PUBLIC HEALTH ASSESSMENT ADDENDUM
MOTCO, INCORPORATED
TEXAS CITY, GALVESTON COUNTY, TEXAS
1. Soil Contamination
The off-site soil investigation, was divided into three sampling areas: top soil, shallow subsurface, and deep subsurface soils. Sixteen top-soil samples (0-6 feet in depth) were collected off site. A slightly elevated level of benzene was found (55.4 ppm) (see Table 9). The highest VOC levels were detected west of Pit 3, outside the site boundary fence at a depth of two to three feet. The highest levels of PAHs were detected northwest of Pit 3. No significant levels of metals were detected in the top soil.
Shallow subsurface soil sampling indicated elevated levels of VOCs and semi-VOCs. (See Table 10.) The highest concentrations of contaminants were found northwest and southeast of the site. VOC contamination consisted of 1,1,2- trichloroethane (1200 ppm), 1,2-dichloroethane (390 ppm) and benzene (44 ppm). Semi-VOC contamination was primarily due to PAHs; however, bis(2-chloro- ethyl)ether, a non-PAH semi-volatile compound, ranged up to at 1,000 ppm.
Elevated levels of arsenic, lead, and barium were also detected in shallow subsurface soil samples (812.3 ppm, 813.5 ppm, and 12,830 ppm respectively). The highest metal concentrations were detected southeast of Pit 7. In addition, arsenic was seen at an elevated level (117.1 ppm) in the deep subsurface soil. (See Table 11.) No other appreciable levels of contaminants were detected in deep subsurface soil.
2. Ground-water Contamination
Fifty-eight off-site monitoring wells were used to investigate the ground water near the MOTCO site. Fifty-one wells were screened in the shallow aquifer and seven were screened in the deep aquifer. In addition, two deep industrial wells owned by Del Industries and Central Freight Lines were sampled. Both industrial wells are used for non-potable purposes. The Del Industries well is screened at 700 feet, and the Central Freight Lines well is screened at 600 feet. Both wells are located downgradient from the site.
Elevated levels of VOCs, semi-VOCs, and metals were detected in the shallow aquifer. (See Table 12.) VOCs with the highest concentrations included 1,2-dichloroethane (164 ppm), 1,1,2-trichloroethane (149 ppm), vinyl chloride (56 ppm), and benzene (15 ppm). Two other VOCs, 1,1-dichloroethene, and 1,2-transdichloroethylene were also detected at elevated levels. The highest concentrations of VOCs were located southeast and northwest of the site.
Two semi-VOCs were detected at elevated levels. Naphthalene and bis(2-chloroethyl)ether had concentrations of up to 220 ppm and 1414 ppm, respectively. The highest semi-VOC concentrations were located southeast of the site.
Several metals were detected at levels above health assessment comparison values. These included arsenic, barium, cadmium, chromium and manganese. Lead levels in the off-site shallow ground water ranged up to 1.4 ppm.
A total of seven off-site monitoring wells were screened in the deep aquifer with only low levels of VOCs, semi-VOCs, and metals were detected in these wells. (See Table 13.)
A private well is also located at the nearest residence at a depth of approximately 160 feet. This residence, however, uses the municipal water supply for potable purposes. In 1982, Black and Veatch took water samples from the private well. Naphthalene (15 ppm), benzene (3.8 ppm), ethylbenzene (4.9), 1,2-dichloro- ethane (0.25 ppm), and toluene (82 ppm) were detected above health assessment comparison values.
3. Surface-Water Contamination
Surface-water sampling was conducted at total of 19 locations. Samples were taken from: drainage ditches adjacent to or downgradient from the MOTCO site, nearby marshes, Jones Bay, the Bayou near the cities of Hitchcock and LaMarque, and the canal in the Omega Bay Subdivision. Table 14 lists chemicals detected as a result of surface-water sampling.
Elevated levels of the VOCs 1,2-dichloroethane (0.192 ppm) and vinyl chloride (0.031 ppm), along with the metals arsenic (0.28 ppm), cadmium (0.027), chromium (0.15 ppm), and manganese (4.0 ppm) were detected. The highest levels of contamination were detected in the surface water of the HL&P drainage ditch on the west side of the MOTCO site.
