# Environmental Fate and Ef fects of the Lampricides TFM and Niclosamide 1 Briefing for the Enviromental Protection Agency November 5, 2012

# Lampricide Fate and Effects • TFM – Hubert, T. D. 2003. Environmental Fate and Effects of the Lampricide TFM: A Review. Journal of Great Lakes Research. 29(Supplement 1):456-474. 

### • Niclosamide – Dawson, V. K. 2003. Environmental Fate and Effects of the Lampricide Bayluscide: A Review. 29(Supplement 1):475-492. 2

# EPA Assessment • Human Health – Moderate to low toxicity – Risk of exposure low – No developmental toxicity – No carcinogenicity – No mutagenicity 

### • Conclusion – No risk to general population 3

# EPA Assessment • Environmental Fate and Effects – Chemically stable and persistent – Some impacts to aquatic organisms – Aquatic communities recover quickly 

### • Conclusions – Risks reduced by • Flushing action of stream • Rapid repopulation from non -treated portions of stream • Treatment on 3-5 year cycles 4

### • Additional studies – TFM • Photodegradation – Niclosamide • Photodegradation • Aerobic aquatic metabolism • Anaerobic aquatic metabolism 5**O H**  **C F** **3**

**N O** **2** TFM Niclosamide **C O**  **N H**  **C l**  **O H**  **C l**  **N O** **2** 6

# Environmental Fate - Hydrolysis • TFM – Resistant to hydrolysis – Half -lives over 1400 days 

### • Niclosamide – Resistant at basic pH – Half -life at pH 5 – 120 hours 7

# Photodegradation pH TFM t 1/2 (h) Niclosamide t 1/2 (h) 5 11 .6 7.2 7 4.15 11 .7 9 3.36 30 8

# Photodegradation • Degradation products – Low molecular weight organic acids • Substituted 2, 3, and 4 carbon organic acids (maleic, oxalic, glyoxylic) – Carbon dioxide 9

# Binding to sediment • Milakokia River 1997 – Sandy sediment – Chemical fell below detection in 24 to 96 hours 

### • Carp River and Fish Creek 2010 – Slight organic content sediment – Same result: below detection in 24 to 96 hours 10

# Aerobic/anaerobic degradation • TFM – Half -lives 2 to 5 days – RTFM, incorporation in high MW organic matter, polymers, humic or fulvic acids 

### • Niclosamide – Half -lives ~ 5 days aerobically; 0.65 to 2.79 days anaerobically – Small carbon compounds and incorporation into humin 11

# Metabolism

OH CF3 NO2 OGlu CF3 NO2 transferase glucuronyl 12

# Metabolism • Aquatic Insects – TFM: Sulfation, glucuronidation – Niclosamide: hydrolysis, conjugation • Fish – TFM: glucuronidation – Niclosamide: glucuronidation, sulfation • Mammals – TFM: glucuronidation, reduction and acetylation, sulfation – Niclosamide: glucuronidation 13

# Uptake and Elimination • Species studied - green algae, aquatic plants, isopods (sowbug), amphipods, crayfish, mayfly, caddisfly, annelid worms (leeches), snails, fingernail clams, and fish • Half -lives ranged from 7 hours to 18 days – Exception: annelid worms, t 1/2 = ~ 221 days • Bioconcentration factors (BCF) for whole body and tissues ranged from less than 1 to ~ 62 – Dioxin: BCF 5,840 in fathead minnow 14

# Effects on Plants • TFM – Aquatic Plants • Toxic at >15 mg/L • Effects at 5 mg/L but plants recover – Green Algae/Blue-green Algae • Reduction in growth at < 10 mg/L • Minor reductions in pH and dissolved oxygen 

### • Niclosamide – No effects at treatment concentrations 15

### • Fish – TFM • Toxicity low to high depending on species • Generally high margins of selectivity – Niclosamide • Highly toxic to most fish • Margin of selectivity lower than TFM 16

### • American eel – Tested elvers – Highly resistant to TFM or TFM/niclosamide mixtures – 4 to 7 times MLC for sea lamprey 17

# Effects on Aquatic Invertebrates • TFM – Slightly to moderately toxic 

### • Niclosamide – Slightly to highly toxic 18

### • Endangered Hungerford’s crawling water beetle – Surrogate Haliplus spp tested – Adults and larvae – Survival unaffected at up to 3.9X MLC – Adults appeared to avoid chemical by crawling out of water 19

### • Mussels – Giant floater, fragile papershell, pink heelsplitter, black sandshell, snuffbox, ellipse – At concentrations of TFM required to kill lampreys mortality is minimal. Adults, juveniles, glochidia are resistant; recruitment not affected. – TFM/1% niclosamide caused some mortality 20

### • Native lamprey study – Lampetra, Ichthyomyzon, Petromyzon – No significant difference in median lethal concentration – Slight difference in MLC between Lampetra and Petromyzon – Some lampetra will survive treatments – Native lamprey will be impacted 21

## Effects on Reptiles and Amphibians

• TFM – Turtles • No effects – Frogs • Effects that vary depending on species, stage of development, and route of exposure – Mudpuppies • Reports of sensitivity and population declines • UMESC study – adults not affected (2.4X MLC) • Juveniles < 100 mm are less resistent to TFM (1.5X MLC) • Juveniles more sensitive to TFM/niclosamide mixture • Niclosamide – Turtles • No effects at treatment concentrations – Frogs • No effects at treatment concentrations 22

# Effects on Birds • TFM – Oral toxicity ranged from 250 mg/kg to 546 mg/kg body weight – Water concentrations of between 15 mg/L and 50 mg/L • Uncoordination and lethargy depending on length of exposure • Niclosamide – Oral toxicity ranged from 500 mg/kg to over 2000 mg/kg – Water concentration of 0.10 mg/L • Produced slight uncoordination in one animal 23

### • Common tern – St. Marys River – Risk from eating dead larvae – In lab exposed larvae to bayer granular and wettable powder – Analyzed for niclosamide – 3.49 ppb tissue concentration – Low acute toxicity exposure risk 24

### • Piping plover – Endangered – Estimate exposure risk • Residues in water and caged insects – Likely exposure for adults 85X below NOEC – Likely exposure for chicks 17X below NOEC 25

## Effects on Mammals • TFM – Oral toxicity 141 to 387 mg/kg – Dermal toxicity: > 2000 mg/kg – Moderate dermal and eye irritation 

### • Niclosamide – Oral toxicity >5000 mg/kg – Dermal toxicity >2000 mg/kg – Inhalation toxicity 1.95 mg/L – Mild eye irritation, no dermal irritation 26

## Effects on Mammals • TFM – No effects to decreased body weights, increased liver weights, and reduced weights in offspring – No cancer, mutations, developmental toxicity or increased tumor incidence – No reproductive effects 

### • Niclosamide – No effects to decreased body weights, increased liver weights, and reduced weights in offspring – No cancer, mutation, developmental toxicity, or increased tumor incidence – Abnormal sperm morphology in mice 27

# Summary • Effects transient • Do not persist • Relatively non -toxic 28

# Questions 29