potential risks associated with leaching of organic contaminants and endocrine disruptors from...
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Potential Risks Associated with Leaching of Organic Contaminants and Endocrine Disruptors from Plastic Piping Materials
Glen R. Boyd ([email protected])
Gregory L. Pierson HDR Engineering, Inc. Ronald J. EnglishSeattle Public Schools
Pacific Northwest Section
AWWA
Vancouver, WAMay 2, 2008
500 108th Ave NE, Ste 1200Bellevue, WA 98004
Outline
• Background• Objective• Current Knowledge & Perceptions• Typical Plastic Plumbing in Schools• Safeguards – Industry Standards• Conclusions
Background - Seattle Public Schools
Number of students: 47,000
No. of schools & admin facilities: 102
Number of schools >40 years old: 60%
(plumbed primarily with galvanized steel piping and moderately tuberculated)
Background - What were the Issues?
• Parents inquiries in late 2003
– Unpleasant appearance of water in several older schools
– Rusty water health concern
– Pb exposure
– Other WQ concerns
• Seattle Schools previously addressed WQ issues in 1990
Background - Phase 1 Testing in 2004
• Objective and Approach
– Assess water quality in Seattle Public Schools
– Sampled 3,000+ sources (primarily fountains)
– Analyzed for Pb plus Cd, Zn, Cu, Fe, turb, color, and colif bact
• Results
– 19% first-draw 250-mL samples Pb >20 g/L (EPA guideline for schools)
– Some fountains exhibited Pb >1000 g/L
• Outcome – Seattle School Board Policy
– Pb must be 10 g/L in first-draw 250-mL sample prior to service
– Implement District-wide Mitigation Program
Background - Sources of Pb are Numerous
• Old galvanized piping inlaterals, risers and service lines
• End-use connective piping
• 50:50 Sn:Pb solder
• Brass valves & other components
• Bubbler heads
• Kitchen and classroom faucets
Background – Upgrade Plumbing
Old end-use connective piping
New plastic tubing and components
Overall Mitigation Program Goal – Meet School Board Policy
Pb 10 g/L in all first-draw 250-mL samples
Background – Parents’ Concern
Metal parts – release of Pb and other metals
Plastic parts – potential release of organics (e.g., EDCs and other)
Water Quality Oversight Committee – Precautionary Principle
Fully evaluate alternatives – prevent or minimize harm
Objective
• Assess potential risks associated with using plastics in place of metals in schools – Review available literature– Review industry standards
Current Knowledge – Endocrine (Hormone) System
• Hormones are synthesized and secreted by glands into blood stream
• Regulation of biological processes– Function of reproductive
system– Brain and nervous system– Metabolism
Current Knowledge – Endocrine Disrupting Compounds (EDCs)
• Endocrine Disruptor – an exogenous substance or mixture that alters functions of the endocrine system and consequently causes adverse health effects
• Dose-Response Relationships– EDCs mimic or antagonize natural
hormones– Low-dose effects – controversial– Timing of exposure is critical
Trussel, R. 2001. JAWWA 93(2):58-65
WHO. 2002. Global Assessment of EDCs.
Current Perception – Why is the Public Increasingly Concerned?
“… study examined nine pesticides … used on cornfields in the midwestern United States.”
“Larvae were treated by immersion with 0.1 ppb each atrazine, S-metolachlor, alachlor, nicosulfuron, cyfluthrin, -cyhalothrin, tebupirimphos, metalaxyl, or propiconizole.”
“Seventy percent of the animals exposed to the nine-compound mixture were unable to sit upright.”
T.B. Hayes et al. 2006. Env. Health Perspect, Vol. 114, S-1, Apr.
Current Perception – Why is the Public Increasingly Concerned?
Meds lurk in drinking water
AP probe found traces of meds in water supplies of 41 million Americans
Associated Press – March 9, 2008
“A vast array of pharmaceuticals — including antibiotics, anti-convulsants, mood stabilizers and sex hormones — have been found in the drinking water supplies of at least 41 million Americans, an Associated Press investigation shows….” Ref: Ref: Env. Health PerspEnv. Health Persp., Oct ., Oct
2000.2000.
Current Perception – Why is the Public Increasingly Concerned?
Containers made with bisphenol A chemical linked to health risks
Associated Press – April 18, 2008
“Hard-plastic Nalgene water bottles made with bisphenol A will be pulled from stores over the next few months because of growing consumer concern over whether the chemical poses a health risk.”
