PUBLIC HEALTH ASSESSMENT ADDENDUM
SIKES DISPOSAL PITS
CROSBY, HARRIS COUNTY, TEXAS
The Sikes Disposal Pits site is a former petroleum-based waste disposal site located in HarrisCounty about 20 miles northeast of Houston, Texas. Although there is evidence of past exposure tosite contaminants, the site currently poses no apparent public health hazard.
Persons who may have been exposed in the past include workers who were exposed to organicvapors and contaminated water and children who played on site and ingested contaminated soil andwater. Contaminants to which past exposure may have occurred include benzene, 1,2-dichloroethane, 1,2-dichloropropane, vinyl chloride, and polychlorinated biphenyls (PCBs). Inaddition, anecdotal reports of strong chemical odors during site operations suggest that past exposureto site contaminants, through inhalation, may have occurred to workers and residents in thesurrounding communities. However, due to the lack of historical ambient air data, we could not confirm or quantify these exposures.
During the course of the investigation we noted that water from residential wells in the RiverdaleSubdivision contained lead at levels above recently revised health standards. Elevated levels ofcoliform bacteria were also present. The source of the lead contamination is unknown and availableinformation suggests that it is probably not related to the site. Since these data were over five yearsold we sampled residential wells to determine current lead levels. Results indicated that levels oflead in Riverdale's residential well water are below the Environmental Protection Agency's PrimaryDrinking Water Regulation action level of 15 µg/L.
PCBs were the only contaminants found on and off site at levels that could cause adverse healtheffects. Chronic exposure to PCBs at levels found on site could result in a moderate increased riskof developing cancer. Chronic exposure to PCBs at levels found off site are estimated to result in noincreased risk of developing cancer.
Potential future exposure to site contaminants could occur through inhalation if the safety measuresemployed during remediation should fail. These safety measures include a perimeter air monitoringsystem, a real-time stack emission monitoring system, an emergency response team capable ofcontaining emissions resulting from excavation activities, and the collection and treatment of allwater runoff prior to release. These safety measures should be adequate to protect public health.
The Agency for Toxic Substances and Disease Registry's (ATSDR) Health ActivitiesRecommendations Panel and the Texas Department of Health (TDH) evaluated the informationdeveloped in this health assessment addendum for consideration of additional health follow-upactions. Since the analysis of the private well water did not indicate lead at levels of health concern,no further follow-up health activities are needed at this time. TDH recommends that optimal dustand vapor control measures are implemented during remediation to insure that workers and residents have good ambient air quality.
In cooperation with the Agency for Toxic Substances and Disease Registry (ATSDR), the TexasDepartment of Health (TDH) will evaluate the public health significance of the Sikes Disposal Pitssite. More specifically, ATSDR and TDH will determine whether adverse health effects fromexposure to site contaminants could occur and will recommend actions to reduce or prevent suchhealth effects. ATSDR, a Federal agency within the Department of Health and Human Services, isauthorized by the Comprehensive Environmental Response, Compensation, and Liability Act of1980 (CERCLA) to conduct health assessments at hazardous waste sites.
The 158-acre Sikes Disposal Pits site, a former petroleum-based waste disposal site, is located inHarris County about 20 miles northeast of Houston, approximately 2 miles southwest of Crosby,Texas, and 17 miles northwest of Galveston Bay (Figure 1, Appendix A). The site is bordered bythe San Jacinto River to the west, U.S. Highway 90 to the south, an unimproved dirt road to the east,and the Jackson Bayou to the north. A portion of the Southern Pacific Railroad traverses thenorthern boundary just south of Jackson Bayou. French Limited, also a national priorities list(NPL) site, is located approximately one-half mile to the east. Figure 2 shows the important features around the site.
The site contains a main waste pit (MWP) to the east, three small waste pits (SWPs) to the west, anold abandoned oil well northwest of the main waste pit and several sand pits from former sandmining operations. Tank Lake, a 1.4-acre natural body of water, lies immediately west of theMWP. See Figure 3 for the important features on the site. The entire Sikes Disposal Pits site lies 8to 20 feet above mean sea level (MSL), entirely within the 50- and 100-year floodplains (25.5 feetand 28 feet, respectively) of the San Jacinto River. The site has been completely flooded at leastfour times since 1969. Located in the central portion of the site, immediately to the east of the MWPis an 8-acre, highly contaminated area referred to as the "Overflow Area". The contamination of thisoverflow area was originally believed to have resulted from the breaching of the dike surroundingthe MWP by flood waters. Evidence also exists indicating that wastes were occasionally burned inthis area.
In addition to several tracts of land with mixed private ownership, Texas Gulf Marine II ownsapproximately 38 acres within the original site boundaries. Southern Pacific Railroad hasapproximately 20 acres of right-of-way within the original boundaries of the site.
Hazardous waste disposal operations at this site started in the early 1960's and continued until 1967. During these operations, chemical wastes from nearby petroleum industries were transported to thesite by vacuum trucks and emptied into the main disposal pit and into the three smaller pits. Additionally, numerous drums with unknown contents were dumped in various locations around thesite.
The Sikes Disposal Pits operation first came to the attention of the state in 1966 when a TexasDepartment of Health inspector observed the unlined main disposal pit and expressed a concernover possible groundwater contamination. In 1967, the Texas Water Development Board (TWDB)investigated the site and concluded that the contents of the pit could contaminate the groundwater ifallowed to remain on the site.
