The Effect of Ionizing Gamma Radiation on Natural and Synthetic Fibers and Its Implications for the Forensic Examination of Fiber Evidence*

Abstract

Circumstances of criminal activities involving radioactive materials may mean fiber evidence recovered from a crime scene could have been exposed to materials emitting ionizing radiation. The consequences of radiation exposed fibers on the result of the forensic analysis and interpretation is explored. The effect of exposure to 1-1000 kGy radiation doses in natural and synthetic fibers was noticeable using comparative forensic examination methods, such as optical microscopy, microspectrophotometry, and thin-layer chromatography. Fourier transform infrared spectroscopy analysis showed no signs of radiation-induced chemical changes in any of the fiber structures. The outcome of the comparative methods highlights the risk of "false negatives" associated in comparing colors of recovered fibers that may have been exposed to unknown radiation doses. Consideration of such results supports the requirement to know the context, including the environmental conditions, as much as possible before undertaking a forensic fiber examination.

Potential effects of ionizing radiation on the evidentiary value of DNA, latent fingerprints, hair, and fibers: A comprehensive review and new results

“…Fluorescent intensity from blue and green excitation began to increase at 90 kGy gamma and was strongly increased at 9000 kGy. This observation differs from the results of Colella et al [90], who reported no spectral changes for white cotton (unlike their results for colored fibers) even for doses of 1000 kGy. Fluorescence in the green increased from pale red to red for 90 kGy, becoming much brighter red for 9000 kGy samples.…”

“…Fading, discoloration, and changes in microscopic appearance were reported for synthetic fibers irradiated by gamma >10 kGy and natural fibers >50 kGy [25,89,90]. Forensic examination was deemed feasible, nevertheless [90,91].…”

“…Fading, discoloration, and changes in microscopic appearance were reported for synthetic fibers irradiated by gamma >10 kGy and natural fibers >50 kGy [25,89,90]. Forensic examination was deemed feasible, nevertheless [90,91]. Among several synthetic fibers, aromatic polyamide (Nomex), polyester (Dacron), and polyamide (Nylon), in decreasing order of stability, are progressively more susceptible to radiation damage [25].…”

“…1. Irradiation sources: (a) alpha planchet; (b) beta 90 Sr/ 90 Y; (c) dry 60 Co irradiator; (d) SRNL neutron activation analysis facility. (Fig.…”

Application of Gamma Irradiation for the Functionalization of Textile Materials

“…In industry it can be used for sterilization, DNA alteration in plants and structure and properties material modification. Research in using gamma irradiation for textiles concerns the optimization of textile dyeing, reducing the ecological impact and cultural heritage artifacts biological decontamination (Ahmad Bhatti et al, 2012;Bashar et al, 2018;Blouin and Arthur, 1958;Chirila et al, 2018;Colella et al, 2011;Geba et al, 2014;Machnowski et al, 2012;Millington, 2000;Shubhra and Alam, 2011;Takács et al, 2001;Takács et al, 2000).…”