Table 4.5 Qualitative measures of likelihood Level Descriptor Example description A Rare May occur only in exceptional circumstances; may occur once in 100 years B Unlikely Could occur within 20 years or in unusual circumstances C Possible Might occur or should be expected to occur within a 5–10-year period D Likely Will probably occur within a 1–5-year period E Almost certain Is expected to occur, with a probability of multiple occurrences within a year Table 4.6 Qualitative measures of consequence or impact Level Descriptor Example description 1 Insignificant Insignificant impact or not detectable 2 Minor Health — minor impact for small population Environment — potentially harmful to local ecosystem with local impacts contained to site. 3 Moderate Health — minor impact for large population. Environment — potentially harmful to regional ecosystem with local impacts primarily contained to on-site. 4 Major Health — major impact for small population Environment — potentially lethal to local ecosystem. Predominantly local, but potential for off-site impacts. 5 Catastrophic Health — major impact for large population. Environment — potentially lethal to regional ecosystem or threatened species. Widespread on-site and off-site impacts. Table 4.7 Qualitative risk estimation Consequences Likelihood 1 — Insignificant 2 — Minor 3 — Moderate 4 — Major 5 — Catastrophic A — Rare Low Low Moderate High High B — Unlikely Low Low Moderate High Very high C — Possible Low Moderate High Very high Very high D — Likely Low Moderate High Very high Very high E — Almost certain Low Moderate High Very high Very high Microbial health risk A quantitative risk assessment can be applied to microbial hazards, based on the approach described in Chapter 3 and Appendix 2 of Phase 1 of the guidelines (NRMMC–EPHC–AHMC 2006). The approach uses the following reference pathogens: • Cryptosporidium for protozoa and helminths • a rotavirus and adenovirus combination for enteric viruses
Type of monitoring Where Parameters Frequency Verification At entry into receiving waters and at point of supplyb Biological monitoring from locations within treatment train Microbial indicators: (E. coli, Clostridium perfringens, coliphage) Inorganic chemicals: (see ADWG) Organic chemicals: Health related chemicals (see ADWG), pesticides, hormones, pharmaceuticals, personal-care products, fire retardants, dioxins etc Disinfection byproducts Biological monitoring Microbial indicators Tested 3 times/week Inorganic chemicals Monthly Organic chemicals. Key parameters monitored monthly, other compounds monitored quarterly or annually based on likelihood of occurrence (from baseline monitoring and catchment surveys) Disinfection byproducts Monthly Biological monitoring Monthly ADWG = Australian Drinking Water Guidelines (NHMRC–NRMMC 2004); DEET = N,N-diethyltoluamide (N,N-diethyl-3- methylbenzamide); NDMA = N-nitrosodimethylamine a Range of parameters based on existing system specific data, catchment surveys, published data, consumers perceptions. Design of point of supply monitoring program should consider program and results from receiving water input.
the Orange County Groundwater Replenishment Scheme (Daugherty et al 2005) and the Singapore NEWater Scheme24 has not detected 17α-ethynylestradiol, estrone or 17β-estradiol. Table A8a Recommended drinking water guideline for pharmaceuticals with agricultural and veterinary applications Pharmaceutical Maximum concentrations detected (μg/L)a ADI (ug/kg/day)b DWG (μg/L) Margin of exposure (DWG ÷ highest concentration) Antibiotics Amoxycillin 0.02 0.43 c 1.5 75 Anhydro-erythromycin A 0.92 5d 17.5 10 Azithromycin 0.072 11 d 3.9 54 Cephalexin 0.09 10 g 35 390 Chlorotetracycline 0.28 30 e 105 e 375 Doxycycline 0.03 3 f 10.5 350 Enrofloxacin 0.015 6.2 f 22 1500 Erythromycin 1.7 5 f 17.5 10 Lincomycin 0.015 1,000 g 3500 230,000 