잔류 의약물질 및 법적으로 금지된 약물은 사람 또는 동물들로부터 배설되어 강, 하천수 및 하수처리장에서 검출될 수 있다. 이러한 물질들은 생태계 교란 및 부적절한 의약품의 노출뿐만 아니라 하수의 진원지인 지역사회에서 사용되고 있는 약물사용 실태를 파악하는데 큰 도움이 된다.

 

하수처리장에서는 물리 화학적 처리과정을 통하여 전부는 아니지만 일부 약물들이 제거되기 때문에 보다 정확하게 그 지역에 사용되는 약물사용 실태를 추적 조사하기 위해서는 하수처리장 유입수에서 검체를 취하는 것이 바람직하다.

 

지금까지 연구조사는 일반적으로 잘 알려진 마약류(코카인, 모르핀, 암페타민, 헤로인, 헤로인 대사물질)들에 집중되었다.

 

하지만 최근 벨기에 Antwerp 대학의 Alexander van Nuijs와 그의 동료들은 하수처리장의 유입수에서 기존 마약류 외에 신종 불법 약물로서 케타민(Ketamine), 케타민 대사체인 노르케타민(norKetamine), 케치논 대사체인 메칠렌디옥시피로발레론 (methylenedioxy pyrovalerone: MDPV), 메페드론(mephdrone, MEPH)과 대마 유도체인 THC-COOH를 액체크로마토그래피-텐뎀질량분석기를 사용하여 추가적으로 연구조사하였다. 실제 자세한 분석 방법과 결과는 “Drug Testing and Analysis 2013” 에 소개되었다.

 

10만명이 넘게 거주하는 벨기에의 Brussels과 Antwerp 배수지역의 하수처리장에서 몇 주 동안 24시간 내내 유입수를 채취한 후 검체로부터 타깃 화합물들을 고상추출(solid-phase extraction)하여 역상컬럼을 통하여 분리하고 THC-COOH는 질량분석기의 음이온 모드로 검출하고 나머지는 양이온 모드로 검출하였다.

 

노르케타민과 디하이드로노르케타민의 검출 피크는 부분적으로 분리되지 못하지만 상호 다른 조각이온(daughter ion)을 MRM(multiple reaction monitoring) 모드에서 각 목적 화합물과 대사체만의 특정 생성 이온만을 모니터링하여 각 각의화합물을 정량하는데 방해되지 않았다.

 

벨기에 Brussels과 Antwerp 배수지역 연구조사 결과, 신종 마약류인 THC-COOH와 케타민은 모든 샘플에서 검출되었고, 노르케타민 역시 검출되었으나 노르케타민은 검출한계 이하로 검출되어 정량할 수는 없었다. 그 외 다른 신종 마약류는 발견되지 않았다.

 

이번 연구결과는 스페인과 영국의 하수처리장 연구조사 결과와 비교하였을 때 벨기에 지역에서 케타민과 THC-COOH의 약물사용 실태는 명확하게 관찰되지 못하였으나 케타민은 낮은 수준으로, THC-COOH는 비슷한 수준임을 확인하였고 Brussels 북부와 Deurne 지역에 비해서 Antwerp 남부 지역에서 대마와 케타민의 사용이 많다는 것도 확인할 수 있었다.

 

본 연구에서는 벨기에 노동절(5월 1일)에 매우 고농도의 케타민과 THC-COOH가 검출되었다는 사실로부터 노동절을 축하하기 위하여 사람들이 불법 사용금지 약물을 특히 많이 사용한다는 것을 확인할 수 있었다. 이번 연구조사는 공공보건의 위험성과 연관된 신종 마약류의 확산 및 실태조사에 유용하게 사용될 수 있을 것이다.

 

 

Wastewater for tracking drug use
Since the original report in 2004, in which unexpectedly high levels of cocaine were discovered in the River Po in Italy, there have been a number of reports of the presence of pharmaceuticals and drugs of abuse in rivers, surface waters and wastewater treatment plants. These studies have been used to gain a rough idea of the trends in drug use in the localities feeding those waters.