4. Sediment Contamination
During the sampling events for the SFSI and EA, 19 off-site sediment samples were taken. The locations of sediment sampling corresponds with the locations of surface-water sampling. Low levels of metals, VOCs, and semi-VOCs were detected in the sediment samples. (See Table 15.) Only chromium (201 ppm) slightly exceeded the HAC value for soil; lead was also detected in sediments up to 483 ppm.
| Contaminant |
Maximum Concentration ppm
|
Sample Depth feet
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
|||||
| Metals (Indicator) | |||||
| Arsenic |
3
|
0-2
|
MMFS
|
50
|
EMEG
|
| Barium |
154
|
1-3
|
MMFS
|
3,500
|
RfD
|
| Cadmium |
0.005
|
2-3
|
MMFS
|
200
|
EMEG
|
| Chromium |
40
|
2-3
|
MMFS
|
200
|
EMEG
|
| Lead |
91.1
|
0-2
|
MMFS
|
None
|
None
|
| Manganese |
NA
|
NA
|
MMFS
|
5,000
|
RfD
|
| Mercury |
1.0
|
2-3
|
MMFS
|
40
|
EMEG
|
| Volatile Organic Compounds | |||||
| Benzene |
55.4
|
0-6
|
WCEA
|
30
|
EMEG
|
| Chloroform |
18
|
2-3
|
MMFS
|
1,000
|
EMEG
|
| 1,1-dichlorethane |
0.19
|
2-3
|
MMFS
|
5,000
|
RfD
|
| 1,1-dichloroethene |
28
|
2-3
|
MMFS
|
400
|
EMEG
|
| 1,2-dichloroethane |
170
|
2-3
|
MMFS
|
200
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
NA
|
3,000
|
EMEG
|
| 1,3-dichloropropylene |
NA
|
NA
|
NA
|
None
|
None
|
| Methylene Chloride |
7.8
|
1-2
|
MMFS
|
2,000
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
5.8
|
2
|
BVII
|
10,000
|
RfD
|
| Toluene |
NA
|
NA
|
NA
|
10,000
|
RfD
|
| 1,2-transdichloroethylene |
NA
|
NA
|
NA
|
1,000
|
RfD
|
| 1,1,2-trichloroethane |
570
|
2-3
|
MMFS
|
2,000
|
EMEG
|
| Trichloroethylene |
0.26
|
2
|
BVII
|
100,000
|
EMEG
|
| Vinyl Chloride |
ND
|
0-3
|
MMFS
|
50
|
EMEG
|
| Semi-Volatile Organic Compounds | |||||
| Acenaphthene |
113
|
0-6
|
WCEA
|
3,000
|
RfD
|
| Acenaphthylene |
114
|
0-6
|
WCEA
|
5,000
|
MRL
|
| Anthracene |
781
|
0-6
|
WCEA
|
15,000
|
MRL
|
| Benz (a) anthracene |
33
|
1-2
|
WCEA
|
5,000
|
MRL
|
| Benzo (a) pyrene |
3.4
|
0-6
|
WCEA
|
5,000
|
MRL
|
| Benzo (b) fluoranthene |
3.1
|
0-6
|
WCEA
|
5,000
|
MRL
|
| Bis(2-chloroethyl)ether |
9.2
|
0-6
|
WCEA
|
1,000
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
ND
|
0-3
|
MMFS
|
1,000
|
RfD
|
| Chrysene |
63.6
|
0-6
|
WCEA
|
5,000
|
MRL
|
| Fluoranthene |
76
|
0-6
|
WCEA
|
2,000
|
RfD
|
| Fluorene |
22
|
0-6
|
WCEA
|
2,000
|
RfD
|
| Naphthalene |
869
|
0-6
|
WCEA
|
66,500
|
MRL
|
| Phenanthrene |
550
|
1-2
|
WCEA
|
5,000
|
MRL
|
| Pyrene |
218
|
0-6
|
WCEA
|
1,500
|
RfD
|
|
|
|||||
NA = not analyzed
ND = not detected
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 10. OFF-SITE SHALLOW SUBSURFACE SOIL
