Developing standard toxicity tests using Austrochiltonia subtenuis

Transcription

1 Developing standard toxicity tests using Austrochiltonia subtenuis Hung Vu, Rebecca Reid, Claudette Kellar, Sara Long, Vincent Pettigorve CAPIM Research Summit 25 th August 2017

2 Criteria for freshwater sediment toxicity testing organisms Relatively sensitive to contaminants Interlaboratory comparisons Laboratory culture Taxonomic identification Ecological important Geographical distribution Contact with sediment Sediment physiochemical tolerance (Images: Internet)

3 Standard freshwater sediment toxicity testing amphipods North America: Hyalella azteca publications Europe: Gammarus pulex H. azteca publications Australia: Austrochiltonia subtenuis - 2 publications G. pulex (Images: Internet)

4 Austrochiltonia subtenuis Australian native species Widespread in southern Australia Abundant in all year round Easy to collect in the field Play an important role in aquatic ecosystems Sensitive to some toxicants Laboratory culture??? Standard toxicity tests???

5 Previous works at CAPIM Determine collecting locations in the field Identify and confirm the right species Create artificial water recipe Stream water + deionized water Moderately hard water Artificial water based on stream water ingredients Choose suitable food types Conditioned leaves Conditioned leaves + fish food flakes YCT (yeast+ Cerophyll +trout chow) + fish food flakes

6 Austrochiltonia subtenuis culture at CAPIM lab

7 Developing standard toxicity tests using Austrochiltonia subtenuis

8 Aims Stage Test name Aims 1 Water test Optimize feeding regime and recovery time after sieving 2 Reference test Assess the relative sensitivity and health of the culture 3 Acute sediment test Optimize test duration, sediment: water ratio, holding time and method 4 Chronic sediment test Develop standard SOP for chronic test 1. USEPA, Methods for Measuring the Toxicity and Bioaccumulation of Sediment-Associated Contaminants with Freshwater Invertebrates, Second Edition 2. Environment Canada, Biological test method: Test for survival and growth in sediment and water using the freshwater amphipod Hyalella azteca

9 Water test Duration: 2 weeks Animal size: pass 297 µm and retain on 212 µm sieves Recovery time after sieving: 2d and 7d Number of feeding regime FR1. 1 ml YCT mg tetramin FR ml YCT mg tetramin FR ml YCT mg tetramin FR4: 0.25 ml YTC on Tuesday and Friday and 2.5 mg tetramin on Friday Number of reps/treatment: 5 Number of animals/rep: 10 Endpoints: Survival and growth Test acceptability: 80% survival

10 Water test results Recovery time Survival percentage (%) A B 2d 7d Recovery time (d) Head length (mm) C C 2d 7d Recovery time (d)

11 Water test results Feeding regime 2d recovery only Survival percentage (%) B B B A 0.3 A A FR1 FR2 FR3 FR1 FR2 FR3 Head length (mm) Feeding regime Feeding regime

12 Water test FR1 FR2 FR3 2 d 7 d

13 Water test FR1 FR2 FR3

14 Water test Summary 2d is sufficient recovery time after sieving FR2 could be suitable feeding regime for amphipod tests

15 Reference test Purpose Indicate the relative condition of the organisms used in the test Demonstrate the laboratory can perform the test procedure consistently Indicate whether the sensitivity of the particular population in use at a laboratory is comparable to that of organism used in other facilities

16 Reference test Reference toxicant: CuSO4 and KCl Duration: 96h Number of reps/treatment: 5 Number of animals/rep: 10 Number of treatments/toxicant: 6 Feeding: FR2 Endpoint: Survival Test acceptability: 90% control survival

17 Reference test Results Control survival: 100% Test acceptability: Cu 96h LC50: 378 µg/l Cu 96h LC50 for H. azteca = 55µg/L (Collyard, 1993) KCl 96h LC50: 280 mg/l KCl 96h LC50 = 305 mg/l ( mg/l) for H. azteca (US EPA, 2000)

18 Reference test Summary Amphipods in the culture are in a good condition The sensitivity of A. subtenuis to KCl was similar to H. azteca KCl should be used as a regular reference toxicant Reference tests should be done every two months

19 Sediment test 1 Test duration and sediment : water ratio Duration: 10d, 14d, 21d Number of reps/treatment: 4 Number of animals/rep: 10 Number of treatments: 4 T1: 40 g sediment ml water T2: 100g sediment ml water T3: 100g sediment + 400ml water T4: Water only Feeding: FR2 Endpoint: Survival Test acceptability: 80% survival

20 Sediment test 1 Results Survival percentage (%) Experimental time (d)

21 Sediment test 1 - Results Survival percentage(%) T1 T2 T3 T4 Treatment

22 Sediment test 2 Sediment size Duration: 14 d Number of reps/treatment: 5 Number of animals/rep: 10 Number of treatments: Whole, coarse, and fine sediment Feeding: FR2 Endpoint: Survival Test acceptability: 80% survival

23 Sediment test 2 Results Survival percentage (%) Whole Coarse Fine Sediment size

24 Sediment test 3 Holding time and method Duration: 14 d Number of reps/treatment: 10 (5 mixing, 5 not mixing) Number of animals/rep: 10 Number of treatments: 1w, 2w, 3w, 4w Feeding: FR2 Endpoint: Survival Test acceptability: 80% survival

25 Sediment test 3 Results A Survival percentage (%) Mixing Treatment Not mixing

26 Sediment test 3 Results A A A Survival percentage (%) B Holding time (wk)

27 Sediment test Summary Experimental duration, sediment: water ratio, sediment size, and mixing during holding time did not significantly affect survival of amphipods Holding time significantly affected survival of amphipod, holding time should not exceed 3 weeks

28 Austrochiltonia subtenuis A model toxicity testing organism for freshwater sediment??? Relatively sensitive to range of concern contaminants? Interlaboratory comparisons? Laboratory culture Taxonomic identification Ecological important Geographical distribution Contact with sediment Sediment physiochemical tolerance

29 Thank you!