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ADDENDUM
ENVIRONMENTAL AND BIOLOGICAL SAMPLING DATA
BIOLOGICAL AND ENVIRONMENTAL SAMPLING DATA
One of the study objectives was to evaluate the feasibility of obtaining historic biological and environmental sampling data and matching the data to study cohort members. Early in the investigation, concerns were raised by former Mesita students about the possible impact of the ASARCO metals smelter. The Texas Department of Health completed a health consultation in 1996 to begin to address those concerns. During the course of the study, participants from both the Mesita and E.B. Jones cohorts continued to express concerns about the environmental impact of the ASARCO smelter and potential health impacts. This addendum summarizes the available biological and environmental data.
BIOLOGICAL DATA
Blood Lead Data
Extensive blood lead testing was conducted by the El Paso City-County Health Department (EPCCHD), the U.S. Centers for Disease Control and Prevention (CDC), and ASARCO in conjunction the environmental investigations of the ASARCO facility in the early 1970s.1,2,3 Preliminary blood lead testing of 1,011 individuals in early 1972 found that 62% of children under age 10 living within one mile of the smelter had blood lead levels greater than or equal to 40 micrograms per deciliter (40 g/dL).1,2 This level was considered to be indicative of excess lead absorption at that time. Forty-three percent of people of all ages living within one mile of the smelter, 8% of people living between approximately one and two miles of the smelter, and 1% of those living beyond two miles of the smelter had blood lead levels 40 g/dL.1 The four children with the highest blood lead levels (between 80 and 90 g/dl) lived in Smeltertown, the residential area closest to the smelter.1 The current childhood blood lead level of concern is 10 g/dL.4
A second study, undertaken in August 1972 by the CDC to better characterize the distribution of lead exposure included 1,369 randomly-selected individuals of all ages from the 13 census tracts closest to the smelter.1 Of the 1,369 individuals, 758 were 19 years old or younger. Approximately 21% of those tested under age 20 living within four miles of the smelter had blood lead levels 40 g/dl; 44% of those 19 years of age or younger living in the zone nearest the smelter (1 mile) had blood lead levels 40 g/dl The highest blood lead levels were observed in the youngest children who lived closest to the smelter. Sixty-nine percent of the children between one and four years old who lived within one mile of the smelter had blood lead levels 40 g/dl (Table 1). The highest blood lead level found during the study (83 g/dl) was for a two-year old girl living in Smeltertown. According to current standards, those children would be considered lead poisoned and immediate intervention would be initiated.4
The CDC and local health department also conducted soil and dust sampling as part of the study.5 The researchers found a highly significant relationship between blood lead levels in children living closest to the smelter and levels of lead in household dust. A similar relationship was noted between blood lead levels and soil levels in children living closest to the smelter.5 In a follow-up study on child blood lead levels conducted in 1977, the mean blood lead levels in children living in the near vicinity of the smelter had decreased significantly from 1972 to 1977.5
The researchers noted the decline in child blood lead levels coincided with the installation of mandated pollution controls at the smelter and the subsequent decline in environmental lead levels. They concluded the decreased blood lead levels in children was causally related to a reduction in lead emissions from the ASARCO facility.5
Hair Samples
Three MS patients who attended Mesita Elementary School provided TDH with childhood hair samples for metals analysis as part of the initial investigation for the health consultation. Samples included those cut from the hair of a 12-year-old girl in 1956, the braid of a 6-year-old girl in 1959, and the ponytail of a 12-year-old girl in 1962. To determine historical exposure levels, TDH had the hair samples analyzed for seven metals by National Medical Services, Inc. in Willow Grove, Pennsylvania. The hair samples from all three girls showed elevated levels of lead and mercury. The hair samples of both 12 year-olds showed elevated zinc and copper levels. In addition, the 1959 hair sample showed an elevated concentration of arsenic and the 1962 sample showed an elevated concentration of cadmium. Table 2 contains the findings for the hair analyses.
Additional Biological Samples
In addition to the hair samples and blood lead levels previously discussed, limited analysis data were also located for urine lead and urine cadmium levels. Due to the sparsity of the data and its poor quality, the results of urine analyses are not presented in this report.
