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WHOLE EFFLUENT TOXICITY

WHOLE EFFLUENT TOXICITY. WHOLE EFFLUENT TOXICITY. What is whole effluent toxicity? testing a wastewater discharge with aquatic organisms to assess the discharge's toxicity WET is a standardized protocol (ex the Standard Methods. WHOLE EFFLUENT TOXICITY. Understanding WET

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WHOLE EFFLUENT TOXICITY

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  1. WHOLE EFFLUENT TOXICITY

  2. WHOLE EFFLUENT TOXICITY What is whole effluent toxicity? • testing a wastewater discharge with aquatic organisms to assess the discharge's toxicity • WET is a standardized protocol (ex the Standard Methods

  3. WHOLE EFFLUENT TOXICITY Understanding WET - An effluent may be complying with all the individual parameter limits but does it guarantee that it will not cause any detrimental effects of the aquatic organisms? • WET attempts to answer this question and quantify the effects • WET is an aquatic toxicity/bioassay test

  4. WHOLE EFFLUENT TOXICITY WHOLE EFFLUENT TOXICITY Understanding WET • Acute test (24 to 96 hrs) • Chronic test (~ 7 days)

  5. WET Freshwater Chronic Test Species Invertebrates: • Ceriodaphniadubia Fish • Pimephalespromelas- Fathead Minnow Algae • Selenastrumcapricornutum

  6. Test Data • Typical dose response where mortality increases as the concentration of effluent in the mixture increases. • LC50 would be somewhere between 25% effluent and 50% effluent. 6.25 % Effluent 12.5 % Effluent 25.0% Effluent 50.0% Effluent 100.0% Effluent Control 0% Mortality 0% mortality 20 % Mortality 40% Mortality 80% Mortality 100% Mortality New Jersey Saline Acute Test Species

  7. Test Result Calculated point estimate or a Pass fail test where a concentration, usually that which is considered a critical concentration of effluent in the receiving water or ambient toxicity test measured against a control Examples of Pass/Fail Acute test Instream waste concentration (IWC) = 75% statistical evaluation using a student-t test compares mortality rates of ambient or IWC sample against a control. Is there a “significant statistical difference between the two results” New Jersey Saline Acute Test Species

  8. Grab vs. Composite • Grab samples offer “snap shot” of effluent • Composite samples offer “average view” of effluent • NJDEP requires sampling based on discharge type • Continuous discharge – 24 hour composite sample • Intermittent discharge – grab or composite each day that is representative of discharge

  9. Grab vs. Composite • Type of sample and frequency of collection is dependent upon the use of the data and the discharge the test is intended to represent. • Samples are not to be used after they have been held for 72 hours. • Samples are to be chilled during or immediately upon collection to 4oC.

  10. WETMonitoring a fathead minnow test Opossum Shrimp Pimephales promelas

  11. WET Procedures

  12. Pimephalespromelas Adults are small fish typically 43 mm to 102 mm, and averaging about 50 mm, in total length. Photo by Karen McCabe from Animal Soup

  13. Tests Results in Canada http://www.ec.gc.ca/

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