Defense Date

1-8-2021

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David Kerstetter, Ph.D.

Second Advisor

Nicole Kirchhoff, Ph.D.

Third Advisor

Donald McCorquodale, Ph.D.

Fourth Advisor

George Duncan, Ph.D.

Abstract

Monochloramine ( is a secondary disinfectant used by water treatment facilities to eliminate lingering bacteria in basins, filters, and pipelines. While an effective disinfectant, monochloramine can have negative effects on aquatic organisms. Organis ms affected by the chemical can include species whose environment is near to effluent sites and aquaculture facilities that use tap water lines or has water intake pipes near to effluent sites. Three species commonly found in south Florida that are lik ely exposed to MCA by effluent sites or aquaculture facilities are mosquitofish Gambusia affinis pink shrimp Farfantepenaeus duorarum and the hard clam Mercenaria mercenaria These species were acutely exposed to MCA over a 48 hour trial at concentrations below the maximum legal residual disinfectant level of 4.0 mg/l ( The probability of mortali ty for each species was determined using standard toxicology protocols. All species were found to have a greater probability of death at higher MCA concentrations. The probability of death drastically decreased over time at moderate to l ow MCA concentrations. Gambusia affinis and Farfantepenaeus duorarum exhibited extreme signs of stress when exposed to MC A in the form of erratic swimming and loss of buoyancy. Mercenaria mercenaria was the only species to survive the 48 hour trials and had the greatest probability of survival. Based on these results, marine and freshwater species are sensitive to monochlo ramine and the chemical should be removed from the water prior to aquaculture or aquarium use Although monochloramine is a threat to individuals kept in tanks, it may not pose a threat to wild individuals due to MCAMCA’s instability and decay over time.

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