Understanding Aquatic and Terrestrial Pollution: Human Impacts on Ecosystems

hi everyone Mount science students we're going to continue talking about Aquatic and terrestrial pollution with this

PowerPoint I have this same disclosure that I had last class so read through this if you

didn't read through it last time and let's just jump right in so most of what we're going to talk about is going to

continue this topic 8.2 human impacts on ecosystems last uh PowerPoint we talked about ecological tolerances or at least

I re um try to refresh your memory on some ecological tolerances but you should know those we've already talked

about coral reefs way back in our biodiversity unit so I'll reference you to that there we're not going to talk

about coral reefs today we are going to talk about oil spills we talked about Oceanic dead zones and

the last PowerPoint we talked about ocean sorry oxygen sag curves today we'll talk about heavy metals we talked

about litter in the last one and we talked about sediment and the last one but we will talk about Mercury

and methyl Mercury okay we're also going to just talk about endocrine disruptors so just be able to

describe endocrine disruptors and describe the effects of them on ecosystems and persistent organic

pollutants or pops but I'll typically just say pops or persistent organic pollutants and describe the effect that

they have on ecosystems and then finally bioaccumulation and biomagnification

um be able to describe those two concepts and describe the effects that they have on human health and the

environment and this may be a concept that you're familiar with from biology class

here's the vocab which I'm going to skip and this is kind of like a two-part lecture so the last time we talked about

all of these ones on the top and here we're going to talk about the second set of pollutants and impacts on ecosystems

that we have and this is by no means an exhaustive list and it's really in no particular order it's just the order

that I chose to discuss them in all right so heavy metals is where we're going to start now the broad definition

is any metal with a high density and atomic mass usually what you're going to be looking at for heavy metals is your

transition metals and then the heavier of the basic Metals so maybe gallium and down

as well as these groups down here so those are what you're going to be looking at for heavy metals in a

chemistry class for example but the definition that I want to use for environmental science

is a metal with high density and atomic mass really that's not the important part I don't really care about that part

because a lot of the time we're going to consider aluminum to be a heavy metal especially if it's

aluminum ions that are getting into your waterways or into your soil those aluminum has a pretty small atomic mass

okay especially compared to something like iron or lead for here the important part is metals

that are potentially toxic to plants and or animals including humans and some of these aren't even true Metals arsenic

for example we're going to consider a heavy metal but it's what we call a semimetal okay one of these staircase

metals all right so for this class just any metal or

metalloid that is toxic to plants or animals and they typically have a high atomic mass and high density that's

going to include Mercury lead cadmium this list that I have down here as well as some other letter less common but

some of these metals have Niche applications used in industry and you'll see them pop up here or there but these

are the major ones that we're going to discuss now the sources of heavy metals they can

Leach from mines they can Leach from mine tailings we talked about that when we talked about mining they can Leach

from overburden they can Leach from slag any of that process from mining they can be discharged from industry so

this is an example of Industrial Waste that's being discharged directly in the river and you can see that metallic

coppery color I'm not sure what metals are in there but it's probably Laden with heavy metals it can Leach from

landfills so just scrap metal you can have uh you can have the leachate in a landfill

leeching out heavy metals we talked about that actually we'll talk about it in one of the future PowerPoints the

next PowerPoint I believe where it talks about the acidity of the landfill from volatore volatile fatty acids driving

down the ph and these heavy metals Leach out in Greater concentrations or leech out more readily at low PH so when you

have low PH more acidic conditions you're going to have high leaching of heavy metals

okay it can Leach from electronic waste happens a lot and from a fossil fuel

combustion this is primarily Mercury okay which is atomic symbol HG so what are the effects of heavy metals

where they're going to vary based off of the chemical that you're actually talking about about the element that

you're actually talking about but in general they're going to cause reduced growth and reproduction in plants and it

can make the soil so toxic that no plants can survive or only a few plants with specially adapted that are

specially adapted for heavy metal soils can survive there is groups of plants that are specially adapted for soils

that are high in heavy metals typically occur around volcanoes where heavy metals weather out of the Rock and

accumulate in the soil and these plants are specially adapted for heavy metal soils

okay but if we don't have those naturally adapted plants then it can be so toxic that nothing can survive there

right you don't see much growing on this side of this mine tail mine tailing Pond but you see some plants that are able to

tolerate it over there in animals they're typically going to cause again it's going to be varied

based off of the element right but developmental reproductive nervous and renal symptoms your renal system is your

kidney kidneys it's going to hurt your liver because you're trying to filter this out

all the time including same thing with the kidneys and it can include cancers I have a good little

diagram here showing the reproductive system the nervous system the digestive system all the different types of um of

uh effects that we can have for heavy metals and again this is generalized and it's going to be

specific for each type of heavy metal all right for example we know that lead leads to cognitive problems and lower IQ

in children now two of the most common and toxic heavy metals are lead and mercury and

since we've already talked about lead in our atmospheric pollution unit let's talk about Mercury here now Mercury

chemical symbol HG also known as quicksilver because it is a liquid at room temperature

it is toxic you would not drink it methyl Mercury though is even more toxic methyl Mercury is

