Document 2RrZNgrRGGM8Op6DvN7qZjwQb

Criteria for Evaluating Lead Hazard of Fainted Surfaces I- Dosage Currently some city housing and health codes limit the lead con tent of surface coverings to 1 percent, percent by weight, calculated as elemental lead, Is a good criteria for content of paint per it. However, this is not a good criteria for evaluating the health hazard present In paint chips from surface coverings of wells, windows, doors, furniture, end other objects. This conclusion can be supported by the example presented in the following table: Table 1. Amount of lead in Single and Multiple layers of Paint vs. Percent-lead Content of Paint Painted Surface Covering Wgc. of Ho. Peint Chip* layers (Milligrams) lead Content of Paint Ohio percent by Weight Amount (Milligrams) 1 10mg U 0. ling 6 60mg n 0.6ng 10 lOOmg n l.Omg k Same *rc*. e.i ., 1 square centimeter of 1, 6, 10 layers of pr.int. The amount of lead increases as the number of layers and hence the Weight of the chips are increased while the percent lead content remains at 1 percent of the weight of the chip regardless' of the nunber of coats of 1 percent paint applied. The health Hazard for a child 0007-SWP-037097 N22958 2 Ingesting a paint chip is related to the amount, specifically the weight, of the lead In the chips he Incests and absorbs. In 1956, at a meeting of the Committee on Hazards to Children of the American Standards Association, the recommendation was made that paints may be considered safe for use on children's toys, furniture, and housing interiors If the lead content does not exceed 1 percent of the total solids. At that time Dr. Julian Chisolm stated that "It is essential to recognize that this recommendation applies only to the two or three layers usually applied to a surface, not to multiple layers of paint as may be found in deteriorated housing." (Pediatrics, JL8, No. 6, Dec. 1956.) II. Measurement * The amount of lead contained in a given surface covering is deter mined .by percent lead content of each layer or coat of paint ar.d the number of coats that have been applied. A paint chip from the surface eoverihg will have a certain volume--treo x thiekness. It is time-consuming and frequently very difficult to determine the number of layers in a given area of paint or to measure the thick ness of chips from hand painted surfaces. .A given area, however, can be marked on a surface covering and a paint chip having the precise area can be removed including all layers of paint down to the wood or other substrate. The amount of lead available in the three dimensional paint chip is the factor determining the health hazard foe children. 0007-SWP-037098 0007-SWP-000112891 3 The amount of lead in a single layer or multiple layers of a Surface eoating can be measured by wet chemical analysis or by x-ray fluorescence analyzers (X-R-F). Here the meaningful units of measure ment 'vould be the actual quantity of lead per unit volume. The X-R-F instruments with radioisotope sources of suitable energy can penetrate successive layers of paint and measure the amount of lead lying within the area "viewed" by the Instrument. Here the meaningful units, accepted by convention, can be expressed as amount per unit area (milligrams per square centimeter). Implicit in such a statement is "area of a given surface covering of a given thickness." 0007-SWP-037099 0007-SWP-000112892 PAINT CHIP MEASUREMENT OF Pb CONTENT Wood 4 Chemicol Anolyi mg/wnU volume (mg/cm^) or mg/untf weigh! of chip X-R-F Anolyiit (mg/cm3) or by convention "(mg/cm2)" 0007-SWP-037100 0007-SWP-000112893 J III. Recommended limit It la recommended that the quantity of lead in surface coverings with single, and multiple layer* of paint, thould not exceed O.O3 mg/c.?-. Where this limit is exceeded the surface covering should be removed, covered, or otherwise treated to ensure that the contained lead is no longer available to children. IV. Rationale for Recommended Limit Rehoe established that 0.6mg of lead per day was the maximum that could be Ingested by an adult with no Increase in blood lead level; at this level input exceeded output with a slight accumulation Of body lead burden. A corresponding value for the child was estimated to be 0.3mg lead per day from all sources by an ad hnc committee of pediatricians and biological acientista qualified in the area of pre vention of lead poisoning in children.* A range of values for esti mated average intake of lead per day in the diet is O.lOOmg to O.HOr.g. Thus, the ingestion of more than 0,2 mgPb/day from supplerentary sources, such as paint chips, would result In an intake in excess of the limiting value recommended for children. The weight of one and multiple layers of dried interior house paint chips have been measured on prepared samples (Table 2.). * In the manuscript of the report, the maximum daily limit for intake of lead from all sources.is referred to as daily permissible intake (DPI). 0007--SWP--037101 0007-SWP-000112894 6 Table 2. Paint Chips, 5 17, lead Conccnt--Ueight Pe r Unit Area Range Average Interior House Paint mg/emz mg/cie2 l layer paint 5.2 - 8.0 6.5 2 layers 11.7 - 14.4 13.0 6 layers 37.0 - 40.8 38.8 The lead content for single end multiple leyers of 1 percent lead by weight can be compared to the limiting value (0.2 mg/day) for Ingestion of lead from non-diet (supplementary) sources (Table 3.). Table 3. Aieu Equivalent v Limiting Value for Supplementary ?b tneeseton (Pb content per unit area per layer paint : So. of Layers Chip Wet mg/cm2 Wgt Pb Content *8 17, by vgt/ptT layer) No. of cm* Containing Approx. 0.2 mgPb 1 6.5 0.065 2 13.0 0.130 6 38.8 0.368 3.1 1.5 0.5 From Table 3 It can be seen that the limiting value will be exceeded If a child ingests more than 1 cm* of a covering of 2 layers of 1 percent lead-based interior house paint. **" I --.H.IW -- ---- I . n --- .. I, . The lead content of a surface covering of dried paint should not exceed 0.03 mg/es?, The area equivalent of the limiting value for one 0007-SWP-037102 0007-SWP-000112895 57 layer of 1 percent Interior house point Is 3.1 cm*. The 0.03 r;/es^, however, does not depend upon the number of layers of paint--e.g., mtny layers of lead free paint may comprise the greater portion of the thickness of the surface covering. Some Estimates of the Quantity of Paint Chips Eaten by Children a. X-ray simulating an abdominal plate classified clinically as Grade 3 contained 1 gram of dried paint chips (Or. Sachs, Chicago); 7 out of 10 abdominal plates showing large amounts of Ingested rubbish fcy children visiting Che clinic htd been classified as Grade 3. The average weight of 69 paint chips taken from deteriorated buildings . // r / in Philadelphia is 69.6 mg/cm* consisting of multiple costs some with high lead content. If the average value Is assumed, the 1 gram of dried paint would represent the covering of approximately 11 cm*. b. A child, with a fecal lead of 180.v.g, hospitalized for encephalopathy, was living in a dwelling in which the painted surface was known to contain 9.5 percent lead by weight. Thus, the quantity of paint chips ingested was approximately l,900mg. Again, using the paint chip weight of 90 mg/cm* observed in Philadelphia, this would represent approximately 20 cm* surface covering. If Philadelphia's observed maximum value for paint ehips was 163 mg/cm*, the area from which the chips wera taken would have been about 11.5 cm*, Examples given in (a) and (b) show that children can ingest large quantities of psint chlp.s in a relatively short period--one or two days. B.C. King May 1971 .I 0007-SWP-037103 0007-SWP-000112896