Section 096-530-2 - WET Testing and Chemical-Specific Testing for Toxic PollutantsA.Dischargers subject to this sectionAll licensed dischargers of industrial process wastewater or domestic wastes discharging to surface waters of the State must meet the testing requirements of this section. Dischargers of other types of wastewater are subject to this subsection when and if the Department determines that toxicity of effluents may have reasonable potential to cause or contribute to exceedences of narrative or numerical water quality criteria. For the purposes of this rule, industrial process wastewater is that which comes in contact with or results from a manufactured product, except for those processes that involve only washing and/or packing a raw material without addition of chemicals to the product.
The following dischargers are exempt from testing requirements of this rule unless the Department determines that there is a need for testing based on the nature, location or circumstances of an individual discharge.
(1) Discharges from individual discharge points licensed to discharge less than 50,000 gallons per day of solely domestic wastewater and with a chronic dilution factor of at least 50 to 1, provided no holding tank wastes containing chemicals are accepted by the facility;(2) Discharges from residential overboard discharge systems; or(3) Discharges from combined sewer overflow discharge points, provided the owner of the sewerage system is conducting or participating in a discharge abatement program. See Chapter 570, Combined Sewer Overflow Abatement.B.Categorization of dischargers. The basis of this categorization is the relative risk of toxic contamination of receiving water by a discharge. Dilution of the discharge in the receiving water is the primary variable used to determine the testing frequency. In determining dilution for a discharge, the Department shall use the chronic dilution factor as calculated pursuant to section 4(A) of this rule. The Department may assign a discharger to a higher testing frequency level if its outfall configuration or local conditions indicate a disproportional increase in the risk of acute toxic effects. Level I Those dischargers having a chronic dilution factor of less than 20 to 1.
Level II Those dischargers having a chronic dilution factor of at least 20 but less than 100 to 1.
Level III Those dischargers having a chronic dilution factor of at least 100 but less than 500 to 1, or dischargers having a chronic dilution factor of more than 500 to 1 and a permitted flow of 1 million gallons per day or greater.
Level IV Those dischargers having a chronic dilution factor of at least 500 to 1 and a permitted flow of less than 1 million gallons per day.
C.Scope of testing. Dischargers must conduct testing using the following organisms for Whole Effluent Toxicity (WET) testing and/or chemical tests for specific compounds.(1)Marine WET organisms. Test species for discharges to marine waters are Mysid shrimp, Mysidopsis bahia (acute only) and the sea urchin, Arbacia punctulata, (chronic only), or other organisms specified by the Department. All WET testing must be reported as a No Observed Effect Level. NOTE: In estuarine situations, the Department shall specify whether marine or freshwater organisms are best suited for an individual discharge.
(2)Freshwater WET organisms. Test species for discharges to freshwater are the water flea, Ceriodaphnia dubia and the brook trout, Salvelinus fontinalis or other salmonid fish species approved by the Department, or other organisms specified by the Department. All WET testing must be reported as a No Observed Effect Level for both acute and chronic levels for each species.(3) "Priority pollutant" testing refers to analysis for levels of priority pollutants listed in Chapter 525, section (4)(VI) in a licensed discharge.(4) "Analytical chemistry" refers to a suite of chemical tests for ammonia nitrogen, total aluminum, total cadmium, total chromium, total copper, total hardness (fresh water only), total lead, total nickel, total silver, total zinc, total arsenic, total cyanide and total residual chlorine.(5) Chemical analyses for compounds in addition to those referred to in paragraphs (3) and (4) above may be required if the Department has reason to believe that specific discharges contain such compounds in concentrations that may prevent attainment of water quality standards of the waterbody. Additionally, the Department may require testing for other compounds that it identifies as being in use in the State and that pose a risk of causing toxic effects if discharged to the surface waters. Such testing may be required of specific types or groups of dischargers that may use, produce or receive the compound(s) in question.(6) All chemical testing must be carried out by approved methods that permit detection of a pollutant at existing levels in the discharge or that achieve detection levels as specified by the Department. When chemical testing results are reported as less then, or detected below the Department's specified detection limits, those results will be considered as not being present for the purposes of determining exceedences of water quality criteria.