hgch3 so you just slap on a methyl group to that mercury atom so you see that methyl group there the carbon and three

hydrogens okay how do you get methyl Mercury well it's anaerobic bacteria that are going

to that are going to create this methyl Mercury so Mercury is going to get into the atmosphere or into the waterways

primarily via industry or from a coal burning power plant coal that has Associated Mercury and the rock with it

and it can get into the atmosphere or just straight into the water it can also be discharged naturally from weathering

or volcanoes okay but at very low at low concentrations compared to human activity

uh once it's in the atmosphere it can cycle globally so it doesn't necessarily mean that you have to be in an area that

has lots of um a lot of industry or coal burning power plants but it's going to be more

concentrated in those areas and it's going to enter the waterways either by just flowing down the river or

by just precipitating into the ocean and when it does so there's going to be anaerobic bacteria that are in the soil

or in the water we're showing the ocean here but they occur in the soil as well um

those anaerobic bacteria are going to convert Mercury to methyl Mercury okay

roughly about 10 percent of the methylmercury and the soil or the water is going to enter your food web where it

starts to biomagnify and that essentially means that it increases in concentration as you go up the food

chain so we're going to talk about bioaccumulation and biomagnification at the end of this PowerPoint so keep this

concept in mind that mercury can bioaccumulate and biomagnify and essentially what you're going to see

is as you go higher up there is a higher concentration of mercury in um and the organism at the higher

trophic levels okay and from here it can enter into the human system right if we eat fish or if

we drink untreated water right it can be in the rivers okay even plants can have some methyl Mercury and then that they

uh that they draw from the soil and they sequester in a vacuole once it's in humans it's readily

deposited in fatty tissue or into the brain which is very fatty and it can cross the blood the uh the the mother

child placental barrier into the fetus and we know that mercury and methyl mercury associated with decreased

cognition neurological impairment um and some cognitive birth defects so it is very alarming for a developing

fetus to be exposed to Mercury which is why pregnant women are told not to eat large predatory fish such as salmon or

tuna especially Oceanic large predatory fish Marlin swordfish sharks would be other other examples

in children or adults again decrease cognition memory impairment all of those things that go along with decreased

cognition all right the next thing that we're going to talk about are endocrine

disruptors this is any pollutant that interferes with your hormonal system or your endocrine system so you should know

that the endocrine system is your system of hormones in the body doesn't necessarily have to be just the gender

um or the sex hormones like estradiol and testosterone the two that I have pictured here note how similar they are

the only difference is occurring down here they do come from the same precursor

molecule but it can be any other hormones as well so down here we're talking about insulin and glucagon okay

um so any pollutant that interferes with the hormones

what they often do is mimic hormones they can block hormones so they can bind to the receiver and block hormones or

they can act as a catalyst to chemically synthesize one hormone from possibly another or just chemically synthesize a

hormone some examples some notable examples bisphenol a BPA

BPA is used in a lot of food um materials so plastic bottles food containers so like that plasticky uh

resin it's really an epoxy lining on a food container so you get takeout from a restaurant and you're in a plot you're

in a paper container and that paper is lined with BPA or some other similar material

you see it lining in metal food cans so next time that you open up a can of baked beans or vegetables or whatever

wash out that can which you should anyway to recycle it but wash out that can and check out the inside of it

you'll see this epoxy coating on the inside of it really thin plasticky coating on the inside of it and that is

most likely BPA okay there was a lot of consumer discussed pushback a little while ago

about BPA and a lot of water bottles you'll see nowadays are labeled as BPA free so this is probably where you've

seen it before but it's notable that most many are still have BPA especially your single

used items one of the most worrying of which is baby food formula cans okay because this

is a um a endocrine disruptor and you know children developing and producing lots

of uh lots of um you know hormones especially at different times during development

now BPA has been linked to diabetes breast and prostate cancer early um puberty right and we're seeing

puberty happen year like earlier in your earlier and earlier as the decades progress and

a lot of it is thought to be due to these endocrine disruptors that are widespread in the environment and

BPA is really good at mimicking estradiol and testosterone so that's why it's in a cancer most often associated

with women a cancer most often associated with men and then especially early puberty you also can see

neurological problems and those neurological problems especially in infants and fetuses Okay so

it is very concerning especially for newborns polychlorinated by phenols or pcbs these

are a persistent organic pollutant which we'll talk about later so it kind of acts as both of these and it has been

used previously it's banned right now in the US like banned since 1978 worldwide

bands since 2001. but it was used as an industrial coolant and lubricant and also in a lot of electronics so it was

used as a um as an insulator and a lot of electronics and that's especially common in Transformers

capacitors resistors Etc and your large Transformers that you see on on power lines

used to contain pcbs and they still do contain pcbs in many areas if you're in an area

that the electrical grid was all established and built before 1978 so we're talking about the 1940s 50s 60s

70s and if it hasn't been renovated so say maybe you're in a poorer District of the

United States it's just cheaper and easier to slap a warning sign onto these Transformers rather than to replace all

of them in that District so you'll see these warning signs especially in rural areas that are older older areas of the