| Contaminant |
Maximum Concentration ppm
|
Sample Depth feet
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
|||||
| Metals (Indicator) | |||||
| Arsenic |
812.3
|
33-35
|
WCEA
|
50
|
EMEG
|
| Barium |
12,830
|
33-35
|
WCEA
|
3,500
|
RfD
|
| Cadmium |
9.0
|
21
|
WCEA
|
200
|
EMEG
|
| Chromium |
911.5
|
43-45
|
WCEA
|
200
|
EMEG
|
| Lead |
813.5
|
33-35
|
WCEA
|
None
|
None
|
| Manganese |
550
|
16
|
BVII
|
5,000
|
RfD
|
| Mercury |
10.3
|
28-30
|
WCEA
|
40
|
EMEG
|
| Volatile Organic Compounds | |||||
| Benzene |
44
|
28-30
|
WCEA
|
30
|
EMEG
|
| Chloroform |
0.01
|
48-50
|
MMFS
|
1,000
|
EMEG
|
| 1,1-dichlorethane |
ND
|
6-50
|
BVII/MMFS
|
5,000
|
RfD
|
| 1,1-dichloroethene |
0.12
|
5
|
WCEA
|
400
|
EMEG
|
| 1,2-dichloroethane |
390
|
6-8
|
WCEA
|
200
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
NA
|
3,000
|
EMEG
|
| 1,3-dichloropropylene |
NA
|
NA
|
NA
|
None
|
None
|
| Methylene Chloride |
.008
|
33-35
|
MMFS
|
2,000
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
ND
|
10-50
|
BVII/MMFS
|
10,000
|
RfD
|
| Toluene |
47
|
43-45
|
WCEA
|
10,000
|
RfD
|
| 1,2-transdichloroethylene |
3.7
|
3+
|
BVII
|
1,000
|
RfD
|
| 1,1,2-trichloroethane |
1200
|
6-8
|
WCEA
|
2,000
|
EMEG
|
| Trichloroethylene |
15
|
6-8
|
WCEA
|
100,000
|
EMEG
|
| Vinyl Chloride |
13
|
6-8
|
WCEA
|
50
|
EMEG
|
| Semi-Volatile Organic Compounds | |||||
| Acenaphthene |
24
|
43-45
|
WCEA
|
3,000
|
RfD
|
| Acenaphthylene |
77
|
43-45
|
WCEA
|
5,000
|
MRL
|
| Anthracene |
140
|
43-45
|
WCEA
|
15,000
|
MRL
|
| Benz (a) anthracene |
6.5
|
43-45
|
WCEA
|
5,000
|
MRL
|
| Benzo (a) pyrene |
4.5
|
43-45
|
WCEA
|
5,000
|
MRL
|
| Benzo (b) fluoranthene |
3.4
|
43-45
|
WCEA
|
5,000
|
MRL
|
| Bis(2-chloroethyl)ether |
1,000
|
23-25
|
WCEA
|
1,000
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
ND
|
6-50
|
MMFS
|
1,000
|
RfD
|
| Chrysene |
290
|
6-8
|
WCEA
|
5,000
|
MRL
|
| Fluoranthene |
17
|
43-45
|
WCEA
|
2,000
|
RfD
|
| Fluorene |
49
|
43-45
|
WCEA
|
2,000
|
RfD
|
| Naphthalene |
213
|
43-45
|
WCEA
|
66,500
|
MRL
|
| Phenanthrene |
78
|
43-45
|
WCEA
|
5,000
|
MRL
|
| Pyrene |
37
|
43-45
|
WCEA
|
1,500
|
RfD
|
|
|
|||||
ND = not detected
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 11. OFF-SITE DEEP SUBSURFACE SOIL
| Contaminant |
Maximum Concentration ppm
|
Sample Depth feet
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
|||||
| Metals (Indicator) | |||||
| Arsenic |
117.1
|
53-55
|
WCEA
|
50
|
EMEG
|
| Barium |
370
|
58-60
|
WCEA
|
3,500
|
RfD
|
| Cadmium |
6.4
|
50
|
WCEA
|
200
|
EMEG
|
| Chromium |
411
|
148-150
|
WCEA
|
200
|
EMEG
|
| Lead |
316.4
|
