水星汞MercuryปรอทIntroduction to Ecotoxicology and One Health, Joint Summer Camp
31 July 2024 | Hokkaido Universitykwik

Background Information
Potchefstroom

South Africa

Background Information
North-West University (NWU):

Water Research Group (WRG):- Undergrad Zoology and Microbiology (2011-13)- Trained Ecotoxicologist- Masters in Environmental Science (2015-16)- Aquatic Scientist- PhD in Environmental Science (2017-20)- Postdoc focusing on mercury (2020-present)

Ecology

Ecotoxicology
OneHealth- Lecturer at Hokkaido University (2024-present)

Parasitology

Did you know?
• Mercury is a very rare element in the Earth’s crust?
• It is the only metal that is liquid at room temperature?
• It is really heavy and dense?
• It is highly toxic even in low concentrations?
• Mercury is used in fluorescent lamps?
• It is highly volatile and produce vapor?
• It does not react with most acids?
• It forms amalgams with all other metals, except iron
• It is a global and persistent pollutant

Ecotoxicology• Ecotoxicology is the study of harmful effects of toxic pollutants in ecosystems• It started in 1969 by René Truhaut• A multidisciplinary approach

Biology
Ecology

Chemistry

ECOTOXICOLOGY
Environ.
SciencePhysiology

AnalyticalChemistryMercury contamination in South
Africa’s aquatic ecosystems:
Any cause for concern?
J.H. Erasmus
W. Malherbe, N.J. Smit, V. Wepener
Water Research Group,
Unit for Environmental Sciences and Management, North-West
University, Potchefstroom 2520,
South Africa

Introduction to Ecotoxicology and One Health, Joint Summer Camp
31 July 2024 | Hokkaido University

Introduction - Mercury

Water
ResearchGroup

Characteristics of mercury:• Liquid at room temperature• Different forms in environment• Good electrical and thermal conductor• Ability to dissolve gold and silver• Enters humans and biota• Have detrimental effects

Metallic

Organic
InorganicIntroduction - Uses

Water
ResearchGroup

Miracle to worst nightmare• Ancient Egyptians (2500 BC)• Barometer (1643), thermometer (1720)• Industrial revolution (1850s)
Electrical and electronics

Extraction of metals

Chlor-alkali process

Medical and dental

Introduction - Uses

Water
ResearchGroup

Miracle to worst nightmare• Ancient Egyptians (2500 BC)• Barometer (1643), thermometer (1720)• Industrial revolution (1850s)
Electrical and electronics

Extraction of metals

Chlor-alkali process

Medical and dental

Introduction - Demand and Supply

Horowitz et al. 2014. Historical mercury releases from commercial products:
global environmental implications. Environ. Sci. Technol., 48:10242-10250

Sodeno 2023. Projected global mercury supply, demand, and excess to 2050
based on impacts of the Minamata Convention. J. Mater. Cycles Waste Manag.,
25:3608-3624

Water
ResearchGroupIntroduction - Emissions to Environment

Zhang et al. 2021. Global health effects of future atmospheric mercury emissions. Nature communications, 12:3035

WaterResearchGroupIntroduction - What we know
Mercury in ecosystems:•Legacy pollutant•

Bioaccumulate•

Biomagnify

Water
ResearchGroupIntroduction - International monitoring

Evers et al. 2024. Global mercury concentrations in biota: their use as a basis for global biomonitoring framework. Ecotoxicology.

Water
ResearchGroupIntroduction - SA perspective

Walters et al. 2011. A review of mercury pollution in South Africa: Current status. J. Environ. Sci. Health, 46:1129-1137

Water
ResearchGroup

Mercury Project - 2022–present

Water
ResearchGroupCase Study 1 - Elasmobranchs

Water
ResearchGroupCase Study 1 - Elasmobranchs• Total of 22 elasmobranch species (n = 86)• South coast: 62• East coast: 104

Water
ResearchGroupCase Study 1 - Elasmobranchsa)

b)

Water
ResearchGroupCase Study 1 - Elasmobranchs• Most species have increased [Hg] compared to 2005-2010 study(McKinney et al. 2016. Sci. Total Environ., 541:176-183)

Water
ResearchGroupCase Study 1 - Elasmobranchs• Most species have increased [Hg] compared to 2005-2010 study(McKinney et al. 2016. Sci. Total Environ., 541:176-183)

Water
ResearchGroupCase Study 2 - Cape white seabream

Water
ResearchGroupCase Study 2 - Cape white seabream• Cape white seabream (Diplodus capensis)• n = 40 from impacted and non-impacted sites
De Hoop MPA

Mossel Bay Habour

WitsandTsitsikamma MPA

Chintsa EastWater
ResearchGroupCase Study 2 - Cape white seabream• Higher [Hg] compared to previous study in 2014
(Bosch et al. 2016. J. Sci. Food Agric., 96:32-48)• Human health risks associated with consumption

Water
ResearchGroupCase Study 3 - Freshwater eels

Water
ResearchGroupCase Study 3 - Freshwater eels
• Two eel species (n = 19)• Higher [Hg] compared to A. marmorata from Ba River,
Vietnam(Le et al. 2012. Coast. Mar. Sci., 35:136-141)• Human health risks – locally and international

WaterResearchGroupCase Study 3 - Freshwater eels
• Two eel species (n = 19)• Higher [Hg] compared to A. marmorata from Ba River,
Vietnam(Le et al. 2012. Coast. Mar. Sci., 35:136-141)• Human health risks – locally and international

Water
ResearchGroupCase Study 4 - Floodplain systems

WaterResearchGroupCase Study 4 - Floodplain systems• Largest floodplain system in SA• Located in a nature reserve• Receives water from variousanthropogenic land-use activities

Water
ResearchGroupCase Study 4 - Floodplain systems• Invertebrate families• Comparable concentrations to river inItaly near chlor-alkali plant(Marziali et al. 2021. Toxics, 9:197)

Water
ResearchGroupCase Study 4 - Floodplain systems• Fish species• Exceeding European biota environmental quality standards

Water
ResearchGroupCase Study 4 - Floodplain systems• Biomagnification• Exceeding European biota environmental quality standards

Water
ResearchGroupCase Study 4 - Floodplain systems• Biomagnification• Exceeding European biota environmental quality standards

WaterResearchGroupWhy unexpected results?

WaterResearchGroup

Conclusions

United Nations Environment Programme, 2019. Technical background report to the global mercury assessment

WaterResearchGroup

Conclusions• Elevated [Hg] even found in relatively “pristine areas”• Hg contamination due to several sources• [Hg] in different biota pose human health risks• Continuous monitoring is needed even in “pristine sites”• The implications not only relevant to this study but a global concern

WaterResearchGroupOne Health Approach

WaterResearchGroupInterdisciplinary approach
Environmental Scientists / Ecotoxicologist

WaterResearchGroup

Environmental / Chemical Engineers

Social Scientists / Communication
Environmental Law“Healthy” Environment and humans

WaterResearchGroupTHANK YOU