Nalgene to phase out hard-plastic bottles
Typical Plastic Plumbing - Seattle Public Schools
Plastic Pipe or Component Description Certification
Sch 80 PVC Connective Piping
⅛ - ¼” PVC and CPVC NSF 61
Sch 80 PVC Fittings
⅜ - ½” PVC and CPVC NSF 61
Polyethylene (PE) flexible tubing
⅜” OD (125 psi, 150°F) NSF 61
Polypropylene (PP) fittings
Fittings for food, any size (212°F) NSF 51
Plastic Materials – Polymeric Chains
• Polyvinyl chloride (PVC) and chlorinated PVC (CPVC)
• Polyethylene (PE)
Ref: www.wikipedia.org
• Polypropylene (PP)
Common Chemical Additives – Manufacturing of Plastics
• Phthalates – plasticizers improve flexibility, workability, softness, and elongation properties
Di-(2-ethlyhexyl)-phthalates (DEHP)
Diisononyl phthalate (DINP)
• Phenolics – stabilizer or antioxidant for material durability
Ref: www.lineone.net
Bisphenol A
• Organotins – heat and UV-oxidation resistance stabilizers used in rigid and flexible PVC and other plastics
Dibutyltin Dimethyltin R2SnX2
Leaching of Chemical Additives in Drinking Water
Chemical Additive
Reported Leaching Levels in Distributed
Water (µg/L)Reference
PhthalatesUSA 0.05-1.1
WHO (2003)Japan 1.2-1.8
PhenolicsJapan >0.94
Hu et al (2002)Chlorinated
BPA v. reactive
OrganotinsNew PVC 0.028-0.053 Sadiki et al
(1996; 1999)Dwellings <0.0005
WHO (2003) – World Health Organization; Hu et al (2002) Environ Sci Technol; Sadiki et al (1996; 1999) Chemosphere.
Safeguards – Industry Standards
• NSF/ANSI Standards and Certification Program – applies to all direct and indirect drinking water additives
NSF International (lead), AwwaRF, ASDWA, CSHEM, and AWWA
• NSF Standard 61
Minimum health effects requirements for chemical contaminants indirectly imparted from materials used in drinking water systems
Safeguards – Industry StandardsTable 2 - Material-specific Analyses
Material TypeRequired Analyses
Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC)
Phenolics1, regulated metals2, VOCs, tin4, antimony5, residual vinyl chloride monomer (RVCM)6
Polyvinyl chloride (flexible) Phenolics1, regulated metals2, VOCs, tin4, RVCM6, phthalates7, zinc8
Polybutylene (PB) VOCs, regulated metals2, phenolics1
Polyethylene (PE) VOCs, regulated metals2, phenolics1
Polypropylene (PP) VOCs, regulated metals2, phenolics1
1 Analysis in accordance with EPA Method 420.2 or other as indicated in NSF/ANSI 61 – 2003e, section B.7.4.2 Antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, thallium4 Required when tin-based stabilizers are used.5 Required when antimony-based stabilizers are used.6 Analysis of residual vinyl chloride monomer in PVC and CPVC products using GC-FID by analyzing 0.5 g of plastic material to method sensitivity of 0.5 ppm (mg/kg).7 Required when phthalate ester plasticizers are used. Analysis shall be for the specific phthalate ester(s) used in the formulation.8 Required when zinc-based stabilizers are used.
Based on Table 3.1 – Material-specific analyses, NSF/ANSI 61-2003e, page 7.
Safeguards – Industry Standards
Table 5 - NSF International drinking water criteria (not externally peer reviewed)
Substance CAS#Total Allowable
Concentration (TAC), mg/L
Bisphenol A 80-05-7 0.2
Butyltin compounds (mono- and di- only)
N/A 0.02 (total)
Diisononyl phthalate 28553-12-0 0.05
Isophthalic acid 121-91-5 0.01
Terephthalic acid 100-21-0 0.01
Derived from Table E1, NSF/ANSI Standard 61-2003e, page E3.
New products must satisfy “risk assessment” based criteria (NSF/ANSI Standard 61-2003e) as summarized in Table 5.
Expert Opinion
National Academy of Sciences, Water Science and Technology Board – Public Water Supply Distribution Systems: Assessing and Reducing Risks (2005)
“A committee … will conduct a study of water quality issues associated with public water supply distribution systems and their potential risks to consumers.”
“The study will consider …… cross connections and backflow, pressure transients, nitrification, permeation and leaching, repair and replacement of water mains, aging infrastructure, and microbial growth.”
“… it is currently believed that leaching is a relatively low priority relative to other distribution system problems.”
http://www4.nas.edu/webcr.nsf/ProjectScopeDisplay/WSTB-U-04-06-A?OpenDocumenthttp://www.nap.edu/books/0309096286/html/R1.html