United States and relatively impoverished areas these can leak and it's been shown that

they often do link all right leak and you get these pcbs going into the soil and into your waterways

they have been linked with skin liver and brain cancers this is typically acute exposure so these were workers at

the um at the plants where they're being used and that's one of the biggest reasons that they were banned in the

1970s was because of acute exposure for workers chronic exposure has been linked to

birth defects infertility neurologic disease and Cancers and for this acute exposure you should include birth

defects onto that also because you know women working pregnant women working at these plants did have a higher incidence

of birth defects than the general population our next one are polybrominated diphenyl

ethers pbdes these are still widely used especially in the United States most of them were banned in Europe in 2006 but

they're still widely used in the United States um

you'll notice that as we move on through these by phenols ethers this is not just one chemical it's a bunch of different

chemicals that are closely related to one another okay so just FYI these are used as flame retardants

anything that you don't want to burn you'll see the areas that we use them for

um but anything that you don't want to burn this is especially so for Plastics but also for upholstery

um for for you know natural fibers as well you can coat them in polybro polybrominated diphenyl ethers but let's

say that we have um let's say that we have some plastic clothing right I'm wearing polyester

right now it might have pbdes on it to use as a flame retardant so that if my shirt catches on fire it doesn't just go

up like you know like us like you know super fast like plastic should or plastic typically does instead you have

this flame retardant on it that makes it to where it doesn't really burn as readily and it doesn't

um you know totally give me three to third degree burns I can get the shirt off before it really

Burns okay phthalates these are very very common

one of the most common Plastics that you'll see is p e T

polyethylated phthalates I believe um polyethylene phthalate I think don't quote me on that

um these are Plastics so phthalates are added are part of plastics that are found in all kinds of uses so I just

have some of them here soft toys are of particular concern because we're talking about you know little kids putting them

in their mouths and chewing on them maybe your dog chewing on it um medical equipment again of particular

concern you have somebody that's getting an IV and the tubing that they're using has phthalates and those phthalates

could come off and very very very small amounts you know we're talking about parts per million parts per billion and

get into somebody's bloodstream Cosmetics that you put on your face okay

some of these are pretty um pretty intimate items that we're using right they're they're on on your

person or going inside of you this can disrupt a couple different hormones insulin and glucagon to um that

have to do with metabolism and then we see effects on male reproductive development

and then masculinization of females so these tend to mimic testosterone they can lead to early puberty they can lead

to um some developmental problems in males but

especially females where you see masculinization of females okay some other suspected endocrine

disruptors and I say suspected there because uh you know legal issues oxybenzone oxybenzone is found in a lot

of sunscreens so again something that you rub onto your skin and can be absorbed through the skin

it has been implicated in Coral bleaching which is why

Aruba banned any sunscreen with oxybenzone in 2019 Palau banned any sunscreen with oxybenzone in 2020 and

Hawaii and the United States banned any sunscreen with oxybenzone in 2021. okay pesticides we'll talk about

atrazine and class we'll talk about DDT later but not in the term of endocrine disruptors but we'll talk about

specifically atrazine and class and then contraceptives there's a professor at the University of Colorado

Denver when I was there and I believe that he's still there that works on this in the South Platte where many many many

people are using birth control pills you know female uses birth control pills she pees out

um many of those chemicals uh urine urinates out many of those chemicals into the toilet the wastewater treatment

plant is not specifically designed to remove these chemicals from the treated water and that treated water is sent out

clean of all pathogens and nutrients but not endocrine disruptors into the waterways and then you have fish and

amphibians that are exposed to these um these chemicals that mimic estradiol and leads to reproductive

reproductive developmental issues okay which we again will see mostly with atrazine but it's interesting to think

about contraceptives from our Wastewater having the same impact so how do these chemicals work how do

these endocrine disruptors work well most of them mimic hormones so they can bind to receptors where a hormone

hormone would typically bind to so if we look at estradiol with BPA bpas and purple there you can see how BPA can

easily bind to any receptor that is binding estrogen at this active site right anything around there it's going

to bind to it very closely mimics estrogen that wasn't intentional that's just you know how it worked out at least

I don't think it was intentional okay so they can mimic hormone and bind to receptors therefore blocking hormones or

over expressing a certain hormone so it really kind of depends on the case they can also act as catalysts to change one

hormone into another to create a hormone de novo or to break down a hormone okay so anything to do with reacting

with or mimicking hormones in the body so in class um we're going to watch one of these two film videos I'm thinking

about watching this one because I like it a little bit more but this one is also very good if you're interested in

this check out the second one or if you're not going to be in class watch them both

and then I intentionally skip that last bullet point on that last slide if you want to go back and read it you can but

I wasn't going to say it just to be not so controversial oil spills so crude oil can get into your Waterway through many

different ways and it doesn't have to be your Waterway it can be ground surface as well so talking about an oil spill

from a leaking pipe for example all right so how can it get into the environment

um first off oil naturally seeps in certain areas if it's close to the surface or if there's a fault or a crack

in the rock or if there's um you know even even under at the bottom of the ocean oil can naturally

seep not a problem in those areas because the organisms there become adapted to it and it's very localized

and it's not a big deal where it is a big deal is when you have a massive influx of oil or even a minor influx of

oil in an area where you have organisms that are not specifically adapted for that

oil to occur okay so how can they get into the environment well damaged tankers the most famous of which is the