In 1980, the Texas Department of Water Resources (TDWR), predecessor of the Texas WaterCommission (TWC), along with the United States Environmental Protection Agency (USEPA)conducted some preliminary sampling of the site and collected environmental samples of wastematerials and surface water. Both sludge and surface-water samples contained volatile and phenolicorganic compounds as well as heavy metals. Because the potential for groundwater contaminationwas high, seven monitoring wells were installed. Samples from these wells revealed the presence ofvolatile and phenolic organic compounds in the groundwater. In 1981, the TDWR declared allwater wells on the site non-potable, and the site was placed on the National Priorities List (NPL).
In 1982, the State of Texas applied for Federal assistance to conduct a full investigation of the siteand in June of that year a Cooperative Agreement was signed, authorizing the TDWR to spendFederal funds to conduct a Remedial Investigation (RI) at the Sikes Disposal Pits site (Reference 1& 2). On January 17, 1983, the TDWR contracted with Lockwood, Andrews & Newman (LAN) toconduct the RI.
The RI was conducted in two phases. The first phase was performed during the spring of 1983 withfollow-up activities during the winter of 1984. Also during the spring of 1983, the USEPAEmergency Response Branch performed an immediate removal action (RA). They removedapproximately 440 cubic yards of phenolic tars from a partially buried pit near the temporary livingquarters of one of the residents, immediately north of U.S. Highway 90. The contaminated materialwas transported to a landfill in Port Arthur, Texas, and the remaining pit was filled with clean sand.
Prior to submission of the final RI document, work began on the Feasibility Study (FS) (October1984). Several data gaps were identified in the RI that were considered essential for the completionof the FS. A decision was made to finalize the RI report and conduct a supplemental samplingprogram (Reference 3 & 4). Field work for the supplemental sampling program began in July 1985. The final Addendum RI Report for these field activities was submitted in June 1986. A draft of theFS was also submitted at that time.
In April 1986, ATSDR completed a Health Assessment for this site (Appendix B). Below is a summary of their conclusions:
- The proposed ten ppm cleanup level for soils and sludges should be sufficient to protect publichealth; however, the residual contamination and its impact on public health should beconsidered in the selection of any future uses of the property which would offer the opportunity for increased public health exposure.
- Additional efforts should be made to identify all local private wells and their water sources. Amonitoring program should be established for those residential wells using the upper and loweraquifers for drinking water to monitor for any changes in flow direction and contamination spread.
- Additional sediment samples should be taken from the drainage ditches, the flood flow channel, and the retention area adjacent to U.S. 90.
- When using background water samples to determine the acceptability of contaminatedgroundwater, the background samples should not exceed Federal or State standards.
- Level B personal protective equipment should be used for all site-invasive activities.
- The abandoned oil well suspected of causing cross contamination between the upper and lower aquifers should be inspected and properly capped.
- The landfill area should be posted in order to warn potential users of the area against water and soil contact. Restricted access should be instituted.
The final Feasibility Study (FS) for the Sikes Disposal Pits site was completed in July 1986(Reference 5). Based on the FS, a Record of Decision (ROD) which selected the remedy was signedin September 1986 (Reference 6). Below is a brief description of the selected remedy:
- On-site incineration of sludges and contaminated soils.
- On-site disposal of residue ash by use as backfill.
- Ban the use of upper aquifer on site, while naturally reducing contaminants to levels that wouldpose an estimated excess lifetime cancer risk of no more than one extra cancer per 100,000 population.
- Treat contaminated surface water as necessary to meet discharge criteria and discharge to the river.
- Monitor the lower aquifer and ban its use on site if the site contaminants enter the aquifer.
In December 1993, Texas Department of Health Staff (TDH) conducted an exposure investigationto determine if residents of the Riverdale Subdivision were continuing to be exposed to lead fromtheir well water. Participating residents were instructed to collect first-draw faucet water samples. TDH staff collected well water samples. All samples were analyzed for lead by the TexasDepartment of Health Laboratory.
The site was in the process of being remediated during the preparation of this report. Incineration ofthe sludges and contaminated soils is ongoing with completion anticipated to be in 1995. ThisAddendum to the original Health Assessment is being prepared to consider new environmental dataand to address community health concerns.
On July 17, 1991, we visited the Sikes Disposal Pits site. The Texas Department of Health staffmembers participating in the site visit were Drs. John F. Villanacci and Nicholas J. Giardino. During our visit, engineers from Lockwood, Andrews & Newman, Inc. (LAN), TWC's oversightengineer for the site, were available to brief us and give us a tour of the facilities. We spent a totalof six hours in the Sikes Disposal Pits site vicinity, three hours on site and three hours off site.
A six-foot chain-link fence, capped with barbed wire, surrounded the entire area requiringremediation. A security guard was posted along the road that allowed access into the facility. Sinceon-site incineration was the chosen method of remediation, construction of the incinerator andaccompanying facilities were in progress. The incinerator was being constructed on top of a largepad (mound of dirt) approximately 30 feet above MSL, a height well above the 100-year flood level.
During our site visit, approximately 130 workers were actively involved in the construction process. Workers were wearing standard construction and protective gear which included hard hats andprotective goggles. We toured the perimeter of the pad and were able to view the entire site from an operating platform located on top of a secondary combustion chamber. This tower wasapproximately 110 feet above the surface of the pad.
