As part of the City of Sanibel commitment to water quality, City staff and others, will be testing area waters. The samples will be used as part of research to help pinpoint and address water quality issues facing Southwest Florida.

City Compiles Regional Water Quality Testing Sites

Sanibel Sanibel City Staff has compiled a regional water quality monitoring sites map. The map indicates all agencies currently collecting water quality information in the waters within and surrounding Sanibel Island. This overview includes monitoring sites from the following municipalities and agencies:

*City of Cape Coral *Florida Department of Environmental Protection *Florida Fish and Wildlife Research Institute *South Florida Water Management District *United States Geological Survey *Sanibel-Captiva Conservation Foundation *Lee County *Florida Healthy Beaches program *Florida International University *City of Sanibel *Charlotte Harbor National Estuary Program

At the direction of City Council, several studies were conducted by the Department of Natural Resources to determine the effects of poor water quality and the presence of algae on the island's beaches on human health. The physicians working group initiated the discussion and began looking at the Lee County Health Department's data from 2000 to 2006. The Florida Healthy Beaches Program data collected from Sanibel and Captiva beaches included Blind Pass, Bowman's Beach, Lighthouse Beach, Sanibel Causeway, South Seas Plantation, and Tarpon Bay Beach from July 2000 to October 2006. The data showed an increasing trend in the number of times Enterococcus bacteria showed up in the moderate range (36-104 colonies/100ml); the number of times Enterococcus bacteria showed up in the poor range (> 105 colonies/100ml); and fecal coliform in the moderate range (200-399 colonies/100ml). However, in August 2002 the Health Department's sampling frequency went from bi-weekly to weekly and the standard for fecal coliform was lowered from 800 CFU/100 ml to 400 CFU/ml for a single sample. As a result, although it appears that there may be a trend, the number of samples collected doubled. The appearance of a trend may just be the result of increased sampling intensity. The overall number of times that samples were in the moderate or poor ranges for Entercoccus and fecal coliform was relatively low when compared to the total number of samples collected. Following evaluation of the Health Department's data, a recommendation was made to City Council to direct staff to 1) assess the adequacy of the Health Department sampling schedule in identifying health concerns associated with Sanibels beaches and 2) to identify additional pathogens present in the red drift algae. 1) Intensive Healthy Beach Monitoring Water samples were collected five days per week at five locations (Blind Pass, Bowman's Beach, Tarpon Bay beach, Lighthouse Beach and Dixie Beach) for a three week period. During the study period, two (of 15) sampling events fell within the "moderate" category for Enterococci bacteria (one at Tarpon Bay and one at Blind Pass), with one approaching the poor range. One sampling event fell into the "moderate" category for fecal coliform (Tarpon Bay). Most of the other samples were at or below the minimum detection limit (MDL) of 2 colonies/100ml.

When compared with Healthy Beaches Program data from the rest of Lee County and other Florida counties (Pinellas, Volusia, and Broward) it is not uncommon to have samples that fall within the "moderate" range. The results of this study would not have triggered closure of the beaches during the sampling period under the State's guidelines. 2) Algae Pathogen Testing To assess the human health risk of red drift algae, specifically the presence of human pathogenic bacteria, algae samples were collected at 5 locations (Blind Pass Beach, Bowman's Beach Park, Tarpon Bay Beach, Lighthouse Beach and Dixie Beach) on December 5, 2006 and sent overnight to Sherry Laboratories for pathogen testing. Samples were quantitatively analyzed for Campylobacter, Clostridium, Salmonella, Staphylococci, and Vibrio. The results of the study indicated that Campylobacter, Clostridium, and Salmonella were not detected or were below the detection limit at all sites. Staphylococci coagulase positive was below the detection limit at all sites. Staphylococci coagulase negative concentrations ranged from 30 cfu/g at Tarpon Bay Beach to 1300 cfu/g at Bowman's Beach (472 cfu/g average). Although Staphylococci coagulase negative bacteria were present, coagulase negative strains are not typically associated with human disease. Staphylococci coagulase positive bacteria (i.e. Staphylococcus aurea, the strain most associated with human disease), were not present. Currently, there are no numeric standards available for acceptable levels of Staphylococci in marine systems. However, it is important to note that since Staphylococci sp. are abundantly present in beach sediments, it is generally not considered a good indicator of beach health. Vibrio concentrations ranged from 50 CFU/ml at Blind Pass Beach to 12,000 CFU/ml at Bowman's Beach (3490 CFU/ml average). However, it is important to note that these results represent total Vibrio species. Of the approximately 75 Vibrio species, only 10-12 of those are human pathogens. Consequently, City Council directed City Staff to pursue further research to determine the occurrence of specific pathogenic Vibrio species, if any, present in the red drift algae. Follow-up Vibrio Study Dr. James D. Oliver, Department of Biology, UNC-Charlotte The city contracted with Dr. James Oliver from the University of North Carolina at Charlottes, Department of Biology to conduct additional sampling to determine if pathogenic Vibrio species were present in the algae, water, and sediments at five beach locations. Samples were collected from Blind Pass Beach, Bowmans Beach, Tarpon Bay Beach, Lighthouse Beach, and Dixie Beach. Vibrio species are gram-negative, motile bacteria that are indigenous to the marine environment, found in estuaries, marine coastal waters, sediments, shellfish, and aquaculture sites worldwide. Only three Vibrio species are of significant pathogenic concern to humans: Vibrio cholerae, V. parahaemolyticus, and V. vulnificus. These species are capable of causing serious human infections which result from the consumption of raw shellfish or exposure of pre-existing wounds to sea water or seafood products. Samples of water, algae and sediment were collected from 5 sites, and each sample was tested in triplicate for a total of 45 samples.

