Suspended Solids from Industrial Discharges

Total suspended solids (TSS) — fine solid particles discharged into waterways — are the most comprehensively reported pollution indicator for industries covered by Quebec's Programme de réduction des rejets industriels (PRRI). In 2023, listed industrial sites discharged 9,231 tonnes of TSS, down from 18,403 tonnes in 2006, a 50% reduction over 17 years. The pulp and paper sector dominates with 87% of the total, having cut its load by 53% (from 17,100 t to 8,000 t). The five sectors covered are: pulp and paper mills, mining, minerals and metals processing, waste management, and petrochemistry.

The pulp and paper sector produces the highest loads, with Westrock/La Tuque (1,126 t/yr average 2019-2023) and Domtar/Windsor (1,098 t/yr) leading. The year 2013 shows a notable spike for the mining and minerals/metals sectors, reaching 1,801 t and 1,812 t respectively, versus averages of 718 t and 531 t across the full period. The overall trend is downward since 2008 for pulp and paper, and more stable for other sectors.

Data is self-reported annually by facility operators. Coverage varies by parameter: TSS data is available for 63% of records, making it the most complete pollutant load metric in the dataset. The waste management sector has very low TSS coverage (180 records out of 710), likely because their effluents are primarily leachate where other parameters are prioritized for reporting.