Because of the complex nature of organisms in the environment, P&G set up model ecosystems or mesocosms to test the effects of substances on organisms within as close to natural conditions as possible.
The goal of all the environmental fate and effects testing at P&G is to make sure our products and their ingredients will not affect the environment. So, the best place to test the toxicity of our ingredients would be in the real environment. But, because of the value of the environment and the possibility of negative effects from our testing, this would not be an appropriate approach. Instead of using the real environment, we use small parts of the environment that have been isolated. These are called "model ecosystems" or"mesocosms".
A model ecosystem is the highest tier of ecotoxicity testing available. Definitions of model ecosystems vary, but they are usually fairly large (>10 meters long for streams, >10,000 litres for ponds), can be indoors or outdoors, contain a diverse array of species and are sustainable for long periods of time. Basically, these are slices of the environment that have been moved into the laboratory for experimental work.
The advantages for using model ecosystems or mesocosms are many and include:
- They allow study of environmental fate and effects at the same time.
- The test system is very realistic and helps us understand how to use in vitro, acute and chronic information to better protect the environment
- Testing is carefully controlled (light levels, chemical concentration, river flow). This level of control could not be found in the environment.
- Complex aquatic communities containing hundreds of species can be evaluated at the same time. Most of these species cannot be cultured or tested under laboratory conditions.
- Interactions among species are included so that effects on one species can cause effects on other organisms.
P&G developed its Experimental Stream Facility or mesocosm in the mid 1980s, generating important data for 15 years before donating it to a local university.