Bad data and exemptions obscure North American pollution picture
The real scale of industrial pollution in North America is unknown because of national reporting exemptions and incomplete data, an international monitoring body says.
The Commission for Environmental Cooperation (CEC) made the declaration this month as it published its annual online update of pollution data from industrial facilities across the continent.
Evan Lloyd, CEC executive director, said: "Regional cooperation on environmental issues depends on comparable and complete data from Canada, Mexico and the United States.
"This information is critical for governments, industry and citizens to address pollution and ensure healthy communities and ecosystems."
The latest update of the CEC industrial pollution data source, Taking Stock Online, was published last week.
It gives a picture of industrial pollution across North America, documenting reported releases and transfers of 5.7 billion kilograms of toxic pollutants released in the air, water and on land in 2006 from industrial facilities in all three countries.
It is a multi-year database covering more than 500 toxic substances and almost 100 major industrial sectors.
Of the 2006 total, Canada accounted for more than 2.1 billion kilograms of released toxins, the US 3.5 billion kilograms and Mexico 28 million.
Some put the figure differentials down to different reporting standards. CEC says the incomplete pollution picture is due to a combination of national reporting exemptions for certain sectors and pollutants and incomplete reporting by some facilities.
It singles out oil and gas extraction, mining and wastewater treatment as examples of sectors where data reporting needs to improve.
For example, some of the toxic pollutants reported in the greatest volume in Canada and the United States, such as carbon disulfide, zinc compounds, methanol, and hydrochloric acid, are exempt from the Mexican reporting system.
CEC says this means once these pollutants are transferred across the border they cannot be tracked.
It also highlights inconsistencies and under-reporting in data for the public wastewater treatment sector.
This sector accounted for 84 per cent of all reported Canadian discharges to water in 2006 but in the United States the sector is exempt from reporting and in Mexico although facilities are required to report few did.
But CEC acknowledges government progress to close the gaps, including by removing sector exemptions.
Taking Stock Online compiles data from the three pollutant release and transfer registers in North America: Canada's National Pollutant Release Inventory, Mexico's Registro de Emisiones y Transferencia de Contaminantes (RETC) and the US Toxics Release Inventory (TRI).