Psychotropic substances in house dusts: a preliminary assessment

Psychotropic substances (PSs) are known to affect air and waters, while scarce attention has been paid to their occurrence in settled dusts although they can reach important concentrations there; moreover, no procedures have been developed for this specific purpose. In this study, a list of PSs (i.e., nicotine, cotinine, caffeine, cocaine, cannabinol, Δ⁹-tetrahydrocannabinol, cannabidiol, amphetamine, heroin, and methadone) were characterized in dusts from Rome and Fiumicino international airport, Italy, and from Ouargla city, Algeria. The analytical procedure, based on ultra-sonic bath extraction, silica column chromatography, and GC-MSD analysis, provided good recovery, uncertainty, sensitivity, and lack of interferences for all substances except amphetamine. In NIST SRM-2585 house dust, nicotine, cotinine, caffeine, cocaine, and cannabinol accounted for ~5.95, 0.87, 4.17, 7.0, and 2.2 μg/g, respectively; on the other hand, methadone, tetrahydrocannabinol, cannabidiol, and heroin (all <0.025 μg/g) were below the detection limit of the method. Two sites at the Fiumicino airport were affected by different loads of PSs (e.g., 0.76 and 2.80 ng/m² of cocaine). In Ouargla, where dust was collected in a primary school and a dwelling, nicotine ranged from ~60 ± 50 to ~86 ± 89 ng/m², cocaine was absent, and cannabinoids (0.35 ± 0.43 ng/m² as total) were found only in the home. In Rome, nicotine, caffeine, cocaine, and cannabinol reached ca. 700, 1470, 0.82, and 2.4 ng/m², respectively, in a smokers' home, but they were ca. 1300, 25,000, 670, and 1700 ng/m² in a non-smoker home. In conclusion, all dusts revealed the presence of illicit PSs. Further studies are necessary to understand the links between the PS amounts in airborne particulates and in dusts, as well as the PS origin and fate in interiors.