Lecture 4 Flashcards
(21 cards)
what are the DDT trends in ringed seals in the Canadian arctic?
- total DDT declined between 1970s-1990s/2000s
- significant increase of the more toxic DDT metabolite DDE and SDDT was found, reflecting the shift from fresh DDT to degraded older sources
what is endosulfan?
- used in agriculture around the world to control insect pests
- listed under Annex A
- causes endocrine dysfunction, immunotoxicity, carcinogenicity
what are polybrominated diphenyl ethers (PBDEs)
- industrial chemical with 209 congeners
- first used as flame retardants to slow the ignition and spread of fire. used in construction materials, textiles, foams, furniture, appliances and plastics
- 3 technical grade mixtures were sold, varying by degree of bromination: penta-, octa-, and deca-BDEs
- listed under Annex A
- sources include substandard discharge, atmospheric deposition, surface runoff
what are the PCB and PBDE trends in harbour seal pups from the Salish Sea?
PCBs began to decrease in 1985 and continued to decline
during the same timeline, PBDEs increased, and then began to level off around 2010
what does no change in PCB concentrations in beluga whale blubber between 1989 and 2015 signify?
- may be attributed to a combination of only slight declines of PCBs in arctic air and to a shift in diet resulting in slower rates of decrease of legacy POPs
- reflects a more persistent background
what are PBDE replacement products?
- replacements for octa-BDE and deca-BDE include BTBPE and DBPDE
- both have been reported in air, water, sewage sludge, sediment, mussels, birds, fish, and house dust
- concentrations of DBPDE in eggs of herring gulls increase after a comparatively short period of usage, suggesting that DBPDE may be more persistent and/or bioaccumulative than deca-BDE
what are chlorinated paraffins?
- short chain chlorinated paraffins (SCCPs) are complex mixtures of alkanes of varying chain length with varying degrees of chlorine content
- listed under Annex A
- used as additives in lubricating oils and coolants in metal working fluids (51% of use) as well as plasticizers and flame retardants in polyvinyl chloride
- make up ~75% of contaminants in SLE belugas (may be an erroneous overestimate due to lack of suitable analytical methods for SCCPs at the time)
- effects include neurotoxicity, endocrine disruption, altering of lipid and amino acid metabolism, carcinogenicity
what are alternatives for SCCPs?
- medium-chain chlorinated paraffins (MCCPs, 14-17 carbon atoms)
- long-chain chlorinated paraffins (LCCPs, 18-30 carbon atoms)
- both accumulate in the environment and biota
- both are considered toxic under CEPA 1999
what are SCCPs response to regulations?
declined in adult male SLE belugas at a rate of 1.67% per year
what are alkylphenols?
- synthetic surfactants found in detergents, cleaning products, pesticides, antistatic agents, lubricants, hair products
- 4-n-nonylphenol (NP) and 4-n-octylphenol (OP) are some of the most common
- exerts endocrine disruption effects since they mimic natural hormones by interacting with estrogen receptors
- sources include discharge of effluents from sewage treatment plants, industrial discharges
what is a surfactant?
- a chemical that lowers surface tension
- each surfactant molecule has a hydrophilic head and a hydrophobic tail
what is 4-NP?
- a surfactant that is persistent in the aquatic environment, moderately bioaccumulative, and extremely toxic to aquatic organisms
- was added to an insecticide formulation sprayed over forests in the atlantic. was later found responsible for declines in local salmon populations, where smolts were exposed to NP in their freshwater habitat
what are per- and polyfluoroalkyl substances (PFAS)?
- group of over 9000 synthetic chemicals that have been used in industry and consumer products worldwide for 70+ years
- has carbon-fluoride bonds, one of the strongest bonds in organic chemistry
- used in a broad range of consumer products and industrial applications such as food packaging and nonstick cookware
- known as ‘forever chemicals’ and are detected in sediments, water, air, biota
- proteinophilic = binds to proteins (not lipids)
- effects include immunotoxicity, endocrine disruption, carcinogenicity
what are 3 exemptions listed under Annex B for PFOS?
- photo imaging
- aviation hydraulic fluids
- fire fighting foam
what are polyaromatic hydrocarbons (PAHs)?
- occur both naturally and as a result of human activities
- hydrophobic chemicals that have a high affinity with organic matter in water and sediment
- tend to not biomagnify
- relatively short half-life
- effects include immunotoxicity, endocrine disruption, cardiotoxicity, carcinogenicity in wildlife including fish, benthic organisms, and marine invertebrates
what are the two major types of PAHs?
1) pyrogenic PAHs: derived from incomplete combustion of organic matter (forest fires, agricultural burning, vehicle emissions). combustion results primarily in the formation of parent (non-alkylated PAHs)
2) petrogenic PAHs: derived from fossil fuels (coal, oil, gasoline, natural gas). includes a wide range of alkylated compounds that are more persistent than their parents
what happened with aluminum smelters in Quebec?
- they were emitting PAHs which were associated with cancer in humans and SLE belugas
- liquid effluent containing substantial amounts of PAH was discharged into the Saguenay river
- after the smelters stopped discharging liquid effluents, PAH concentrations declined. this resulted in a decrease in the number of beluga carcasses with cancer
what are microplastics?
- plastic doesn’t break down chemically, it breaks up physically into smaller and smaller pieces
- plastic particles that are <5mm
what is the difference between primary and secondary microplastics?
primary microplastics: deliberately manufactured (microbeads and nurdles)
secondary microplastics: the breakdown products of larger items such as plastic bottles, bags, packaging, nets and textiles
what are emerging pollutants?
new chemicals without regulatory status and with an impact on the environment and human health that is poorly understood
what are 5 emerging pollutants?
- pharmaceuticals and personal care products
- 6PPD-Quinone and other tire chemicals
- current use pesticides
- PFASs
- plastics and microplastics
