Chemical contamination assessment : a review

In 1998, the first GERPAC conference was organized. A few years before, the first studies concerning environmental contamination with cytostatic drugs were published. Chemical analysis showed that preparation and administration areas in hospitals were contaminated with these toxic drugs. Adverse health effects were found in patients treated with the drugs but little was known about the potential adverse health effects in healthcare workers such as pharmacy technicians and nurse handling the drugs.

Over the last 20 years, many contamination studies have been published and even exposure of the healthcare workers was assessed by analysis of the drugs in their urine. Despite all safety precautions such as clean room facilities, the use of isolators and biological safety cabinets, and personal protective equipment, many healthcare workers are still exposed. However, implementation of closed handling systems and robotics for preparation have shown a substantial reduction of environmental contamination and consequently potential exposure. Unfortunately, these preparation devices are not available in every hospital and especially not in the economically poorer countries even in the European Union.

Taking wipe samples to check environmental contamination has become very popular in many hospitals around the globe. Analytical techniques have become available for many hospitals to do in house testing or ask external laboratories for analysis of the wipe samples. Over the years, more sophisticated and sensitive analytical techniques became available and lower levels of contamination could be measured. In the nineties, we detected levels of µg/cm2 but nowadays we can measure much lower levels of pg/cm2. Inherent to a lower detection limit is that the number of positive wipe samples will increase. This raises the question : how relevant is measuring contamination at pg/cm2 in terms of workers exposure and risks for adverse health effects ? Is there an adverse health effect to be expected if healthcare workers work in environment with contamination levels at a pg/cm2 level ? So, what is the risk ? These questions have resulted in a debate a few years about what is a safe level of environmental contamination. The outcome was that nowadays contamination levels < 0.1 ng/cm2 are considered as safe, and levels > 10 ng/cm2 are considered as unacceptable. Both values are used as reference values.

Recently, the EU Parlement and Commission has updated the Carcinogens and Mutagens Directive (2004/37/EC). Most probably, reprotoxic agents will be added soon too. However, the directive does not currently acknowledge the dangers of hazardous drugs in healthcare. Considering the adverse health effects of cytotoxic drugs and the fact exposure still exists, more needs to be done to prevent healthcare workers from the most dangerous chemical risk factors in healthcare according to EU-OSHA. This means that exposure to cytotoxic drugs is on the agenda in Brussels to improve the safety of the 12 million healthcare workers in Europe handling these drugs more or less every day. It is expected that monitoring of surface contamination will become mandatory.

During the next 20 years, the updated Carcinogens and Mutagens Directive will be implemented in all EU member states. This includes wipe testing for measuring surface contamination but probably also frequent exposure testing of the healthcare workers for example by urine analysis comparable to the doping tests that are performed in sports nowadays (multidrug testing). Maybe there will be biological exposure limits for several cytotoxic drugs based on risk assessment. To achieve this more scientific work needs to be done.

References :
http://www.exposurecontrol.net
http://www.europeanbiosafetynetwork.eu

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