From the viewing tower, we saw that approximately three quarters of the site had been devegetated. The LAN engineers explained that this was to facilitate future excavation activities and that theharvested trees were reduced to wood chips and buried on the site. We were able to see five of thenine perimeter air monitors. The function of these monitors would be to continuously monitorambient air, from all wind directions, during excavation activities. If the monitors locateddownwind of excavation activities detect emissions above predetermined acceptable levels, theexcavation activites will be modified to lower the emissions to acceptable levels. Modification of theactivities may include options such as using foam blanketing agents or reducing the area ofexcavation. Incineration will be stopped when the continuous emission monitors installed on theincinerator indicate that emissions from the incinerator are above acceptable levels. The incineratorhad a large stack that was part of an emergency system designated to protect downstreamequipment. The stack is employed in limited emergency conditions that could result in immediatedanger to workers on the site or the public beyond the site. The stack has a burner assemblydesigned to provide for thermal destruction of organic compounds in the kiln off gasses duringemergency conditions.
On the eastern most portion of the pad site, we observed the construction of two large, lined,temporary storage ponds. We were told that in the event of heavy rains, water from the excavationsites would be isolated by berms and diverted to these ponds for sampling and necessary remediationprior to discharge into the San Jacinto river. East of the pad site, immediately adjacent to TankLake, was a temporary drum storage area and a vehicle decontamination area. We saw additionaldrums in and around the MWP. The waters of the MWP were discolored and had an oily sheen. The overflow area was discolored and from the tower appeared to be covered with a tar-likesubstance.
There were two smaller waste pits immediately northwest of the pad site. Immediately south ofthese pits adjacent to the visitors parking lot were several mounds of sand intermingled with an oilytar-like substance. We noted an odor that appeared to be coming from this area. The LANpersonnel informed us that this area contained the contaminated material excavated from the pad siteprior to building the pad. The area surrounding the site was very swampy with small and largebodies of water all around. Immediately south of the pad site was an active marina. We were toldthat several varieties of poisonous snakes including cottonmouth, copperhead, and coral had beenseen on the site. Additionally, alligators had been seen on the site and we were shown a photographof an alligator found on the site.
During the site visit we visited three of the subdivisions immediately surrounding the site, Riverdaleto the south, Rogge to the northeast, and Sleepytime to the east. (See Figure 2.) The closestresidence to the site, a single family home, was approximately 500 feet to the south of the site.
We saw a boat on the bank of Shriver Lake less than 500 feet from the site boundary. Additionallywe saw a man fishing in Riverdale Lake immediately southeast of the site and were told by residentsthat fishing in the surrounding bodies of water was a common occurrence. We were also told byresidents that, in the past, land now included in the site was leased for hunting. Several residentstold us that their children had played on the site before it was fenced. We saw children of all ages inall three of the subdivisions. The Harris County Landfill, located to the east of Riverdale, wasfenced and inaccessible.
TDH staff revisited the site December, 1993 during the private well sampling episode. The site was in the process of being remediated during the preparation of this report. Incineration of the sludges and contaminated soils is ongoing with completion anticipated to be in 1995.
Several small communities, including Riverdale, Barrett, Magnolia Gardens, and Crosby, are withinthree miles of the site. The Riverdale community lies southeast of the site, south of Highway 90. This community consists of large lots with residential housing. The closest residence is less than500 feet from the site. The 1985 RI indicated that Riverdale had a population of about 100 people.
Approximately 7,613 persons live in the Crosby-Barrett area immediately surrounding the site. According to preliminary 1990 U.S. Bureau of the Census data, 4,863 persons live in the townships:1,811 persons in 731 homes in the City of Crosby; and 3,052 persons in 1,077 homes in the City ofBarrett. Within the rural area immediately surrounding the site, in the same census tracts as thetownships (tracts 252, 253, 255, and 258), there are 2,750 persons in 1,074 homes (see Figure 2). The racial makeup of the Crosby-Barrett area is 54 percent white and 46 percent non-white. Ofthese two groups, six percent are of hispanic origin. The percentage of non-white persons in the Cityof Barrett is higher (97% non-white in Barrett as compared to 17% non-white in Crosby). Twenty-four percent of the population in the above mentioned areas are under 18 years of age.
The Sikes Disposal Pits site is located in the less developed eastern portion of Harris County. Nosignificant acreage of agricultural land is located within a one-mile radius of the site; however,pasture and cropland are found outside the floodplain on both sides of the San Jacinto River atgreater distances from the site.
The area immediately surrounding the site is largely undeveloped with numerous abandoned sandpits and low-lying swampy areas. The U.S. Army Corps of Engineers has determined that TankLake and the swampy drainageways that run through the eastern and southern portions of the siteare classified as wetlands, and are therefore under the jurisdiction of the Department of the Army. Inaddition, the San Jacinto River and Jackson Bayou are considered navigable waterways and are,therefore, subject to the rules and regulations of the River and Harbor Act of 1899, also under theDepartment of the Army's jurisdiction. The waters of the San Jacinto River and Jackson Bayou arewithin 500 feet of the site boundaries and vary from fresh to brackish water depending on rainfall,river stage, and tidal conditions downstream.
The only major industrial development within three miles of the site is the Champion PaperCompany plant, north of U.S. 90 and west of the San Jacinto River. In the past, commercial timberoperations and mineral exploration activities had been conducted northeast of the site. The propertyadjacent to the Riverdale subdivision was used as a landfill by Harris County in the late 1960's andsubsequently as a pipe storage yard.