Exxon Valdez and 1989 and Alaska but that is by no means the largest and is by no means an isolated incident ice um

oil tankers um like there's oil spills from oil tankers

all the time if you want to go uh check it out go to Wikipedia and see a list you'll be amazed at how many there are

and how few of them you have ever heard of oil can leak from pipelines so there was

a leak in the Keystone Pipeline in 2019 but if you have a leak in a pipeline a pipeline is moving oil you know

sometimes hundreds of miles even maybe thousands of miles if you have a leak on one bolt or one gasket fails and that

entire pipeline you can have an oil leak in that area offshore rigs you guys probably all know

the deep water Horizon incident in 2010 where the deep water Horizon um you know exploded essentially kind of

and released lots and lots and lots of oil into the Gulf of Mexico um oil can be intentionally dumped we

don't see it very often but you can see cases of intentionally dumping of oil and then War you don't see that very

often either but where you did see it was pretty massive so the Kuwaiti oil fires of and the Gulf War oil spill of

1991 especially so essentially as Saddam Hussein was uh was retreating from Kuwait he intentionally set the oil

fields on fire and spilled oil in the Gulf there to uh to to to slow down the the U.S forces

okay so the effects that oil has on ecosystems these hydrocarbons are toxic for many organisms especially if they're

ingested but even topic like a topic on the surface of an organism on their skin or whatever they it is toxic okay

you typically see liver and kidney damage because you're trying to process these um these uh chemicals and you're

trying to get them out of the body and your liver and kidney are the two organs that are responsible for that primarily

in the water oil can coat bird plumage and mammal fur what this does is it reduces buoyancy it reduces insulation

and it reduces their Mobility a bird that is coated in oil cannot fly okay all of their little filaments on their

feathers stick together and it doesn't provide lift for them to be able to fly these otters

rely on the little droplets of sorry not droplets but the little uh bubbles of air that gets trapped in their fur to

help them float and to provide them insulation or the oil basically coats all the fur

smashes it down next to the body or adheres it down next to the skin and they no longer have these little

bubbles of air they no longer have insulation so they can freeze in these very cold Waters and they have to

struggle to stay afloat so they could possibly drown and die if it gets in the eyes it can blind to

animals it can mask scents and water so this especially hunts or sorry especially hurts any organism that

relies on scent for hunting and it can result in mothers abandoning Offspring if they don't have scent cues otters is

another good example of that surface oil reduces light for photosynthesis It Coats algae so those

algae can die It Coats Plankton kelp seagrasses all of these it can coat them and prevent photosynthesis from

occurring but even if you have oil just floating on the surface which it typically does float not always but most

of the time it floats and it just reduces the photosynthetic the amount of light for photosynthesis

that goes into that water column and reduces net primary production most oil is going to float but some of

it does sink and it kills benthic organisms in pretty much the same ways as above okay so it's not just that all

oil floats some of these heavier hydrocarbons especially become kind of waterlogged in a sense can end up

sinking so that was by no means an exhaustive list of the impacts on organisms but

it's a pretty good starter list okay now oil spills also have human impacts it does hurt local economies right not only

are you losing that oil that you could otherwise sell right all of this is non-recoverable

um pretty much you can't sell it anymore but the clean on the cleanup is going to

cost a lot of money a lot of human labor and a lot of time all right it's going to reduce tourism in the area so if this

pretty beach um used to have lots of tourists no tourists are going to come if it's

coated in oil the deep water Horizon incident in 2010 13 years ago is what I'm going to use for really all of these

it was a huge cost of cleanup the EPA and uh FEMA had a huge cost of cleanup as well as local communities

there was a massive reduction in tourism in the Gulf States especially like you know the gulf coast

it negatively impacted Fisheries um the shrimp industry still has not fully recovered from this uh from that

oil spill there was just it just so heavily impacted um the fishing industry and the Gulf

States that they're still feeling the effects of it there's long-term ecological impacts as

well there's an article that I linked to schoology from just about a week ago so 13 years after the incident the

Deepwater Horizon incident that talks about how um how the salt marshes started to Die the

salt marshes along the Gulf of the Gulf Coast started to die due to the influx of oil so the oil essentially poisoned

the plants along the coast and because the plants were no longer there to hold the soil or the sediment in place the

coast started to erode away and then as they eroded away the oil that got locked in the soil and in the dead

plants was deposited on a new set of plants a little bit further Inland kills them and then erodes away that soil so

there's these long-term ecological impacts that you know nobody would have predicted before the oil spill occurred

and before they detected it a decade later how can we clean up oil spills all of

these are going to be costly labor-intensive and or time consuming some of them more so than others for

some of these things the first one that I think is the best in terms of

um and being environmentally friendly is to use some species of bacteria that can metabolize oil so they can Munch through

oil and metabolize oil there's not many species of bacteria that can do it but if you have a really good large lab

culture of these specific species you can release them into into your waterways right after an oil

spill and they can start to get rid of that oil for you so it's kind of using nature to help with this

if you can accelerate this whole process by by using mechanical methods such as

skimming which I'm showing right here so they're skimming that oil along the surface again most oil is going to float

