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Chapter 14 Test

Terms in this set (78)

BPA
chemical that has been widely used in the linings of cans and as a component of hard plastics
how many americans have BPA in their urine
93%
hundreds of studies on which animals have shown many apparent effects of BPA
mice and rats
BPA is structurally similar to which hormone
estrogen
- can induce some of its effects in animals
experimental data
the percentage of mice showing problems during cell division rose with increasing dose of bisphenol A
what to do about BPA
- Canada has banned the use of BPA
- the US now restricts its use only in children's products
- but consumer pressure has lead many manufacturers to seek out alternatives to BPA in more products
BPA is one of many factors in the environment that could influence
health
much research and discussion addresses the influence of various
environmental components on human health
some impacts are
indirect or highly delayed (decades later), making it difficult to establish causation
we face four types of environmental hazards
physical hazard, chemical hazards, biological, and cultural
much of environmental health consists of
taking steps to minimize the risks of encountering hazards and to mitigate (make less severe) the impacts of hazards we do encounter
physical hazards
arise from natural environmental processes, such as UV radiation from sunlight and natural disasters
- we can minimize risks
slip slop slap campaign for sun exposure in Australia (physical hazards)
government campaign to raise awareness for the high sun exposure which can lead to sun cancer
- trying to prevent sun burns and sun cancer
addressing avalanche danger in Washington State
- people go across the avalanche danger zones to get to the fresh snow
this can be dangerous
chemical hazards
include synthetic chemicals such as pharmaceuticals, disinfectants, and pesticides
- also includes some hazardous, natural toxins like lead and venom
biological hazards
biological hazards results from interactions with other organisms
- infectious disease transmitted directly and via vectors
story of cholera
cause of lack of sanitation and untreated water
- not much in US because we have better sanitation
- most often happens in small l villages and after earthquakes
malaria
- in sub tropic and tropical climates
spread through mosquitos
- in US we don't have it a lot because we have pesticides, and we drained our swamps killing off most the bugs
- most common cases from foreign countries (africa, and south america)
cultural hazards
result from our place of residence, our socioeconomic status, our occupation, or our behavioral choices (drug use, diet, proximity to toxic waste, smoking and second hand smoke)
- the fewer economic resources or political clout one has, the harder it is to avoid cultural hazards or environmental health risks in general
vintage cigarette ad in US attitudes and public policy change
as scientific data mount
smoking was prohibited from US flights starting in
1988
even though US had made precautions permitting smoking in areas, globally
% of males smoking any tobacco product are still persisting globally
major killers such as cancer, heart disease, and respiratory disorders have some genetic basis but they are influenced by
environmental factors
leading causes of death across the world
cardiovascular diseases (31%)
leading causes of death by infectious diseases
respiratory infections (3.2 million), diarrheal diseases (1.8 million), Aids (1.7), TB (.8), Malaria then meningitis
diseases causes the vast majority of
human deaths worldwide
lifestyle trends in the US are altering the
prevalence of noninfectious disease in ways both good (less smoking) and bad (more obesity)
in 2010 how much of the US was obese and how much was overweight
1/3 obese and 1/3over weight
in our world of global mobility and dense human populations, novel diseases (or new strains of old diseases) that emerge in one location are more likely
to spread to other locations, even worldwide
influenza pandemic of 1918
20 million people died,
- people didn't have vaccines (different strains so sometimes they don't work)
2009 swine flu pandemic
killed over 18,000 people
malaria was once a significant problem in
the US
Malaria was eliminated from the Southern US by 1949 through
a coordinated effort to drain mosquito breeding grounds and spray habitat with DDT
although malaria has been largely eliminated from the US and parts of Europe, it still kills how many people per year world wide?
