(b)fluoranthene	100 ± 4	95 ± 5
Benzo(k)fluoranthene	96 ± 2	100 ± 1
Benzo(a)pyrene	89 ± 1	94 ± 6
Indeno(1,2,3 cd)pyrene	92 ± 2	84 ± 2
Dibenzo(a,h)anthracene	92 ± 3	83 ± 2
Dibenzo(g,h,i)perylene	100 ± 2	84 ± 1

Table 4. Parameters for estimating human cancer risk for adults.

Exposure factors	Adult
Ingestion rate, IngR (mg/day)	100
Exposed skin area, SA (cm^2)	3300
Skin adherence factor, AF soil (mg/cm^2)	0.2
Exposure frequency, EF (days/year)	313
Exposure duration, ED (year)	25
Exposure time, ET (h/day)	8
Body weight, BW (kg)	60
Averaging time, AT (days) = (70 years× 365 days/year)	25,550
Averaging time, AT*  (h = (70 years × 365 days/year × 24 h/day)	613,200

Table 5. Toxicity equivalent factors (TEFs), recovery-corrected concentrations (μg/kg) of PAH and μg TEQ/kg of the samples 1–12(A) and 13–24(B).

						(A)
Sample Nr. →Compound (TEF*) ↓	1	2	3	4	5	6	7	8	9	10	11	12
Fluorene (0.001)	6 ± 0.2	27 ± 0.2	8 ± 0.2	14 ± 0.2	16 ± 0.1	31 ± 0.2	27 ± 0.2	114 ± 0.1	66 ± 0.1	59 ± 0.1	18 ± 0.3	211 ± 0.1
Phenanthrene (0.001)	9 ± 0.1	67 ± 0	14 ± 0.4	39 ± 0.3	53 ± 0.2	55 ± 0.3	67 ± 0.3	21 ± 0.3	95 ± 0.2	95 ± 0.3	51 ± 0.1	443 ± 0.1
Anthracene (0.01)	26 ± 0.1	4 ± 0.1	6 ± 0.1	2 ± 0.1	3 ± 0.1	4 ± 0.3	3 ± 0.2	12 ± 0.1	5 ± 0.1	5 ± 0.1	1 ± 0.1	<dL**
Fluoranthene (0.001)	3 ± 0.1	2 ± 0.2	9 ± 0.2	17 ± 0.1	4 ± 0.1	<dL	<dL	<dL	1 ± 0.2	33 ± 0.2	24 ± 0.2	128 ± 0.3
Pyrene (0.001)	1 ± 00.3	13 ± 0.3	9 ± 0.1	3 ± 0.3	12 ± 0.1	11 ± 0.1	9 ± 0.1	36 ± 0.2	11 ± 0.3	Nd	<dL	<dL
Benzo(a)anthracene (0.1)	7 ± 0.3	11 ± 0.3	4 ± 0.3	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Chrysene (0.01)	4 ± 0.1	33 ± 0.1	12 ± 0.1	<dL	<dL	<dL	<dL	<dL	1 ± 0.2	<dL	<dL	<dL
Benzo(b)fluoranthene (0.1)	6 ± 0.4	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(k)fluoranthene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(a)pyrene (1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Indeno(1,2,3 cd)pyrene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Dibenzo(a,h)anthracene (1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(g,h,i)perylene (0.01)	<dL	<dL	19 ± 0.2	112 ± 0.1	84 ± 0.2	145 ± 0.4	<dL	<dL	<dL	<dL	<dL	<dL
Total	47	157	72	187	172	246	103	183	179	192	94	782
μg TEQ/kg	3.96	1.58	0.81	1.21	0.96	1.59	0.13	0.29	0.23	0.24	0.10	0.78