Feasibility of Linking Biological Samples
Although we were able to locate biological sampling data from the early 1970s which contain some personal identifiers, the amount of identifying information is limited. In an initial attempt to link the historic biological data with members of the study cohorts based only on first and last name of the students, we were able to confirm a link on approximately 6% of the cohort. With additional work it may be possible to link a much larger percentage of the members of our cohort with historic biological sampling data.
ENVIRONMENTAL DATA
Air
There is a paucity of air data prior to 1969; however, records from 1969 forward indicate a substantial release of pollutants from the ASARCO facility into the environment. It is probable that emissions prior to 1969 were at least as high as those reported after this date, although the composition of the emissions may have varied. Records show that the smelter emitted approximately 5,000 tons of total particulates from its stacks between 1969 and 1971.2 This included 1,116 tons of lead; 560 tons of zinc; 1.2 tons of arsenic; and 12 tons of cadmium emitted in the three year period.2 Less complete data are available regarding the estimated quantities of copper and mercury emitted during this period. ASARCO reported stack emissions of smaller quantities of such metals as bismuth, manganese, selenium, and tellurium. According to ASARCO statements, the smelter also was emitting approximately 230,500 tons of sulfur dioxide (SO2) per year, or 640 tons per day, during this period.6 Data regarding the specific quantities of emissions prior to this time were not available for review.
The EPCCHD documented particulate emissions in violation of permitted levels (including total particulates, lead, zinc, cadmium, and arsenic) between April 1972 and September 1973.7,8 Violations occurred at least twice each month (except May 1972) and up to six to seven times per month. The highest total particulate level recorded for a 24-hour period was 2,943 g/m3. Mean concentrations of airborne metal particulates were highest immediately downwind of the smelter and levels decreased logarithmically with distance from the smelter. Twenty-four hour samples were collected throughout 1971 and again between June 1972 and June 1973. The average of the monthly mean lead level immediately downwind of the smelter in 1971 was 92 g/m3 ; in 1972 and 1973, the average of the monthly means was 43 g/m3. Levels fell to background values at approximately 2.5 to 3 miles from the smelter.3 The maximum daily levels of metals recorded immediately downwind from the smelter were: lead, 349.47 g/m3; zinc, 214.85 g/m3; cadmium, 53.29 g/m3; and arsenic, 21.88 g/m3. 7,8
Annual ambient air concentrations for lead, zinc, cadmium and arsenic were abstracted from TNRCC air sampling data for three locations in El Paso for 1972, 1973, and 1974 (Table 3).9 One of the sampling locations was located in the Kern Place-Mission Hills neighborhood at the Kern Place Fire Department and the other two sampling locations were located in the vicinity of the smelter. Yearly variation in the annual averages was small for all metals of interest. The highest concentrations were observed at the International Boundary and Water Commission (IB&WC) office, located on West Paisano Drive. The IB&WC office was located approximately 0.25 miles north of the smelter. The Executive Center sampling location is approximately 1.0 miles north-northeast of the smelter and showed the lowest levels of metals in ambient air samples. The Kern Place Fire Station was approximately 1.7 miles east of the smelter. The pattern of metals concentrations in the sampling results is to be expected given the prevailing wind patterns in El Paso (Figure AA-1). The Executive Center sampling location is upwind of the smelter and the other two are downwind. It is also important to note that levels are highest near the smelter and decrease with distance. Although these data do not provide complete coverage of El Paso, they corroborate the patterns observed in the soil sampling data as discussed below. Atmospheric deposition of metals may cause or contribute to contamination of the soil. Consequently, similar spatial patterns of metals contamination would be expected in the soil and dust sampling data.
Soil/Dust
Many original soil and dust sampling results were located in the archives at the EPCCHD. Tables 4 through 7 summarize the data by location and year sampled. Table 4 provides a summary of sampling results for nine locations in El Paso from 1972. Tables 5 and 6 provide summaries for the study neighborhoods for 1972 through 1974; Table 7 for two additional locations in El Paso in 1972 through 1974. For site-specific sampling results presented in Tables 5 through 7, caution must be used in interpreting the results because of the limited number of samples located for review.