Natural Resource Use
The Chicot aquifer, which underlies the site, provides fresh water to the majority of the wells in thearea. In the site area the Chicot aquifer consists of an upper aquifer and a lower aquiferhydraulically separated by approximately 65 feet of highly impermeable clay strata. The upperaquifer extends from ground surface to a maximum depth of 55 feet. The lower aquifer extendsdown to approximately 500 feet. Below the Chicot aquifer is the deeper Evangeline aquifer. TheEvangeline is the most important source of fresh groundwater for the Houston metropolitan area. The 1985 RI identified 70 water production wells within approximately three miles of the site. Thirty of those wells were located in the Riverdale subdivision immediately southeast of the site. The Riverdale wells are primarily shallow (24 to 300 feet), small-diameter (2- to 4-inch casings),domestic water supply wells. See Figure 4 for the location of all wells.
The climate in Harris County is warm and humid with an average of 48.18 inches of rain each year(Texas Almanac, 1988-1989) (Reference 7). Although the monthly rainfall is well distributed, amaximum 24-hour rainfall of over 15 inches has been recorded. Rain falling on the site leaves by acombination of evaporation, infiltration, and overland flow to adjacent water bodies.
Surface-water runoff from the Sikes Disposal Pits site occurs during flooding or heavy rainfall. Runoff from the MWP east of Tank Lake is to the east and south into a drainageway coming fromthe vicinity of the French Limited site. The flow moves southwest, going under U.S. 90 and thenthrough Gordon, Rickett, Faucett and McCraken Lakes to the San Jacinto River. Overflow from thethree pits west of Tank Lake flows west to the San Jacinto River or north under the railroad bridgeto Jackson Bayou.
Water from the San Jacinto River flows into Galveston Bay, which is located about 16 milesdownstream. The commercial fishing industry is substantial in downstream portions of the SanJacinto River and throughout Galveston Bay. Recreational fishing in the San Jacinto River andJackson Bayou near the site is known to occur but the amount and frequency of this fishing has notbeen determined. The variety of sport fish include bass, bream, and catfish.
In addition to sport fishing, the southern portion of the site bordering U.S. Highway 90 has beenused for multiple purposes. These include sand-pit operations, boat launching, water skiing, andswimming. Off-road vehicle events have also been held in this area.
On June 20, 1991, Harris County Health Department officials were contacted about the availabilityof any health data on residents living in the vicinity of the Sikes Disposal Pits site. Other thanroutinely collected birth and death data, they reported no additional health outcome data associatedwith the site. In Texas, this type of data is generally not retrievable for cities with less than 2500people. Although Barrett has a population greater than 2500 this data was not available. SinceHarris County has a population of over 2.5 million, it would be very difficult to specifically identifybirth and death data from Crosby and Barrett without a special study.
The Texas Department of Health Cancer Registry Division maintains incidence and mortality datafor cancer in Texas. After meeting with representatives from the Cancer Registry Division, wedecided that we could not use the available cancer data for the following reasons: (1) incidence datafor Texas Public Health Region 4, in which the site is located, are incomplete and wouldunderestimate the true incidence rates and (2) cancer mortality data are not available for cities withless than 2500 persons, thus we would be unable to obtain data specific to the Crosby and Barrettareas.
No investigations associated with this site are listed in the Texas Department of Health, Division ofEpidemiology, Epidemiology Investigation Index file. This file covers investigations conducted from the 1960's to the present time.
In an initial effort to determine community health concerns, we contacted the USEPA, the TWC,TDH Region 4, and the Harris County Health Department. The USEPA was the only agency whichhad records that included community health concerns associated with the site. The information inUSEPA files included newspaper articles, telephone log sheets, and records of communication. Additionally, during our site visit we spoke with representatives of the Crosby Chamber ofCommerce and went door to door to speak with a sample of residents from the surroundingcommunities to obtain their health concerns. The individual residents to whom we spoke lived in theRiverdale, Rogge, and Sleepytime subdivisions, all within a 3/4-mile radius of the site. All theresidents that we spoke to were given a brief explanation of the purpose of our visit. The following health-related concerns were obtained:
- Could the site be the cause of lung problems, skin rashes, eye problems, warts, mental retardation and baldness?
- Will the emissions from the incinerator be harmful to children and pets?
- Will the incinerator be permanent?
- Will odors and fallout result from the incineration process?
- Will water from the site be dumped into the San Jacinto River and will it contaminate the fish?
- Could the deaths from respiratory disease have resulted from exposure to site contaminants?
- Could the site be responsible for mouth ulcers, upper respiratory infections, and ear infections in a two- year-old child?
- Could exposure to site contaminants be responsible for the slow development of a two year old child, development being defined by the inability to talk yet?
- Will there be medical waste and body parts burned in the incinerator?
- Are the residential well and Municipal Utility District waters safe to drink?
- Can the site be responsible for the poor quality of water in Barrett (bad odor, taste and discoloration)?
- Can the site be responsible for the whole body swelling experienced by a resident after drinking water from Barrett?
- Can the site be responsible for the large amount of cancer that residents have reportedly observed in people living in the area?
- Should the residents be concerned about having previously eaten fish and game taken from the site?
- Should residents be concerned about the fact that their children used to play on the site prior to the site being fenced?
No new community health concerns were reported to TDH staff during the December, 1993 site visit and residential well sampling.
This section contains lists of the contaminants of concern. However, inclusion on the list does notimply that a contaminant represents a threat to public health. Subsequent sections of this HealthAssessment will evaluate these contaminants to determine if exposure to them has public healthsignificance. ATSDR selects these contaminants based upon the following factors:
- Concentrations of contaminants on and off site.
- Field data quality, laboratory data quality, and sample design.
