Biomagnification

Biological Amplification What is it? Toxic pollutants enter the ecosystem that are absorbed or ingested by organisms. Some substances accumulate in organism’s tissue over time.

Bioaccumulation An increase in the concentration of a pollutant in a biological organism compared to its concentration in the environment It is how pollutants enter a food chain

Biomagnification Increase in the concentration of a pollutant as it passes from one trophic level to the next http://www.tutorvista.com/content/biology/biology-iv/ecosystem/biological-magnification.php

Biomagnification Small amount in environment → Large concentration at top of food chain http://www.tutorvista.com/content/biology/biology-iv/ecosystem/biological-magnification.php

Why should we care? Because the two processes together mean that when we release even small amounts of pollutants into the environment, eventually they build-up in organisms to toxic dosages http://oceanservice.noaa.gov/education/kits/estuaries/media/supp_estuar09a.html

Where do pollutants come from? Coal burning power plants Factories Farms, lawns, and gardens.

Characteristics of pollutants: In order for biomagnification to happen, substance must be: Long lived Soluble in fat Mobile Biologically active

Characteristics of pollutants: Putting it into perspective: Only some substances biomagnify Most substances are water soluble and are excreted into the water Many breakdown quickly Many are not biologically active

Ex. Biomagnification Water Phytoplankton Zooplankton Small fish Large fish Top Predator: Human, osprey, eagle, otter – highest amount of toxic chemical http://www.dc.peachnet.edu/~ccarter/Millerlec-12/sld053.htm

Follow link to video http://happylibrarianblogs.blogspot.com/2008/01/biomagnification-video.html It can happen in terrestrial systems too!

Pollutants that undergo biomagnification Mercury Persistent organic pollutants (POPs)

Mercury Source: Emissions from coal-burning power plants, metal processing, medical and other waste Refer to notes on deposition xx/xx Made bioavailable by bacteria Inorganic mercury → Organic form of mercury that is biologically active Previous class on acid deposition – focused on Coal fired electric plants. Plants in MidWest – mercury released in atmosphere travels and comes down with the acid deposition from nitrates and sulfates. 12 states have law suit about mercury deposition against midwest states. Remind them of map we looked at in previous class.

Mercury Elementary Mercury (Hg) Methylmercury (CH3Hg) – most toxic form Form ingested by consuming fish Concentrated in muscle tissue More in older fish than younger fish Note – changed from Hg to this form by bacteria

Where in the US is it a problem? Low pH (acidic) lakes in Northeast and and Northcentral US Everglades (FL) Certain Wetlands Coastal wetlands along San Francisco Bay, Gulf of Mexico and Atlantic Coast http://sofia.usgs.gov/sfrsf/rooms/mercury/food_chain/

Impacts of Wildlife Loons – diet of fish Decrease in chicks in areas of high mercury Large concentration of mercury in eggs Great Egrets – study in Everglades indicates behavior of juveniles is effected Deformities in developing animals http://www.usgs.gov/themes/factsheet/146-00/

Risk to People Exposed by eating contaminated fish Pregnant women and children most at risk 60,000 children born annually suffering from neurodevelopmental problems due to in utero exposure to mercury http://img.alibaba.com/photo/11388452/Frozen_Sushi.jpg

Fish Advisories 13 states have state wide advisories for fish from rivers and lakes 40 states have advisories on selected bodies of water Parts of Eastern Coast and Gulf of Mexico have advisories

Concerned about the fish you eat? Recommendations per the FDA Avoid shark, swordfish, king mackerel and tilefish = all are high in Mercury 12 oz can be consumed a week of a variety of fish and shellfish that are lower in mercury. Fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. Note, albacore tuna has more mercury than canned light tuna. You may eat up to 6 oz of it in a week.

