Presentation on theme: "Assessing The Risk of Bisphenol-a Kyla Bedard Doug Brown Katie Gibbons Kate Riley Stephanie Walsh."— Presentation transcript:
Assessing The Risk of Bisphenol-a Kyla Bedard Doug Brown Katie Gibbons Kate Riley Stephanie Walsh
BPA News Video http://www.youtube.com/watch?v=Mor3xRZuKMU
BPA Facts 2,2,-bis (4-hydrotphenyl) propane high productive chemical used in manufacture of numerous consumer goods and products a known endocrine disrupting chemical In 2004, 2.3 billion pounds produced in U.S 3/4 used in manufacture of polycarbonate resins for food and beverage storage Polycarbonate is recycling #7
Migration of BPA from polycarbonate material Studies have found solid evidence that BPA does migrate from PC plastics into the food, drink or water in contact.
2008 study by Le, et al. Compared migration of BPA from new and used high quality PC drinking bottles into water Hot vs. room temperature water Results: BPA leached from all bottles At room temp: [BPA] released increased over time [BPA] released from new and used bottles about equal [BPA] in heated samples doubled that of room temp. After heated bottles cooled, elevated rate of BPA migration when filled with room temp. water
2003 study by Brede et al. Tested 12 new PC baby bottles Simulated normal use (dishwashing, boiling, brushing) Results: Before washing: levels of BPA present in water in each After washing: significant increase in the migration of BPA Migration levels of BPA into water decreased between 51 and 169 washings Conclusions: Initial increase in [BPA] migration due to use, then decrease Overall, used and new PC bottles leach about equal amounts
2003 study by Howdeshell et al. Examined new and used PC cages to see if BPA would passively release into water at room temp. Results: Significant amounts BPA released from used cages Smaller, detectable levels released from new cages Laboratory animals kept in cages exposed to [BPA] Le et al. study acknowledged this difference in findings: Attributed difference to washing technique of used cages to be in compliance with federal law Washed at temperatures exceeding 82°C, while normal washing of PC water bottles would not exceed 50 °C
2003 study by Sajiki & Yonekubo Examined BPA migration from PC tubing to seawater, freshwater and purified water at 20°C and 37°C Results: [BPA] released increased with time and temperature BPA leaching velocity fastest in seawater Addition of phosphates to water increased BPA migration Conclusions: BPA degrades naturally in seawater due to microbial communities However, should we worry about BPA leaching when massive amounts of plastic is dumped into the oceans each year? Leaching from plastic debris in warmer, shallow ocean waters may lead to a problems
Non-Human Studies Most use rodents Orally administer BPA Four highlighted studies of BPA studies
Relevance to Humans? Metabolism rate Body mass Chemical breakdown Gestation Period Brain Function Endocrine System
Overview of Study on Growth and Development BPA imitates T3 cells Induces over stimulation of GH mRNA and in response the body limits secretion of GH Main defect is stunted brain development in rats
PCOS in Rats Polycystic Ovary Syndrome (PCOS) Symptoms found in pregnant rats exposed to high doses of BPA Women with symptoms of PCOS reportedly have higher levels of BPA than non-PCOS women
Impacts of BPA on Rats Chronic exposure to male fetuses results in prostate and bladder defects Early onset of puberty in male and female rats (at high doses) Altered ratios of male to female births Decrease in sperm and embryo counts (high doses)
Human Risks Calafat, et. al, 2005 A human reference population, n=394 95% of sample at concentrations ≥ 0.1 µg/L of urine mean concentration of 1.33 µg/L
Padmanabhan, et. al, 2008 unconjugated BPA in the blood of pregnant mothers at levels ranging between 0.5 ng/mL and 22.3 ng/mL Sugiura-Ogasawara, et. al, 2005 women who are exposed to high levels of BPA were more likely to have recurrent miscarriages Patients were found to have 2.59 ± 5.23 ng/mL of BPA in their blood
Haighton, et. al, 2002 BPA is not likely to be directly carcinogenic to humans Diel, et. al, 2002 BPA is not able to induce the proliferation of breast cancer cells BPA may be a very potent inhibitor of cell apoptosis
Staples et. al, 2002 Adverse effects on survival, growth, and reproduction occurring at concentrations of 160 µg/L and above Typical surface water concentrations of BPA in the range of 0.001 to 0.10 µg/L Ecological Effects
BPA is not carcinogenic and does not selectively affect reproduction or development. The No-Observed-Adverse- Effect-Level for BPA, confirmed in multiple laboratory animal tests, is 50 mg/kg body weight/day
The estimated dietary intake of BPA from polycarbonate plastic and epoxy resin food contact applications, based on the results of multiple migration studies with consistent results, is less than 0.000118 mg/kg body weight/day
This potential human exposure to BPA is more than 400 times lower than the maximum acceptable or "reference" dose for BPA of 0.05 mg/kg body weight/day established by the EPA.
Risk Assessment Last risk assessment by the EPA based on research conducted in the 1980s In 2007 the European Food Safety Authority released a risk assessment for BPA including increasing the Tolerable Daily Intake (TDI) from 5 micrograms/kg weight/day to 50 micrograms/kg weight/day
Currently the LOAEL is 50mg/kg/day established by the US EPA Many studies are finding adverse effects with doses less than the LOAEL A literature review by Saal and Hugues 2007 showed that out of 115 published studies using BPA doses lower than the LOAEL, 31 of those published studies reported significant effects caused by doses at or below 50 μg/kg/day.
Adverse effects from these studies include; rate of growth and sexual maturation, hormone levels in blood, reproductive organ function, fertility, immune function, enzyme activity, brain structure, brain chemistry, and behavior.
The global production rate of products containing BPA exceeds 6.4 billion lb/year That rate of production is expected to increase 6- 10% Because alternatives to BPA use exist, a new risk assessment needs to be conducted by the EPA to establish a valid LOAEL that is representative of the latest scientific findings
Alternatives to polycarbonate water bottles Stainless Steel - reusable, lightweight bottles are made of stainless steel inside and out. Stainless steel doesn't leach or react, but avoid freexing or filling with hot water. A popular supplier is Klean Kanteen. Glass - pose no health risks, but have the obvious disadvantage of being breakable. Polypropylene - look for bottles made of #5 PP (polypropylene) HDPE (Polyethylene) - look for bottles made of #2 HDPE (high density polyethylene), or a #4 LDPE (low density polyethylene). HDPE is a softer opaque plastic made from petroleum. Scientists and health advocates have reported no known problems with HDPE. Nalgene makes bottles of this material. Enamel coated aluminum - Sigg is a popular supplier Corn-based - these reusable bottles use no plastic or petroleum based materials.
Questions? Do you think there is a risk associated with BPA? Can we eliminate the risk of BPA? Are there bigger issues at hand?