Chemical Contamination in Former Clandestine Methamphetamine Laboratories

Abstract

The effectiveness of commonly used surface testing and decontamination methods was investigated for 20 suspected former clandestine methamphetamine laboratories in New Zealand. Methamphetamine surface contamination was collected via wipe sampling and measured quantitatively with GC-MS using an isotopically labelled methamphetamine internal standard. Methamphetamine surface wipe concentrations (n = 137) ranged from below detection limits (0.005 μg/100 cm2) up to 6100 μg/100 cm2. The median concentration was 2 μg/100 cm2 and 95 % of concentrations lay between detection limits and 500 μg/100 cm2. Results showed that some testing methods in use in New Zealand in 2008 - 2010 were unreliable, and that some decontamination methods used at that time were ineffective. All but three of the sites tested had surface concentrations exceeding the New Zealand Ministry of Health surface clean-up guideline of 0.5 μg/100 cm2. Only glass and very smooth impervious surfaces were effectively cleaned. Building materials that were analysed for methamphetamine (n = 15) had concentrations ranging from below detection limits up to 5,200 μg/g methamphetamine. Pseudoephedrine was the second most common contaminant found. The ratio between pseudoephedrine and methamphetamine was strongly correlated with the suspected site of manufacture. There were 39 compounds found to be associated with methamphetamine manufacture, of these 11 were associated only with drug synthesis, and 14 were associated with methamphetamine precursor activities. Six compounds were found that could originate from either methamphetamine smoking or methamphetamine manufacture, and five compounds were found that could originate as analytical artifacts or from methamphetamine manufacture. The compound 1,2-dimethyl-3- phenylaziridine was detected at several sites, and may be a more useful manufacture indicator compound than methamphetamine. A novel method for sampling and quantitation of airborne methamphetamine at μg/m3 concentrations was developed using dynamic SPME GC-MS and isotopically labelled methamphetamine. Air was sampled for airborne methamphetamine and other semivolatile organic compounds at 11 suspected former clandestine methamphetamine laboratories using SPME GC-MS, and methamphetamine was detected in the air at three former clandestine methamphetamine laboratories. There was a positive correlation between the detection of airborne methamphetamine and high methamphetamine surface concentrations.