Concerned about the fish you eat? Check out the Mercury calculator at http://gotmercury.org/article.php?id=1034 For information on Sustainable Seafood Choices check out Monterey Bay Aquarium and print out a pocket sized card http://www.mbayaq.org/cr/seafoodwatch.asp

Origins of the term “Mad as a Hatter” Hg(NO3)2 Mercury is a compound that was used to soften fur in the making of felt hats. The phrase “Mad as a Hatter”, and the Mad Hatter of Alice in Wonderland -- both refer to the toxic effect of mercury on the central nervous system of the hat makers, producing mental effects and "hatter's shakes". http://www.ci.springfield.or.us/Museum/Mad%20Hatter%20Tea%20Party.jpg

Persistent Organic Pollutants (POPs) Also called organochlorines Synthetic organic chemicals that persist in the environment and biomagnify through the food web Poses a risk to human health and the environment Sources: Pesticides, some plastics, paints, industrial chemicals, bleaching, burning garbage Examples: DDT, PCBs, dioxin

Ban on POPs 1995 UN estimated 20,000+ substances with properties of POPs Stockholm Convention 2004, banned 12 worst “The Dirty Dozen” U.S. signatory in 2001 Congress has not ratified Signed by Congress needs to change 2 laws on books before it can ratify. Does not appear to be any pressure to make changes for this to happen. http://www.nature.com/nrmicro/journal/v4/n9/images/nrmicro1498-i3.jpg

Stockholm Convention Treaty The Dirty Dozen DDT - pesticide PCBs - Industrial Dioxin - waste Furans - waste Aldrin - pesticide Chlordane - pesticide Dieldrin - pesticide Endrin - pesticide HCB – pest/ waste Heptachlor - pesticide Mirex - pesticide Toxaphane - pesticide

Exposure Environmental exposure – many will stay in soil or water for decades Slow to breakdown Humans consume toxins via fish, meat and dairy

DDT (dichloro-diphenyl-trichloroethane) Insecticide used to control malaria and typhus by killing mosquitoes and lice. Commonly used after WWII Inventor received Nobel Prize Overused on crops as a pesticide Typhus killed 3 million people in WWII. Originally DDT was heralded as a wonder pesticide. Low toxicity to humans. Saved many lives. Tell stories of sprayer truck and children playing in its wake. Mention Carson’s Silent Spring and the finger pointed at DDT as a threat, beginning of environmental awareness. http://commons.wikimedia.org/wiki/Image:DDT_WWII_soldier.jpg http://www.flahumforms.org/FloridaDream/images/Thumbnails/1948-Spraying-DDT-in-war-ag.jpg

Ex. DDT Concentration of DDT increased 10 million times! http://www.cfkeep.org/html/stitch.php?s=98965698293378&id=34347859802049

DDT problems Eggshell thinning DDT interferes with metabolism of calcium Result - thin shells in predator birds such as osprey, bald eagles, brown pelicans Birds unable to brood (aka sit on) their eggs without breaking them www.ctaudubon.org/action/osprey.htm animals.nationalgeographic.com

DDT problems (cont’d) Feminization Acts as a hormone disrupter, mimics estrogen Has impacted sex ratio in some birds

DDT - it’s a long term problem It has a half life of 15 year; it takes 15yrs for its quantity to be ½ its original

DDT - it’s a long term problem It has a half life of 15 year; it takes 15yrs for its quantity to be ½ its original Ex. If we start with 100 kg, we will still have ~ 1 kg after 100 yrs Year Amount Remaining 100 kg 15 50 kg 30 25 kg 45 12.5 kg 60 6.25 kg 75 3.13 kg 90 1.56 kg 105 0.78 kg

DDT current use Banned in US in 1972 Still used overseas to prevent malaria Estimated it save millions of lives annually in Africa

Even Polar Bears have POPs in their system Top predator POPs are everywhere! Even Polar Bears have POPs in their system Top predator All toxins in prey is transferred to them, stored in fat Concentration increases 5 – 10x each trophic level http://www.smh.com.au/ffximage/2006/12/28/polar_bear_narrowweb__300x387,0.jpg

Health Impact of POPs Some cause cancer, damage nervous system Some act like hormones (estrogens) leads to: Developmental changes, birth defects Reproductive and Behavioral problems Toxins can be passed to young

Thought to ponder Even pollutants in small quantities can build up to toxic/lethal doses

Solutions to Toxic Pollution Worst ones are banned or no longer used in U.S. Still need to eliminate/reduce the processes that create toxins (i.e. burning coal)

http://gotmercury.org/article.php?id=1034 http://www.seaturtles.org/article.php?list=type&type=75 http://www.ec.gc.ca/Science/sandemay00/article4_e.html