In vitro bioavailability of heavy metals in pressure-treated wood dust.
Pressure treatment with chromium, copper, and arsenic (CCA) is the most prevalent method for protecting wood used in outdoor construction projects. Although these metals are tightly bound to the wood fibers and are not released under most conditions of use, we examined the bioavailability of metals in CCA pressure-treated wood dust in vitro. Cytotoxicity and metallothionein (MT) mRNA expression were examined in V79 Chinese hamster lung fibroblast cells incubated with respirable-size wood dust generated by sanding CCA-treated and untreated (control) Southern yellow pine. In colony survival studies, increased cytotoxicity (p < 0.05) occurred in V79 cells treated with CCA wood dust (351 +/- 77 microg/ml, mean +/- SE) compared with control wood dust (883 +/- 91 microg/ml). Increased cytotoxicity with CCA wood dust also occurred in an arsenic resistant subline of V79 cells, thus suggesting that arsenic was not responsible for the increased cytotoxicity. Metallothionein mRNA was significantly increased after 48 h of treatment with CCA wood dust compared with control wood dust. Incubation of CCA wood dust in cell culture media resulted in the transfer of copper, but not chromium or arsenic, into the media. Moreover, the treatment of cells with this filtered extract resulted in significantly increased metallothionein mRNA, suggesting that bioavailable copper is responsible for inducing metallothionein mRNA in V79 cells. Thus, these bioassays suggest that metals become bioavailable during in vitro culture of phagocytic V79 cells with CCA wood dust.
Gordon
Terry
T
Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, New York 10987, USA. gordont@env.med.nyu.edu
Spanier
Jonathan
J
Butala
John H
JH
Li
Ping
P
Rossman
Toby G
TG
D000818:Animals; D001149:Arsenates / Q000009:adverse effects / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002857:Chromium / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D004391:Dust / Q000009:adverse effects* / Q000032:analysis; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008668:Metallothionein / Q000096:biosynthesis / Q000235:genetics; D019216:Metals, Heavy / Q000009:adverse effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D014934:Wood
D001149:Arsenates; D004391:Dust; D019216:Metals, Heavy; D012333:RNA, Messenger; D002857:Chromium; C040890:chromated copper arsenate; D003300:Copper; D008668:Metallothionein; D001151:Arsenic