- Comparison of site-related concentrations with background concentrations, if available.
- Comparison of site-related concentrations with ATSDR health assessment comparison (HAC) values for (1) non-carcinogenic endpoints and (2) carcinogenic endpoints.
The data tables and text that follow include the following acronyms and symbols:
*EMEG = Environmental Media Evaluation Guide.
*NCREG = Non-carcinogenic Risk Evaluation Guide.
*CREG = Cancer Risk Evaluation Guide
*PAHs = Polycyclic Aromatic Hydrocarbons
*PCBs = Polychlorinated Biphenyls
*RfD = Reference Dose
*MRL = Minimum Risk Level
*CSF = Cancer Slope Factor
*ppm = parts per million
*ppb = parts per billion
*µg/L = Micrograms Per Liter (equal to parts per billion)
*mg/kg = Milligrams Per Kilogram (equal to parts per million)
*µg/m3 = Micrograms per cubic meter of air
Health Assessment Comparison (HAC) values are contaminant concentrations for specific mediathat are used to include contaminants for further evaluation. Exceeding a HAC value does notimply that a contaminant represents a threat to public health. HAC values include Non-carcinogenicRisk Evaluation Guides (NCREGs), Cancer Risk Evaluation Guides (CREGs), and other relevantguidelines. NCREGs are HAC values based on ATSDR's EMEGs, USEPA's RfDs or othernon-carcinogenic health comparison values; CREGs are HAC values based on the risk of one excesscancer in a million persons exposed over a lifetime.
The data presented in this subsection were collected for the TDWR (now TWC) and the USEPA byLAN, Environmental Science and Engineering, Inc. and Harding Lawson Associates, during the RIin January of 1983. Additionally, air quality data were collected by IT-DAVY in 1990 (Reference8), residential well data by Jacobs Engineering in December, 1987 (Reference 9) and surface-waterrunoff data by ENSR Consulting and Engineering (ENSR) in 1989 (Reference 10). The surface-water runoff data were collected just after the May 1989 flood, for the French Limited Task Group,Inc. (FLTG), the PRP's for the French Limited NPL site.
Numerous waste deposits are spread across the entire Sikes Disposal Pits site. Table 1 presents adescriptive summary of the types of these waste deposits. The locations of the sampled wastes listedin Table 1 are shown on Figure 5. Much of this waste is covered by sand and therefore is not visiblefrom the surface. In addition, LAN suggests that during the hot summer months contaminated blacktar-like substances became softer and settled into different positions adjacent to or inside drums inwhich they were found. Some of these semi-liquid materials appear to move horizontally in thedownhill direction (Reference 1).
Uncertainty exists regarding the volume estimates presented in Table 1. Sampling in most areas wasdone only to a depth of three feet and in some locations only one sample was taken. Nevertheless,the volume estimates are the best that can be made using the available data.
The location of the ten samples collected that were composited for analysis is shown in Figure 6. Nine of the ten composited samples contained tars, hardened and liquid sludges, hardened resins orpigments, and gritty sludges. The results of these analyses are presented in Table 2. Bis(2-ethylhexyl)- phthalate, beryllium, pyrene, and lead were found at concentrations exceeding HACvalues.
A separate discussion of subsurface and surface soil results cannot be made since LAN madecomposite soil samples of varying depths ranging from zero to one inch to two to three feet. Ingeneral the physical consistency of the soil was such that the top-most layers (0 to 18 inches belownormal ground surface level) of the composite samples consisted of a black waste-like material, themiddle layers (6 to 36 inches) consisted of a soil/waste mixture, and the bottom-most layers (12 to60 inches) consisted of plain soil with no visible contamination. Table 3 contains the contaminantsof concern in the soil and Figure 7 shows the soil core-sampling locations. In this media benzene,1,2-dichloroethane, beryllium, PCB's and lead were all found to exceed HAC values (Table 3).
|Location||Type of Waste||Size of Area |
|Depth and/or Volume (ft.)||Sample Number||Remarks|
|Large Main Waste Pit||Tars, Sediments, Sludges||88,000||1.5 (avg.)||SE06 & SE07||Stringy tars in some areas.|
|Small Main Waste Pit||Tars, Sediments, Sludges||33,000||0.7 (avg.)||SE05||Couldn't penetrate some areas.|
|Overflow Area||Tars, Sediments, Sludges||3,430||3.0 (avg.)||Core Samples||Viscous tars and sludges.|
|Small Waste Pit 1||Tars, Sediments, Sludges||1,500||2.0 (avg.)||SE01||Hard asphaltic material.|
|Small Waste Pit 2||Tars, Sediments, Sludges||8,100||0.5 (avg.)||SE02||Sludge.|
|Small Waste Pit 3||Tars, Sediments, Sludges||9,500||0.2 (avg.)||SE03||Sludge with heavy oil film on water.|
|A-Barrels||Solidified Sludge||4,000||~20 mostly crushed barrels||Barrels are in the berm of the new sand pit.|
|B-Barrels||Solidified Sludge, Gritty Sludges, Tars||40,000||~600 barrels|
|C-Dry Pit||Hard and Soft Tars||2,830||1.0 (avg.)||WO07C||Reddish brown, soft tars. Some barrels here.|
