Document mm1OgoXVrdG8gDM6bmQ9o6dVZ

March 14, 1972 Mr. S. 4. Hiicocfc Lead Develop--nt Association 34 Bcxfcaley Square London V.l, England Door Sid: Thank you for your loetor of February 16th. Z an sorry to boro taken oo loot to reply but I have boon doing quite s bit of travailing and an only nor catching up on sons of mj corraopondonea. filth regard to tba procioortlnp of tha Land in tba Karlroonant Conference, I will toko eora of ordering then yself. Ton hove oskod for holy on too topics which ora sxtranaly controversial. tint of all, I can only say that thara is rosily no universally roeogniaod level for load in blood. Certainly physicians flbo hove studied land poisoning, whether in children or adults, ora in ogroonant that eoneontratians move BO ug/100 C ora onooeaptnbly high. However, earn phyaieiana foal that levels above 40 ug/100 C nay eauso oartoin blochanical ohangaa which am roally yroallnical toadcity. Z think that tha noot authoritative article on this subject was written lest year by Dr. J. Jnllm Chlsoln in the February issue of Scientific Amriea: In his article. Dr. Chlsoln points oat that them am no rtenonsrrsfhla affects of land la bleed below s concentration of 30 ug/100 ( letwnm 30 and 30 ug/100 C, there nay be ninlnel et&cllniaal affects. Above this ceneentmtien, vo see a conpeneatlen phase and then actual injury. In a practical sense, the only persons dto am actually ill am them who shov a functional injury. Good practice, however, colls for inclusion of on acceptable safety factor which would lower the acceptable concentration to below the sowyQuestion level. Generally, in the felted States the level which is considered to be aatside the range of namal is 40 ug/100 G. This particular figure hoe been given credence by the Motional Academy of Scloscos and also by tha U.S. Daportnsnt of Boalth, Education, and Velfere. With regard to your second enaction, them new cm ncay who frequently refer te lead as emulative poison. Land is emulative la the sane sense that calories ere emulative. If we toko in too aaay calories, obesity results, but if we take in the proper mount of calorics to bo offset by our energy usage, then no obesity results. The sons occurs with lead. If the concentration of load taken in is low enough, then the body does net eeeunalato this natal, the theory that land in tha bones cm be released under certain physiological conditions has no apparent substance. Actually, eslclun lsvtls in tha blood am ouch nors critical than load. In order to relccas oum c very mall mount of load, enoxuous mount of celciun would have to ho released producing hypcrealcmla. Donald Baritrap hoc done sons 2- c Imm culture week showing that lead can ha released fro* hona tlaaoa hat la doing to, tha hona la nearly destroyed. I hopa that thaaa cedants aro of h m oaa to 70a hot If they an unclear, please do not hesitate to eo*e back to on. While I had planaad to visit laropa this spring, tha proas of othar activities including tha upcoming XM hearings ony praraat aa fro* until fall. At that time, thara la an Intarnattonal Synpoeiu* on tha environ--ntal haalth aapacta of load schadnlad to ha hold In A--tarda*. I probably vlll ba attandlng that conference, pazhapo to proaant a papar and will, of course, taka cars of othar European business while thara. Iha XIZRO tachnical and progra* review co**ltta* *aatlnga have not boon folly sat, hot tha tantalise dataa for tha tachnical naatlngs ara fro* Sapta*bar 18 through 29, vhlla tha progra* review ca--dttee Meetings ara scheduled fro* October 30 through Bovaaber 6. I think that that takas care of all for now. Bast regards. Sincerely, J. F. Cole, Sc.D. Director, Environmental Haalth J?C:lg enc. LIA-75001