Unfortunately, we were not able to determine the completeness of the sampling data because a master listing of all sampling activities could not be located. However, the data that were reviewed do provide an assessment of the extent and magnitude of environmental heavy metals contamination in and around El Paso, particularly the Kern Place-Mission Hills and Smeltertown neighborhoods in the early 1970s.
The EPCCHD collected soil and household dust samples between June and December 1972.10 Elevated levels of lead, zinc, cadmium, and arsenic were found in soil and dust samples collected from Smeltertown, Kern Place (Kern fire station and Mesita School), and other areas of El Paso. The maximum concentrations detected are presented in Table 4.
Sampling conducted at the Mesita Elementary School in 1972 showed the average lead soil concentration was 533 ppm (Table 5). The average lead soil concentration was less for 1973 (143 PPM) and 1974 (122 PPM), suggesting that clean-up activities may have occurred prior to 1973 sampling activities. A similar pattern is observed for zinc sampling data (1972: 340 PPM, 1973: 231 PPM, 1974: 163 PPM) at Mesita Elementary, but not for cadmium or arsenic. Neighborhood sampling results suggest similar levels of lead and zinc were located throughout the Kern Place-Mission Hills neighborhood as well. The 1972 average for soil lead concentration in the Kern Place-Mission Hills neighborhood was 418 PPM with a range of concentrations from non-detectable levels to 1,000 PPM There is a marked decrease in the average and range of concentrations between 1972 and both 1973 and 1974. A similar pattern was not observed for zinc, cadmium, or arsenic.
Table 5 also contains a summary of dust sampling results.11 These results include rooftop sampling which may indicate metals contamination at levels higher than would typically be encountered by children. The average concentration of both lead and zinc in dust at Mesita Elementary was found to be approximately 1,900 PPM and remained relatively consistent from 1972 to 1974. Dust samples collected from other locations in the Kern Place-Mission Hills neighborhood showed more variability in the average and range of metals concentrations reported.
Table 6 summarizes the soil and dust sampling efforts at the E.B. Jones Elementary School and at other sites in Smeltertown. Sampling results for E.B. Jones Elementary School were only found for 1972. The average soil lead concentration was 3,767 PPM and ranged from 600 PPM to 9,700 PPM in six samples collected at the school. Sampling results for other metals were not located. The 1972 Smeltertown neighborhood average soil lead concentration was similar to those found for E.B. Jones (3,897 PPM). The average remained relatively unchanged from 1972 to 1973, but decreased by 1974 (1973: 3,203 PPM, 1974: 1,541 PPM). Soil levels of zinc remained relatively constant over the three years for which sampling data were found (1972: 1,180 PPM, 1973: 2,548 PPM, 1974: 1,225 PPM).
Dust sample summaries show a wide range of metals concentrations observed in both 1972 and 1974 (Table 6). One dust sample from E.B. Jones analyzed in 1972 showed a dust lead concentration of 34,540 PPM Results from this sample for other metals were not identified. Samples taken from Smeltertown show a large range of metals concentrations ranging from non-detectable levels to 69,550 PPM lead.
Sampling summaries for El Paso High School and the University of Texas El Paso (UTEP) are presented in Table 7. For El Paso High School, the average lead concentration in soil declined from 900 PPM in 1972 to 473 PPM in 1974, as did the cadmium levels (20 PPM to 7 PPM). The zinc levels in soil remained relatively constant (334 to 375 PPM); no pattern was noted for arsenic. For 1972 and 1974 at El Paso High School, dust lead concentrations were approximately 3,000 PPM Zinc and cadmium levels increased from 1972 to 1974, but this is based on only four samples over both years.
Sampling results for UTEP were only available from 1972 and 1974 for both soil and dust. The lead concentration in soil increased from 1972 (300 PPM) to 1974 (537 PPM), as did the zinc and cadmium soil levels. The lead dust concentration decreased from 7,967 PPM in 1972 to 1,816 in 1974. The dust concentrations of zinc and cadmium remained relatively constant over the two years sampled. No sample results for arsenic were located for 1972.
