Test 3 (lec 14-21) Flashcards
Air Pollutants
Airborne substances (gases,
particulates or biological matter) released into the
atmosphere, deliberately or inadvertently, from
natural or anthropogenic sources that have the potential to harm human health and the environment
Major concerns for air pollution
human health effects of smog, acidification of surface waters, crop and forest damage and damage to built
structures
how many people are estimated to be exposed to dangerous levels of air pollution
2.4 billion
Types of Air pollutants
Gases, Aerosols, Particulates
Aerosols examples
sulphates, fine droplets of organic
material
Particulates examples
soot (carbon); various oxides and
salts of metals and other inorganics; chemical
mixtures of particles with organic substances
adsorbed onto them
Air pollution risk management
- Long range goals to decrease ozone concentrations in air
- Emission controls for vehicles
- Control orders for certain industries
- Warnings – susceptible persons to avoid exposure (smog advisories)
Air sampling
involves collecting an air sample over a period of time that is then sent to a laboratory for analysis to
identify and quantify specific compounds
air monitoring
uses electronic devices to provide real-time
readings of airborne contaminants.
solutions for pharmaceuticals
Reduce sources of pharmaceuticals to
environment
Main solution is to reduce levels in
treated sewage before release
PPCPs
pharmaceuticals and personal care products
PFAs
Per- and Polyfluoroalkyl Substances. highly used in commercial products
what has a very long residence time! Strongest bond in organic chemistry
PFAs
how to predict PFA risk
literature review and Toxicity tests conducted in a laboratory and in the field
Toxicant effects at the individual level can be differentiated into
what two forms
lethal and sub-lethal
Contaminant lethality can be divided into what two groups
acute lethality, chronic lethality
acute lethality
death followed by exposure within 96 hours
chronic lethality
death followed by prolonged exposure
3 shortcomings of behavioural toxicology
- Some behaviours are hard to score
- High variability in some behaviours
- Hard to extrapolate from lab to wild
settings
disadvantages of conventional toxicity tests
time consuming, costly, needs high numbers of test organisms
novel approach methods
Defined as any technology, methodology, approach, or combination that informs chemical
hazard and risk assessment method
replacement novel approach method
Methods which avoid or replace the use of animals
refinement novel approach method
Methods which minimize suffering and improve animal welfare
reduction novel approach method
Methods which minimize the number of animals used per experiment
Ecotoxicogenomics
Study of gene and protein expression using –omics technology
to understand the effects of environmental contaminants
Omics technology
◦ Transcriptomic- study of gene expression levels
◦ Proteomics- study of protein expression levels
◦ Metabolomics- study of metabolites within organisms
benefits of Ecotoxicogenomics
Enhances toxicity data (toxicity mechanisms)
Reduces suffering of organisms (shorter test duration)
Compatible with in vitro systems
PFAS exposure can lead to what
endocrine disruption, decrease in immune response, oxidative stress
Water pollution impacts from pulp and paper production
- Oxygen consuming substances
- Toxic chemicals (Hg, chlorinated compounds, wood extractives)
- Persistent bioaccumulative compounds
Physical changes to lakes and rivers from pulp and paper production
- Dams
- Log floating, physical damage to benthic habitats
- Water consumption for processing
potential by-products or waste from pulp or paper
- Sugars (= energy)
- Lignin (= glue)
- Extractives
- Tall Oil (fatty acids)
- Turpentine (alcohols, phenolics)
- Resin Acids
- Phytosterols
Lignin degradation by pulping and bleaching creates what
toxic phenolics and polyphenolics
characteristics of Chlorine,
hypochlorous acid pulp bleaching
- Very efficient, not much fibre breakage
- generates chlorinated compounds;
- abandoned in the early 1990’s (crisis of
chlorinated dioxins in fish & shellfish )
new pulp mill impacts after 1980s
eutrophication due to nutrient enrichment from waste treatment
ultimate goal for pulp and paper process
zero discharge, closed loop mill (re-use water)
solutions for pulp and paper process
Instead of end-of-pipe solutions, improve the
pulping and bleaching processes
challenges for improving pulp and paper process
remove chemicals from effluents without increasing
toxicity, creating solid waste, or releasing air pollutants
components of wood (good, bad, ugly)
– The good: Cellulose (wood fibre used for paper and box board)
– The bad: Phenolics from lignin
– The ugly: Extractives (resins & fatty acids, phytosterols)
paper bleaching
produces white paper by chemical oxidation to remove lignin, but….
– Chlorine bleaching generates persistent, bioaccumulative, and toxic (PBT) chemicals
– Chlorine production results in Hg release and environmental Hg methylation
Impacts of pulp mill effluents on aquatic ecosystems
oxygen depletion, bioaccumulation of PBTs, degraded fisheries
Brownfields
Abandoned, idle, or underutilized commercial
or industrial properties where past activities
have caused known or suspected
contamination, but where there is an active
potential for redevelopment
Brownfields positive attributes
- Location in urban areas
- Sites preferred over Greenfield development
- Arteries – roads, rail, water
- Municipal services in place
- Possible heritage interest
Brownfields negative attributes
- Depress local property values
- Catalyst for poor property standards, loss of
community pride - Human health & environmental risks
- Loss of tax revenues
- Cost to clean up and redevelop
Human health and environmental risks of brownfields
– Risk from immediate exposure to contaminates soil
(plants, animals, humans)
– Risk from substances moving from soil to ground or surface water
brownfields incentives
- Allow a municipality to direct funds and implement
policy initiatives toward a specifically defined project
area - Intended to encourage rehabilitation initiatives and/or
stimulate development - Once implemented, the plan allows municipalities to
provide tax assistance, grants or loans to assist in the
rehabilitation of lands and/or buildings within the
defined Community Improvement Project Area
ecotoxicology
- The study of chemical effects in ecosystems and natural
communities - Seeks to understand relationships among the structures of
chemicals, their environmental behaviour, distribution, and
effects on species of interest
why waste-to-energy?
Removes or greatly reduces the need for landfill sites, avoiding potential
problems down the road
Reduces the need for waste treatment (i.e. sewage and other solids in
wastewater)
Reduces our footprint on natural resources – by utilizing waste, we avoid
using a renewable or fossil resource
Reduces costs – companies may avoid paying for feedstocks or disposal
costs
criteria for success of waste-to-energy
Technically sound approach
Environmentally sustainable (low GHG emisssions)
Economical (efficient use of fuel, acceptable per unit cost)
Safe, reliable operations
Small footprint and attractive design
‐ Must be acceptable to communities where power is needed, to reduce
transmission & distribution losses
Simple, quick permitting process
what do waste-to-energy systems focus on
normally organics (biomass),Plastics may also be a good source
of energy – while they are petroleum
based, disposal of these products
has been difficult
problem with combusting plastics
Combusting plastic without proper controls
can result in increased CO2, but also the
production of dioxins, furans, heavy metals
(e.g. mercury) and polychlorinated biphenyls
design principles for complete combustion
- Temperatures must be very high and/or residence times must be very
long in order to ensure that all material is reduced to constituent gases
(CO, CO2, CH4, H2) as well as trace elements - Trace elements, including heavy metals, must be recovered and
disposed of separately – this can be done by separating slag - Proper monitoring and reporting is required to ensure that plants are
operated with a minimal impact on the surrounding environment
why is there municipal reluctance
- Municipalities not eager to sign up for long-term contracts
- Communities highly concerned about the potential pollutants involved in
combustion of waste streams - Many new technologies and players – difficult to know what the winner is
- Very difficult to validate performance, particularly for small communities
