Slipping through the net

There is growing concern over the lack of legislation for emerging environmental contaminants. Now new methods developed in Spain could help us find out just how big the problem is. Julián Morán gives us the low-down.

Scientists at the Spanish Council for Scientific Research in Barcelona are developing faster and more accurate methods for analysing wastewater samples for the presence of newly emerging contaminants. The fully automated, mass spectrometry-based methods allow multiple compounds to be identified and quantified, including drugs of abuse, such as cocaine, amphetamines, opiates and cannabis, and pharmaceutical medicines, such as anti-inflammatories and antibiotics. Legislation controlling permissible levels of pharmaceutical compounds in the environment has not yet been established and the findings will be important in assisting decisions to classify some of these newly emerging contaminants as pollutants.

The use of many pesticides is strictly regulated in the EU, but environmental scientists are becoming increasingly concerned about a number of emerging contaminants, including medicines and household products, that are entering the water system through sewage in urban areas. So far, there is no legislation to control the levels of these emerging contaminants in the environment. However, recent progress in environmental chemistry techniques is making it quicker and easier to identify, quantitate and monitor these substances, and to determine their potential harmful effects.

Methods of this kind are being developed by scientists at the department of environmental chemistry, at the Insituto de Investigaciones Quimicas y Ambientales de Barcelona (IIQAB) in Spain. This institute specialises in research into the environmental sciences and is part of the Consejo Superior de Investigaciones Cientificas (CSIC; Spanish Council for Scientific Research). The IIQAB’s department of environmental chemistry, which is led by Professor Damià Barceló, is involved in a number of water quality and soil-related EU projects. Its focus includes developing protocols for advanced analytical chemistry, in order to improve methods of monitoring and analysing known pollutants. The laboratory has also been involved in studies of the bioavailability of emerging organic pollutants in water-soil systems, and investigations of the contaminants’ potential effects on the environment.

“We are looking at a variety of substances in the environment, from known pollutants including brominated flame retardants and pesticides, to those with unknown effects, such as medicines, recreational drugs and surfactants,” explained Damià Barceló, full research professor and head of the CSIC’s department of environmental chemistry. “We look at how they enter the water system through sewage and how these substances affect fish and other life forms.”
 
Recently, Damià Barceló’s team developed an automated method for analysing the quantities and types of a variety of drugs of abuse, or their metabolites, in wastewater1. This approach makes it possible to estimate and monitor the public’s consumption of these drugs in real time. Traditional methods for estimating drug abuse in the population can be costly and inaccurate, relying on surveys and on social, medical, and criminal statistics. In contrast, mass spectrometry-based approaches, which were first developed by Zuccato et al.2 for testing water from sewage treatment plants, provide accurate real-time data, extremely quickly and without invading the privacy of members of the public. The increased speed and efficiency also reduces labour and administrative costs for the relevant authorities.

Legislation controlling levels of pharmaceutical compounds is yet to be established

The CSIC scientists’ latest study is the first fully automated procedure to be developed for determining different classes of drugs of abuse, and uses on-line solid phase extraction LC/MS/MS. Key components of the automated method included an automated on-line SPE sample processor (Prospekt-2 from Spark Holland) for preconcentration of the samples, and a hybrid triple quadrupole-linear ion trap mass spectrometer (4000 Q TRAP, with turbo ion spray, from Applied Biosystems/MDS Sciex) for analysis. The hybrid mass spectrometer can identify, characterise and quantitate metabolites with excellent analytical accuracy and precision, enabling multiple compounds to be identified within a single run, including those present at very low levels (i.e. within the nanograms to picograms per litre range).

In their recently published study, the CSIC scientists examined sewage water samples from regions of Barcelona and Valencia for the presence of 19 different compounds simultaneously. The compounds were from five different classes of drugs: cocaine and related substances, amphetamine-like drugs including MDMA (ecstasy), opiates including heroin and morphine, cannabinoids, and LSD and its metabolites. Eight of these compounds, including heroin and LSD metabolites, had not previously been analysed in water samples.

