EEM - Biological Monitoring

EEM is a performance measurement tool that assesses the adequacy of the discharge limits specified under the Regulations to protect the broad variety of receiving environments in Canada. EEM is an iterative system of monitoring and interpretation phases and goes beyond end-of-pipe measurement of chemicals in effluent to examine the effectiveness of environmental protection measures directly in aquatic ecosystems. Discharge limits provide national minimum standards that are intended to protect fish, fish habitat and the use of fisheries resources by humans.

For EEM, an effect is determined by a statistically significant difference in fish or benthic invertebrate community indicators between exposure and reference areas (or along a gradient of effluent exposure), or exceeding certain contaminant levels (levels of dioxins and furans for PPER and mercury for MMER) in fish.

To enable the above determinations by industry, Environment Canada develops guidance documents on how to conduct cost-effective and scientifically defensible studies that assess impacts on aquatic ecosystems. Detailed information on the EEM endpoints and indicators can be found in the Technical Guidance documents. These documents are widely used by regulated industries in assessing the health of aquatic ecosystems. Environment Canada synthesizes the data generated by the regulated industries at a national level, couples broad geographic coverage with consistently applied regulatory requirements, and provides unique information on the impacts of pulp and paper and metal mining effluents on aquatic environments.

Assessing fish health

Fish health can be affected directly via effluent toxicity or indirectly via effluent effects upon their prey. In EEM studies, fish health is assessed using changes in indicators of reproduction, condition, growth and survival. These changes may be reflective of biochemical or physiological changes in fish, and can also be predictive of community level effects such as loss of a species.

Assessing fish habitat

Fish habitat is assessed by conducting a benthic invertebrate community survey. This is done by collecting benthic invertebrates in exposure and reference areas (or along a gradient of exposure areas) and comparing measurements among the areas. Community-level effects are determined directly via measurements of density, taxon richness and changes in community structure (evenness and similarity).

Assessing fish usability

Fish usability by humans is assessed by monitoring levels of certain contaminants in edible fish tissue. Under certain conditions specified in the Regulations, pulp and paper mills are required to measure dioxins and furans, and metal mines are required to measure mercury.