Figure 1.

Physicochemical features of asbestos and its modification by iron chelators. (a) Scanning electron microscopy images of chrysotile, crocidolite and amosite with different iron content (×5000). Each asbestos presented a different appearance. Iron content is from a reference paper.^{( 26 )} (b) Energy dispersive X‐ray spectroscopic spectrum of chrysotile, crocidolite and amosite. Crocidolite and amosite showed high content of iron. (c) Electron spin resonance (ESR) analyses of chrysotile, crocidolite and amosite in the presence of H₂O₂. Ferrous iron was used as positive control. The signals are those of hydroxyl radicals. (d) ESR analyses of chrysotile, crocidolite and amosite in the presence of H₂O₂ and different iron chelators. n = 3, means ± standard error of the mean; *P < 0.05, **P < 0.01, ***P < 0.001 vs each asbestos plus H₂O₂ alone; ^# P < 0.05, ^## P < 0.01, ^### P < 0.001 vs chrysotile plus H₂O₂ within each chelator group; ^$ P < 0.05, ^$$ P < 0.01, ^$$$ P < 0.001 vs crocidolite plus H₂O₂ within each chelator group. ADP, adenosine 5′‐disphosphate; AMP, adenosine 5′‐monophosphate; ATP, adenosine 5′‐triphosphate; cGMP, cyclic guanosine monophosphate; DES, desferal; DTPA, diethylenetriaminepentaacetic acid; EDTA, ethylenediaminetetraacetic acid; GDP, guanosine 5′‐diphosphate; GMP, guanosine 5′‐monophosphate; GTP, guanosine 5′‐triphosphate; NTA, nitrilotriacetic acid.