Interdisciplinary approach to determining the use of drugs of abuse in wastewater using a survey and gas chromatography-mass spectrometry

Abstract

(a) To use a gas chromatography-mass spectrometry (GC-MS) method for the analysis of drugs of abuse in wastewater in Botswana. (b) To explore the knowledge of the BIUST community on the use, disposal, and fate of medicinal and illegal drugs in wastewater using a survey. Wastewater-based epidemiology (WBE) is increasingly becoming an alternative method for estimating drug usage and consumption in a population. The data obtained through WBE on drug usage and consumption is near real-time and it allows analysts to monitor current patterns and trends in novel psychoactive substances, illicit drugs, and therapeutic compounds. WBE can be complemented with other conventional methods to obtain data on drug use and abuse such as survey questionnaires. The survey is administered in communities where wastewater samples are collected. The data obtained through the two means are compared and a correlation is established if any. Through survey responses, researchers can obtain the demographic information of participants, frequency of use, and mode of administration of drugs. Twenty-two influent wastewater samples were collected at five wastewater treatment plants (WWTP) in Botswana between July 2019 and October 2019 using the grab sampling method. Solid-Phase extraction with Strata-X Drug B SPE cartridges was used for sample extraction before analysis by GC-MS. Toxicology checkout mixture (TCM) with 28 analytes, caffeine and ibuprofen standards were used. The online survey questionnaire was administered to the BIUST community between March 2021 and May 2021 using convenient sampling. Data analysis was done using the Statistical Package for the Social Sciences. The GC-MS method was used as a screening method targeting pharmaceuticals and illicit drugs (opioids, sedatives, stimulants, and hallucinogens). Ibuprofen and caffeine were reliably identified in wastewater samples. The online survey respondents indicated the use of different pharmaceutical drugs such as ibuprofen and panado (acetaminophen). Survey respondents also indicated the use of different illicit drugs such as marijuana, cocaine, and methamphetamine. For the survey, 80.8% of the respondents used medicinal drugs compared to 15.8% who used illegal drugs. Of the respondents who indicated to have used medicinal drugs, 88.7% used painkillers, while 4.1% used antidepressants. Of the respondents who had used illicit drugs, 94.7% used hallucinogens while only 10.5% used stimulants such as cocaine. All the pharmaceutical and illicit drugs that participants indicated to have used were targeted in wastewater samples. A GC-MS method was successfully used for qualitative analysis of wastewater samples in which ibuprofen and caffeine were detected. The two compounds were also targeted. Illicit drugs which were targeted in wastewater when TCM was analyzed were not detected. The survey respondents indicated the use of medicinal and illicit drugs with the former being used more. The respondents also indicated that leftover/expired medicinal/illicit drugs are thrown in the litter bins or flushed down the drain. Most respondents are aware of the fate of the drugs in wastewater. The survey results do not correlate with the analytical results as the drugs in the survey answers were not detected in wastewater from BIUST, although ibuprofen was detected in other wastewater samples used for this research. Ibuprofen, a common pharmaceutical and caffeine, were detected in wastewater collected for this research using a screening method. With further refinement, this method can be used to monitor weekly, monthly, or seasonal variations in drug use in Botswana. The survey respondents indicated the use of different medicinal and illicit drugs, with medicinal drugs being used more. Results obtained from the research will assist stakeholders in Botswana in the fight against drug abuse as they provide information on commonly used drugs, frequency of use, and demographic information of participants.