Total Vibrio counts in water and algae were highest at Lighthouse Beach, 1100 and 48000 CFU/ml(g), respectively. Total Vibrio counts in sediment were highest at Dixie Beach (110,000 CFU/g). Although Vibrio species were present, Blind Pass Beach and Tarpon Bay Beach were negative for all three of the pathogens tested. Bowman's Beach Pathogenic V. vulnificus was detected in water (50 CFU/ml) and sediment (430 CFU/ml) samples. This level of V. vulnificus may be of concern, but being part of the normal bacterial flora of sea water (and thus algae), there is really nothing that is practical that can be done. These levels, however, are far lower than what is typically found in a single oyster, and thus are relatively in low numbers.

Lighthouse Beach V. parahaemolyticus was identified in samples from all sources at Lighthouse Beach: water (7 CFU/ml), algae (84 CFU/g), and sediment (78 CFU/g). It appears that this site has the appropriate environmental conditions that favor the presence of V. parahaemolyticus; however, all were negative for the hemolysins (TDH and TRH) that are required for pathogenesis and should not be of concern. V. vulnificus was also identified within the sediment (330 CFU/g). This level of V. vulnificus is not considered especially high.

Dixie Beach From sediment at this site, 860 CFU/g were identified as V. parahaemolyticus. These isolates were TDH positive (TRH negative) indicating that they are of a strain type which can be associated with human infection. This was the only site where V. parahaemolyticus samples tested positive to the hemolysin gene, TDH and the only intercoastal site tested. Except for the sediment samples at Dixie Beach, total Vibrio concentrations were generally low at all sites sampled, and from all sources. These tended to increase (particularly in algae samples) moving from west to east along the Gulf side of the island and peaked at the Lighthouse sampling site (see figure, left). While pathogenic Vibrio species were found at a variety of sites around the island, it was only at the Lighthouse site where V. parahaemolyticus was found in all samples (water, sediment and algae). Furthermore, this was the only site to have pathogens present in algae samples. On the day of sampling a fish kill was reported at the Lighthouse sampling site, presumably due to an off-shore red tide algal bloom. However, our results are not able to determine if there is an association between Total Vibrio and/or Vibrio pathogen concentrations and red tide. I After reviewing this report, Gary Maier of the Lee County Health Department provided the following comparisons to Vibrio data collected from Charlotte Harbor in 1998. This study analyzed water (monthly) and sediment (quarterly) samples for V. vulnificus from 12 sites in Charlotte Harbor. WATER TESTING: On Sanibel (UNC-Charlotte Study, January 2007), V. vulnificus in water ranged from not detected (ND) to 71 CFU/ml, with an average of 24 CFU/ml. In the Charlotte Harbor study, in December 1998, V. vulnificus in water ranged from ND to 21 CFU/ml, with an average of 9 CFU/ml. In the Charlotte Harbor study, in September 1998 (highest for the water), V. vulnificus in water ranged from 12 to 165 CFU/g, with an average of 71. SEDIMENT TESTING: On Sanibel (UNC-Charlotte Study, January 2007), V. vulnificus in sediment ranged from ND to 433 CFU/g, with an average of 152 CFU/g. In the Charlotte Harbor study, in December 1998, V. vulnificus in sediment ranged from 17 to 2,610 CFU/g, with an average of 568. In the Charlotte Harbor study, in May 1998 (highest for the sediment), V. vulnificus in sediment ranged from 464 to 68,500 CFU/g, with an average of 14,245 CFU/g.