Monensin 0.08 10 g 35 440 Penicillin G 0.03 0.43 c 1.5 50 Penicillin V 0.21 0.43 c 1.5 7.1 Sulfadimethoxine 0.06 10h 35 580 Sulfamethazine 0.68 10h 35 52 Sulfamethiazole 0.13 10h 35 269 Sulfamethoxazole 1.9 10h 35 18 Terramycin (oxytetracycline) 0.66 30 e 105 e 160 Tetracycline 0.11 30 e 105 e 950 Trimethoprim 0.35 20 g 70 200 Tylosin 1.1 300 g 1050 950 Nonsteroidal anti-inflammatory drugs (NSAIDs) Aspirin 2.1 8.3f 29 14 Diclofenac 0.81 0.5 f 1.8 2.2 Dipyrone 7.5 150f 525 70 Ketoprofen 0.38 1 g 3.5 9.2 Tolfenamic acid 1.6 5 g 17.5 11 β-andrenergic blockers Carazolol 0.12 0.1i 0.35 2.9 24
Figure A3 Cumulative frequency distribution of Munro no observed effect levels (NOELs) and corresponding NHMRC and WHO NOELs for compounds with Australian and WHO drinking water guidelines A. 100 80 60 40 Munro data (n=56) 20 NHMRC/WHO data (n=62) Regression equations: Munro Y = 11.615 Ln(x) + 37.995 (R2 = 0.9288) ADWG/WHO Y = 12.448 Ln(x) + 40.746 (R2 = 0.9570) 0 0.001 0.01 0.1 1 10 100 1000 B. NOEL (mg/kg/day) 100 80 60 3 40 Munro data (n=6) 20 NHMRC/WHO data (n=8) 0 Regression equations: Munro Y = 20.592 Ln(x) – 10.71 (R2 = 0.6991) ADWG/WHO Y = 15.636 Ln(x) + 8.3364 (R2 = 0.9877) 0.001 0.01 0.1 1 10 100 1000 NOEL (mg/kg/day) C. 100 80 60 0.15 40 20 Munro data (n=49) NHMRC/WHO data (n=53) Regression equations: Munro Y = 11.775 Ln(x) + 39.714 (R2 = 0.9153) ADWG/WHO Y = 13.367 Ln(x) + 44.296 (R2 = 0.9434) 0 0.001 0.01 0.1 1 10 100 1000 NOEL (mg/kg/day) ADWG = Australian Drinking Water Guidelines; NHMRC = National Health and Medical Research Council; NOEL = no observed effect level; WHO = World Health Organization a All compounds in Table 4.4 in common with Munro database. b Class I compounds (corresponding Munro database derived TTC value indicated by arrow).
WHO (World Health Organization) (2000). Environmental Health Criteria 218 Tris(2- butoxyethyl)phosphate, tris(2-ethylhexyl) phosphate and tetrakis(hydroxymethyl) phosphonium salts, WHO. WHO (World Health Organization) (2002a). OECD Screening Information DataSet High Production Volume Chemicals: Triphenyl phosphate, United Nations Environment Programme. WHO (World Health Organization) (2002b). OECD Screening Information DataSet High Production Volume Chemicals: Caffeine. United Nations Environment Programme. WHO (World Health Organization) (2004a). Brominated Acetic Acids in Drinking-Water: Background Document for Development of WHO Guidelines for Drinking-Water Quality, WHO, Geneva. WHO (World Health Organization) (2004b). Halogenated Acetonitriles in Drinking-water: Background Document for Development of WHO Guidelines for Drinking-Water Quality, WHO Geneva. WHO (World Health Organization) (2005). Global Assessment of the State-of-the-Science of Endocrine Disrupters, International Programme on Chemical Safety, WHO, Geneva. WHO (World Health Organization) (2006a). Guidelines for Drinking-water Quality, third edition, incorporating first addendum, WHO, Geneva. WHO (World Health Organization) (2006b). Environmental Health Criteria 237 Principle for evaluating health risks in children associated with exposure to chemicals WHO, Geneva. Wilson RM, Sigal EA, Bacigalupo CM, Willes RF and Munro IC (2000). Derivation of Risk Mangement Criteria for Chemicals of Unknown Toxic Potency at Contaminated Sites. Human and Ecological Risk Assessment 6:131–139. WSAA (Water Services Association of Australia) (2002a). Sewerage Code Version 2.1. WSAA (Water Services Association of Australia) (2002b). Water Supply Code, Dual Water Supply Supplement Version 1.1. WSAA (Water Services Association of Australia) (2004). Health Risk Assessment of Firefighting from Recycled Water Mains, Occasional Paper 11. WSAA (Water Services Association of Australia) (2006) Refilling the Glass, Position Paper 2. WSAA (Water Services Association of Australia) (2007) Draft National Wastewater Source Management Guideline.