(7) Whenever WET, priority pollutants and analytical chemistry tests are required during the same time period, all tests must be performed on the same initial sample of effluent.D.Test schedules. In order to characterize a discharged effluent, all dischargers subject to this section must carry out a toxicity testing program consisting of screening tests and surveillance tests according to the schedule set forth in this section. This testing program must be conducted on effluents representative of normal flow, production and operating conditions. All screening and surveillance testing conducted must be reported to the Department and all valid tests will be used to determine compliance with this rule. Where any test demonstrates that a discharge may cause or contribute to an exceedence of a numerical or narrative water quality criterion, additional tests must be conducted pursuant to an approved toxicity reduction program (see section 3(C)). Such testing may not be used to fulfill minimum testing requirements of this section. (1)Routine testing requirements.Screening tests must be performed during the fourth year of a discharger's license, but at least once every five years, unless otherwise directed by the Department in order to accommodate license renewal schedules. The screening testing period begins 24-months prior to the expiration of a discharger's license and proceeds for four (4) calendar quarters (1 year). During other years, surveillance testing must be conducted. More frequent testing may be required by the Department in order to properly characterize a discharge in consideration of changed conditions or receiving water requirements. Screening level testing
| Level | WET Testing | Priority pollutant testing | Analytical chemistry |
| I | 4 per year | 1 per year | 4 per year |
| II | 2 per year | 1 per year | 4 per year |
| III | 1 per year | 1 per year | 4 per year |
| IV | 1 per year * | 1 per year * | 4 per year * |
Surveillance level testing
| Level | WET Testing | Priority pollutant testing | Analytical chemistry |
| I | 2 per year | None required | 4 per year |
| II | 1 per year | None required | 2 per year |
| III | 1 per year | None required | 1 per year |
| IV | 1 per year * | None required * | 1 per year * |
*These routine testing requirements for Level IV are waived, except that the Department shall require an individual discharger to conduct testing under the following conditions.
(a) The discharger's permit application or information available to the Department indicate that toxic compounds may be present in toxic amounts; or(b) Previous testing conducted by the discharger or similar dischargers indicates that toxic compounds may be present in toxic amounts. Additionally, new or substantially changed dischargers assigned to Level IV must conduct testing during the first two years of the discharge. Further testing is waived provided the testing done does not indicate any reasonable potential for exceedence as calculated pursuant to section 3(E).
(2) Required testing must be representative of the discharge and any seasonal or other variations, and must be distributed during the year as follows. | Tests per year | Distribution |
| 4 | One test each calendar quarter |
| 2 | One test in January to June and one test 6 months later. For surveillance tests, different months will be used in 4 successive years. |
| 1 | For surveillance tests, different calendar quarters will be used in 4 successive years. |
(3)Reduced testing(a) The Department may reduce testing requirements for dischargers that discharge less than 12 months per year in proportion to the actual number of months discharged, but to not less than one test per year where testing would otherwise be required. The Department may adjust test schedules to provide the most representative sampling program.(b) Dischargers in Levels III and IV may be waived from conducting surveillance testing for individual WET species or chemicals provided that testing in the preceding 60 months does not indicate any reasonable potential for exceedence as calculated pursuant to section 3(E).(c) Dischargers in Level II may reduce surveillance testing to one WET or specific chemical series every other year provided that testing in the preceding 60 months does not indicate any reasonable potential for exceedence as calculated pursuant to section 3(E).(d) Dischargers in Level I may reduce surveillance testing to one WET or specific chemical series per year provided that testing in the preceding 60 months does not indicate any reasonable potential for exceedence as calculated pursuant to section 3(E).(4) All dischargers having waived or reduced testing must file statements with the Department on or before December 31 of each year describing the following. (a) Changes in the number or types of non-domestic wastes contributed directly or indirectly to the wastewater treatment works that may increase the toxicity of the discharge;(b) Changes in the operation of the treatment works that may increase the toxicity of the discharge; and(c) Changes in industrial manufacturing processes contributing wastewater to the treatment works that may increase the toxicity of the discharge.(5)Waiver or Reduction of Testing of Industrial Discharges. The Department may waive or reduce testing or replace testing with requirements adequate to characterize the toxicity of identified pollutants when a discharger provides information adequate to: (a) Identify all toxic pollutants present or demonstrate that no toxic pollutants are used in its processes in toxic amounts;(b) Demonstrate that chemicals used in or formed by the discharger's industrial processes are not known or suspected to result in the formation of toxic pollutants in toxic amounts; and(c) Demonstrate the discharger does not process or treat waters known or suspected to contain toxic pollutants.06-096 C.M.R. ch. 530, § 2