The study found that cocainics were present in the highest quantities, followed by amphetamine-like compounds, opiates, cannabinoids, then LSD and its metabolites. The levels of cocainics and morphine were higher in samples from Barcelona than those from Valencia, but cannabinoids were relatively higher in Valencian samples. Samples from the Barcelona region came from the El Prat de Llobregat water treatment plant, which processes sewage from 1.3 million inhabitants. The scientists discovered that these people collectively consume an average of 1.5 to 2kg cocaine a day, which equates to 20,000 doses per day – and this figure doubles at weekends. However, one dose of cocaine is typically 100 mg, and the quantitites found in the water samples were in the nanogram range, so the levels of drugs present were not considered to be harmful. Furthermore, the drugs are almost completely eliminated from wastewater at water treatment plants, meaning that tap water is not affected.

Damià Barceló’s new method has a number of unique features, including the ability to work with much smaller sample volumes (5 ml) compared with previously established methods, which required volumes of 100 - 125 ml for conventional off-line solid phase extraction. The smaller volumes allow easy sample storage and freezing, which not only halts any biological activity within the samples that might affect the analysis, but also avoids the risk of contamination or alteration of the sample that could be caused by addition of preservatives. Until now, small sample volumes were not used because they risked compromising the method sensitivity, but the detection capabilities of the 4000 Q TRAP overcome this issue.

“These days we need to look at very small amounts of contaminants in the water system, so we need very sensitive mass spectrometry techniques that can detect substances at the nanograms to picograms per litre level,” Damià explained. “Instruments such as the Q TRAP allow us to reach very low limits, so we can detect almost any contaminant and that’s a major advantage.”

The CSIC scientists have used their LC/MS/MS-based approaches to identify, quantify and monitor various other compounds in the environment, including pesticides, brominated flame retardants, industrial and household chemicals, and medicines. In a recent investigation, the team monitored 29 different medicines that included tranquillisers, antibiotics and anti-inflammatory drugs (such as Ibuprofen), in water samples taken from along the course of the river Ebro, which runs from Cantabria out to the Mediterranean sea. They discovered substantial quantities of these 29 medicines that equated to about 300 kg per year for each of the medicines monitored. “These medicines are emerging contaminants; their effects are currently unknown so there is no existing legislation for many of these drugs. It is vital that the various research studies that are now underway are taken seriously,” said Damià. “For example, the anti-epileptic drug, carbamazepine, has been shown to have cardiovascular effects in fish, and antibiotics are also found in relatively high concentrations (50 - 300 ng/litre) in rivers in some agricultural areas.”

In April 2008, a number of new compounds were added to the EU’s list of priority substances and emerging contaminants (Water Framework Directive 2000/60/CE). These included two medicinal drugs known to be present in the water system: carbamazepine, (an anticonvulsant drug), and diclofenac, (an anti-inflammatory drug), both of which are known to take much longer to break down than other medicinal substances such as Ibuprofen. “These changes represent a positive step forward, indicating for the first time that some of these emerging contaminants will be regulated in the future,” Damià concluded.

References
1. Postigo C, Lopez de Alda MJ, Barceló D (2008). Fully automated determination in the low nanogram per liter level of different classes of drugs of abuse in sewage water by on-line solid-phase extraction-liquid chromatography-electrospray-tandem mass spectrometry. Analytical Chemistry 80: 3123-3134

2. Zuccato E, Chiabrando C, Castiglioni S, Calamari D, Bagnati R, Schiarea S, Fanelli R (2005). Cocaine in surface waters: a new evidence-based tool to monitor community drug abuse. Environmental Health 4: 14-21

By Julián Morán. Julian has a degree in Analytical Chemistry and, since 1998, has been working as a sales specialist with a focus on areas in the applied markets, such as environmental and toxicology applications.