Evaluation of the recovery of waterborne Giardia cysts by freshwater clams and cyst detection in clam tissue

1999 ◽  
Vol 85 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Thaddeus K. Graczyk ◽  
Ronald Fayer ◽  
David Bruce Conn ◽  
Earl J. Lewis
Keyword(s):  
Freshwater Clams ◽  
Clam Tissue ◽  
Giardia Cysts

Size- and age-specific patterns of trace metal concentrations in freshwater clams from an acid-sensitive and a circumneutral lake

1987 ◽  
Vol 65 (10) ◽  
pp. 2436-2442 ◽  
Author(s):  
Scott G. Hinch ◽  
Linda A. Stephenson
Keyword(s):  
Tissue Concentrations ◽  
Metal Concentrations ◽  
Elliptio Complanata ◽  
South Central ◽  
Freshwater Clams ◽  
Metal Levels ◽  
Water Competition ◽  
Specific Manner ◽  
Clam Tissue ◽  
Binding Substrate

We collected freshwater clams (Elliptio complanata) from an acid-sensitive and a circumneutral lake in south central Ontario and compared tissue metal concentrations. Clams from the acid-sensitive lake had higher concentrations of Cu and Cd and lower concentrations of Zn and Mn than clams from the circumneutral lake. Tissue concentrations did not reflect metal levels in the water. Competition may be occurring between metals for binding substrate in clam tissue. Clam size and (or) age successfully predicted tissue metal concentrations, but in a metal-specific and tissue-specific manner. Clam biomonitoring studies should therefore control for size and age variability. Lake buffering capability was not very important in influencing size- and age-specific patterns of tissue metal concentrations. However, this conclusion is based solely on data from two lakes.

Giardia and Virus Monitoring of Sewage Effluent in the State of Arizona

1989 ◽  
Vol 21 (3) ◽  
pp. 43-47 ◽  
Author(s):  
Joan B. Rose ◽  
Ricardo De Leon ◽  
Charles P. Gerba
Keyword(s):  
United States ◽  
Produced Water ◽  
Wastewater Reuse ◽  
Limited Resource ◽  
The State ◽  
Sewage Effluent ◽  
Sand Filtration ◽  
Southwestern United States ◽  
Treatment Facilities ◽  
Giardia Cysts

Arizona, located in the arid Southwestern United States, is heavily dependent on groundwater. In order to protect this limited resource, wastewater reuse has been implemented. Virus and Giardia monitoring of wastewater used for irrigation has also been initiated as a means for controlling the public's exposure to these pathogens. Treatment facilities must produce wastewater with no detectable Giardia cysts and one virus plaque forming unit (pfu) per 40 liters (L) for unrestricted reuse. For restricted reuse, 125 pfu/40 L is allowed. Methods based on filtration were used to monitor facilities at monthly, quarterly or biannual frequencies. Results after two years of monitoring are presented. All 11 treatment facilities produced water meeting the virus standard of 125 pfu/40 L. Only plants which used sand filtration and disinfection achieved consistent levels of virus below 1 pfu/40 L. Out of 70 samples, 74% contained no detectable viruses. Giardia was detected in 29 to 50% of the samples. Most plants would need to upgrade their treatment in order to meet standards for unrestricted irrigation.

Occurrences of Giardia cysts in beach water

1998 ◽  
Vol 38 (12) ◽  
pp. 73-76 ◽  
Author(s):  
B. S. W. Ho ◽  
T.-Y Tam
Keyword(s):  
Health Risk ◽  
Water Sample ◽  
Water Samples ◽  
High Concentration ◽  
Potential Health ◽  
Infectious Dose ◽  
Potential Health Risk ◽  
E Coli ◽  
Beach Water ◽  
Giardia Cysts

A total of 64 beach water samples with various bacteriological quality (Grades 1 to 4) were analysed for their bacteriological and parasitological contents (E coli and Giardia cysts respectively). Results indicated that Giardia cysts were detected in less than 10% of the Grade 1 beach water samples with E coli concentrations of <24/100mL. For Grades 2, 3 & 4 beach water samples, Giardia cysts were found, respectively, in 85, 50 and 64% of the samples. Except for one beach water sample which had an unusually high concentration of Giardia cysts (23 cysts/L), they were generally present at moderate concentrations (<10 cysts/L) in all other beach water samples. Despite moderate levels of Giardia cysts present in beach water of different grades, the potential health risk faced by swimmers bathing in local beach water needs to be carefully assessed as Giardia is known to have a low infectious dose.

scholarly journals Low-cost internal controls for detection of Giardia cysts in water samples

2019 ◽  
Vol 71 ◽  
pp. 177-179
Author(s):  
Melissa Solano Barquero ◽  
Eric Morales Mora ◽  
Luz Chacón Jiménez ◽  
Erick Cordero Jara ◽  
Liliana Reyes Lizano ◽  
...  
Keyword(s):  
Water Samples ◽  
Low Cost ◽  
Internal Controls ◽  
Giardia Cysts

