Understanding the distribution of positive Legionella samples in healthcare-premise water systems: Using statistical analysis to determine a distribution for Legionella and to support sample size recommendations.

OBJECTIVE: To significantly fit a statistical distribution to the proportion of positive Legionella samples in a series of water samples from multiple facility-premise water systems. DESIGN: Statistical fit test. SETTING: A hospital and associated long-term care facility (LTCF) in New York State, as well as temporal and culture data from a deidentified hospital site supplied by one of the vendor laboratories. METHODS: Culture samples (n = 1,393) were segmented into 139 test cycles with roughly 10 samples in each. The proportion of positive samples was standardized to 25 total samples per test to give a distribution of discrete values. These values were analyzed for fit with the following discrete distributions: Poisson, negative binomial, geometric, and zero-inflated Poisson. RESULTS: The zero-inflated Poisson distribution fitted to the copper-silver ionization (CSI)-treated and untreated test cycles indicates that 88% of the expected positive proportions should occur by the 30% cutoff (rounded up to 8 positive samples among 25 total samples), similar to the 93% expectation for just CSI-treated test cycles. The other treatment in these data (chlorine dioxide) was not effective in treating Legionella in the sampled buildings, and if there is an underlying distribution to these specific test cycles, it is not the zero-inflated Poisson distribution. CONCLUSIONS: In a well-maintained or well-treated premise water distribution system, ~30% or lower proportion of positive Legionella samples should occur. Anything above that cutoff is either very unlikely or not expected at all and indicates a problem in the water system.

Development of recreational water spray ground design regulations in New York State, an engineering approach.

The New York State Department of Health developed regulations for the design and operation of spray grounds to address the potential for recreational water illnesses associated with this type of venue. The water treatment component of the new regulation was based on a first-principles approach to address the unique challenges of spray grounds. The regulation departs from traditional recreational water treatment methods by requiring a novel filtration approach and the installation of UV disinfection. The water treatment system was also required to incorporate automatic control systems to ensure the water quality is maintained with a minimum of operator involvement. The treatment process specifications were based on pathogen and contaminant loadings that are likely to be encountered at spray grounds. The regulation was finalized in 2007, giving New York State a reliable means of protecting the health of spray ground patrons.

Use of copper-silver ionization for the control of legionellae in alkaline environments at health care facilities.

BACKGROUND: There are multiple treatment options for the control of legionellae in premise hot water systems. Water chemistry plays a role in the efficacy of these treatments and should be considered when selecting a treatment. This study demonstrated the efficacy of copper-silver ionization (CSI) under alkaline water conditions in 2 health care facilities. METHODS: Monitoring for copper (Cu) and silver (Ag) ions was performed, and the corresponding percentage of positive Legionella cultures was monitored. Low Legionella colony forming units (CFU), with a mean <10 CFU/100 mL, and ≤30% positive culture for each sampling period, along with no recurrent disease, were considered indicative of control. RESULTS: CSI treatment was shown to reduce both the number of CFU found and the percentage of samples found to be culture positive. After treatment was established, culture positivity was, for example, reduced from 70% (>10(3) CFU/100 mL) to consistently <30% (38 CFU/100 mL). CONCLUSION: Control of legionellae in premise water systems may be a complex process requiring long-term assessments for adequate control. This work found that CSI could be successful in controlling Legionella under alkaline water conditions, and the evidence suggests that Ag ions are responsible for the control of Legionella pneumophila 1, L pneumophila 6, and L anisa.

A pilot study on the assessment of trace organic contaminants including pharmaceuticals and personal care products from on-site wastewater treatment systems along Skaneateles Lake in New York State, USA.

On-site wastewater treatment systems (OWTSs or septic systems) are designed to treat and dispose effluents on the same property that produces the wastewater. Approximately 25% of the U.S. population is served by such facilities. Nevertheless, studies on the treatment efficiency and discharge of organic contaminants through septic effluents are lacking. This pilot study showed the occurrence of organic contaminants including pharmaceuticals and personal care products (PPCPs), perfluoroalkyl surfactants (PFASs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) in septic effluents, adjacent lake water samples, household drinking water in homes that use lake water or a well adjacent to the lake as a source of drinking water, and offshore lake water samples. Septic effluent as well as lake and tap water samples were collected from several households with OWTSs around Skaneateles Lake located in central New York. The advanced on-site systems were installed in some households for the purpose of limiting nutrient levels in the effluent to protect the local surface water. Additionally, because many of these systems serve homes with limited land, advanced treatment systems were needed. The median concentrations of ten PPCPs (ranged from 0.45 to 388 ng/L) and eleven PFASs (ranged from 0.20 to 14.6 ng/L) in septic water were significantly higher (p ≤ 0.01) than in lake water samples. The median concentrations of PPCPs and PFASs in lake and tap water samples were not significantly different (p ≥ 0.65). The median concentrations of ∑PBDEs in septic, lake, and tap water samples were 7.47, 3.49, and 2.22 ng/L, respectively, and those for ∑PCBs were 33.1, 29.2, and 28.6 ng/L, respectively. The mass flux of PPCPs (i.e. the mass flow of PPCPs per unit area per unit time) through the disposal of treated septic effluent from textile biofilter and aerobic treatments to the dispersal unit ranged from 12 (carbamazepine) to 66900 µg/m(2)/day (caffeine) whereas that for PFASs ranged from 7.0 (perfluorobutanesulfonate) to 833 µg/m(2)/day (perfluorooctanoic acid). Based on the ratio of measured concentrations and method detection limit, triclocarban, perfluorooctanoic acid, and perfluorooctanesulfonate have the potential to be used as chemical tracers of septic water contamination in Skaneateles Lake. The median concentrations of atenolol, a beta-blocker drug, in septic water were significantly (ρ = 0.86, p = 0.01) correlated with enterococci counts.

A review of potable water accessibility and sustainability issues in developing countries - case study of Uganda.

Providing sources of sustainable and quality potable water in Uganda is a significant public health issue. This project aimed at identifying and prioritizing possible actions on how sustainable high quality potable water in Uganda's water supply systems could be achieved. In that respect, a review of both the current water supply systems and government programs on drinking water in Uganda was completed. Aspects of quantity, quality, treatment methods, infrastructure, storage and distribution of water for different water systems were evaluated and compared with the existing water supply systems in the U.S., Latin America and the Caribbean, for purposes of generating feasible recommendations and opportunities for improvement. Uganda utilizes surface water, groundwater, and rainwater sources for consumption. Surface water covers 15.4% of the land area and serves both urban and rural populations. Lake Victoria contributes about 85% of the total fresh surface water. Potable water quality is negatively affected by the following factors: disposal of sewage and industrial effluents, agricultural pesticides and fertilizers, and surface run-offs during heavy rains. The total renewable groundwater resources in Uganda are estimated to be 29 million m3/year with about 20,000 boreholes, 3000 shallow-wells and 200,000 springs, serving more than 80% of the rural and slum communities. Mean annual rainfall in Uganda ranges from 500 mm to 2500 mm. Groundwater and rainwater quality is mainly affected by poor sanitation and unhygienic practices. There are significant regional variations in the accessibility of potable water, with the Northeastern region having the least amount of potable water from all sources. Uganda still lags behind in potable water resource development. Priorities should be placed mainly on measures available for improvement of groundwater and rainwater resource utilization, protection of watersheds, health education, improved water treatment methods and distribution in rural areas, and pollution control and monitoring. Implementing these changes can promote potable water accessibility especially to the poor populations living in rural and urban slum areas because they comprise the majority (80%) of Uganda's population.