SUMMARY
These historic environmental data taken as a whole suggest that soil metals concentrations were elevated in Smeltertown and the Kern Place-Mission Hills neighborhoods in the early 1970s and may be indicative of metals contamination during the 1950s and 1960s. According to the U.S. Geologic Survey, the ranges in mean concentrations for the metals of concern in the Western United States (west of the 96th meridian) are: lead, < 0.10 PPM to 700 PPM; zinc, < 20 PPM to 1,500 PPM; and arsenic, < 0.10 PPM to 97 PPM No values are reported for cadmium. The historic sampling data from El Paso available for review often either exceeded these background concentrations or fell in the upper portion of the range of mean values.
The historic biologic data, particularly the blood lead data collected in the early 1970s demonstrates exposure to the metals in the air, soil, and dust during the time period of the blood lead studies. Landrigan et al. concluded that particulate lead in dust and air accounted for most of the lead exposure in El Paso children and that the smelter was the principal source of the lead.1 Blood lead surveys indicate children living in the study neighborhoods in the early 1970s not only had potential exposure opportunity, but were actually exposed to harmful levels of lead. The hair sample data from ponytails of three girls who lived in the study neighborhoods in the late 1950s and early 1960s may also be considered evidence of exposure to heavy metals although the exact source of the metals exposure cannot be determined with certainty.
> The environmental and biological data could not easily be matched to individuals with a high degree of confidence, but could potentially be used to reconstruct general risk estimates based on residence during childhood. The environmental and blood lead data, however, were collected after the study period and not during the time period of primary concern.ADDENDUM REFERENCES
1. Landrigan PJ, Gehlbach SH, Rosenblum BF, et al. Epidemic lead absorption near an ore smelter, the role of particulate lead. N Engl J Med 1975; 292:123-129.
2. CDC. Epidemiologic notes and reports: human lead absorption - Texas. MMWR 1973;22:405-407.
3. Rosenblum BF, Shoults JM, Candelaria RM. Lead health hazards from smelter emissions. Texas Medicine 1976;72:44-56.
4. CDC. Preventing Lead Poisoning in Young Children. Atlanta. U.S. Department of Health and Human Services/Public Health Service, October 1991.
5. Morse DL, Landrigan PJ, Rosenblum BF, Hubert JS, Housworth J. Epidemiologic follow-up of an environmental lead problem. JAMA 1979;242:739-741.
6. El Paso City-County Health Department. Unpublished records. Report of investigation at American Smelting and Refining Company. El Paso, Texas. February 2-4, 1971.
7. El Paso City-County Health Department. Letter J.M. Shoults, Acting Environmental Engineer to Troy Webb, Assistant Attorney General, regarding a report of violations against ASARCO. October 5, 1973.
8. El Paso City-County Health Department. Unpublished records. Pages entitled "Particulate Violations by El Paso City-County Health and ASARCO." For the period April 24, 1972 - December 13, 1972. Undated.
9. Personal communication. Benny Villamen, TNRCC and Matthew Garabedian, TDH. Retrieval of ambient air data for El Paso, 1972-1974, from the TNRCC AIRS database.
10. El Paso City-County Health Department. Memorandum from J.M. Shoults, Acting Environmental Engineer to John Ross, Assistant City Attorney, regarding report of monitoring required by judgment and order of injunction no. 70-1701 for the period June through December 1972. April 19, 1973.
11. El Paso City-County Health Department. Memorandum from J.M. Shoults to John Morrison regarding roof samples for lead. April 17, 1972.
