CONTAMINATION OF RIVER SEDIMENTS AND SOILS IN KEENE, N.H., FROM LEAD PAINT

Transcription

1 CONTAMINATION OF RIVER SEDIMENTS AND SOILS IN KEENE, N.H., FROM LEAD PAINT Timothy ALLEN Geology and Environmental Studies, Keene State College Keene, NH Recently the Keene State College (KSC) Child Development Center playground was found to be contaminated with chips of lead paint. Lead exposure is known to cause severe health effects in children. My students and I set out to determine how widespread this problem is across the rest of the campus. We collected samples of paint chips and soils from around the perimeter of selected buildings built prior to the banning of lead paint. Paint chips were qualitatively scanned for the presence of lead using X-ray fluorescence spectrometry (XRF). Soil samples were dried, pulverized and pressed into powder pellets, which were then quantitatively analyzed for total lead concentration by XRF. All of the paint chip samples scanned had lead present. Soil lead concentrations range from 19 mg/kg to 22,486 mg/kg. Most of the buildings we sampled have soil lead levels well above the US-EPA s recommended action levels of 4 mg/kg for play areas, and 12 mg/kg for non-play areas. In addition, previous research had show sediments of the Ashuelot River running through the KSC campus to be contaminated with lead, well above sediment quality guidelines. Areas upstream on the river are known to be contaminated with industrial wastes, but it is not clear that this is the source of the lead that we have observed. As part of the above study, we collected paint chips from bridges spanning the river over the contaminated areas, and like the paint on the buildings, these were also found to be rich in lead.

2 1) Methods Soil samples were oven dried at 15 C, and passed through a 2 mm sieve. A split was pulverized in an aluminum oxide planetary ball mill, and an aliquot of the resulting powder mixed with binder and pressed into a pellet. Pressed powder pellets were analyzed by Wavelength-Dispersive X-ray Fluorescence Spectrometry, with measured intensities ratioed against the Compton Scattering peak. Calibrations were done with USGS and NIST Standard Reference Materials R=.9999 Lead Calibration Line Paint chip samples were either loaded directly into the spectrometer, or pressed against a paper backing, and qualitatively scanned for heavy element x- ray lines using the LiF1 analyzing crystal Standard value (ppm) Rigaku ZSX 1e sequential Wavelength Dispersive X-ray Fluorescence Spectrometer Crystal Mill (1 position) 12 Position Sample Turret (not shown) 4 kw Rh X-ray tube ultra thin Be end window Diaphragm (1) Primary Slits* (2) Analyzing Crystal Flow Counter Secondary Slits* Airlock Scintillation Counter Loading Turret

3 2) Building Paint Chip Qualitative Analyses 14 Grafton House Paint Chip 12 Red=scan of back of chip Blue=scan of front of chip 1 8 Pb-LB1Pb-LA Zn-KA 6 4 Ti-KA Pb-LG1 2 X-ray Intensity (kilocounts/second) X-Ray Tube Peaks Zn-KB LiF2 crystal angular position 2-theta (degrees) equivalent to X-ray wavelength Blake Street Paint Chip Ti-KA 6 4 X-Ray Tube Peaks 2 X-ray Intensity (kilocounts/second) Ti-KB1 Pb-LG1 Pb-LB1 Pb-LA Zn-KA Fe-KA LiF2 crystal angular position 2-theta (degrees) equivalent to X-ray wavelength 14 Joslin Paint Chip Pb-LB1 Pb-LA 6 4 Zn-KA Pb-LG1 2 X-ray Intensity (kilocounts/second) Ba-KA X-Ray Tube Peaks Zn-KB LiF2 crystal angular position 2-theta (degrees) equivalent to X-ray wavelength Ti-KA

4 3)