 

Any drugs or their metabolites that are excreted by users will be directed to local wastewater treatment plants and this will be a more accurate location for monitoring drug use in the region than rivers or seas, since the wastewater treatment process removes some of the drugs, but obviously not all. In fact, the European Monitoring Centre for Drugs and Drug Addiction acknowledges the use of wastewater as a means of tracking drug use in communities.

 

 

Most of the studies carried out so far have concentrated on the classical drugs of abuse like cocaine, morphine, amphetamines, heroin, and the heroin substitute methadone. Now, Alexander van Nuijs and co-researchers from the University of Antwerp, Belgium, and the University of Bucharest, Romania, have extended the idea to some emerging illicit drugs present in the influent at wastewater treatment plants.

 

They developed and validated a LC-tandem-MS method for the simultaneous measurement of ketamine (KET) and its metabolites norKET and dehydronorKET, the cathinone derivatives methylenedioxypyrovalerone (MDPV) and mephedrone (4-methylmethcathinone, MEPH) and the cannabis metabolite THC-COOH. The method and results were reported in Drug Testing and Analysis.

 

Daily dose
Wastewater influent was collected over a few weeks for periods of 24 hours at a time from three Belgian treatment plants, each with a catchment area of more than 100,000 people living in Brussels and Antwerp. Portions of each were extracted by solid-phase extraction, with a polymeric reversed-phase sorbent outperforming a mixed-mode cation exchange sorbent, largely due to the failure of the latter to retain THC-COOH.

 

The target compounds in the extract were separated on a short reversed-phase C18 column. It was preferred over several other columns because it separated THC-COOH from the remaining analytes, which was preferred because it is detected by mass spectrometry in negative-ion mode while the others are detected in positive-ion mode. This way, only one polarity switch is needed during each run.

 

The chosen column also provided good separation of most of the analytes, eluting them within 8.5 minutes. The peaks for norKET and dehydronorKET partially overlapped but the use of different transitions during multiple reaction monitoring prevented any problems. The total run time, including column equilibration, was just 13 minutes.

 

In the mass spectrometer, the protonated or deprotonated molecules were monitored in each case in multiple reaction monitoring mode, selecting specific product ions to give unique transitions for each analyte. Deuterated analytes were used as internal standards.

 

District variations in drug use
The optimised method gave quantitation limits of 2 ng/L for THC-COOH and 5 ng/L for the remaining drugs and metabolites and the other analytical data were all deemed to be acceptable.

 

When the wastewater influents were tested, THC-COOH and KET were found in samples from all of the treatment plants. NorKET was also detected from its retention time and the observed mass spectral peaks but it was below the detection limit. The remaining three target compounds, dehydronorKET, MEPH and MDPV were not detected.

 

The concentrations of THC-COOH were of the same order as those reported from other studies but the levels of KET were lower than those in Spanish and UK influent wastewater. However, the differences could be due to several factors including variations in the amount of drug consumed in the different regions, sampling times and the stability of the compounds in a particular wastewater treatment plant.

 

The researchers suggested that a better way to compare results from different locations would be to use mass loads which are normalised for the number of inhabitants served by a particular treatment plant. This would reduce any variations due to sampling time and location. In this way, the daily levels for the three Belgian treatment plants were compared.

 

No clear trends were observed for KET or THC-COOH. However, the data revealed more cannabis and ketamine was abused in the Antwerp South region than in Brussels North and Deurne. This conclusion agrees with the results from another study looking at the abuse of cocaine and amphetamines in 19 European studies which saw higher loads for Antwerp South.

 

Another notable occurrence was the high concentrations of KET and THC-COOH on May 1st, which is Labour Day in Belgium. It seems that the residents celebrated this public holiday with a few extra recreational drugs.

 

This method can be used with wastewater treatment plant influent to extend the assessment of illicit drugs to these emerging drugs, helping to identify trends in drug use and the associated public health risks.