Drying of Cryptosporidium oocysts and Giardia cysts to slides abrogates use of vital dyes for viability staining

2014 ◽  
Vol 96 ◽  
pp. 68-69 ◽  
Author(s):  
Lucy J. Robertson ◽  
Stijn Casaert ◽  
Yazel Valdez-Nava ◽  
Md. Amimul Ehsan ◽  
Edwin Claerebout
Keyword(s):  
Viability Staining ◽  
Vital Dyes ◽  
Cryptosporidium Oocysts ◽  
Giardia Cysts

Plasmalogens, fatty acids and alkyl glyceryl ethers of marine and freshwater clams and mussels

2009 ◽  
Vol 116 (2) ◽  
pp. 491-498 ◽  
Author(s):  
Lumír O. Hanuš ◽  
Dmitri O. Levitsky ◽  
Ilia Shkrob ◽  
Valery M. Dembitsky
Keyword(s):  
Fatty Acids ◽  
Freshwater Clams

scholarly journals ECC–RT-PCR: a new method to determine the viability and infectivity of Giardia cysts

2012 ◽  
Vol 16 (5) ◽  
pp. e350-e353 ◽  
Author(s):  
Absar Alum ◽  
Basel Sbai ◽  
Hamas Asaad ◽  
Joseph R. Rubino ◽  
M. Khalid Ijaz
Keyword(s):  
New Method ◽  
Rt Pcr ◽  
Giardia Cysts

Impact of a wastewater treatment plant on Cryptosporidium oocysts and Giardia cysts occurring in a surface water

2000 ◽  
Vol 41 (7) ◽  
pp. 31-37 ◽  
Author(s):  
E. Carraro ◽  
E. Fea ◽  
S. Salva ◽  
G. Gilli
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Mean Values ◽  
Cryptosporidium Oocysts ◽  
The Impact ◽  
Receiving Water ◽  
Giardia Cysts

The aim of this study was to assess the impact of a municipal wastewater treatment plant (MWTP) on the occurrence of Cryptosporidium oocysts and Giardia cysts in the receiving water. All MWTP effluent samples were Giardia and Cryptosporidium contaminated, although low mean values were found for both parasites (0.21±0.06 oocysts/L; 1.39±0.51 cysts/L). Otherwise, in the raw sewage a greater concentration was detected (4.5±0.3 oocysts/L; 53.6±6.8 cysts/L). The major occurrence of Giardia over Cryptosporidium, both in the influent and in the effluent of the MWTP, is probably related to the human sewage contribution to the wastewater. Data on protozoa contamination of the receiving water body demonstrated similar concentrations in the samples collected before (0.21±0.07 oocysts/L; 1.31±0.38 cysts/L) and after (0.17±0.09 oocysts/L and 1.01±1.05 cysts/L) the plant effluent discharge. The results of this study suggest that the MWTP has no impact related to Giardia and Cryptosporidium river water contamination, and underline the need for investigation into the effectiveness of these protozoa removal by less technologically advanced MWTPs which are the most widespread and could probably show a lower ability to reduce protozoa.

Occurrence and persistence of bacterial and viral faecal indicators in wastewater biofilms

2007 ◽  
Vol 55 (8-9) ◽  
pp. 377-385 ◽  
Author(s):  
S. Skraber ◽  
K. Helmi ◽  
R. Willame ◽  
M. Ferréol ◽  
C. Gantzer ◽  
...  
Keyword(s):  
Dynamic Equilibrium ◽  
Wastewater Treatment Plants ◽  
Plate Count ◽  
Cryptosporidium Oocysts ◽  
The Matrix ◽  
Thermotolerant Coliforms ◽  
Viral Indicators ◽  
The Stability ◽  
Faecal Indicators ◽  
Giardia Cysts

Biofilms within wastewater treatment plants can capture enteric microorganisms initially present in the water phase immobilising them either definitively or temporarily. Consequently, fates of microorganisms may totally change depending on whether they interact or not with biofilms. In this study, we assessed the stability of wastewater biofilms comparing the evolution of the concentrations of bacteria (heterotrophic plate count [HPC], thermotolerant coliforms [TC]) and viral (somatic coliphages [SC] and F-specific phages [F+]) indicators in the biofilms and in the corresponding wastewaters at 4 and 20 °C. Additionally, we assessed the monthly occurrence of these bacterial and viral indicators as well as of pathogenic protozoa (Cryptosporidium oocysts and Giardia cysts) in three native wastewater biofilms for four months. Our results show that viral indicators (SC and F+) persist longer in biofilms than in the corresponding wastewaters at 4 °C as well as at 20 °C. In contrast, persistence of bacterial indicators (TC and HPC) depends on both the temperature and the matrix. Differences between viral and bacterial persistence are discussed. Monthly analysis of native wastewater biofilms shows that bacterial and viral indicators, as well as Cryptosporidium oocysts and Giardia cysts, attach to wastewater biofilms to a concentration that remains stable in time, probably as a result of a dynamic equilibrium between attachment and detachment processes.

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