Microplastics and Phthalates Flashcards
What is the definition of a microplastic?
tiny pieces of plastic less than 5mm in diameter
What is the difference between primary and secondary microplastics?
primary: enter as the size they are
secondary: result from breakdown of larger pieces of plastic
What are the examples of microplastics?
fibres, pellets, films, fragments, foam and microbeads
What are the two largest contributors of primary microplastics?
- Synthetic textiles (35%)
- Tire dust (28%)
What is the greatest source of microplastics in the home?
Washing machines
How do microplastics get into our waterways?
leeching from landfills, wastewater treatment effluent, directly depositing trash into water ways
What are the impacts of microplastics on organisms?
ingestion by organisms and/or trophic transfer
vectors for toxins/pathogens
What are the effects of microplastics specifically pertaining to fish?
behavioural, sensory and neurological functions
intestinal permeability increased and decreased gut microbiome diversity
metabolism and growth negatively affected
What is the largest contributor to human consumption of microplastics?
drinking water from plastic bottles
What are some of the most concerning results from the studies regarding microplastics?
increased gut permeability causing distribution of microplastics to the liver and muscle, causes disrupted metabolism and insulin resistance as well as gut microbiome being disrupted
can pass BBB
What are some of the negative results that come from ingesting microplastics?
oxidative stress, translocation, inflammation, accumulation and toxicity from additive chemicals
What are the challenges that arise when working on a solution to regulate these?
no universally accepted definition, toxicological information is limited, limited knowledge on what affects bioavailability and no standardized or analytical techniques for detection
What are phthalates?
esters of phthalic acid
What are the chemical properties of phthalates?
longer backbone-increased permeability and durability and volatility
low melting point
What is considered a high molecular weight phthalate and what are they used for?
9-13 carbon atoms-used to make vinyl plastic more flexible
What is considered a low molecular weight phthalate and what are they used for?
3-8 carbon atoms-used as solvents in personal or cosmetic care products
Why are the use of plasticizers concerning?
are not bound to plastic so they can leech off, and can make up to 60% of total weight of plastic product
How are phthalates metabolized and excreted?
two phase metabolism via the CYP450 enzymes and glucuronidase
excreted by urine and have a half life of less than 24hrs
What occurs during the bioactivation of phthalates?
DEHP is converted to MEHP which can cross placental barrier and accumulates in milk and can get into sertoli cells
What is the major route of exposure for phthalates in humans?
food like fatty meats, fish and milk
What are some examples of how phthalates can get into our food?
tubing through automated milking system and plastic food packaging
What are the concerns for females regarding phthalate exposure?
estrogen disruption, pre term babies, lower birth weights, increased miscarriages, increased abdominal fat
What are the concerns for males regarding phthalate exposure?
found in semen which reduces fertility and lowers testosterone, increased abdominal fat
What are the concerns for children regarding phthalate exposure?
boys: shorter anogenital distance with age and shorter penile size
girls: reach puberty faster
What is the concerns with phthalate exposure to aquatic species?
induce vitellogenin exposure in males and reduces the sex ratio population of fish