Table

						(B)
Sample Nr. →Comp’d (TEF*)↓	13	14	15	16	17	18	19	20	21	22	23	24
Fluorene (0.001)	21 ± 0.3	13 ± 0.3	<dL*	21 ± 0.2	23 ± 0.3	6 ± 0.2	68 ± 0.1	76 ± 0.1	8 ± 0.1	29 ± 0.2	9 ± 0.1	8 ± 0.3
Phenanthrene (0.001)	45 ± 0.2	56 ± 0.2	<dL	332 ± 0.1	59 ± 0.2	29 ± 0.1	248 ± 0.2	197 ± 0.2	19 ± 0.1	136 ± 0.3	45 ± 0.2	75 ± 0.1
Anthracene (0.01)	<dL	<dL	<dL	28 ± 0.1	<dL	8 ± 0.1	12 ± 0.2	3 ± 0.1	17 ± 0.2	19 ± 0.2	6 ± 0	18 ± 0.1
Fluoranthene (0.001)	17 ± 0.1	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Pyrene (0.001)	<dL	17 ± 0.3	<dL	59 ± 0.1	11 ± 0.1	8 ± 0.1	77 ± 0.2	56 ± 0.1	21 ± 0.1	39 ± 0.2	11 ± 0.3	28 ± 0.2
Benzo(a)anthracene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	6 ± 0.4	9 ± 0	9 ± 0.1	<dL	<dL
Chrysene (0.01)	<dL	16 ± 0.1	<dL	12 ± 0.1	<dL	5 ± 0.1	21 ± 0.2	<dL	<dL	8 ± 0.1	8 ± 0.2	10 ± 0.1
Benzo(b)fluoranthene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(k)fluoranthene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(a)pyrene (1)	473 ± 0.2	269 ± 0.3	19 ± 0.2	369 ± 0.2	202 ± 0.1	417 ± 0.1	167 ± 0.1	88 ± 0.3	89 ± 0.1	98 ± 0.1	51 ± 0.1	106 ± 0.3
Indeno(1,2,3 cd)pyrene (0.1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Dibenzo(a,h)anthracene (1)	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL	<dL
Benzo(g,h,i)perylene (0.01)	<dL	<dL	<dL	34 ± 0.1	<dL	<dL	<dL	45 ± 0.3	<dL	<dL	69 ± 0.3	69 ± 0.3
Total	556	371	19	855	295	473	593	471	163	343	343	314
μg TEQ/kg	473.08	269.25	19.00	370.15	202.09	417.17	167.62	89.41	90.12	99.37	51.90	107.08

*B(a)P-TEF according to US-EPA (1993); ** <dL = under detection limit.

Figure 2. Concentrations of PAHs in soil samples for site 1–8 (A), 9–16 (B) and 17–24 (C).

Figure 3. The total estimated cancer risks of exposing to soil samples 1 to 24 PAHs through different exposure pathways.

Table 6. Total calculated incremental lifetime cancer risks (ILCRs) from exposure to PAHs in soil samples through all exposure pathways.

Pathway→Site↓	Ingestion	Dermal	Inhalation	Total	Theor. no. of cancer cases per 10^6
1	2.42E-07	6.92E-09	2.16E-09	2.51E-07	0
2	8.11E-07	2.31E-08	7.19E-09	8.41E-07	1
3	3.72E-07	1.06E-08	3.30E-09	3.86E-07	0
4	9.65E-07	2.76E-08	8.57E-09	1.00E-06	1
5	8.88E-07	2.53E-08	7.89E-09	9.21E-07	1
6	1.27E-06	3.62E-08	1.13E-08	1.32E-06	1
7	5.32E-07	1.52E-08	4.72E-09	5.52E-07	1
8	9.45E-07	2.69E-08	8.39E-09	9.80E-07	1
9	9.23E-07	2.64E-08	8.21E-09	9.58E-07	1
10	9.91E-07	2.83E-08	7.45E-09	1.03E-06	1
11	4.85E-07	1.38E-08	4.30E-09	5.03E-07	0
12	4.04E-06	1.15E-07	3.59E-08	4.19E-06	4
13	2.87E-06	8.19E-08	2.55E-08	2.98E-06	3
14	1.92E-06	5.46E-08	1.70E-08	1.99E-06	2
15	9.81E-08	2.80E-09	8.71E-10	1.02E-07	0
16	4.42E-06	1.26E-07	3.91E-08	4.59E-06	5
17	1.52E-06	4.34E-08	1.35E-08	1.58E-06	2
18	2.44E-06	6.96E-08	2.17E-08	2.53E-06	3
19	3.06E-06	8.73E-08	2.72E-08	3.17E-06	3
20	2.44E-06	6.95E-08	2.16E-08	2.53E-06	3
21	8.42E-07	2.40E-08	7.48E-09	8.73E-07	1
22	1.77E-06	5.05E-08	1.57E-08	1.84E-06	2
23	1.39E-06	5.05E-08	1.57E-08	1.46E-06	1
24	1.62E-06	4.62E-08	1.44E-08	1.68E-06	2

Peters C, Harlin K. (1995). Standard operating procedure for the analysis of PAHs and Atrazin by GC/Ion rap MS, SOP number CH-IN-003.1

 Google Scholar

USEPA. (1993) Provisional Guidance for Quantitative Risk Assessment of PAHUS Environmental Protection Agency (1993) EPA/600/R-93/089

 Google Scholar