23. (1) On one day in each year after 1994, on a day on which samples are picked up at the plant under subsection 22 (1), each discharger shall collect and pick up a duplicate sample for each sample picked up on that day under subsection 22 (1) at one process effluent sampling point at the discharger’s plant and shall analyze each duplicate sample for total suspended solids. (2) There shall be an interval of at least six months between successive pick-up days at the plant under subsection (1).  O. Reg. 561/94, s. 23. Monitoring — Process Effluent — pH Measurement

24. (1) Each discharger shall, on one day in each week,  during the time period applicable to the plant under subsection 20 (4) or (5), collect a grab sample from each process effluent monitoring stream at the discharger’s plant and shall analyze each sample for the parameter pH. (2) There shall be an interval of at least four days between each of the collections at a stream under subsection (1) in each week. (3) All samples collected under this section shall be collected at the same time as samples collected under section 22.  O. Reg. 561/94, s. 24 (1-3). (4) Revoked:  O. Reg. 170/96, s. 6. (5) Instead of collecting a grab sample under subsection (1) from a stream, a discharger may use an on-line analyzer at the sampling point on the stream and analyze the effluent at the sampling point for the parameter pH once in each week during the time period applicable to the plant under subsection 20 (4) or (5). (6) For the purposes of this section, a discharger shall use either the sampling point established under section 8 on the stream or an alternate sampling point located downstream of the sampling point but before the point of discharge of the stream to surface water or to an industrial sewer used in common with another plant. (7) Before using an alternate sampling point under subsection (6), a discharger shall give the Director a written notice describing the location of the alternate sampling point, together with a revised version of the list and plot plan submitted under section 9 showing the alternate sampling point.  O. Reg. 561/94, s. 24 (5-7). Monitoring — Acute Lethality Testing — Rainbow Trout

25. (1) Where a discharger is required by this section to perform a rainbow trout acute lethality test, the discharger shall perform the test according to the procedures described in the Environment Canada publication entitled “Biological Test Method: Reference Method for Determining Acute Lethality of Effluents to Rainbow Trout”, as amended from time to time.  O. Reg. 235/07, s. 4. (2) Each rainbow trout acute lethality test required by this section shall be carried out as a single concentration test using 100 per cent effluent.  O. Reg. 561/94, s. 25 (2). (3) On one day in each month, on a day on which samples are picked up at the plant under subsection 22 (1), each discharger shall collect and immediately pick up a grab sample at each process effluent sampling point at the discharger’s plant and shall perform a rainbow trout acute lethality test on each sample.  O. Reg. 561/94, s. 25 (3). (4) There shall be an interval of at least 15 days between successive pick-up days at the plant under subsection (3).  O. Reg. 561/94, s. 25 (4). (5) All samples picked up under subsection (3) in a month shall be picked up on the same day in the month.  O. Reg. 561/94, s. 25 (5). (6) Where a discharger has performed tests under subsection (3) for 12 consecutive months on samples collected from the same sampling point and the mortality of the rainbow trout in each test did not exceed 50 per cent, the discharger is relieved of the obligations under subsection (3) relating to the sampling point and shall instead collect and immediately pick up a grab sample at the sampling point on one day in each quarter and perform a rainbow trout acute lethality test on each sample.  O. Reg. 561/94, s. 25 (6). (7) Samples picked up at a plant under subsection (6) shall be picked up on a day on which samples are picked up at the plant under subsection (3).  O. Reg. 561/94, s. 25 (7). (8) If no samples are being picked up at a plant under subsection (3) during a quarter, samples picked up at the plant during the quarter under subsection (6) shall be picked up on a day on which samples are picked up at the plant under subsection 22 (1).  O. Reg. 561/94, s. 25 (8). (9) There shall be an interval of at least 45 days between successive pick-up days at the plant under subsection (6).  O. Reg. 561/94, s. 25 (9). (10) All samples picked up under subsection (6) in a quarter shall be picked up on the same day in the quarter.  O. Reg. 561/94, s. 25 (10). (11) If a rainbow trout acute lethality test performed under subsection (6) on any sample from a sampling point results in mortality of more than 50 per cent of the test rainbow trout, subsections (6) to (10) cease to apply in respect to samples from that sampling point, and a discharger shall instead comply with the requirements of subsection (3) relating to the sampling point, until the tests performed under subsection (3) on all samples collected from the sampling point for a further 12 consecutive months result in mortality for no more than 50 per cent of the rainbow trout for each test.  O. Reg. 561/94, s. 25 (11). (12) A discharger shall notify the Director in writing of any change in the frequency of acute lethality testing under this Regulation at the discharger’s plant, within 30 days after the day on which the change begins.  O. Reg. 561/94, s. 25 (12). (13), (14) Revoked:  O. Reg. 561/94, s. 25 (15). (15) Spent:  O. Reg. 561/94, s. 25 (15). (16) Subsections (2) to (15) apply with necessary modifications to each cooling water effluent sampling point and, for the purpose, the reference in subsection (3) to each process effluent sampling point shall be deemed to be a reference to each cooling water effluent sampling point and the reference in subsections (3) and (8) to subsection 22 (1) shall be deemed to be a reference to subsection 28 (1).  O. Reg. 561/94, s. 25 (16). Monitoring — Acute Lethality Testing — Daphnia magna

26. (1) Where a discharger is required by this section to perform a Daphnia magna acute lethality test, the discharger shall perform the test according to the procedures described in the Environment Canada publication entitled “Biological Test Method: Reference Method for Determining Acute Lethality of Effluents to Daphnia magna”, as amended from time to time.  O. Reg. 235/07, s. 5. (2) Subsections 25 (2) to (16) apply with necessary modifications to Daphnia magna acute lethality tests and, for the purpose, a reference to rainbow trout shall be deemed to be a reference to Daphnia magna.  O. Reg. 561/94, s. 26 (2); O. Reg. 170/96, s. 7. (3) Each discharger shall pick up each set of samples required to be collected from a sampling point at the discharger’s plant under this section on a day on which the discharger collects a sample from the sampling point under section 25, to the extent possible having regard to the frequency of monitoring required at the sampling point under this section and section 25.  O. Reg. 561/94, s. 26 (3). Monitoring — Chronic Toxicity Testing — Fathead Minnow and Ceriodaphnia dubia