98 of it floats so you can skim that oil bring it all into a certain area and then dump all those bacteria in there

you can use certain binder molecules that conglomerate the oil um

or you can use chemical solidifiers to change that oil from a liquid to a solid to help with this process any way that

you can concentrate this oil another way to clean this up is what they call chemical dispersants

now you add this chemical which can be just as toxic as the oil to the Waterway and that chemical causes the oil slick

to break up to dissipate it actually it sort of acts as a surfactant and you cause those oil molecules to just kind

of by sight like Disappear by sight they don't disappear in reality you just

can't see them anymore they just dissipate it kind of just spreads the oil out all everywhere and you can't see

it anymore and everything's all hunky-dory and you can bring back tourism but it doesn't get rid of the

oil it doesn't get rid of the carbon hydrocarbons it just disperses them in the water so I don't think it's a great

solution but it is one very common way of cleaning them up another is a clinical solidifier which

is very similar except the opposite they can be pollutants themselves as well but they change that oil from a liquid to a

solid and you can more easily clean it up such as scraping it off of a beach or whatever

control burning this is probably the most common and the cheapest all that you do is burn the oil okay

super easy to remove it all that you do is throw A Match Into the Water I'm sure it's more complicated than that maybe a

flare um and it just burns all of that oil on the surface that does create a lot of

air pollution and environmental damage itself but it is very effective at getting rid of those hydrocarbons and

it's very quick and very easy and very cheap and requires the least amount of Labor

dredging is something that you'd have to do for the oil that sinks Okay so we've talked about dredging

several times it's basically scooping up sediment at the bottom of a river at the bottom of the ocean

Etc skimming we just talked about so it's shown right here vacuuming is

interesting so you can skim all this and then suck up that oil so these two can be used in Tangent

Beach raking you are seeing both of these people up here doing that one person is actually using a rake one

person using a shovel but you know big deal and then Washington animals the effectiveness of this is variable but

it's better than doing nothing and many animals have been saved by washing it is just that some of these animals are so

poisoned by it that they that they succumb to their that they succumb to the toxins regardless

now there is new tech that's always being researched and one thing that um I've seen is that like human hair is

really good at binding to oil so for whatever reason oil binds to human hair very well so you use skim skimmers that

have human hair and you can just like drop it in like a mop into the water and then kind of bring it up all laid in

with oil that's some new tech I would caution you from using new tech on an AP test

because if it hasn't been proven as a solution I would avoid using it okay now obviously

it's going to be best to prevent spills rather than clean them up afterwards and this is one of the arguments for

transition away from fossil fuels is because if you're not using oil at all then you never have an oil spill

all right the last set of toxins that we'll talk about are persistent organic pollutants or pops or pops

um I'm probably just going to call them persistent organic balloons these are any organic molecule they do have to be

organic that resist breakdown by any means that could be biological means so they're not metabolized by bacteria or

fungi or other decomposers could be chemical means so just um reacting with inorganic chemicals in the environment

and it could be photolytic means so that's like reacting by light okay so especially ultraviolet radiation will

not degrade these like many um chemicals are for this reason they're also called

Forever chemicals you'll see them referred to as forever chemicals by the news media a lot rather than persistent

organic pollutants because uh the general populace is too stupid to have three words in a row

sorry I should have said that forever chemicals okay persistent organic pollutants

um these persist in the environment for years decades centuries or even thousands of years okay some of these

are going to be in the environment for thousands of years almost all these are going to be

synthetic some of them do and occur naturally for example dioxins which we'll talk about occur naturally

whenever you combust anything that has a high concentration of chlorine in them but not many organic molecules do and

most of those are petrochemicals so really it's like synthetic but they can be released from volcanism as well

they include a lot of different types and for a lot of different uses many of them are lipid soluble and

therefore bioaccumulate and biomagnify and fatty tissue which we'll talk about in one of the future slides many of the

examples that we'll talk about have been found in most human blood like virtually every human blood has a chemical called

pfoa in it and you have to go to like the most isolated groups of people on the planet to find

um to find uh somebody that does not have pfoa in their blood you and I guaranteed

we do I'd put a thousand dollars on it okay now one piece of legislation that I have

referenced before and we'll reference um in the coming slides is the Stockholm convention on persistent organic

pollutants you do not need to know this one for the AP test so I'm going to go through it really really quickly it was

signed in 2001 effective 2004 as of 2019 184 party Nations have signed it notably though the US has not Italy has not

Israel has not so there is not consensus around the world but this does control a lot of

um a lot of persistent organic pollutants and prevents them from being used or manufactured

and there should be noted that the U.S EPA has a lot of overlap with this list so that's one of the reasons that the US

didn't sign on board but honestly I think that they should have now some notable persistent organic

pollutants um that we'll talk about all of these examples have been banned worldwide due to the Stockholm

convention with the notable exception of DDT which is still being used to control mosquitoes for malaria and other

mosquito-borne illnesses but I've put these into different classes the first class is pesticides

