Human Alteration of the Mercury Cycle PDF

Lecture 15 – Fall 2024 Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy Announcements Link for more information: https://drive.google.com/file/d/1AgTPbKV_AIz4IvYK1nfE1iRYQJlQY4wp/view Human Alteration of the Mercury Cycle - Emissions and Overview - Depo...

Lecture 15 – Fall 2024 Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy Announcements Link for more information: https://drive.google.com/file/d/1AgTPbKV_AIz4IvYK1nfE1iRYQJlQY4wp/view Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy  Mercury Overview Naturally occurring element in earth’s crust, air, water and soil Natural sources: volcanic eruptions, geothermal vents, evaporation from naturally enriched soils, wetlands and oceans Forms: elemental mercury (Hg0), inorganic mercury (Hg2+), organic mercury (CH3Hg) and mercuric salts (HgCl2) Natural range of concentrations: ~1-50 ng/L  Mercury Concentrations in Deposition: Past and Present Many natural (volcanic) and anthropogenic sources Green: pre-industrial Red: industrial Year (AD) Blue: volcanic eruptions Gold: gold rush Purple: manufacturing Total Mercury (ng/L) toxics.usgs.gov/pubs/FS-051-02/  Mercury Concentrations in Deposition: Past and Present Many natural (volcanic) and anthropogenic sources Green: pre-industrial Red: industrial Year (AD) Blue: volcanic eruptions Gold: gold rush Purple: manufacturing Total Mercury (ng/L) toxics.usgs.gov/pubs/FS-051-02/  How is Mercury Used to Obtain Gold? Amalgamation: brings free gold particles into contact with mercury. When gold and mercury connect, the two create a mixed compound. Gold is dissolved into the mercury. At the end of the operation: mercury and gold amalgam are separated, and the mercury recycled. Allows the collection of very small sized particles of gold. Why Mercury? Only metal which occurs as a liquid at room temperatures http://www.geus.dk/program-areas/common/the_borax_method_2011.pdf http://www.thejakartapost.com/news/2009/01/12/mercury-gold-mining-a-third-world-toxic-threat.html  Global Emissions of Mercury in 2015 Highest Rates in Asia and Africa https://www.epa.gov/international-cooperation/mercury-emissions-global- context#:~:text=Mercury%20emitted%20into%20the%20air%20eventually%20settles%20into%20water%20or,and%20anim als%20that%20eat%20fish.&text=Learn%20more%20about%20mercury%20exposure%20in%20the%20United%20States.  https://www.epa.gov/international-cooperation/mercury-emissions-global- context#:~:text=Mercury%20emitted%20into%20the%20air%20eventually%20settles%20into%20water%20or,and%20anim als%20that%20eat%20fish.&text=Learn%20more%20about%20mercury%20exposure%20in%20the%20United%20States.  https://www.epa.gov/international-cooperation/mercury-emissions-global- context#:~:text=Mercury%20emitted%20into%20the%20air%20eventually%20settles%20into%20water%20or,and%20anim als%20that%20eat%20fish.&text=Learn%20more%20about%20mercury%20exposure%20in%20the%20United%20States. Global Emissions of Mercury by Activity http://mercurypolicy.scripts.mit.edu/blog/wp-content/uploads/2013/01/2013UNEPemissions.jpg Global Emissions of Mercury by Activity Burning coal at electrical power plant = fossil fuel combustion http://mercurypolicy.scripts.mit.edu/blog/wp-content/uploads/2013/01/2013UNEPemissions.jpg Global Emissions of Mercury by Activity Burning coal at electrical power plant = fossil fuel combustion Gold mining http://mercurypolicy.scripts.mit.edu/blog/wp-content/uploads/2013/01/2013UNEPemissions.jpg Global Sources of Mercury Emissions by Region UNEP; http://mercurypolicy.scripts.mit.edu/blog/?p=72 Temporal Trends in Mercury Emissions Around the Globe Increasing in Asia Decreasing in U.S. and Europe a http://www2.epa.gov/international-cooperation/mercury-emissions-global-context  Anthropogenic Sources of Mercury in the U.S. Coal-fired electric power plants (40% of total U.S. mercury emissions) Industrial boilers (10% of total U.S. mercury emissions) Burning hazardous waste (5%) Chlorine production (5%) Manufacturing products (thermometers, some batteries, electrical switches)  Anthropogenic Sources of Mercury in the U.S. Coal-fired electric power plants (40% of total U.S. mercury emissions) Industrial boilers (10% of total U.S. mercury emissions) Burning hazardous waste (5%) Chlorine production (5%) Manufacturing products (thermometers, some batteries, electrical switches) Primary way people exposed: eating mercury in fish and other biota Temporal Trends in Mercury Emissions by Source for the U.S. EPA.gov Temporal Trends in Mercury Emissions by Source for the U.S. Utility coal boilers = electrical power plants (fossil fuel combustion) = largest source of mercury emissions EPA.gov  Utility coal boilers = electrical power plants (fossil fuel combustion) = largest source of mercury emissions Now declining Temporal Trends in Mercury Emissions by Source for the U.S. Utility coal boilers = electrical power plants (fossil fuel combustion) = largest source of mercury emissions Since 1990s: Drop in mercury emissions from medical waste incinerators and fossil fuel combustion EPA.gov Temporal Trends in Mercury Emissions by Source for the U.S. Utility coal boilers = electrical power plants (fossil fuel combustion) = largest source of mercury emissions Since 1990s: Drop in mercury emissions from medical waste incinerators and fossil fuel combustion How did medicinal waste incinerators reduce mercury waste? EPA.gov Temporal Trends