|D-Dry Pit||Very Tack Tar in very soft area||3,000||2.0 (avg.)||WO07A||Plastic gallon jusg and prtially buried barrels. Reddish brown.|
|E-Dry Pit||Hard Tar with Crust||1,500||2.0 (avg.)||WO07B||Small bottles and vermiculite in area, possibly from lab disposal. Possibly connected to Large Main Pit at one time.|
|G-Pit||Tars - Some Liquidy||5,000||2.0 (avg.)||WO08A||Liquid tar down to 1 to 2 feet.|
|H-Pit||Tars - Soft and Tacky||7,500||1.0 (avg.)||WO08B||Some cinders on surface - very spongy area. Holes filled with water and oil.|
|I-Pit||Tars - Soft and Tacky||4,000||1.0 (avg.)||WO08C||Some cinders on surface - very spongy area. Holes filled with tars, slowly.|
|J-Burn &/or Overflow||Tars - Hard and Soft||3,000||1.0 (avg.)||WO08D||Cinders in very spongy area.|
|K-Main Dump Area||Tars - Hard and Soft||14,000||2.0 (avg.)||WO09||~80 barrels in area that is very soft in spots.|
|L-Waste Pile||Yellow Crystalline Material||1,260||2.0 (avg.)||WO010|
|M-Barrels||Solidified Sludge||600||~20 Barrels||Barrels about half full.|
|N-Surface Tars||Hardened Tars||7,850||0.5 (avg.)||Tars cover about half of area being interspersed between trees and weeds.|
|O-Small Pits||Liquid Tars||Four Pits area 13 ea.||2.0 (avg.)||WO06||Very liquidy waste. Barrels may have been present.|
|P-Dry Pits/Spill Area||Tars - Soft||1,260||1.0 (avg.)|
|Q-Dump Areas||Barrels, Roof Shingles, Tar Concrete Debris||Four areas 2,827 ea.||Located along drainage ways crossing road.|
|R-Dry Pit||Tars - Very Soft||4,800||2.0 (avg.)||WO05A||Very soft area - holes fill with tar, slowly.|
|S-Dry Pit||Tars - Soft||2,400||2.0 (avg.)||WO05B||Tars are tacky and stiff.|
|T-Dry Pit||Tars - Liquid||1,200||2.0 (avg.)||WO05C||Gritty liquid sludge.|
|U-Field with Barrels||Solidified Sludge||70,700||10 Barrels||Barrels about one-fifth full and may have burned.|
|V-Barrels||Solidified Sludge||1,260||20 Barrels||Barrels about one-fifth.|
|W-Barrels & 5 gal. cans||Solidified Sludge||1,260||20 Barrels||Barrels about one-tenth|
|CONTAMINANT||LOCATION|| MAX. CONC |
|HAC VALUE (mg/kg)|| HAC |
|Volatile Organic Compounds|
# Composite of Tars, Resins, and Sludges: W005, W006, W007, W008, W009
|CONTAMINANT||DATE||LOCATION||MAX. CONC |
|HAC VALUE (mg/kg)|| HAC |
|Volatile Organic Compounds|
Composite 3 - COO2A, COO4A, C007A, COO9A, CO11A, and CO15A
(Core Soil Samples Taken within one foot of soil surface.
Composite 4 = COO2A, COO7A near MWP (See Figure 7)
Composite 5 = CO04A, CO09A, and CO11A at intermediate distances from the main pit.
Composite 6 = CO13A, CO15A farthest from MWP
Significant contamination of sediment was found in the MWP and SWPs. LAN estimates a total of5,910 cubic yards of contaminated sediment in the MWP and 3,345 cubic yards in the SWPs. EvenTank Lake, which was supposedly never used for waste disposal, contained 1,400 ppm to 2,500ppm total extractable organics in its sediments (Reference 1).
As of July 1985, no sediment or sludge-like materials were observed floating on top of any of thepits. According to LAN sludge/sediment material may have been removed from the pits by floodingprior to the May 1983 flood (Reference 1). Future transport of sludge/sediment material out of thepits by high waters or flooding is therefore not likely.
Table 4 summarizes the chemical pollutants of concern in sediments while Figure 8 shows sedimentsampling locations. In composite samples taken from the MWP and SWPs, PCB's, lead, beryllium and thallium were found at levels exceeding HAC values.
|CONTAMINANT||DATE||LOCATION||MAX. CONC |
|HAC VALUE (mg/kg)||HAC |
|Volatile Organic Compounds|
# Lab Composites of SE05, SE06, SE07, and Main Waste Pit samples
** RfD for thallium selenite was used.
NOTE: No specified depth for samples.
On-Site Surface Water
LAN collected 21 surface-water samples at the site. Twelve of these samples were collected byLAN in July 1983 just after the May 1983 flood. Additional surface-water samples were collectedin February 1984 to determine the impact the flood may have had on contaminant levels in thesurface waters on site. Nine new areas were sampled and seven samples were repeated from the July1983 sampling. Sampling was either done directly at the surface of the water using a container orjust below the surface drawing water up with a pump.
The results of chemical analyses of the surface-water samples are summarized in Table 5 and arekeyed with Figure 9. Four volatile organic compounds, one base/neutral compound, and PCBs were all detected at levels that exceed HAC values.
|CONTAMINANT||DATE||LOCATION|| MAX. CONC. |
|HAC VALUE (µg/L)||HAC |
|Volatile Organic Compounds|
Most of the contaminants of concern are located in the MWP, and the SWPs with the exception ofbenzene which was detected northwest of the MWP near the railroad tracks, and 1,2-dichloroethanedetected between the MWP and the SWPs.
LAN also noted, in the course of the analyses of the surface-water samples, that the time of year hadan effect on the concentration of contaminants in the surface-water samples. LAN attributes this totemperature effects; cooler temperatures lower the water solubilities of most of the organiccompounds analyzed.