DDT is the most famous pesticide dichlorodipiphenyl trichloroethane we'll talk about a little bit more on the next

slide these second generation pesticides are also all banned in fact DDT is a for as

a second generation pesticide also um where you'll see these is if you ever read the book Silent Spring by Rachel

Carson which you actually will read a section of for this class very famous book started off the

environmental movement all of these were banned in the United States primarily because of Silence brain

uh flame retardants many brominated ethers and brominated diethers have been banned but they're used as flame

retardants very similar to the ones that we talked about before per and polyfluorinated or sorry per and

polyfluoroalkyl substances pfas okay you'll see this a lot because they're one of the ones that are coming

up more and more in the news these were used as or are being used still many of them surfactants flame retardants oil

and waterproofing non-stick Coatings um the one that we're going to talk about is pfoa

perfluoroctanoic acid or C8 you may have heard of that before but we'll talk about them on the future slides

pcbs so see those endocrine disruptors for the pcbs and then polychlorinated dipenzoid

dipenzodiaxins pcdds these are inaccurately referred to as dioxins

and I'm going to perpetuate that by referring to them as dioxins from here on out

so some three notable ones that I want to expand on DDT dichlorodipiphenyl trichloroethane you

can see the chemical structure of it and the top Center what I want you to think of is anything with chlorine just

whenever you see chlorine in a molecule think of it about being toxic okay this is a pesticide that was widely used

since World War one now it was first chemically synthesized in the mid early 1800s but it wasn't identified as a

pesticide until 1939 by Paul Mueller who was subsequently awarded the Nobel Prize for identifying this as a pesticide and

it's kind of ironic that we later banned it after we've figured out how bad it was some of the pictures that you see

here are some human exposure to it so they used the Army the US Army used to use DDT as a lice um and really any

other arthropod um um

like uh preventative and and treatment so this fellow right here is getting his hair sprayed with DDT to eliminate lice

these people are using it indoors and this person is standing in a field that's being crop dusted by DDT right

these people are all getting exposure and even nowadays we can still use DDT specifically to control mosquitoes but

its use is used illegally to as a as a pesticide on fields somewhat often not very often at all

rather rarely actually okay again DDT was banned in 1972 in large part due to Rachel Carson's book

Silent Spring a decade prior and before it was banned about 600 000 tons of DDT were used just in the United States

so this was there is a lot of it and again it is a persistent organic pollutant so this DDT that was used in

the United States ends up in the waterways around the United States right rural runoff ends up

in the waterways ends up in the ocean and now we have DDT circulating in the ocean potentially from the 19 1960s and

1950s okay dioxins are the second notable group

that I want to talk about now most dioxins are not intentionally produced the vast majority of them and there are

tons notice these variables right here those mean that these can go on for like quite some time uh chains

um basically what dioxin means is that there's these two

chlorinated Benzene rings that are held together by these oxygen Bridges anyway not important most dioxins are not

intentionally produced very few of them are intentionally produced for industry most of them are a byproduct

unintentional byproduct that unintentional byproduct is anything that has to do with chlorine

so think about um bleaching of most things so bleaching paper for example

using very highly concentrated chlorine like bleach um

it's going to be due to smelting all right metal smelting anything that contains chlorine a rock that contains

chlorine you're probably going to be emitting some dioxins these are gases for the most part but they can be water

soluble as well um and then incineration this is the primary cause of dioxins especially

anything that contains um chlorine right PVC is a great example

polyvinyl chloride right um now

in February of this year 2023 there was a train derailment in Ohio where they released lots and lots and lots of vinyl

chloride the monomer to make polyvinyl chloride one of the after quite a while one of the responses was to burn off

much of that vinyl chloride that released lots and lots and lots of dioxins into the atmosphere that was one

of the um there was a huge environmental disaster

I mean maybe not huge but it was a pretty big environmental disaster the primary source within incineration

of all dioxins is backyard Barrel burning so we've talked about um recycling copper before in this class

you can recycle copper it's great to recycle copper now how do you get copper wire out of

the plastic that is used to insulate it and coat it well you can use a razor blade and slice off that plastic and

just go to town slicing off that plastic and it's very labor intensive and it takes a long time or you can take all

that copper wire with the plastic on it the plastic insulation put it into a metal Barrel light on fire and burn off

all that plastic and then recover the copper which does not burn okay that's the most common way

to do it especially if you are poor and trying to recycle copper for an income and

um you know time is is money right so you're going to burn it all off that's going to release a lot of dioxins into

the atmosphere okay and there is many different compounds I would encourage you to check out the Wikipedia page for

dioxins and just scroll through all of the uh all the different compounds but in general they can bioaccumulate and

biomagnify which we still are going to talk about they can lead to thyroid disorders nervous system disorders

cancers developmental disorders Etc are in probably the most infamous case of dioxin exposure was through the

herbicide and defolian agent orange during the Vietnam war um so a little bit of backstory the U.S

is fighting the fighting the North Vietnamese who were Communists backed by China led by Ho Chi Minh also known as

the Vietcong the viacon were very good at guerrilla warfare they were essentially kicking the US's butt on the

ground because the U.S had a more traditional fighting style was not used to fighting in dense jungle and the the