ADDENDUM TABLES
Table 1. - Blood lead levels by distance from smelter, August 1972 (Landrigan et al, 1975).
| Distance from smelter | Age range (year) | Number Tested | Percent
with BLL* 40-59 g/dl |
Percent
with BLL* > 59 g/dl |
|---|---|---|---|---|
| Less than one mile | 1-4 | 49 | 55% | 14% |
| 5-9 | 101 | 34% | 11% | |
| 10-19 | 109 | 25% | 6% | |
| 20 + | 98 | 16% | 0 | |
| One to three miles | 1-4 | 83 | 23% | 4% |
| 5-9 | 124 | 12% | 0 | |
| 10-19 | 292 | 3% | 1% | |
| 20+ | 513 | 3% | 1% |
* BLL: Blood Lead Level: Concentration of lead per unit whole blood (mg/dl whole blood).
Table 2. - Results of historical hair sample analysis.*
| Metal |
Concentration (g/g), by year sample collected |
Normal range according to laboratory report (g/g) |
||
|---|---|---|---|---|
| 1956 12-year-old girl |
1959 6-year-old girl |
1962 12-year-old girl |
||
| lead |
146.1 |
42 |
49.3 |
5 - 29 |
| zinc |
330 |
102.7 |
250 |
130 - 220 |
| cadmium |
2.56 |
2.24 |
21.24 |
0.25 - 3.4 median = 1.5 |
| arsenic |
0.41 |
8.46 |
0.45 |
75% = 0.03 - 0.3 20% = 0.3 - 3 5% are up to 4 |
| mercury |
27 |
1.6 |
2.1 |
0.4 - 1.2 |
| copper |
320 |
16.8 |
240 |
5 - 46 |
| chromium |
0.21 |
0.29 |
0.85 |
0.26-1.46 |
* Each sample was an approximate six-inch length and was analyzed as a composite of the whole.
Shaded cells = concentrations exceeding "normal range," as defined by the laboratory.
Table 3. - Annual ambient air concentrations of selected metals (mg/m3): El Paso, Texas, 1972 to 1974.
|
Annual
Average (mg/m3)
|
| Sampling Area | Metal |
1972 |
1973 | 1974 |
|---|---|---|---|---|
| Kern Place Fire Department |
Pb | 2.34 | 2.13 | 2.09 |
| Zn | 0.06 | 0.70 | 0.63 | |
| Cd | 0.02 | 0.04 | 0.06 | |
| As | 0.08 | 0.09 | 0.07 | |
| Executive Center 4120 Rio Bravo |
Pb | 1.00 | 1.01 | 0.93 |
| Zn | 0.33 | 0.38 | 0.33 | |
| CD | 0.01 | 0.02 | 0.03 | |
| As | 0.05 | 0.03 | 0.03 | |
| IB&WC 1616 W. Paisano |
Pb | 10.02 | 8.63 | 6.28 |
| Zn | 8.25 | 5.71 | 4.51 | |
| CD | 0.54 | 0.39 | 0.34 | |
| As | 0.96 | 0.83 | 0.46 | |
Table 4. - Maximum concentration of metals found in soil and dust samples* collected by El Paso City-County Health Department, June through December 1972 (EPCCHD, April 1973)
|
Maximum
concentrations of metals (PPM)
|
| Sampling Area | Soil/Dust |
Lead
|
Zinc
|
Cadmium
|
Arsenic**
|
|---|---|---|---|---|---|
| Smeltertown | Soil | 11,450 | 7,325 | 320 | 660 |
| Dust | 103,750 | 64,428 | 2,213 | 1,984 | |
| Kern Fire Station | Soil | 600 | 640 | 80 | 80 |
| Dust | 84,000 | 148,740 | 350 | 600 | |
| Sunset Heights | Soil | 1,400 | 760 | 60 | 120 |
| Dust | 5,900 | 7,920 | 160 | 560 | |
| Mesita School | Soil | 700 | N/A | N/A | 300 |
| Dust | 7,824 | N/A | 380 | 488 | |
| Vilas School | Soil | 450 | N/A | 614 | N/A |
| Dust | 4,950 | N/A | 1,000 | N/A | |
| White School | Soil | 350 | N/A | N/A | N/A |
| Dust | 41,600 | 83,875 | N/A | N/A | |
| Roosevelt School | Soil | 1,600 | N/A | N/A | N/A |
| Dust | 5,215 | N/A | 225 | N/A | |
| Coronado High | Soil | 350 | N/A | N/A | N/A |
| Dust | 29,387 | N/A | N/A | 241 | |
| El Paso High | Soil | 1,200 | N/A | N/A | N/A |
| Dust | 3,500 | N/A | N/A | N/A |
* Information regarding the method of collection for dust samples was not available.