It should be noted that most of the surface-water samples were collected after a major flood andtherefore do not represent average or equilibrated surface-water contaminant concentrations. Flooding has caused waters from the MWP to flow into the overflow area and surface water to becarried away from the site northwest under the railroad tracks toward the Jackson Bayou as well assouth across U.S. Hwy 90 into portions of the Riverside Community.
Table 6 and Figure 10 show that the shallow aquifer under the Sikes Disposal Pits site has beencontaminated with a variety of volatile organic and metallic compounds. As can be seen in Figure10, a plume of contamination extends as far east as GW20 and as far south as GW18.
|CONTAMINANT||DATE||LOCATION||MAX. CONC |
|HAC VALUE (µg/L)||HAC |
|Volatile Organic Compounds|
|Vinyl Chloride||RI 2/84||GW17||370||0.32||0.0184||MRL/CSF|
|Arsenic||SI 7/85||GW03 & GW03D||60||16||NA||MRL|
NOTE: See Figure 10 for sampling locations.
D = Deep Well
RI = Remedial Investigation
SI = Supplemental Investigation
* Value based on the RfD for thallium(I)chloride
** EMEG for lead is based on EPA's National Drinking Water Action level of 15 µg/L.
+ PDWRAL = Primary Drinking Water Regulation Action Level
Dewatering of the sand pits northeast of shallow monitoring well GW03 may have facilitated themovement of the groundwater towards these pits. These pits, which are now filled by wood-fiberwaste from a pulp and paper plant, were sampled (sample SO04) in an effort to determine the natureof the fibrous woody material. LAN sampled the top four to five feet of the material and found novolatile organic materials present.
According to LAN the dewatering of the sand pits in the south and southeast may have facilitatedthe southerly migration of contaminants from the MWP and the Overflow Area through the shallowaquifer. Natural events such as flooding may also have facilitated this migration. Many of thevolatile organic compounds and numerous metals were found at levels exceeding HAC values.
On-Site Air Quality
IT Corporation and Davy McKee Corporation (IT-DAVY) put in nine fence-line ambient airmonitors around the Sikes Disposal Pits site to collect air quality data. Over a seven-day period inOctober 1990 IT-DAVY sampled for total suspended particulates, vinyl chloride, methylenechloride, 1,1-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, toluene, and ethylbenzene. The highest particulate concentration was 237 µg/m3, the next highest was 125 µg/m3, the rest werebelow 100 µg/m3. The only volatile organic chemical detected was 1,1,1-trichloroethane. Thischemical was detected by at least one monitoring position on each day. The highest level detectedwas 0.087 µg/m3 which was below both the chronic (1000 µg/m3) and subchronic (10,000 µg/m3)HAC values for this compound.
During the RI, on-site ambient air concentrations of volatile organic compounds were measured withan instrument calibrated to benzene. The measured levels were one to two ppm above normalbackground levels and during one sampling event were as high as ten ppm.
To see whether or not soil contamination was a problem in off-site neighborhoods, LAN collectedfive off-site soil samples. Samples SO05, SO06 and SO07 were collected in and around theRiverdale community in areas that are, on occasion, flooded (see Figure 11). Soil samples SO08and SO09 were collected off-site in background areas that did not flood. All of the samples takenwere composites of five subsamples within a 20-foot diameter area at a depth of zero to eight inches.
Chloroform was detected, by LAN, in samples SO05 through SO07, but at levels that were belowHAC values. LAN detected bis(2-ethylhexyl)phthalate and lead in all five samples. Theconcentrations of bis(2-ethylhexyl)phthalate exceeded the HAC value and ranged in value from 210ppb to 520 ppb. The concentrations of lead (4.7 to 36 ppm) were low and well within normalbackground levels for soil. None of the other semivolatile organic compounds analyzed were abovedetection limits. Also, none of the metals analyzed exceeded HAC values.
The background soil samples taken by LAN in areas SO08 and SO09 were also contaminated withbis(2-ethylhexyl)phthalate at concentrations ranging from 260 ppb to 300 ppb. These levels wereabove the HAC value. LAN did not discover any other contaminants at significant levels in thesebackground samples.
In the early sampling, bis(2-ethylhexyl)phthalate and lead were the only two contaminants commonto both the waste site and the off-site soil samples. LAN suggested that the absence of other sitecontaminants in the off-site soil samples indicated that there had been no migration of contaminantsoff site to the western portion of the Riverdale community. The contaminants found off site mayhave come from other sources (see section "Other Sources of Off-Site Contamination").
Subsequent off-site samples were also taken around Riverdale Lake after the May 19, 1989 flood. The results of this sampling are presented in the "Riverdale Lake Area Remediation Program,Crosby, Texas August 1989" (Reference 11). The post-flood samples contained PCB's atconcentrations exceeding HAC values with concentrations as high as 253 mg/kg. The off-site PCBcontamination observed after the flood indicates that, at least in the case of the 1989 flood,contaminants were transported to off-site areas; since these contaminants were also found on theFrench Limited site, we could not determine their origin. In 1989, the PCB contaminated areas wereremediated. The maximum level after phase II of the cleanup of 7.1 ppm was still above the HACvalue for PCB's.
Contamination of soil and sediment mixed in with the May 1989 San Jacinto storm-water runoffwere also tested by ENSR. No site contamination was detected in these sediments.