148-150
|
WCEA
|
None
|
None
|
| Manganese |
NA
|
NA
|
NA
|
5,000
|
RfD
|
| Mercury |
0.6
|
53-55
|
WCEA
|
40
|
EMEG
|
| Volatile Organic Compounds | |||||
| Benzene |
ND
|
53-160
|
MMFS
|
30
|
EMEG
|
| Chloroform |
ND
|
50-160
|
MMFS
|
1,000
|
EMEG
|
| 1,1-dichlorethane |
NA
|
NA
|
NA
|
5,000
|
RfD
|
| 1,1-dichloroethene |
ND
|
50+
|
MMFS
|
400
|
EMEG
|
| 1,2-dichloroethane |
0.12
|
53-55
|
WCEA
|
200
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
NA
|
3,000
|
EMEG
|
| 1,3-dichloropropylene |
NA
|
NA
|
NA
|
None
|
None
|
| Methylene Chloride |
ND
|
53-160
|
MMFS
|
2,000
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
ND
|
53-160
|
MMFS
|
10,000
|
RfD
|
| Toluene |
NA
|
NA
|
NA
|
10,000
|
RfD
|
| 1,2-transdichloroethylene |
NA
|
NA
|
NA
|
1,000
|
RfD
|
| 1,1,2-trichloroethane |
0.025
|
53-55
|
WCEA
|
2,000
|
EMEG
|
| Trichloroethylene |
NA
|
NA
|
NA
|
100,000
|
EMEG
|
| Vinyl Chloride |
ND
|
53-160
|
MMFS
|
50
|
EMEG
|
| Semi-Volatile Organic Compounds | |||||
| Acenaphthene |
ND
|
50+
|
WCEA
|
3,000
|
RfD
|
| Acenaphthylene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Anthracene |
ND
|
50+
|
WCEA
|
15,000
|
MRL
|
| Benz (a) anthracene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Benzo (a) pyrene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Benzo (b) fluoranthene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Bis(2-chloroethyl)ether |
ND
|
50+
|
WCEA
|
1,000
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
ND
|
50+
|
MMFS
|
1,000
|
RfD
|
| Chrysene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Fluoranthene |
ND
|
50+
|
WCEA
|
2,000
|
RfD
|
| Fluorene |
ND
|
50+
|
WCEA
|
2,000
|
RfD
|
| Naphthalene |
ND
|
50+
|
WCEA
|
66,500
|
MRL
|
| Phenanthrene |
ND
|
50+
|
WCEA
|
5,000
|
MRL
|
| Pyrene |
ND
|
50+
|
WCEA
|
1,500
|
RfD
|
|
|
|||||
NA = not analyzed
ND = not detected
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 12. OFF-SITE SHALLOW GROUND WATER
| Contaminant |
Maximum Concentration ppm
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
||||
| Metals (Indicator) | ||||
| Arsenic |
0.036
|
WCEA
|
0.01
|
EMEG
|
| Barium |
22.0
|
WCEA
|
0.7
|
RfD
|
| Cadmium |
0.060
|
WCEA
|
0.005
|
EMEG
|
| Chromium |
0.140
|
WCEA
|
0.05
|
EMEG
|
| Lead |
1.4
|
WCEA
|
None
|
None
|
| Manganese |
13.9
|
BVII
|
1
|
RfD
|
| Mercury |
0.0026
|
WCEA
|
0.008
|
EMEG
|
| Volatile Organic Compounds | ||||
| Benzene |
15.05
|
WCEA
|
0.007
|
EMEG
|
| Chloroform |
0.020
|
WCEA
|
0.2
|
EMEG
|
| 1,1-dichlorethane |
0.112
|
BVII
|
1
|
RfD
|
| 1,1-dichloroethene |
8.7
|
WCEA
|
0.09
|
EMEG
|
| 1,2-dichloroethane |
164.0
|
WCEA
|
0.05
|
EMEG
