No Need to kill Seán Duke reports that there is a way to achieve faster, cheaper, more ethical toxicity testing
he current methods of testing for toxicity in the environment are quite crude, slow, and expensive, involving counting dead animals exposed to toxins over time. What about introducing a new approach that is faster, cheaper, more sensitive, and – something that is becoming increasingly important – does not involve killing animals? This is what has been achieved by Dimitri Papkovsky, UCC researcher, who has developed toxicity tests by adapting and applying some existing testing technology. The context for this work is the EC REACH (Registration, Evaluation, Authorisation and Restriction of Chemical Substances) Directive which became law on 1 June ’07. Under REACH a long list of chemicals including heavy metals, organic solvents, pesticides and aromatic hydrocarbons, must be closely monitored and controlled. At the moment, toxicity testing involves a number of tests that make use of animal ‘models’ including fish, and mice. There is a drive in the EU now, however, to phase out these type of animal tests and move to something more ethical and humane. As well as involving the killing of animals, the current tests, said Dimitri, are not very fast, and do not allow a high throughput of samples – something that’s required more and more these days. Also, they are also based on subjective assessments that can be inaccurate, such as determining an animal is dead when it might simply be immobile.
T
Sensitive tests can be carried out on cell cultures or on tiny organisms such as the water flea, above, and best of all, there is no scientific need to kill them.
The samples are sealed off from the outside inside the microplate. This is important because oxygen levels are being measured and contamination from air is a threat. “People, for example, maintain “The microplate serves as a small cultures of fish, like trout or zebra fish, container where we can expose the in large tanks and then they receive organism to the toxicant,” said Dimitri. (toxic water) samples,” explained “Clinical tests are (already) done in Dimitri. “They put fish in these these type of microplates. So, we don’t samples, they incubate for 24, 48 and need to develop a new instrument, we 72 hours. Basically they are counting don’t need to develop the number of dead, these plates, we’re just and the number of alive adopting our assays and animals to determine the system to what is already level of toxicity.” available.” In contrast, Dimitri Under REACH there uses cells and small is a list of in the region organisms – such as of 30 ‘priority’ industrial Daphnia ‘the water flea’ chemicals, said Dimitri, – to develop his toxicity which now need to be tests. This is ethically monitored and assessed more desirable than for their toxicity. To doing toxicity testing on achieve this Ireland higher animals like mice. will require a national Furthermore, the strategy monitoring system, is set up to test ‘suband he said that his lethal’ effects of toxicity, technology would be well so organisms and cells suited to be applied to are not killed in any case. Prof Dimitri Papkovsky that system by providing The approach is to look a range of simple tests. at respiration and oxygen There is a follow-on project, said consumption as a measure of toxicity. Dimitri, where a specific group of “We don’t need to kill the animals,” chemicals, as defined by REACH, said Dimitri, “we just need to detect are being targeted. Furthermore he changes in respirations, so potentially is working closely with the EPA, as this approach is more sensitive. It is well as an industrial partner, Luxcel more humane and it can be automated Biosciences – a company working in and miniaturised. We do it on a standard environmental monitoring, to bring micro-plate, with 100 samples analysed this testing technology into more simultaneously over a period of one widespread use. hour. Then you have your toxicity data pretty much straight away.”
SCIENCE SPIN Issue 36 Page 29
SPIN