North Vietnamese had a very intimate knowledge of the terrain and the jungle and were very good at guerrilla warfare

right they would pop out of the Jungle kill a whole bunch of U.S soldiers and then go right back into the into the

jungle and without losing a single person okay very simplified but basic history

the US's response was essentially a scorched Earth response but instead of burning the entire jungle what they did

was use chemicals to do something similar they removed all right they used defoliants and herbicides 245

T and 24d to remove the leaves and kill the plants and these jungles essentially if your

Quarry goes to ground leave no ground to go to that was their thought if they couldn't hide in the jungle then you

could um defeat them so they sprayed DDT over wide stretches

of Vietnam it's estimated that about 12 percent of the total land area of South Vietnam was sprayed by agent orange I

think I just said DDT I don't know why but Agent Orange um DDT was not used I mean it was

probably used by the US to combat lice but not for um not as a defaulting it's a pesticide

okay so Asian orange they sprayed 12 percent of the land area of South Vietnam with Asian orange plus areas in

North Vietnam Laos and Cambodia over 20 million gallons of Agent Orange were sprayed

and even though the numbers have not been released by the US Military and the U.S military would refute these numbers

advocacy groups in the United States veteran advocacy groups estimate that every single soldier in Vietnam was

exposed to Asian orange to some degree even if you're back in base camp still being exposed from Trace Amounts and the

Wind Trace Amounts and the water Trace Amounts and food okay the Vietnamese government and the

U.S highly refutes these the US government definitely refutes these claims but I tend to trust the people

that are on the ground living with it rather than a country halfway around the world that did the damage but anyway

um the Vietnamese claim that 4.8 million people um 4.8 Vietnamese people were exposed to

agent orange during the war 400 000 were killed or maimed 500 000 birth defects resulted from agent orange

exposure and the Red Cross estimates that a million people are still living with the negative health effects of

Agent Orange and it wasn't the active ingredients in agent orange itself that led to this although I would almost put

money on it that they are toxic it was mostly this tcdd tetrachloride benzodioxin which agent orange was

contaminated with and due to this contamination these people were um were exposed to this this

dioxin and again you can read the cancers I'm going to skip that but heavy heavy human toll on both U.S personnel

and the Vietnamese who did not know that they were being exposed to these types of chemicals

although I'm sure that when you're a person on the ground being burned by high concentrations of this uh defoliant

and herbicide that you know that you're being exposed to harmful chemicals anyway let's talk about

perfluoro octanoic acid pfoa C8 I'd like to show a documentary about this but I think it's too long we'll probably watch

a short video about it this is one of the many pfas um that exist again these are per and

polyfluorinated alkyl or polyfluoroalkyl substances I always say that Ron and you see all of the fluorines on it just like

chlorine whenever you see tons of fluorine stay away from it um so polyfluorinated and you should

know from chemistry or biology that every time that you see one of these branches or one of these bins in an

organic molecule there's a carbon there okay so we just don't draw in all the carbons

these were used as surfactants flame retardants oil and water proofing and non-stick Coatings

pfoa is specifically a notoriously used in the production of Teflon which you probably have a Teflon or

teflon-like pan at home but it was found in Industrial Waste from these uh Teflon producing factories

most notably in the eastern and Midwestern United States but you see it in a lot of other uses as well and a lot

of other objects so anything that you don't want to get stained that could be clothing that could be carpeting

whenever you see waterproof clothing I would stay away from it whenever you have like a plasticky

um a plasticky like lining to a to a paper bag to a cardboard box it could be BPA it could be pfoa or pfas in general

okay um I I would tend to stake away stay away from those now pfoa has been found in the blood of

99 of the sampled US population around or below one part per billion but again I would put a thousand dollars on it

that every single one of us that's watching this video has pfoa in our blood okay and higher concentrations

it's implicated in kidney testicular colon and prostate cancers ulcerative colitis especially the more severe cases

of it thyroid disease high cholesterol pregnancy induced hypertension birth defects miscarriages Etc

okay so it was banned in the United States and using the Stockholm um and with a Stockholm um convention but very

similar um molecules are being used most notably gin X

is now being used in replacement which is probably just as bad you just take one chemical that you have tested

repeatedly and found that it has negative health effects and ban it and then substitute it very very chemically

similar chemical that you haven't tested yet probably just as bad now this is probably the video that we'll watch in

class um but check out this article it's on um it's on schoology also if you're

interested optional and let's wrap this up by talking about bioaccumulation and biomagnification now bioaccumulation is

the gradual buildup of chemicals in organisms and this is essentially that the rate of absorption of these

chemicals is greater than the rate of breakdown or excretion and you typically don't break them down and you typically

don't excrete them you just um stash them away unintentionally and fatty tissue most of these are going to

accumulate in fatty tissue but you're going to accumulate them greater than or equal sorry greater than the rate of

breakdown or excretion okay most often it's going to be um your persistent organic pollutants and heavy