** Arsenic sampling was not conducted in June and July.
N/A: Not available
Table 5. - Soil and dust sampling summaries for selected heavy metals [average concentration, range of concentrations ( ), and number of samples (N = #)] for El Paso, Texas: Mesita Elementary School and Kern Place-Mission Hills neighborhoods, 1972 to 1974.
| Metals | Soil (PPM) | Dust (PPM) |
|---|
| 1972 | 1973 | 1974 | 1972 | 1974 | |
|---|---|---|---|---|---|
| Mesita Elementary School | |||||
|
533
|
143
|
122
|
1900
|
1853
|
|
| Lead |
(200 - 600)
|
(100 - 200)
|
(70 - 198)
|
(1,200 - 2,600)
|
(1,300 - 2,210)
|
|
N=6
|
N=3
|
N=3
|
N=2
|
N=3
|
|
|
340
|
231
|
163
|
1920
|
1852
|
|
| Zinc |
(340)
|
(115 - 300)
|
(65 - 338)
|
(1,920)
|
(1,045 - 2,360)
|
|
N=1
|
N=3
|
N=3
|
N=1
|
N=3
|
|
|
ND
|
53
|
2
|
100
|
65
|
|
| Cadmium |
(ND)
|
(10 - 140)
|
(ND - 5)
|
(100)
|
(25 - 100)
|
|
N=1
|
N=3
|
N=3
|
N=1
|
N=3
|
|
|
|
8
|
49
|
|
158
|
|
| Arsenic |
N/A
|
(5 - 10)
|
(11 - 120)
|
N/A
|
(135 - 175)
|
|
|
N=3
|
N=3
|
|
N=3
|
|
| Kern Place - Mission Hills | |||||
|
418
|
200
|
265
|
3,140
|
2,505
|
|
| Lead |
(ND -1,000)
|
(80 - 470)
|
(50 - 430)
|
(100 - 31,880)
|
(1,615 - 3,770)
|
|
N=21
|
N=9
|
N=9
|
N=24
|
N=12
|
|
|
148
|
158
|
250
|
804
|
2,236
|
|
| Zinc |
(60 - 270)
|
(65 - 300)
|
(70 - 1,018)
|
(45 - 3,040)
|
(1,322 - 3,700)
|
|
N=4
|
N=9
|
N=12
|
N=4
|
N=12
|
|
|
5
|
11
|
7
|
8,695
|
107
|
|
| Cadmium |
(ND - 10)
|
(80 - 470)
|
(ND - 15)
|
(210 - 31,880)
|
(ND - 521)
|
|
N=4
|
N=9
|
N=12
|
N=4
|
N=12
|
|
|
|
7
|
42
|
|
159
|
|
| Arsenic |
N/A
|
(2 - 25)
|
(7 - 165)
|
N/A
|
(114 - 227)
|
|
|
N=9
|
N=12
|
|
N=12
|
|
| Key for Interpreting cells: |
Average
|
|
|
(Min. - Max.)
|
||
|
# of events
|
||
| ND = non-detectable |
Table 6. - Soil and dust sampling summaries for selected heavy metals (average, range, number of sampling events), El Paso, Texas: E. B. Jones Elementary School and Smeltertown, 1972 to 1974.
