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The Ministers of Environment and Health have released for final publication the assessment report for the priority substance textile mill effluents. Notice concerning the assessment of this substance and a summary of its assessment report was published in the Canada Gazette, Part 1 June 23, 2001. The synopsis of the report is provided below.

A draft of this Assessment Report was made available for a 60-day public comment period (July 1, 2000 - August 30, 2000). Following consideration of the comments received, the Assessment Report was revised as appropriate. A summary of the comments and their responses may also be accessed from this page.

For paper copies of the Full Assessment Report, please contact the Inquiry Centre at Environment Canada:

To obtain an electronic version of the Assessment Report in PDF, please request a copy from the following address: ESB.DSE@ec.gc.ca

Synopsis

Textile mill effluents (TMEs) are wastewater discharges from Canadian textile mills that are involved in wet processes such as scouring, neutralizing, desizing, mercerizing, carbonizing, fulling, bleaching, dyeing, printing and other wet finishing activities. They are not generated at facilities that conduct only dry processing (carding, spinning, weaving and knitting), laundering or manufacture of synthetic fibres through chemical processes. In the context of this report, TMEs do not include waste streams such as air emissions or solid waste.

As of 1999, there were 145 wet processing textile mills operating in Canada. Most wet processing mills were located in Quebec (58%), followed by Ontario (34%), Nova Scotia (3%), New Brunswick (2%), British Columbia (1%) and Prince Edward Island (1%). Most wet processing mills in Canada (96%) discharged to municipal wastewater collection systems, 99% of which had some form of wastewater treatment. The highest percentage of TMEs received secondary treatment (61%), followed by primary (28%), tertiary (9%) and none (1%). The dilution potential for TMEs varied principally according to the volume and flow of the receiving environment, and the total TMEs discharged ranged from 17% to 0.000 01% of the receiving environment.

TMEs contain a wide range of chemicals and are known to have a range of pH, temperature, colour and oxygen demand characteristics. The assessment did not attempt to determine the contribution of individual components of TMEs to toxicity or environmental effects and was based instead on the impacts of whole effluents.

However some effort was made to determine the environmental risk of nonylphenol and its ethoxylates in TMEs due to the availability of information produced by concurrent PSL2 Assessment for that substance.

In order to supplement the sparse database on the environmental effects of TMEs, a number of studies were undertaken in support of the assessment. The combined results of a battery of whole-effluent toxicity tests indicated a reduction in toxicity with increasing intensity of treatment of TMEs. The battery of tests used included rainbow trout (Oncorhynchus mykiss) acute lethal, Daphnia magna acute lethal, Microtox® (Vibrio fischeri) acute sublethal, Microtox® chronic sublethal, Ceriodaphnia dubia chronic (lethal and reproduction) and algal growth (Selenastrum capricornutum). All untreated TMEs had effects on all of the organisms tested. Primary-treated TMEs had slightly less toxicity than untreated effluents. Most of the secondary-treated effluents produced no effects on test organisms, with two exceptions, both of which discharged to municipal wastewater treatment systems. At one of those sites, where the treatment system was believed to be not operating optimally, aquatic toxicity was detected in all whole-effluent toxicity tests conducted. At the other site, significant inhibition of reproduction in C. dubia was detected; however, no aquatic toxicity was observed in the other three tests conducted. No tertiary-treated TMEs produced effects on test organisms.

There were limited data available on the aquatic toxicity of samples obtained from aquatic environments receiving TMEs. There were no data on the aquatic toxicity of environmental samples near untreated TME discharges, and only one site receiving primary-treated TMEs was studied. At that site, chronic toxicity (C. dubia survival and reproduction) was detected at 120 m below the outfall, and acute toxicity to the bacterium V. fischeri was detected 30 m from the outfall. No acute toxicity was measured in samples from environments receiving TMEs that were subject to secondary or tertiary treatment. At a single site receiving untreated TME, an in situ bioassay was conducted using caged clams (Anodonta implicata), and significant mortality occurred up to 120 m downstream of the outfall. Pore water from sediments taken from locations up to 80 m from an outfall discharging primary-treated TME inhibited fertilization in the white sea urchin (Lytechninus pictus). Toxicity was not detected using a variety of other sediment toxicity tests at sites receiving secondary-treated TMEs.

Studies measuring impacts on benthic invertebrate communities in aquatic environments receiving TMEs were conducted at single locations for each of untreated, secondary-treated and tertiary-treated effluents. Changes in community structure were detected 120 m below the outfall at the untreated site; however, no impacts were detected at the sites where secondary or tertiary treatment was provided by a municipal wastewater treatment system.

Estimated Toxic Exposure Values based on nonylphenol toxic equivalency quotients (EEV_TEQ) for nonylphenol (NP) and nonylphenol ethoxylates (NPEs) in untreated TMEs exceeded the chronic toxicity threshold for invertebrates in 90% of samples and the chronic toxicity threshold for fish in 86% of samples. Eighty-three percent of untreated samples had NP and NPE EEV_TEQs falling within the range of acute toxicity to fish, invertebrates and algae. All five primary-treated TME samples had NP and NPE EEV_TEQs falling within the range of acute toxicity to fish and invertebrates and exceeding chronic toxicity benchmarks for those organisms.

Based on the available data, it is concluded that textile mill effluents are entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity. Thus, it is concluded that textile mill effluents should be considered "toxic" as defined in Section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999) and that evaluation of options under CEPA 1999 to reduce exposure should be considered a priority at this time.

It is recommended that options to reduce environmental risk be examined on a site-specific basis. In addition, pollution prevention opportunities for the management of TMEs should be identified and evaluated, with particular attention to the use and release of NP and its ethoxylates. Given the fact that most textile mills in Canada have their wastewater treated at municipal wastewater treatment plants, it is recommended that discussions with the appropriate authorities (municipal and/or provincial) be undertaken to address the risks. This may require additional effects monitoring of TMEs and municipal effluents.