Minimum Bromine Concentrations

Minimum bromine concentrations shall be maintained at all times in all areas as follows: 1) All AQUATIC VENUES: 3.0 PPM (MG/L), and 2) SPAS: 4.00 PPM (MG/L).

Bromine concentrations established by state and local jurisdictions have not been found to correlate with data supporting the concentrations being used. However, every state or local jurisdiction that allows bromine as a disinfectant requires bromine at higher concentrations than CHLORINE and almost twice as much in SPAS and warmer POOLS. Commercially available test kits are not capable of distinguishing free bromine (Br2, HOBr, OBr-) from combined bromine (bromamines). The bromine value specified in test results is the concentration of total bromine, not the free available halogen that is tested with CHLORINE. To determine total bromine, test kit manufacturers use a CHLORINE value and multiply it by 2.25. The 2.25 conversion factor accounts for the molecular weight difference between elemental bromine and elemental CHLORINE (Br = 79.90 grams per mole and Cl = 35.45 grams per mole). Further, presently used field test kits assay only for total bromine. Bromine is commonly used in indoor commercial SPAS, probably due to these two factors. First, bromamines (bromine and ammonia combined) do not produce irritating odors as do chloramines. Second, bromine efficacy is less impacted than CHLORINE’S at a higher pH, which typically occurs in a SPA environment. At pH of 7.5, 94% of bromine is hypobromous acid, whereas at the same pH, hypochlorous acid is 55% in chlorinated water. At pH of 8.0 bromine still has 83% hypobromous acid, while in a chlorinated water, hypochlorous acid is 28%.³³⁴ Bromine is also not very common in outdoor POOLS because like CHLORINE, bromine is destroyed rapidly in sunlight. Cyanuric acid was developed to combat the problem in chlorinated POOLS, but does not provide a stabilizing effect for bromine. While reviewing the literature and surveillance data from CDC, evidence that outbreaks have occurred when required minimum bromine concentrations have been maintained is lacking. Therefore, in absence of any clear research, the decision to use common state requirements as the recommended levels is prudent. SPAS have been implicated in many skin disease outbreaks throughout the years. One paper suggests that a common culprit, Pseudomonas aeruginosa, were rapidly reestablished in whirlpools (less than 103 cells per mL) when disinfectant concentrations decreased below recommended levels (chlorine: 3.0 PPM (mg/L); bromine: 6.0 PPM (mg/L)). The authors studied the reoccurrence of bacteria following cleaning and halogen shock treatment³³⁵. This study emphasized the need for maintaining a consistent CHLORINE level in the SPA. CDC recommends 4-6 PPM (mg/L) for bromine. The MAHC recommends a follow up study to evaluate the efficacy of bromine on P. aeruginosa, since it is so commonly found in SPAS; and because bromine is very common disinfectant used in SPAS, prevention and treatment is essential. There are few peer-reviewed studies on bromine efficacy in real world POOLS and SPAS in the literature. Brown et al. reported reasonable bacterial control with 2.0 total bromine in an 118,000 gallon (447 m3) INDOOR POOL using BCDMH³³⁶. Normal day time BATHER COUNTS were around 0.21 persons per 500 gallons (1893 L) per hour but often increased to as high as 0.85 in the evening. The POOL did not use supplemental OXIDATION but did replace 5% of the water daily which likely contributed to the low reported ammonia nitrogen and organic nitrogen. Shaw reports a retrospective analysis of brominated and chlorinated semi-public SPAS in Alberta.³³⁷ The data used was from the microbiological results of the weekly samples required under provincial regulations. The treatment systems compared include BCDMH (oxidation method not specified), bromide salt regenerated by hypochlorous acid/potassium monopersulfate continuous feed, CHLORINE gas, hypochlorite (type not specified), dichlor, and trichlor. The concentrations were generally in line with provincial regulations of 2 PPM (mg/L) total bromine and 1 PPM (mg/L) free CHLORINE. The brominated SPAS had a higher failure rate in all three bacterial parameters. There were several complaints of both contact dermatitis and Pseudomonas folliculitis from the brominated SPAS during the period studied, but due to the nature of the retrospective studies, it was not possible to link the reported RWIs to the concentration of the disinfectant at the time of the complaint. It appears from composite data that when semi-public SPAS are operated using the U.S. EPA minimum halogen concentration of 1.0 PPM (mg/L) free CHLORINE or 2 PPM (mg/L) total bromine that Pseudomonas aeruginosa can be isolated from the brominated SPAS at greater than twice the frequency than from chlorinated SPAS. Bromates Ozone and bromide ions in water form hypobromous acid and bromate ions. Bromates have been classified by the International Agency for Research on Cancer (IARC) as having sufficient evidence of carcinogenicity in laboratory animals. As a result, WHO has set a provisional drinking water guideline value of 10 ug/L. The U.S. EPA has established a maximum CONTAMINANT level of 10 ug/L for bromate in drinking water. BCDMH (1-bromo-3-chloro-5, 5-dimethylhydantoin) is the most common form of bromine used in commercial POOLS and SPAS today. The function of DMH is to inhibit the formation of bromates. At present there is little information on the functionality of using DMH in this manner. Since there is not a convenient field test kit available, an operator has no way of knowing what the DMH level is in the water or when it may go below 10 PPM (mg/L) to allow bromates to form. We also do not know what the maximum safe level of DMH should be. To rely on DMH for bromate prevention, suitable test methods and further research are necessary. Operators should consider that ozone should likely not be used with bromine systems when there is a substantial likelihood of ingestion of the water. When ozone is used in conjunction with organic bromine sources (BCDMH or DBDMH—another common source of bromine), the ozone readily converts residual bromide ion back to hypobromous acid. This process reduces ozone. With the continued addition of BCDMH, DBDMH, or sodium bromide, the bromide levels will continue to climb in the POOL or SPA. Continuous build-up of bromide will constantly reduce ozone; diminishing ozone’s effective OXIDATION (and destruction) of organics and microorganisms in the water. Because of the wide variation in the concentration of bromide and the potential for bromate ingestion at least one ozone manufacturer does not recommend the installation of ozone units in bromine-treated facilities. Disinfection DISINFECTION using bromine is more complex but less well documented than DISINFECTION using CHLORINE. Hypobromous acid is the putative biocidal chemical species at recreational water pH. Hypobromous acid reacts with inorganic ammonia and forms monobromamine, dibromamine, and nitrogen tribromide, depending on the pH and concentration of ammonia.