metals okay now some animals use this as a defense mechanism

um monarch butterflies are a great example monarch butterflies live on the um live off of milkweed which is toxic

to everything else because it has cardiac glycosides in it and these monarch butterflies are immune to that

poison and they bioaccumulated in their tissue so that the Monarch is therefore poisonous so some of these some animals

naturally do this but they're adapted to do so okay they are definitely not adapted for

lead persistent organic balloons Etc and bioaccumulation leads to

biomagnification also known as bioamplification but you'll almost certainly see this term this is when you

increase the concentration of a toxin or pollutant as you increase in the trophic levels so in this example on the right

let's say that we have DDT in our water our D our concentration of DDT in the water is point zero zero zero zero zero

three parts per million okay but let's say that phytoplankton eat up that or sorry let's say there's

phytoplankton in the water they're swimming in that water all day every day sorry swimming they're floating in that

water all day every day and they're absorbing that water to do photosynthesis and they're absorbing

Trace Amounts of DDT as well but they're doing it all the time and they're accumulating that DDT and their little

phytoplankton bodies okay they're going to have maybe point zero zero zero five parts per million

okay and then zooplankton eat those phytoplankton and the zooplankton are swimming around

in this DDT laced water getting it from the water itself and they're eating all of these um

these phytoplankton that have DDT in their bodies and they're eating them all day every day and they start to

accumulate more and more and more DDT and now they have 0.04 parts per million and then the small fish eat the

phytoplankton and you see where I'm going with this they're swimming in that water laced with this Baseline amount of

DDT all the time that DDT is getting into their bloodstream via the gills and they're eating this steady diet of

zooplankton that has .04 parts per million at DDT all the time all day every day and they accumulate up to and

it magnifies up the trophic level and they accumulate 0.5 parts per million and then the big fish

accumulates even more magnifies even further and then finally when you sample the Osprey that's eating this steady

diet of fish large fish that has two parts per million of DDT in their bodies and the Ospreys only diet all that eats

is these fish then it ends up having about 25 parts per million DDT in its body way way way way higher than the

Baseline amount in the water that this Osprey isn't even swimming around in Okay so

a couple examples DDT and Mercury you'll see here DDT causes eggshell thinning and birds we'll watch a video kind of

talking about this and then Mercury or methyl Mercury more appropriately um

again in your large fish and this is why pregnant women shouldn't be eating large fish because they're getting

um you know maybe one two five parts per million methyl Mercury that can be transferred straight to the

fetus and lead to neurological disorders all right the last thing that we're going to talk about is tacking on a

piece of legislation to this PowerPoint and that is the Delaney Clause so the Delaney Clause it's a little bit weird

that they have you know this but you do need to know this piece of legislation um this is part of the food additives

Amendment um sorry this is part of the food additives amendment of 1958 which in itself is part of the food drugs and

cosmetics act so this is like one clause and an amendment that is part of this larger act so it's it's really odd so it

basically gives the FDA oversight overs the safety of food drugs medicine and cosmetics but we are specifically

looking at this one Clause so what is that one clause so what is the Delaney Clause it's basically

um saying that no chemical additive can be put into food that's been known to cause cancer and either humans or

animals it's important to say or animals because a lot of the tests that are being done for carcinogens are on lab

animals mice rats monkeys Etc right now it covers food additives it covers any animal drugs that can

accumulate in any type of tissue or product from animals color additives or naturally occurring carcinogens so for

example you cannot buy root beer that contains Sassafras root because saffron is known to cause carcinogen okay so all

root beer is pretty much uh no longer flavored with this and it is artificial flavors

it used to apply to pesticide levels and processed foods but only when their concentrations increased during

processing so that was a little bit weird it never applied to pesticides on raw food so it does not test and does

not cover pesticides on raw food okay so you you can have pesticides residue on a head of broccoli for example

now pesticides I say used to be on this because they were removed from the Delaney clause in 1996 when they were

added to the food quality protection act which you don't really need to know nor do you need to know any of these dates

this right here is what you need to know now a little bit of history about the enforcement of the Delaney clause

it was written back in the 1950s before we really had these uh tools for analytical chemistry to detect very

minute amounts of um chemicals of toxins of known carcinogens so at the time it was really

difficult to differentiate between high concentrations and super Trace Amounts so even though we can detect Trace

Amounts today we have this de minimis clause and the de minimis Clause basically says if a carcinogenic food

additive is present at a concentration in less than one part per million it's considered negligible and it is allowed

so this doesn't the Delaney Clause is not a blanket statement saying that no carcinogens can be in food there is this

de minimis exemption to it and even though we can detect one part per million of a known carcinogen in our

food that is not going to be enforced on the Delaney Clause because of this uh of

this exemption okay so even though we can detect it it's still permissible because it's considered a trace amount

and is considered safe all right so my goal was to keep this PowerPoint under an hour which I am

going to fail at if I go through all the learning objectives um but just read through these be

familiar with them we pretty much talked about all of them and all the points and expanded on quite a few of it

um so we should be good any questions let me know send me an email come to office hours and I hope you guys learned

something and I'll see you on class bye