By Jung Min-ho



Methamphetamine is the most common illicit drug in Korea and more than 400 kilograms of the highly addictive stimulant is consumed here annually, researchers said Tuesday.



Pusan National University's research team, led by Prof. Oh Jeong-eun at the Department of Environmental Engineering, has found that 410 kilograms of the drug is used every year and its daily consumption per 1,000 inhabitants is 22 milligrams.



The team calculated the amounts using a method called "sewage epidemiology." In cooperation with researchers from the University of Queensland in Australia, the team analyzed samples from 15 sewers in five cities across the country ― Busan, Ulsan, Changwon, Miryang and Gimhae.



The research showed daily consumption of methamphetamine is nearly 20 times larger than the amount seized by the prosecution annually.



Their findings were published in the latest issue of Science of the Total Environment, an international scientific journal.



According to the report, amphetamine, codeine and MDA are among the widely-used illegal drugs in Korea.



The report says cocaine, methadone, morphine and marijuana ― drugs that are common in many other countries in Asia, Europe and the United States ― were not found. Even the amount of methamphetamine consumed here is still comparatively small. The report says it is less than 2 percent of the amount consumed in some European countries.



What is meaningful about their work is that their discoveries came out of sewage epidemiology ― a technique used for the first time in Korea.



For obvious reasons, illegal drug users aren't always honest about their habits on surveys. Through the method, researchers can get more direct evidence of how much drugs they consume by looking into what ends up in the sewage system.



The idea is that screening for drugs that pass through the body and then get flushed down the toilet is a more accurate way to assess the drug use of a community or a country. After all, it is harder to manipulate what goes into the sewers.



Based on the concentrations of each drug ― and knowing certain factors like how much of a drug gets excreted by the body ― researchers calculate backward to figure out drug usage.



"The reason why drugs are found in sewage is that people either tossed them there or the urine of people on drugs was flushed," Oh said. "Our research was conducted only in a limited number of regions this time. It needs to be expanded to Seoul and other cities in Gyeonggi Province."



