Decimal reduction times of Pyrodinium bahamense var. compressum and Escherichia coli in chlorine- and ultraviolet-treated seawater.
OBJECTIVE
Decimal reduction times (D-values) of the vegetative cells of Pyrodinium bahamense var. compressum and Escherichia coli in ultraviolet- and chlorine-treated seawater were established.


RESULTS
The cells of the test organisms were exposed to ultraviolet- and chlorine-treated seawater and maintained at 20-35 ppt salinity and 20 to 35 degrees C. The dinoflagellate cells which cause Paralytic Shellfish Poisoning (PSP) were found to be more resilient than the bacterial cells. Ultraviolet treatment was found to be more effective than chlorine to both test organisms. Irreversible morphological changes in the treated dinoflagellate cells were noted, including protoplast discoloration, cellular membrane leakage and damage to the thecal armour.


CONCLUSIONS
The vegetative cells of both test organisms in seawater were more sensitive to ultraviolet treatment than to chlorine exposure. Generally, the dinoflagellate cells were less susceptible than bacterial cells to both disinfection treatments.


CONCLUSIONS
Results of this study may have significant implications in depuration procedures for molluscs and cleaning protocols for ballast waters of ships.
Azanza
M P
MP
College of Home Economics, University of the Philippines, Diliman 1101, Quezon City, Philippines. ma_patricia.azanza@up.edu.ph
Azanza
R V
RV
Gedaria
A I
AI
Sententa
H G
HG
Idjao
M V
MV
D000818:Animals; D049872:Bivalvia; D002713:Chlorine / Q000494:pharmacology; D004141:Dinoflagellida / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects*; D004203:Disinfection; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects*; D012623:Seawater / Q000382:microbiology / Q000469:parasitology; D012758:Shellfish / Q000009:adverse effects / Q000469:parasitology; D012965:Sodium Chloride / Q000032:analysis; D014466:Ultraviolet Rays; D014871:Water Microbiology; D018508:Water Purification
D012965:Sodium Chloride; D002713:Chlorine