|
| 1,2-dichloropropane |
.069
|
BVII
|
0.07
|
EMEG
|
| 1,3-dichloropropylene |
0.173
|
BVII
|
None
|
None
|
| Methylene Chloride |
0.026
|
BVII
|
0.5
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
NA
|
NA
|
2
|
RfD
|
| Toluene |
0.184
|
BVII
|
2
|
RfD
|
| 1,2-transdichloroethylene |
1.012
|
BVII
|
0.2
|
RfD
|
| 1,1,2-trichloroethane |
149.0
|
WCEA
|
0.4
|
EMEG
|
| Trichloroethylene |
0.105
|
BVII
|
20
|
EMEG
|
| Vinyl Chloride |
56.0
|
WCEA
|
0.01
|
EMEG
|
| Semi-Volatile Organic Compounds | ||||
| Acenaphthene |
ND
|
MMFS
|
0.6
|
RfD
|
| Acenaphthylene |
ND
|
MMFS
|
1.0
|
MRL
|
| Anthracene |
ND
|
MMFS
|
3.0
|
RfD
|
| Benz (a) anthracene |
ND
|
MMFS
|
1.0
|
MRL
|
| Benzo (a) pyrene |
ND
|
MMFS
|
1.0
|
MRL
|
| Benzo (b) fluoranthene |
ND
|
MMFS
|
1.0
|
MRL
|
| Bis(2-chloroethyl)ether |
1,414
|
WCEA
|
0.02
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
ND
|
MMFS
|
0.2
|
RfD
|
| Chrysene |
ND
|
MMFS
|
1.0
|
MRL
|
| Fluoranthene |
ND
|
MMFS
|
0.4
|
RfD
|
| Fluorene |
ND
|
MMFS
|
0.4
|
RfD
|
| Naphthalene |
220
|
WCEA
|
13.3
|
MRL
|
| Phenanthrene |
0.2
|
WCEA
|
1.0
|
MRL
|
| Pyrene |
ND
|
MMFS
|
0.3
|
RfD
|
|
|
||||
*Transmissive Zones 1,2, & 3
ND = not detected
NA = not analyzed
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 13. OFF-SITE DEEP GROUND WATER*
| Contaminant |
Maximum Concentration ppm
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
||||
| Metals (Indicator) | ||||
| Arsenic |
0.005
|
WCEA
|
0.01
|
EMEG
|
| Barium |
0.362
|
WCEA
|
0.7
|
RfD
|
| Cadmium |
ND
|
MMFS
|
0.005
|
EMEG
|
| Chromium |
0.008
|
WCEA
|
0.05
|
EMEG
|
| Lead |
0.001
|
WCEA
|
None
|
None
|
| Manganese |
NA
|
NA
|
1
|
RfD
|
| Mercury |
ND
|
MMFS
|
0.008
|
EMEG
|
| Volatile Organic Compounds | ||||
| Benzene |
ND
|
MMFS
|
0.007
|
EMEG
|
| Chloroform |
ND
|
MMFS
|
0.2
|
EMEG
|
| 1,1-dichlorethane |
ND
|
MMFS
|
1
|
RfD
|
| 1,1-dichloroethene |
0.005
|
WCEA
|
0.09
|
EMEG
|
| 1,2-dichloroethane |
0.007
|
WCEA
|
0.05
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
0.07
|
EMEG
|
| 1,3-dichloropropylene |
ND
|
MMFS
|
None
|
None
|
| Methylene Chloride |
ND
|
MMFS
|
0.5
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
ND
|
MMFS
|
2
|
RfD
|
| Toluene |
NA
|
NA
|
2
|
RfD
|
| 1,2-transdichloroethylene |
NA
|
NA
|
0.2
|
RfD
|
| 1,1,2-trichloroethane |
0.006
|
WCEA
|
0.4
|
EMEG
|
| Trichloroethylene |
ND
|
MMFS
|
20
|
EMEG
|
| Vinyl Chloride |
ND
|
MMFS
|
0.01
|
EMEG
|
| Semi-Volatile Organic Compounds | ||||
| Acenaphthene |
ND
|
MMFS
|
0.6
|
RfD
|
| Acenaphthylene |
ND
|
MMFS
|
1.0
|
MRL
|
| Anthracene |
ND
|
MMFS
|
3.0
|
RfD
|
| Benz (a) anthracene |
ND
|