³³⁸ These inorganic bromamines are all considered more biocidal than their corresponding CHLORINE analogs. Hypobromous acid is converted to inert bromide ion upon biocidal action in a manner similar to that seen with hypochlorous acid. One key difference between bromine and CHLORINE DISINFECTION is that bromide is readily oxidized back to hypobromous acid and chloride is not. Further, hypobromous acid is a much weaker oxidizer than hypochlorous acid. As a consequence of these two differences, exogenous OXIDATION of brominated waters (e.g. shocking with chlorine) is more important for safe operation than it is in chlorinated waters. In reviewing the published epidemiological studies on RWIs, it is often difficult to determine the exact treatment system used because the SUPPLEMENTAL TREATMENT SYSTEM is not described. Further, presently used field test kits assay only for total bromine and are not capable of distinguishing free bromine from biocidal inorganic bromamines or from non-biocidal organic bromamines. Bromamines Current POOL and SPA operating manuals state that combined bromine (bromamines) is as efficacious as free bromine. This may be an over generalization of the complex nature of bromine chemistry. Bromine reacts with inorganic ammonia and forms analogous compounds (Br2, hypobromous acid, monobromamine, dibromamine, and nitrogen tribromamide) depending in the pH and concentration of ammonia.³³⁹ All three bromine-ammonia derivatives are biocidal, but all three are also less stable than their corresponding CHLORINE compounds. As with their CHLORINE analogs, the ratios of the bromamines are highly dependent on the ratio of ammonia to bromine. Further, at low ammonia to bromine ratios the biocidal action appears to be substantially reduced³⁴⁰. The levels of ammonia that result in loss of bromine efficacy have been detected in SPA water³⁴¹. At these documented concentrations of bromine and ammonia, the predominant bromamine is most likely dibromamine, which has an estimated half-life of 10 minutes³⁴². The MAHC was not able to locate data on the efficacy of organic bromamines. Future Research Needs Cryptosporidium Inactivation Methods to hyper-brominate recreational water in response to diarrheal fecal accidents have not been established. Research in this area is lacking. Bromine Associated Rashes Note to readers: These comments have been inserted to point future researchers toward an under-investigated area of public health and are not meant to imply a negative bias toward bromine. Literature reviews demonstrate a large number of reports describing rashes associated with brominated water. These rashes fall into two general categories: * Contact dermatitis due to brominated species in the water, and * Dermal infections due to Pseudomonas aeruginosa. These are most easily differentiated by incubation time. The vast majority of contact dermatitis reactions occur within 24 hours of immersion, sometimes within minutes. These are often referred to as “bromine itch” and are widely reported in the medical literature³⁴³,³⁴⁴,³⁴⁵. In most cases the putative etiological agent is thought to be bromamines. This type of dermatitis appears to be a result of cumulative exposure to bromine treated water and is particularly prevalent among medical personnel who provide aquatic physical therapy³⁴⁶. The exact compounds inducing contact dermatitis have not been identified. One study strongly suggests that the use of bromine with supplemental OXIDATION minimizes contact dermatitis³⁴⁷. In numerous epidemiological studies, poor water quality is commonly, but not always, reported (Woolf and Shannon report an extreme example of a foamy pool leading to multiple cases of contact-related RWI³⁴⁸). The typical incubation period for Pseudomonas aeruginosa folliculitis is several days but can be as short as 24 hours. Outbreaks of Pseudomonas aeruginosa folliculitis are routinely associated with inadequate sanitation in both chlorinated and brominated waters. The minimum concentration to prevent such outbreaks has not been established but appears to at least one PPM (mg/L) free CHLORINE and two PPM (mg/L) total bromine. A survey of the literature since the mid-1980s shows more dermal RWI outbreaks reported in brominated waters than in chlorinated waters. It is not known whether the reports reflect the true incidence, a bias in reporting of bromine systems, or a bias in reporting RWIs in SPAS, which tend to use bromine disinfectants. There are many unanswered questions surrounding bromine-treatment systems commonly used in AQUATIC VENUE DISINFECTION. After reviewing the literature, the MAHC has concluded the following research is essential to understanding bromine DISINFECTION. Further research needs to address, in priority order: * The efficacy of bromine to establish a minimum concentration for AQUATIC VENUES and warm water SPAS and THERAPY POOLS, * The maximum bromine concentration that should be allowed, * The contribution of bromamines to DISINFECTION and BATHER rashes, * Methods to better control bromamines, * Creation of a test kit to differentiate free bromine from combined (as is currently practiced with chlorine) in the water, * Use of DMH in respect to bromate formation, * Establish a safe maximum level, * Creation of a test kit to establish levels in the water, and * Fecal accident recommendations to control Cryptosporidium when using a bromine POOL.