600,000 people
cigarette smoke and radon are leading
indoor hazards and are the top 2 causes of lung cancer in developed nations
asbestos
the long, thin microscopic fibers of asbestos have many properties that were useful for buildings (insulate, muffle sound), but when the fiber of such products is inhaled, it leads to lung scarring and disease
- now there are increasing restrictions on its use
lead
heavy metal that, when ingested can cause damage to the brain, learning problems and behavioral abnormalities
when was leaded gasoline phased out of the US
in 1900s resulting in improved air quality and health
most paints contained lead until
1978
millions of toys imported from China were recalled in 2007 why?
because they were found to be coated with lead paint
the percentage of US children aged 1-5 with high levels of lead in the blood has
declined as a result of public health education and the government-mandated removal of lead from paint and gasoline
flint, Michigan water crisis
lead in water 6.3% of kids have lead in blood
chemicals have played a crucial role in increasing our standard of living but
their use carries a potential human health risks
- toxicologists try to weigh the benefits and risks of each chemical to determine whether it should be widely used
toxicology is
the study of poisonous substances
- modern society is
exposing us the more and more synthetic chemicals
determining which of these substances pose threats to human health is
a complicated scientific endeavor
a substances toxicity depends not only on its chemical identity but also on
quantity
the risks of a substance must be balanced against
the rewards and the availability of a less toxic alternative
nearly all US streams and most aquifers in agriculture and urban areas contain
pesticides throughout the year
not all synthetic chemicals pose
health risks and relatively few are know with certainty to be toxic
of the roughly 100,000 synthetic chemicals on the market today
very few have been thoroughly tests
toxicants come in different types
carcinogens, mutagens, teratogens, neurotoxins, and endocrine disruptors
carcinogens
substances or types of radiation that cause cancer
carcinogen can be difficult to identify because
1. there may be a long lag time between exposure to the agent and detectable onset of cancer
2. only portion of people exposed to a carcinogen will eventually get cancer
mutagens
substances that cause genetic mutations in the DNA of organisms
most mutations have little or no effect but
some can lead to severe problems like cancer
if mutations occur in an individuals per or egg cells then
the individuals offspring suffer the effects
teratogens
specifically cause birth defects
- for example even a single does of Thalidomide taken during pregnancy (for morning sickness) could cause birth defects
- in 1961 the drug was pulled from market after scientists recognized the connection
neurotoxins assault the nervous system
includes venoms produced by animals such as snakes and stinging insects, heavy metals such as lead and mercury, pesticides and some chemical weapons developed of ruse in war
Mercury Poisoning of Humans in Minamata Bay , Japan in
1930s and 1960s- issues to neurological systems
endocrine disruptors
interfere with the functions of body hormones, either by blocking them, accelerating their breakdown, or mimicking their effect
BPA and phthalates are
endocrine disruptors with links to a variety of negative health issues
phthalates are
chemicals used as softeners in plastics and fragrance enhancers in cosmetics
- these are also endocrine disruptors, linked to birth defects, breast cancer, low sperm counts
how can toxicants travel far from where they are released
through wind and water
as you go higher up a trophic level the amount of DDT
increases
biomagnification
the increasing concentration of a toxin in the tissues of organisms at successively higher levels in a food chain
as a result of biomagnification
organisms at the top of the food chain generally suffer greater harm from a persistent toxin
DDT (egg shell thining), PCB, Mercury, and other toxins
magnify
biological magnification is a current
health concern
biomagnified toxins tend to be
soluble and don't biodegrade well
bioaccumulation
keep adding more, growing over time
not all toxicants are
synthetic
not all synthetic chemicals are
toxic
manipulative lab experiments and field observations indicate that the herbicide atrazine is an
endocrine disruptor that causes the feminization of male alligators and frogs
LD50
the amount of the substance it takes to kill half the population of study animals used
- threshold expected if body's organ can fully metabolize or excrete a toxicant at low doses, but become overwhelmend at high concentrations
two approaches exist for determining safety
innocent-until-proven guilty approach (USA)
precautionary principle (Europe)
-----
tradeoff of maximizing technological innovation and economic activity vs. minimizing risk to human health and environmental quality
in the US, most synthetic chemicals are
not thoroughly tested before being brought to market
international treaties have been developed to
minimize toxic chemicals that persist in the environment, bioaccumulate and biomagnify up the food chain
- for example over 150 nations have ratified the 2004 Stockholm convention POPs
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