Drug residues escape wastewater treatments

By analyzing wastewaters for a range of urinary biomarkers, it is possible to reliably detect drug abuse patterns in cities.  The findings of a comparative study of illegal drug consumption in 19 European cities based on wastewater analysis have been published in Science of the Total Environment.

Thomas KV et al. Comparing illicit drug use in 19 European cities through sewage analysis. Science of The Total Environment 2012; 432: 432-439

The four Spanish cities, Barcelona, Castelló de la Plana, Santiago de Compostela and Valencia had a higher consumption of cannabis and cocaine compared with other drugs like ecstasy and methamphetamines.

The study was a collaboration of research centers and universities from 11 European countries. The teams collected urban wastewater from 19 European cities during one week in March 2011 and used urinary biomarkers to test the samples for cocaine, amphetamines, ecstasy, cannabis and methamphetamines. The analysis enabled researchers to estimate each of the 19 cities’ drug consumption. The teams normalized the results according to the size of the city investigated, so that larger cities like London or Barcelona could be directly compared with smaller cities like Castelló de la Plana or Santiago de Compostela.

The highest consumption of cocaine in milligrams per day per 1,000 inhabitants was found in Antwerp, followed by Amsterdam, Valencia, Eindhoven and Barcelona. In Castelló, the consumption of cocaine is comparable with cities like Utrecht or London, and slightly higher than Santiago, which had the same level of consumption as Brussels, Milan or Paris. In contrast, cocaine consumption in Nordic countries was observed to be low in comparison. According to estimations, 365 kilograms of cocaine are consumed daily, which, according to the UN’s Office of Drugs and Organized Crime relates to about 10 to 15% of the worldwide cocaine consumption.

Unlike cocaine, methamphetamines consumption was observed to be higher in North and North-western Europe, particularly in Scandinavia and the Czech Republic. The teams noted that drugs belonging to the group of amphetamines, methamphetamines and amphetamines were the main drugs found in European wastewater. Neither of these drugs were found in the wastewater from Castelló, whilst Barcelona’s, Valencia’s and Santiago’s wastewater showed low to medium levels of these drugs, which were lower compared with the levels detected in the north of Europe.

The teams did not detect MDMA (Ecstasy) in Castelló, although they found that Valencia and Santiago had around half of the consumption of Barcelona. However, ecstasy consumption was much lower than compared with Holland and Belgium.
Unsurprisingly, the highest consumption of cannabis was found in Amsterdam in the Netherlands, followed by France and Spain. The researchers have taken Spain’s strategic position in marijuana trafficking into account, which has expanded the cannabis market. The cannabis consumption in Barcelona, Castelló and Santiago was relatively high, and marginally higher compared to the consumption per capita in Valencia.

Drug consumption surveillance programs are very beneficial tools for developing efficient policing legislations, but also to assess the efficacy of current policies to tackle the drug addiction problem.

Prior to analyzing the wastewater, measuring drug consumption was typically based on surveys conducted in different sectors of society including consumers with different addiction levels, such as the general public. Researchers also used additional information from police data for drug seizures, data on hospital admissions and other medical data. However, these methods proved to be significantly unreliable, in particular with regard to illegal drug use, since these studies were based on surveys. Another negative factor for the traditional methods of measuring drug consumptions is that results are usually obtained on an annual basis and over a large geographical area, usually by state.

In contrast, the wastewater analysis approach of analyzing wastewater from water purification plants (EDAR) enabled the research centers to obtain reliable information of the overall consumption of investigated drugs in real-time.

According to project co-coordinator of the collaborative project, Kevin Thomas, a NIVA researcher, the wastewater analysis provides important information alongside current estimation methods. Thomas explains: “Via waste water investigation we can estimate a city’s drug consumption. Furthermore, we can quickly measure changes in consumption habits over a short period of time. For example, we can determine if there has been a massive drug disposal via drainage when police raids or drugs seizes take place.”

Similar studies have been performed previously, though the scale of the present study is far greater than previously reported.

There are important messages about the scale and patterns of illicit drug use across Europe. The magnitude of the issue is truly amazing.

However, one other issue is worth a moments thought. These drug residues may arise, in some tiny part, from a stash of drugs flushed down the toilet as the police hammer at the door – we have all seen the TV programmes! The greatest part, probably far in excess of 99% of the total arises through excretion of the drugs taken, whether by injection, smoking, snorting or swallowing.

What goes in, must come out. This applies to illicit drugs, to prescribed prescription-only medicines, and to over-the-counter products. It is a lesson that must be learned by those guardians of the environment – in the UK, The Environment Agency -who seek to regulate drug waste disposal from healthcare providers and who are deeply troubled by the almost invisible residues in an empty syringe while they ignore, deliberately or otherwise, the elephant in the room. What about the disposal of drugs from domestic sources? And the big one; what about the excretion of the administered dose that leaves the body with urine and faeces then passes to the environment via an ineffective wastewater treatment infrastructure.

It is incorrect to claim that small amounts of drug waste do not matter. Every contributor to global pollution plays its part and cannot be overlooked. But where an aggressive regulatory process constrains certain treatments and places massive additional costs on healthcare providers with, inevitable, a greater environmental impact from incineration over non-burn technologies for sharps waste, this sits uncomfortably against the far greater but parallel issues that see innumerable tonnes of pharmaceutical residues enter the environment.

Those faced with additional regulatory constraints and additional costs for what must be a trivial issue must, at the very least, feel uncomfortable about this dichotomy. Regulators often fail to see an overall picture, perhaps deliberately, and promulgate an irrational regulatory framework based on a scientifically flawed ideology that must not succeed.

Quo Vadis? Science and Regulation as Uneasy Bedfellows


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.