5 4) Soil Results Table Sample ID Pb Cu Cr Ni Zn mg/kg mg/kg mg/kg mg/kg mg/kg Adams Tech Blake, north Blake, west Blake average 1324 Butterfield (a) Butterfield (b) Butterfield average 36 Cheshire A (dripline) Cheshire B (dripline) Cheshire average Cheshire 2 ft Cheshire 3 ft Cheshire 4 ft Cheshire 4 ft (replicate) Cheshire 5 ft Elliot Dripline Elliot FrontLawn Grafton drip (a) Grafton drip (b) Grafton average 2466 Grafton 1 ft Grafton 2 ft Hale (a) Hale (b) Hale (c) Hale (d) Hale average 9315 Huntress A (dripline) Huntress A (replicate) Huntress B (dripline) Huntress C (dripline) Huntress average 3642 Huntress 2 ft Huntress 5 ft Huntress 22 ft Huntress 44 ft Joslin B Joslin A Joslin average 21 Parker A Parker B Parker C Parker average 25 Sculpture Studio Background Soils Bank Bank Inlet Inlet Inland Inland Background average

6 Grafton Huntress 5) Soil Lead content with distance from building 2 15 Grafton Huntress Cheshire Elliot Distance from "Dripline" (feet) Cheshire Elliot Mansion

7 6) Prior River Sediment Results Shown below are total Lead concentrations (ppm) in Ashuelot River sediment samples (Allen et al., 23; Allen & Burns, 26), relative to respective NOAA Sediment Quality Screening Threshold Effects Level (TEL), Probably Effects Level (PEL) and Upper Effects Threshold (UET) values for Lead, based on toxicological studies on benthic organisms (Buchman, 1999). US 1 Pb BP WS 8 6 IS WN CV (4) RR (5) AF (4) HW 4 2 UET DS DS HW AF RR CV WN IS BP WS US

8 7) Bridge Paint Chip Qualitative Analyses Railroad Trestle Paint Chips 1 Scan using LiF2 analyzing crystal angular position 2-theta (degrees) equivalent to wavelength A-Field Bridge Truss Paint Chips 12 Scan using LiF2 analyzing crystal angular position 2-theta (degrees) equivalent to wavelength A-Field Bridge Rail Paint Chips 15 Scan using LiF2 analyzing crystal angular position 2-theta (degrees) equivalent to wavelength

9 8) Discussion All of the paint chip samples showed the presence of some Lead (Pb). Other dominant tinting elements were Zinc (Zn) and Titanium (Ti). The two-sided analysis of the Grafton paint chip shows that the building has Pb paint that apparently has subsequently been covered with Zn/Ti paint, thus masking somewhat the Pb content when analyzed from the current surface. This may explain the relatively low Pb content of the 81 Blake Street paint chip (which was only analyzed from the front). Soils adjacent to buildings that have Lead paint can be very highly contaminated with lead, although the degree of contamination is often highly variable, and the extent of contamination is generally limited to within about 1 feet or so of the building. The dripline soils around some of Keene State College s buildings are also contaminated with Copper (Cu), presumably from roof flashing, and Zinc (Zn), presumably from paint and/or roof flashing. Previous studies showed significant Lead contamination of sediments in the Ashuelot River. In this study, paint chip samples collected from bridges spanning some of the contaminated river sediment sites were found to have significant Lead content. These bridges may be the source of Lead contamination in the river sediments. Don t eat the mud from the bottom of the Ashuelot River in Keene, and don t play in the dirt around old buildings on the Keene State College campus.

10 References Allen, T., *Comeau, M., *Carson, H., *Hurd, E., 23, A Reconnaissance of the Heavy Metal Content of Ashuelot River Sediments, Studies in New England Geography, No. 17, 23 pages. Allen, T., and *Burns, E., 26, Occurrence and Distribution of Trace-Metal-Contaminated Sediments in the Ashuelot River, Keene, N.H., (abstract) Geological Society of America Abstracts with Programs, 38(2):12 Buchman, M.F., 1999, NOAA Screening Quick Reference Tables, NOAA HAZMAT Report 99-1, Coastal Protection and Restoration Division, National Oceanic and Atmospheric Administration, Seattle, WA, 12 pages. EPA, 23, Protect Your Family From Lead In Your Home, EPA747-K-99-1, Environmental Protection Agency, Washington, DC, 13 pages. Acknowledgements This project was carried out by students enrolled in the Fall 27 edition of my new course ENST 22 Investigating Environmental Problems, with additional data supplied by students enrolled in the Fall 26 and Fall 27 editions of my established course GEOL 315 Environmental Geology, all at Keene State College. This research was made possible by National Science Foundation grant #8786.