Those of us, well-versed with wastewater management, will find it hard to believe that wastewater can be used for crime prevention, or more appropriately, to “flush” out the drug dealers!

Here it is how, in brief – more can be read at: www.nature.com/news/using-waste-water-to...drug-dealers-1.20581

In some European cities, the wastewater is sifted so that police can track down the crime by studying the results. It is called wastewater-based epidemiology.

The toilet bowl and its contents, once extremely private, are becoming public. Improved sensing techniques and analysis have made the contents of sewers and waste pipes a powerful source of data. Although people may tell lies, the urine they send down the drain rarely does.

For a decade or so, the analysis of wastewater has mostly been used to obtain information that people would prefer others did not have — their use of illegal drugs. Drugs broken down in the body leave telltale traces of metabolites, some of which can be found, quantified and back-calculated to work out how much of the original substance was present.

Combined with a reliable estimate of the number of people who may have contributed to the sample, the analysis can offer guidance on average consumption and how it changes.

Heroin use in one European city was estimated by measuring morphine in the sewers and subtracting what was known to have been prescribed medically. Between October 2013 and December 2014, the scientists estimated that average daily consumption of pure heroin in the city was 13 grams. During the study, the police arrested two dealers, and analysis of phone records and interviews with users suggested that the dealers sold about 6 grams a day between them, about half the total market. This supported police intelligence that heroin, unlike other drugs such as methamphetamine, was supplied by a small number of local dealers who could be effectively targeted.

When they flush the toilet, most people don’t think about what happens next. You can flush, but you can’t hide.

F H Mughal