in Mercury Emissions by Source for the U.S. Utility coal boilers = electrical power plants (fossil fuel combustion) = largest source of mercury emissions Since 1990s: Drop in mercury emissions from medical waste incinerators and fossil fuel combustion How did medicinal waste incinerators reduce mercury waste? Now people add activated carbon during burning process → C attached to mercury and precipitates EPA.gov  Anthropogenic Sources of Mercury Coal-fired electric power plants (40% of total U.S. mercury emissions) 25% emissions from coal-burning power plants deposited within contiguous U.S. 75% enters global Hg cycle Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy  Mercury in Atmospheric Deposition Some of the highest rates are in the northeastern U.S. Settles into water or onto land (can then be washed into water) Dominant source of Hg in aquatic environments Nadp.sws.uiuc.edu/mdn Mercury in Atmospheric Deposition: Highest in Southeastern US Interaction Between Sulfur Deposition and Mercury Interaction Between Sulfur Deposition and Mercury When sulfate present + anoxic conditions: microbes increase methylation of Hg2+ Link to S deposition: increases toxicity of mercury Important for Northeastern U.S. because of high rates of S deposition Mercury Cycle Mercury Cycle  Problems with Mercury Mercury emitted to the atmosphere → comes down in wet and dry atmospheric deposition  Problems with Mercury Mercury emitted to the atmosphere → comes down in wet and dry atmospheric deposition Micro-organisms convert Hg2+ → CH3Hg (methylmercury): Bio-accumulates: can be 10 million-times in aquatic food chains Further accumulates in birds and mammals Wildlife: Decreased reproduction (loons) Decreased endocrine function (fish) Decreased growth/deformities (frogs)  Problems with Mercury Mercury emitted to the atmosphere → comes down in wet and dry atmospheric deposition Micro-organisms convert Hg2+ → CH3Hg (methylmercury): Bio-accumulates: can be 10 million-times in aquatic food chains Further accumulates in birds and mammals Wildlife: Decreased reproduction (loons) Decreased endocrine function (fish) Decreased growth/deformities (frogs) Humans: Consume CH3Hg in fish Harms developing nervous system of babies Causes learning disabilities in children Adults: can harm brain, heart, kidneys, lungs and immune system of all ages Mercury Concentrations in Water and Aquatic Biota in Eastern North America Figure 3, Driscoll et al. 2007  Mercury Concentrations in Water and Aquatic Biota in Eastern North America 0.3 ppm considered toxic to humans Figure 3, Driscoll et al. 2007 Hg Concentrations in Fish of the Northeastern U.S. Figure 5, Driscoll et al. 2007 Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy  Example of Earlier Success with Policy Response to Mercury Emissions 1997: EPA issued Emission Standards for Medical Waste Incinerators Incinerators must now comply with strict emission controls 1990→2006: Mercury emissions decreased 95%  Policy Response to Mercury Emissions Clean Air Mercury Rule March 15, 2005: Issued by EPA Goal: reduce mercury emissions from coal-fired power plants First ever U.S. rule to regulate utility emissions of Hg Current levels of Hg Emissions: 48 tons/yr Goal: Reduce to 26 tons in 2010 and 15 tons in 2018  Policy Response to Mercury Emissions Clean Air Mercury Rule March 15, 2005: Issued by EPA Goal: reduce mercury emissions from coal-fired power plants First ever U.S. rule to regulate utility emissions of Hg Current levels of Hg Emissions: 48 tons/yr Goal: Reduce to 26 tons in 2010 and 15 tons in 2018 December 2011 EPA finalized national emission standards for mercury, particle pollution and other harmful pollutants from electric power plants. Known as MATS: “Mercury and Air Toxics Standards”  Policy Response to Mercury Emissions Clean Air Mercury Rule March 15, 2005: Issued by EPA Goal: reduce mercury emissions from coal-fired power plants First ever U.S. rule to regulate utility emissions of Hg Current levels of Hg Emissions: 48 tons/yr Goal: Reduce to 26 tons in 2010 and 15 tons in 2018 December 2011 EPA finalized national emission standards for mercury, particle pollution and other harmful pollutants from electric power plants. Known as MATS: “Mercury and Air Toxics Standards Other Federal Regulation Federal bans on mercury in paints and batteries State-required recycling programs Mercury Export Ban Act of 2008: Prohibits export of Hg from U.S. effective Jan 1, 2013  Policy Response to Mercury Emissions Clean Air Mercury Rule March 15, 2005: Issued by EPA Goal: reduce mercury emissions from coal-fired power plants First ever U.S. rule to regulate utility emissions of Hg Current levels of Hg Emissions: 48 tons/yr Goal: Reduce to 26 tons in 2010 and 15 tons in 2018 December 2011 EPA finalized national emission standards for mercury, particle pollution and other harmful pollutants from electric power plants. Known as MATS: “Mercury and Air Toxics Standards Other Federal Regulation Federal bans on mercury in paints and batteries State-required recycling programs Mercury Export Ban Act of 2008: Prohibits export of Hg from U.S. effective Jan 1, 2013. International Treaty: Minamata Convention on Mercury Designed to protect human health and environment from anthropogenic mercury emissions by limiting production or trade of products with mercury Human Alteration of the Mercury Cycle - Emissions and Overview - Deposition - Policy