MMFS
|
1.0
|
MRL
|
| Benzo (a) pyrene |
ND
|
MMFS
|
1.0
|
MRL
|
| Benzo (b) fluoranthene |
ND
|
MMFS
|
1.0
|
MRL
|
| Bis(2-chloroethyl)ether |
0.025
|
WCEA
|
0.02
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
0.021
|
WCEA
|
0.2
|
RfD
|
| Chrysene |
ND
|
MMFS
|
1.0
|
MRL
|
| Fluoranthene |
ND
|
MMFS
|
0.4
|
RfD
|
| Fluorene |
ND
|
MMFS
|
0.4
|
RfD
|
| Naphthalene |
0.002
|
WCEA
|
13.3
|
MRL
|
| Phenanthrene |
ND
|
MMFS
|
1.0
|
MRL
|
| Pyrene |
ND
|
MMFS
|
0.3
|
RfD
|
|
|
||||
*Upper Chicot Aquifer
ND = not detected
NA = not analyzed
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 14. OFF-SITE SURFACE WATER
| Contaminant |
Range Concentration ppm
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
||||
| Metals (Indicator) | ||||
| Arsenic |
0.28
|
BVII
|
0.01
|
EMEG
|
| Barium |
0.32
|
BVII
|
0.7
|
RfD
|
| Cadmium |
0.027
|
BVII
|
0.005
|
EMEG
|
| Chromium |
0.15
|
BVII
|
0.05
|
EMEG
|
| Lead |
0.19
|
BVII
|
None
|
None
|
| Manganese |
4.0
|
BVII
|
1
|
RfD
|
| Mercury |
0.0014
|
BVII
|
0.008
|
EMEG
|
| Volatile Organic Compounds | ||||
| Benzene |
NA
|
NA
|
0.007
|
EMEG
|
| Chloroform |
ND
|
MMFS
|
0.2
|
EMEG
|
| 1,1-dichlorethane |
0.003
|
WCEA
|
1
|
RfD
|
| 1,1-dichloroethene |
NA
|
NA
|
0.09
|
EMEG
|
| 1,2-dichloroethane |
0.192
|
WCEA
|
0.05
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
0.07
|
EMEG
|
| 1,3-dichloropropylene |
NA
|
NA
|
None
|
None
|
| Methylene Chloride |
NA
|
NA
|
0.5
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
NA
|
NA
|
2
|
RfD
|
| Toluene |
ND
|
MMFS
|
2
|
RfD
|
| 1,2-transdichloroethylene |
NA
|
NA
|
0.2
|
RfD
|
| 1,1,2-trichloroethane |
0.252
|
BVII
|
0.4
|
EMEG
|
| Trichloroethylene |
NA
|
NA
|
20
|
EMEG
|
| Vinyl Chloride |
0.031
|
WCEA
|
0.01
|
EMEG
|
| Semi-Volatile Organic Compounds | ||||
| Acenaphthene |
NA
|
NA
|
0.6
|
RfD
|
| Acenaphthylene |
ND
|
MMFS
|
1.0
|
MRL
|
| Anthracene |
NA
|
NA
|
3.0
|
RfD
|
| Benz (a) anthracene |
NA
|
NA
|
1.0
|
MRL
|
| Benzo (a) pyrene |
NA
|
NA
|
1.0
|
MRL
|
| Benzo (b) fluoranthene |
NA
|
NA
|
1.0
|
MRL
|
| Bis(2-chloroethyl)ether |
NA
|
NA
|
0.02
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
ND
|
MMFS
|
0.2
|
RfD
|
| Chrysene |
NA
|
NA
|
1.0
|
MRL
|
| Fluoranthene |
NA
|
NA
|
0.4
|
RfD
|
| Fluorene |
NA
|
NA
|
0.4
|
RfD
|
| Naphthalene |
ND
|
MMFS
|
13.3
|
MRL
|
| Phenanthrene |
ND
|
MMFS
|
1.0
|
MRL
|
| Pyrene |
ND
|
MMFS
|
0.3
|
RfD
|
|
|
||||
ND = not detected
NA = not analyzed
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
TABLE 15. OFF-SITE SURFACE SEDIMENT
| Contaminant |
Range Concentration ppm
|
Reference
|
HAC Value ppm
|
HAC Source
|
|
|
