Introduction to Aquatic Toxicity Testing: Permits to Test Method Requirements

Transcription

1 Introdction to Aqatic Toxicity Testing: Permits to Test Method Reqirements Stephen L. Clark Pacific EcoRisk CWEA AC18 Remix Agst 22,

2 Presentation Overview Overview of Whole Efflent Testing (WET) Permit Reqirements and Forthcoming Policy Changes EPA Test Methods Overview Confonding Factors Leading to False Positives Defined here as incorrectly identifying a sample as toxic when in fact it is not Conclsions/Q&A 2

3 NPDES Permit WET Testing Reqirements 3

4 Where is WET in NPDES Permits? It s not that complicated.search for toxicity 4

5 Where is WET in NPDES Permits? Efflent Limitations and Discharge Specifications Receiving Water Limitations Special Provisions Permit Reopener 5

6 Where is WET in NPDES Permits? Special Stdies, Technical Reports, and Additional Monitoring Reqirements: Toxicity Redction Reqirements 6

7 Where is WET in NPDES Permits? Special Stdies, Technical Reports, and Additional Monitoring Reqirements: Toxicity Redction Reqirements 7

8 Where is WET in NPDES Permits? Monitoring and Reporting Program: Acte Testing Freqency Sample Type Test Species Methods (incldes sample adjstments) Test Failre 8

9 Where is WET in NPDES Permits? Monitoring and Reporting Program: Chronic Testing Freqency Sample Types Sample Volmes Test Species Methods Reference Toxicant Test Diltions Test Failre Reporting Reqirements 9

10 Where is WET in NPDES Permits? Fact Sheet Narrative and Flow Chart (some regions) 10

11 WET Policy Changes 2019? w Reasonable potential analysis w Nmeric limit (MDEL and MMEL) w Species screening to identify the most sensitive species w Freqency of monitoring based on size of discharge (e.g., 5 mgd = monthly) w Reqire data analysis sing the TST prove that yor sample is not toxic Rewards testing with high precision (i.e., low variability) Consider increasing # replciates for some species w Release of draft for pblic review in Fall

12 Overview of Whole Efflent Testing 12

13 Acte vs. Chronic Toxicity Testing Reqirements Acte Testing Efflent monitoring tool Efflent composite or grab sample/flowthrogh testing Testing at 100% efflent only Sample collection - one sample to for daily samples Typically 96-hor exposre Endpoint: srvival Toxicity typically defined as <90% srvival Chronic Testing Receiving water (RW) monitoring tool Efflent composite (permit may specify RW as control) Testing of efflent diltions (based on diltion credit, RW impact) Sample collection - typically 3x to 7x 48 hors p to 7-day exposre (species) Endpoint: May also inclde sb-lethal Toxicity defined by toxic nit (TU) or Pass/Fail 13

14 Whole Efflent Testing Whole efflent toxicity testing sed in the National Polltant Discharge Elimination System (NPDES) Permits Program is gided by varios testing manals. 14

15 Typical NPDES Test Species Algae Invertebrates Fish 15

16 Freshwater Algae: Selenastrm capricorntm Now Raphidocelis sbcapitata 96 hor static test with a algal cell growth endpoint

17 Freshwater Invertebrate: Ceriodaphnia dbia Ebert, 2005 Three brood static renewal test with a srvival and reprodction endpoint

18 Freshwater Invertebrate: Fathead Minnow 7 day static renewal test with a srvival and growth endpoint

19 Marine Algae: Giant Kelp (Macrocystis pyrifera) Kelp Sporophylls Embryonic gametophyte 48 hor static test with a germination and growth endpoint

20 Marine Invertebrate: Echinoderm Prple Urchin/Sand Dollar 72 hor static test with a larval development endpoint or 40 minte fertilization test

21 Basic Experimental Design Control 6.25% 12.5% 25% 50% 100% efflent efflent efflent efflent efflent

22 What Happens Before, Dring, and After the Test? Sample is logged in and basic water qality parameters (e.g., ammonia, chlorine, D.O., ph, etc.) are measred These may reslt in a reqirement to modify the test design May reslt in the addition of secondary controls (e.g., condctivity control for low or high condctivity samples) Test Soltions prepared Methods vary on the lab control water (i.e., mssels may be different from fish) Saltwater tests reqire freshwater samples to be salinity-adjsted Many methods provide flexibility regarding the selection of lab control water

23 Toxicity Testing Procedres Organisms are added to the test soltions Daily measrements (e.g., ph, D.O.) and observations (e.g., srvival) occr May reqire action by the lab if the water qality parameters (e.g., dissolved oxygen) are ot of range Soltions may be renewed At test termination, final water qality parameters are measred, the test endpoint (e.g., growth, srvival) is evalated, and the data are statistically analyzed to determine if the sample is toxic Pacific EcoRisk mltiple QC reviews of data daily

24 Confonding Factors 24

25 False Positives Lab Control Media Lab control treatment media selection can affect the determination of toxicity for the Selenastrm test 6 5 Selenastrm growth (x10 6 ) (167%) (135%) (137%) (148%) 1 0 Cltre Medim EPAMH DMW (Perrier) DMW (Arrowhead) DMW (Evian:Arrowhead) Efflent 25

26 False Positives Microbes Ceriodaphnia dbia Epibionts organisms that live on the external srface of another organism Other microbial interferences Redced reprodction Mitigation measres: Assre that compositor tbing is replaced before each compliance monitoring event to avoid costly accelerated monitoring and TIEs 26

27 Concentration Response Relationships Mst Be Assessed All or nothing Stimlatory at low concentrations and detrimental at higher concentrations Stimlatory at low concentrations bt no effect at higher concentrations Interrpted concentration response - significant effect bracketed by nonsignificant effect Interrpted concentration response - non-significant effect bracketed by non-significant effect Significant effects only at highest concentration Significant effects at all test concentrations bt flat concentration response crve Significant effects at all test concentrations with a sloped concentration response crve Inverse concentration response relationship 27

28 Unsal Response Crve Example Mst evalate test sensitivity (PMSD), nsally high control response, diltion water (lab vs. receiving water), and consider pathogen interference Be catios to not jmp to conclsions that pathogens are the only driver. If weight of evidence leads to pathogens, perform appropriate treatments (e.g., filtration, UV, chlor/dechlor, and antibiotics) for conclsion. 28

29 Other Potential False Positives Matrix interferences: Low hardness waters High hardness waters Can case cell lysing in Selenastrm Can case low reprodction to mortalities in Ceriodaphnia Basic testing errors and reporting errors 29

30 Qestions? Stephen L. Clark Vice President & Special Projects Director