| Metal | Soil (PPM) | Dust (PPM) | |||
|---|---|---|---|---|---|
|
|
1972 | 1973 | 1974 | 1972 | 1974 |
|
E.B. Jones Elementary School*
|
|||||
|
|
3,767 | 34,540 | |||
|
Lead
|
(600 - 9,700) | N/A | N/A | (34,540) | N/A |
| N=6 | N=1 | ||||
|
Zinc
|
N/A | N/A | N/A | N/A | N/A |
|
Cadmium
|
N/A | N/A | N/A | N/A | N/A |
|
Arsenic
|
N/A | N/A | N/A | N/A | N/A |
|
Smeltertown
|
|||||
|
|
3,897
|
3,203
|
1,541
|
8,647
|
16,514
|
|
Lead
|
(600 - 10,750)
|
(330 - 10,230)
|
(100 - 4,840)
|
(4,200-13,540)
|
(ND - 69,550)
|
|
N=29
|
N=12
|
N=12
|
N=3
|
N=12
|
|
|
1,180
|
2,548
|
1,225
|
7,710
|
9,690
|
|
|
Zinc
|
(1,040 - 1,320)
|
(280 - 7,905)
|
(80 - 3,557)
|
(3,540 - 11,880)
|
(ND - 27,725)
|
|
N=2
|
N=12
|
N=12
|
N=2
|
N=12
|
|
|
80
|
102
|
60
|
430
|
563
|
|
|
Cadmium
|
(60 - 100)
|
(15 - 190)
|
(ND - 160)
|
(200 - 660)
|
(ND - 1,865)
|
|
N=2
|
N=12
|
N=12
|
N=2
|
N=12
|
|
|
|
140
|
150
|
|
757
|
|
|
Arsenic
|
N/A
|
(2 - 480)
|
(6 - 341)
|
N/A
|
(ND - 2,920)
|
|
|
N=12
|
N=12
|
|
N=12
|
|
| Key for Interpreting cells: |
Average
|
|
|
(Min. - Max.)
|
||
|
# of events
|
||
| ND = non-detectable |
Table 7. - Soil and dust sampling summaries for selected heavy metals (average, range, number of sampling events), El Paso, Texas: El Paso High School and University of Texas El Paso, 1972 to 1974.
| Metal | Soil (PPM) | Dust (PPM) |
| 1972 | 1973 | 1974 | 1972 | 1974 | |
|---|---|---|---|---|---|
| El Paso High School | |||||
| 900 | 670 | 473 | 2,800 | 3017 | |
| Lead | (900) | (330 - 1050) | (268 - 760) | (2,800) | (2,600 - 3,450) |
| N=1 | N=3 | N=3 | N=1 | N=3 | |
| 340 | 375 | 334 | 1400 | 2130 | |
| Zinc | (340) | (195 - 490) | (310 - 370) | (1,400) | (1,240 - 3,250) |
| N=1 | N=3 | N=3 | N=1 | N=3 | |
| 20 | 15 | 7 | 70 | 88 | |
| Cadmium | (20) | (10 - 20) | (5 - 8) | (70) | (50 - 125) |
| N=1 | N=3 | N=3 | N=1 | N=3 | |
| 23 | 48 | 155 | |||
| Arsenic | N/A | (13 - 30) | (26 - 85) | N/A | (115 - 185) |
| N=3 | N=3 | N=3 | |||
| University of Texas El Paso | |||||
| 300 | 537 | 7,967 | 1,816 | ||
| Lead | (200 - 400) | N/A | (500 - 580) | (ND - 26,080) | (1,327 - 2,231) |
| N=2 | N=3 | N=6 | N=3 | ||
| 160 | 433 | 2810 | 2,698 | ||
| Zinc | (120 - 200) | N/A | (365 - 440) | (2,100 - 3,520) | (2,302 - 3,414) |
| N=2 | N=3 | N=2 | N=3 | ||
| ND | 12 | 78 | 61 | ||
| Cadmium | (ND) | N/A | (10 -15) | (56 - 100) | (ND - 101) |
| N=2 | N=3 | N=2 | N=3 | ||
| 27 | 152 | ||||
| Arsenic | N/A | N/A | (22 - 33) | N/A | (90 - 210) |
| N=3 | N=3 |
| Key for Interpreting cells: |
Average
|
|
|
(Min. - Max.)
|
||
|
# of events
|
||
| ND = non-detectable |
ADDENDUM
APPENDIX AA-1
WIND ROSE
This page last updated on October 3, 2001
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