||||
| Metals (Indicator) | ||||
| Arsenic |
33
|
WCEA
|
50
|
EMEG
|
| Barium |
408
|
BVII
|
3,500
|
RfD
|
| Cadmium |
0.98
|
BVII
|
200
|
EMEG
|
| Chromium |
201
|
WCEA
|
200
|
EMEG
|
| Lead |
483
|
WCEA
|
None
|
None
|
| Manganese |
1800
|
BVII
|
5,000
|
RfD
|
| Mercury |
1.3
|
WCEA
|
40
|
EMEG
|
| Volatile Organic Compounds | ||||
| Benzene |
NA
|
NA
|
30
|
EMEG
|
| Chloroform |
0.014
|
WCEA
|
1,000
|
EMEG
|
| 1,1-dichlorethane |
NA
|
NA
|
5,000
|
RfD
|
| 1,1-dichloroethene |
NA
|
NA
|
400
|
EMEG
|
| 1,2-dichloroethane |
0.027
|
BVII
|
200
|
EMEG
|
| 1,2-dichloropropane |
NA
|
NA
|
3,000
|
EMEG
|
| 1,3-dichloropropylene |
NA
|
NA
|
None
|
None
|
| Methylene Chloride |
NA
|
NA
|
2,000
|
EMEG
|
| 1,1,2,2-tetrachloroethane |
NA
|
NA
|
10,000
|
RfD
|
| Toluene |
0.016
|
WCEA
|
10,000
|
RfD
|
| 1,2-transdichloroethylene |
NA
|
NA
|
1,000
|
RfD
|
| 1,1,2-trichloroethane |
0.019
|
BVII
|
2,000
|
EMEG
|
| Trichloroethylene |
NA
|
NA
|
100,000
|
EMEG
|
| Vinyl Chloride |
NA
|
NA
|
50
|
EMEG
|
| Semi-Volatile Organic Compounds | ||||
| Acenaphthene |
NA
|
NA
|
3,000
|
RfD
|
| Acenaphthylene |
0.30
|
BVII
|
5,000
|
MRL
|
| Anthracene |
NA
|
NA
|
15,000
|
MRL
|
| Benz (a) anthracene |
NA
|
NA
|
5,000
|
MRL
|
| Benzo (a) pyrene |
NA
|
NA
|
5,000
|
MRL
|
| Benzo (b) fluoranthene |
NA
|
NA
|
5,000
|
MRL
|
| Bis(2-chloroethyl)ether |
NA
|
NA
|
1,000
|
EMEG
|
| Bis(2-ethylhexyl)phthalate |
0.36
|
BVII
|
1,000
|
RfD
|
| Chrysene |
NA
|
NA
|
5,000
|
MRL
|
| Fluoranthene |
NA
|
NA
|
2,000
|
RfD
|
| Fluorene |
NA
|
NA
|
2,000
|
RfD
|
| Naphthalene |
0.025
|
WCEA
|
66,500
|
MRL
|
| Phenanthrene |
0.22
|
BVII
|
5,000
|
MRL
|
| Pyrene |
0.26
|
BVII
|
1,500
|
RfD
|
|
|
||||
ND = not detected
NA = not analyzed
BVII = Black & Veatch Initial Investigation, Dec. 1981
MMFS = Management Migration Feasibility Study, Vol.2, May 1988
WCEA = Woodward & Clyde Endangerment Assessment, May 1989
5. Biota Contamination
An investigation of aquatic fauna was conducted in 1988 to determine whether biologic organisms in the vicinity of the MOTCO site were accumulating any chemical constituents. Two species of aquatic fauna, one crustacean (blue crab) and one fish (mullet), were collected from five locations. Samples were taken from locations 0.5 mile upgradient and 0.125 miles, 0.25 mile, 0.5 mile, 1 mile and 2.5 miles downgradient from the MOTCO site. Blue crabs were chosen because they are bottom feeders with a relatively small habitat range, making them good indicators of chemical migration to the off-site aquatic food chain. Mullet were chosen due to their abundance and relative ease of collection.
