RIO DE JANEIRO, Brazil – In addition to waste and rats, a city’s sewer system holds valuable information about the drug use of its residents.
In Brasília and other cities in the Federal District, the Federal Police (PF) is testing a scientific investigation method, known as the Quantitative Toxic Analytes (Quantox) Project, which uses sewage to map drug consumption.
“Quantox might just provide the most accurate X-ray of the use, trends and evolution of drugs in Brazil,” said Wilson Jardim, a researcher with the Chemistry Laboratory at the University of Campinas (Unicamp). “This tool has a very low margin of error.”
Quantox is being conducted under the National Institute of Advanced Analytical Science and Technology (INCTAA), a virtual institution that brings together the PF and researchers from Unicamp and the University of Brasília (UnB), among others.
The PF’s first Quantox screening, which solely focused on cocaine, was done in 2010. The investigation was carried out using samples collected from six sewage treatment plants in the Federal District during March 16-17 and June 1-2 of that year.
In the August samples, analysts identified traces of benzoylecgonine, a compound that’s formed when the body metabolizes cocaine before it’s excreted through drug users’ urine. Quantox also located areas where the drug is being refined, as the washing of the cocaine-making equipment and the discarding of leftovers leave cocaine residue in the sewer.
At the time, Quantox estimated an annual consumption of two tons of cocaine in the Federal District. The satellite city of Samambaia, which accounted for 35% of the samples analyzed, registered the highest levels of cocaine consumption, estimated to be 512 kilograms a year.
The Quantox data allow the PF to trace their counter-narcotics strategies and determine whether the number of seizures is sufficient.
Since 2010, this experiment has been systematically conducted in Brasília, said Fernando Sodré, an adjunct UnB professor and researcher with INCTAA.
In October 2012, in a round of experiments with a larger number of samples, scientists tried to determine variation in drug use during different days of the week.
The research turned into a Master’s thesis by chemist Rafael Feitosa, with Sodré serving as his adviser. Comparing data from 2010 and 2012, there wasn’t much variation, according to Sodré. However, the weekly results showed consumption doubled during weekends.
“It was something that everyone imagined, but we were able to confirm Quantox’s level of accuracy when this data was scientifically proven,” Sodré said.
He added Quantox’s major benefit is its ability to provide real-time data to the PF.
“Other types of research intro drug use, such as interviews, statistics and data comparisons, can take months or even years,” Sodré said. “The entire dynamic of the drug supply may have changed by then.”
Though the process has been carried out sporadically in Campinas, the fact the city has a low level of sewage treatment prevented a study similar to the one carried out in the cities of the Federal District.
“To carry out a secure and thorough study, it would be ideal for the municipality to have 100% sewage collection or most of the sewage being directed to a treatment plant without the release of raw sewage into rivers,” Jardim said. “Unfortunately, the lack of sewage treatment is a common problem in most Brazilian cities.”
When the sewage is treated, researchers know in advance the details of the region being studied, such as its population and breakdown of socioeconomic statuses, Jardim said.
“Brasília was an excellent model for a well-prepared and reliable map because 93% of the sewage produced in the city is treated,” Sodré said.
As a solution, the Quantox researchers are analyzing the possibility of accessing the sewage before it is disposed. In this case, they would access it through manholes and take samples.
Another alternative involves analyzing the water into which the sewage has been released.
“In Campinas, we already have conducted analyses of the water to detect drugs,” he added.
The process is now awaiting funding to reach other parts of Brazil, according to Adriano Maldaner, a federal forensic expert from the PF’s National Institute of Criminology (INC).
“We have a proposal to expand Quantox to at least one metropolitan area per region of the country,” Maldaner said. “We submitted a bid to the National Council for Scientific and Technological Development (CNPq).”