In December 1987, Jacobs Engineering, under contract to the EPA, tested several residentialdrinking-water wells, located in the Riverdale subdivision (Table 7). They tested for volatileorganic compounds, metals, chlorinated organic pesticides, PCBs, and coliform groups of bacteria. Although lead was not above the current MCL of 50 µg/L, the reported maximum levels were abovethe recently revised HAC value of 15 µg/L.
Additional residential well samples taken during the Post San Jacinto River May 1989 Flood EventSoil and Water Analysis Program also revealed lead levels above the revised HAC value. Berylliumand thallium were reported as being below detection limits; however, the reported detection limitswere above HAC values. Coliform exceeded the 1 colony/100mL standard in six out of 19 samples.
In December 1993 the Texas Department of Health analyzed water samples for lead from 17 homesin the Riverdale subdivision. Analyses of water from first-draw indoor-faucet samples revealed leadranging from <1.0 µg/L up to 3.9 µg/L. Of the 17 residences, five were unable to provide first-drawsamples; for these homes water samples were taken from an outside tap nearest the well. Wellsamples for these homes revealed lead ranging from <1.0 µg/L up to 7.0 µg/L. These levels arebelow the Environmental Protection Agency's Primary Drinking Water action level of 15 µg/L.
|CONTAMINANT||DATE||MAX. CONCENTRATION |
|HAC VALUE (µg/L)||HAC |
|Antimony||12/87||BDL of 54||6.4||NA||RfD|
|6/89 ENSR||BDL of 5|
|6/89 EPA||BDL of 60|
|Beryllium *||12/87||BDL of 2||80||0.0083||MRL/CSF|
|6/89 ENSR||BDL of 20|
|6/89 EPA||BDL of 5|
|Cadmium||12/87||BDL of 5||8.0||NA||MRL|
|5/89 ENSR||BDL of 10|
|5/89||BDL of 20|
|Thallium *||12/87||BDL of 5||1.28||NA||RfD|
|6/89||BDL of 10|
* = Detection limit values are greater than current health criteria values
+ PDWRAL = Primary Drinking Water Regulation Action Level
Fillets of various fishes were composited and then analyzed for metal contamination and PCBs(Table 8). Fish were caught at the mouth of the Jackson Bayou upstream from the site, and in theSan Jacinto river both upstream and downstream from the site. Figure 12 shows these locations. PCB concentrations exceeded HAC values at sampling locations FT104, FT105, FT101, FT108,FT109, FT106, and FT107. Since PCB concentrations on the Sikes site are low, it is questionableto assume that the Sikes site is responsible for the PCB contamination found in the fish. Thepossibility exists for fish in the San Jacinto River and Jackson Bayou to be exposed to contaminants from a variety of sources.
|CONTAMINANT|| SAMPLE |
| MIN. - MAX. |
| HAC VALUE |
| HAC |
| SAMPLE |
|CHROMIUM||FT03B,FT108||BDL - 0.08||17.5||MRL||2/84, 6/83|
|COPPER||FT104,FT01A||0.14 - 2.17||140.5||NAS*||2/84, 6/83|
|NICKEL||FT108,FT03B||BDL - 0.16||70.0||MRL||2/84, 6/83|
|ZINC||FT109,FT01A||2.57 - 36.20||700.0||RfD||2/84, 6/83|
|MERCURY||FT108,FT30B||BDL - 0.11||1.05||RfD||6/83, 6/83|
|PCB's||FT108,FT01B||0.021- 0.546||0.00045||CREG||2/84, 6/83|
Other Sources of Off-Site Contamination
There are several other sources located around the site which may contribute to the off-sitecontamination in the area. However, no data are available to determine the degree of interactionbetween these other sources and the Sikes Disposal Pits site.
As mentioned previously there is a former municipal landfill located immediately southeast of thesite. Because the contents of this landfill are unknown, it is impossible to determine its contributionto the observed off-site contamination. The landfill is currently the subject of an EPA investigation.
The French Limited NPL site is located immediately to the east of the Sikes Disposal Pits site. Water runoff and ambient air emissions from this site would impact many of the same areas as theSikes Disposal site. The main contaminants of concern associated with the French site are: benzene,1,2-dichloroethane, 1,2-dichloropropane, vinyl chloride, bromodichloromethane, carbontetrachloride, chloroform, dibromochloromethane, t-1,3- dichloropropane, naphthalene, PAHs,dibutylphthalate, PCBs, thallium, and lead (refer to the draft French Limited NPL site HealthAssessment Addendum, not attached).
A search of the 1987, 1988, and 1989 Toxic Chemical Release Inventories (TRI) revealed releasesfrom two sources located in the same zip code area as the site. These were the Penwalt Corporation,Lucidol Division and KMCO Incorporated. The Penwalt Corporation did indicate the release ofbis(2-ethylhexyl)- phthalate, one of the site contaminants. Additionally, exhaust from automobilestraveling on U.S. Highway 90 could have been a source of lead contamination in the past.
The USEPA has approved LAN's workplan QA/QC criteria and has overseen all aspects of the RIand SRI activities, ensuring all QA/QC standards were met. The USEPA has, in addition, reviewedand approved all LAN QA/QC reports through August 1990. The analysis and conclusions in thishealth assessment addendum are valid only if the referenced information is complete and valid.
The Sikes Disposal Pits site area supports many species of wildlife. Poisonous snakes and alligatorswere reportedly seen by workers on the site. During our site visit, we did not personally observe anywildlife.
Although there were numerous physical hazards associated with the construction of the incinerator and supporting facilities, these hazards were those common to most construction sites.