The aquatic samples were analyzed for metals and semi-volatiles. Table 16 lists chemicals detected in biota analyses.
TABLE 16. CONTAMINANT CONCENTRATIONS IN BLUE CRAB AND MULLET*
| CONTAMINANTS** |
ORGANISM
|
UPSTREAM VALUE (ppm)
|
DOWNSTREAM VALUE
(ppm)
|
|
|
|||
| arsenic |
blue crab
mullet |
0.33
0.23 |
0.43 - 0.70
0.23 - 0.43 |
| barium |
blue crab
mullet |
0.76
3.7 |
0.70 - 1.7
0.93 - 4.9 |
| chromium |
blue crab
mullet |
1.3
23.0 |
1.1 - 4.3
8.4 - 24.1 |
| copper |
blue crab
mullet |
14.4
1.7 |
24.0 - 37.7
0.94 - 3.4 |
| lead |
blue crab
mullet |
0.17
0.23 |
0.17 - 0.26
0.19 - 1.2 |
| mercury |
blue crab
mullet |
ND
ND |
ND - 0.10
ND |
| selenium |
blue crab
mullet |
0.36
0.23 |
0.27 - 0.47
ND - 0.32 |
| benzyl alcohol |
blue crab
mullet |
ND
ND |
ND
2.5 |
| di-ethyl phthalate |
blue crab
mullet |
ND
ND |
2.7
4.4 |
| di-n-butyl phthalate |
blue crab
mullet |
ND
ND |
0.18
ND |
|
|
|||
ND = not detected
* sampling data from Woodward-Clyde Consultants, November 1987
** no other contaminants detected
A few metals were detected in both aquatic species; however, there was not a significant difference between the levels detected in the upgradient and downgradient species. Arsenic was detected in all downgradient samples. The highest level found was 0.7 ppm in blue crab samples from Jones Bay and the marsh southwest of MOTCO. Lead was detected in all samples, with the highest level at 1.2 ppm in the mullet sample from Jones Bay. Copper, with the highest concentration at 37.7 ppm (blue crab from the marsh southwest of MOTCO) was also detected in all samples. All values reflect whole specimen sampling.
Of the semi-VOCs, only three were detected at low levels in the downgradient samples. Both mullet and blue crab contained di-ethyl phthalate, but di-n-butyl phthalate was detected only in blue crab. Benzyl alcohol was detected at 2.5 ppm in mullet. No sample was found to contain all three semi-volatile compounds.
6. Air Contamination
Initial air quality monitoring was conducted in the vicinity of the MOTCO site in September 1981 to evaluate the necessary levels of respiratory protection for initial site work. Air sampling did not take place during the SFSI or the EA. Six sampling pump locations were chosen with two upwind and four downwind of the MOTCO site. One sample was taken downwind of the tank area where the highest on-site OVA reading occurred. During sampling events the general wind direction was toward the west-southwest. No contaminants of concern were identified as a result of air quality monitoring.
C. Quality Assurance and Quality Control
Quality assurance and quality control information for the MOTCO site was reviewed by TDH staff. Analyses that did not meet accuracy and precision standards were flagged as unusable in the SFSI and EA and were not used in the preparation of this Health Assessment Addendum. In preparing this Addendum to the Health Assessment, TDH staff members relied on the information provided in the referenced documents and assumed that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The analyses and conclusions in this Health Assessment Addendum are valid only if the referenced information is complete and reliable.
On May 16, 1990, TDH and GCHD staff, with assistance from the MOTCO Trust Group, performed a site visit. The entire site is fenced and has locked and monitored entrances. The fence is also posted with warning signs.
The major on-site physical hazards are the remaining six waste pits, which cover 4.6 acres of the 11.3 acre site. The maximum pit depth is estimated at 15 to 20 feet. At the time of the site visit, the waste pits were open, with only yellow caution tape posted around the circumference of each pit. No on-site fences or other physical barriers were present to prevent persons from falling into or entering the waste pits.
Another on-site physical hazard was equipment that is used to construct and operate the incinerator and to excavate waste pits. In addition, the two water-filled borrow pits, located southwest of the site, could pose a drowning hazard, although the pits are not directly a result of the MOTCO site activities.
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