Toxicology of climate change

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A presentation about the various ways that climate change increases human exposure to toxins.

A presentation about the various ways that climate change increases human exposure to toxins.

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  • Changes in weather and temperature have resulted in increased exposure to natural and anthropogenic toxins. As we regulate and decrease industrial pollution, climate change's propensity to increase production of natural toxins and mobilize persistent pollutants become a bigger part of the picture.
    Wildfires are a good example. Large fires quadruples in frequency, area burned has increased 6fold, fire season now 2 months longer
  • Wildfires are the largest contributors to dioxin production in the US
  • Dioxin in smoke, deposited on range and farmland resulting in human ingestion and accumulation in fatty tissues.
  • PAH also in wildfire smoke adhered to very fine particulates. In addition to consumption of contaminated food , Inhalation is a signifcant exposure route, can cause lung cancer. PAHis very persistent. levels are used by paleontologists studying prehistoric fires.
    Runoff from burned areas, has higher levels of PAH than urban runoff.
  • Soil is a significant source of lead exposure. About 30% of kids with elevated blood levels don't live in houses with lead paint. The correlation of lead poisoning incidence with areas with old housing could be because by virtue of their age, those communities have seen a lot of traffic and have a higher legacy burden of lead in their soil.
  • Lead exposure can occur by inhalation and contact with airborne dust. Dust levels and air lead levels follow a seasonal pattern, rising when temperature is warm and soil is dry.
  • Children's blood lead levels follow the same seasonal pattern which can be predicted by a model incorporating soil moisture and air temperature. The longer we have hot dry weather, the more exposure to lead kids will get.
  • Another source of dust is dry lake beds which can contain high levels of minerals left behind when the water evaporated. Owens Lake emits about 300,000 tons of PM-10 per year: 30 tons of this is arsenic and 9 tons is cadmium.Aerosols sampled from Owens dust storms commonly contains significant amounts of arsenic concentrated in the <10 micron fraction. levels can be as high as 400 ng/m3
  • Evaporation of surface water concentrates and existing contaminants
    Flow reverses, surface water moves into groundwater
    Increased pumping for irrigation drops water table
    Arsenic in aquifer bound to other minerals converts to arsenate and arsenite (more mobile and 500x more toxic )
  • Unused fertililzer not taken up by drought stunted plants will sink down into groundwater with next rain and also run into rivers and lakes, increasing HABs
  • Combination of nutrient load from ag runoff and warm water causing increased fresh water algae blooms.
    2 problems:
    1) microcystin The extensive HAB on Lake Erie in 2011
    microcystin concentrations exceeding 1000 ug/L limit is 1ug/l
    2) increased dissolved organic carbon resulting in trihalomethanes, carcinogenic byproducts of chlorine disinfection
    Use of choloramine- not as effective LA Naegleria in public water systems, In DC lead leached from pipes
  • Hepatotoxins
  • Toxin measurements from a reservoir,
    An increasing problem
  • 30% of all lakes tested in the midwest were + for microcystin
  • HABs in ocean are also the result of ag drainage of nutrients and warmer water.
    Toxins concentrate in clams, mussels, oysters and cause human illness
  • Brevetoxin- neuro sx, bronchospasm
    Domoic- memory loss
    Saxitoxin- paralytic
  • Poisoning events are increasing, closures by PHDs are becoming more frequent
  • Aspergillus infection during drought makes aflatoxin
  • FDA allowed blending for feed in 4 states.
  • 1999 national nutritional survey blood samples analysed last year for aflatoxin. 1% detectable.
    Latinos more than double.
  • Latinos also have higher rates HCC. They additionally have higher incidence of fatty liver disease, another risk factor for HCC. With an increasing proportion of the population being Latino, it would be sensible to lower the FDA permissible levels so everyone is protected.
  • Estimations of average fish consumption have become political issues between industry, government, environmentalists, and native american groups. WA using thimbleful at day, OR uses estimate that is 3 times higher,
    Adults in columbia river intertribal fish commission's member tribes who eat fish frequently (48 meals per month) over a period of 70 years may have cancer risks that are up to 50 times higher than those in the general public who consume fish about once a month.


  • 2. Dioxin
  • 3. Polyaromatic Hydrocarbons PAH
  • 4. Lead
  • 5. Seasonal Variation Atmospheric Lead and Soil
  • 6. Seasonal Variation Child Blood Lead
  • 7. Dry Lake Arsenic
  • 8. Drought and Water Quality
  • 9. Nitrate
  • 10. Microcystin and Trihalomethanes
  • 11. Fresh Water Algae Toxins Microcystins Anatoxins Nodularins BMAA (beta-N-methylamino-alanine) Euglenophycin
  • 12. Marine Biotoxins
  • 13. Shellfish Toxins  Brevetoxin  Domoic Acid  Saxitoxin Neurotoxic Amnesic Paralytic
  • 14. Plant Mycotoxins
  • 15. Crop Mycotoxins  Aflatoxin Hepatitis, Liver Cancer  Fumonisin Esophageal Cancer, Birth Defects  Vomitoxin Immunotoxic Vomiting, Anorexia, Growth Retardation,
  • 16. US Crop Mycotoxins 2012-13
  • 17. Aflatoxin Biomarkers NHANES Schleicher, 2013
  • 18. Liver Cancer by Ethnicity
  • 19. Storm Runoff
  • 20. Mercury
  • 21. Migration of Persistent Organic Pollutants
  • 22. POP Concentration in Seawater Increases in Higher Latitudes Wania,
  • 23. Unequal Exposure
  • 24. Wendy Ring MD, MPH