Herman Gibb, PhD, MPH Gibb Epidemiology Consulting Arlington, VA, USA

1. Mercury exposure and health impacts among individuals in the artisanal & small-scale gold mining (ASGM) community Herman Gibb, PhD, MPH Gibb Epidemiology Consulting Arlington, VA, USA

2. Different forms of mercury • Elemental mercury • Inorganic mercury (e.g., mercuric nitrate, mercuric chloride, mercurous chloride, mercuric sulfide, mercuric acetate) • Organic mercury (e.g., methylmercury, ethylmercury)

3. Biomarkers of mercury • Hair (methylmercury) • Blood (all forms of mercury) • Urine (elemental and inorganic mercury)

4. Mad as a hatter • In the 19th and 20th Centuries, inorganic mercury (mercuric nitrate) was used in the production of felt for hats. The hatters were exposed to mercury vapor from a reaction that released volatile free mercury. • As early as 1829, adverse health symptoms including mental confusion, emotional disturbances, and muscular weakness were reported among hatters. • A U.S. Public Health Service estimated that in 1934, 80% of American hat makers had mercurial tremors – what the workers referred to as “the shakes.” • The term “mad as a hatter” is associated with the syndrome.

5. The minamata incident • Minamata Disease Symptoms: • Ataxia • Numbness in the hands and feet • General muscle weakness • Narrowing in the field of vision • Damage to hearing and speech • Extreme cases: • Insanity • Paralysis • Coma • Death • One of the most severe incidents of mercury poisoning occurred in Minamata, Japan, when a local company dumped what is estimated to have been 27 tons of methylmercury into Minamata Bay over a period of 1932-1968. • The methylmercury accumulated in shellfish and fish. • Consumption of the fish and shellfish resulted in the deaths of cats, dogs, pigs, and humans. What became known as Minamata disease is a neurologic syndrome caused by severe mercury poisoning. • Children born to mothers who consumed the fish and shellfish were born with severe congenital deformities.

6. The minamata convention • The Convention is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. • The treaty was developed under the aegis of the United Nations Environment Programme. • The Convention was opened for signature in October 2013 in Minamata, Japan. • There are now 102 signatories (countries) to the Convention.

7. The minamataconvention • Article 7 and Annex C of the Convention address artisanal and small-scale gold mining (ASGM) and the development of national plans for ASGM. The Convention calls for nations to gather health data, train health care workers, and raise awareness in regard to ASGM activity. • All countries in South America are signatories of the Convention with the exception of Suriname.

8. How and why is mercury used in asgm? • Mercury forms an amalgam with the ore. • Mercury is heated and vaporizes leaving the gold behind. • The method is cheaper than other methods, can be done by one person and is quick and easy. UNEP 2012 UNEP 2012

9. How big is the problem? • Mercury vapors in the air around amalgam burning sites can be alarmingly high and almost always exceeds the WHO limit for public exposure of 1.0 µg/m³. • Mercury from ASGM is responsible for 37% of the global emissions of mercury and is the largest single source of air and water mercury. UNEP 2013

10. How widespread is the problem? • Approximately 15 million people, including approximately 3 million women and children, participate in the ASGM industry in 70 countries. • These 70 countries are found primarily in East and Southeast Asia, Sub-Saharan Africa & South America. UNEP 2013

11. Health effects among those engaged in ASgm Source: Gibb & O’Leary 2014

12. Health effects AMONG those indirectly exposed TO ASgm Individuals not directly engaged in ASGM but living in ASGM communities or communities near ASGM Source: Gibb & O’Leary 2014

13. Urinary mercury concentrations AMONG those working or living in asgm communities neurologic signs kidney effects

14. Hurtado et al. 2006 • 50 µg/L has been associated with kidney damage • 100 µg/L is associated with neurologic effects Mean urinary mercury levels of various exposure groups

15. Mean & range of hair mercury concentrations of female residents of ASGM communities PTWI

16. Mean & range of hair mercury Concentrations of children and infants of asgm communities

17. Air measurements at ASGM Operations in Venezuela & Peru Drake et al. 2001 (Venezuela) • Range: 0.1-6,315 µg/m³ • Mean: 183 µg/m³ • 20% of the measurements (N=61) were above 50 µg/m³ Hurtado et al. 2006 (Peru) Amalgam smelter • Range: 530-4,440 µg/m³ • Mean: 2,423.3 µg/m³ • N=6 Working and/or living in quimbaletes • Range: 12-55 µg/m³ • Mean: 30.5 µg/m³ • N=6 Living in artisanal mining town • Range: 3-23 µg/m³ • Mean: 11.8 µg/m³ • N=5

18. ASGM Mercury consumption and associated emissions In south america [Adapted from UNEP (2013) Technical Background Report for the Global Mercury Assessment] *Quality of Data: Worst (1) to Best (4)

19. Summary • The problem of mercury emissions from ASGM is widespread – ASGM occurs in 70 countries and is responsible for 37% of the global emissions of mercury • Health effects associated with ASGM have been reported in at least 10 countries on 3 continents. These effects are primarily neurologic, kidney, and immunologic. • Urinary mercury concentrations in ASGM communities are significantly elevated above concentrations associated with health effects. • Hair mercury concentrations in women living in or near ASGM communities are significantly elevated above the hair mercury concentrations associated with WHO’s Provisional Tolerable Weekly Intake. • Hair mercury concentrations in children living in or near ASGM communities are elevated above those of other fish eating populations. • Brazil has the most gold miners in South America (estimated 500,000), but the amount of mercury emissions (tons released) is estimated to be higher in Bolivia, Colombia, and Peru.