Consumption of illicit drugs and benzodiazepines in six Spanish cities during different periods of the COVID-19 pandemic.

Wastewater-based epidemiology (WBE) can provide objective and real time information about the use of addictive substances. A national study was conducted by measuring the most consumed illicit drugs, other drugs whose consumption is not so widespread but has increased significantly in recent years, and benzodiazepines in untreated wastewater from seven wastewater treatment plants (WWTPs) in six Spanish cities. Raw composite wastewater samples were collected from December 2020 to December 2021, a period in which the Spanish and regional governments adopted different restriction measures to contain the spread of the COVID-19 pandemic. Samples were analyzed using a validated analytical methodology for the simultaneous determination of 18 substances, based on solid-phase extraction and liquid-chromatography tandem mass spectrometry. Except for heroin, fentanyl, 6-acetylmorphine and alprazolam, all the compounds were found in at least one city and 9 out of 18 compounds were found in all the samples. In general, the consumption of illicit drugs was particularly high in one of the cities monitored in December 2020, when the restrictions were more severe, especially for cannabis and cocaine with values up to 46 and 6.9 g/day/1000 inhabitants (g/day/1000 inh), respectively. The consumption of MDMA, methamphetamine and mephedrone was notably higher in June 2021, after the end of the state of alarm, in the biggest population investigated in this study. Regarding the use of benzodiazepines, the highest mass loads corresponded to lorazepam. This study demonstrates that WBE is suitable for complementing epidemiological studies about the prevalence of illicit drugs and benzodiazepines during the COVID-19 pandemic restrictions.

Simultaneous determination of aflatoxins B1, B2, G1 and G2 in commercial rices using immunoaffinity column clean-up and HPLC-MS/MS.

Rice is frequently contaminated with aflatoxins, that are highly toxic fungal substances and strongly involved on hepatic cancer. In this work, different extraction and clean-up methods were evaluated for the simultaneous extraction and clean-up of aflatoxins B1, B2, G1 and G2 from rice. Favourable results were obtained by using methanol - water (80:20, v/v) extraction followed by immunoaffinity columns for clean-up, with recoveries of 86-92%, standard deviations between 5 and 11%, LOD ranged between 0.09 and 0.32 µg/kg, and LOQ between 0.31 and 1.06 µg/kg. Method validation and sample analysis were performed by using HPLC-MS/MS. Nine rice samples from different origin, varieties and specific characteristics, acquired in Spanish supermarkets were analysed. In two basmati samples from the same batch aflatoxin B1 was detected at (1.62 ± 0.08) µg/kg and (0.77 ± 0.03) µg/kg, both lower than the levels established by European Regulation for aflatoxin B1 in cereals.