Arctic Pollution and Contaminants

• Pollution and contamination in the Arctic originates from non-local sources, with toxins transported from elsewhere.
• The Arctic Monitoring and Assessment Program (AMAP) was established in 1991 to monitor and assess Arctic pollution.
• AMAP's mandate is to provide reliable information on the Arctic environment's status and threats, along with scientific advice for Arctic governments to take remedial and preventive actions related to contaminants and climate change.

Types of Contaminants in the Arctic

• Organics, such as Persistent Organic Pollutants (POPs).
• Metals, including Mercury (Hg), Cadmium (Cd), and Lead (Pb).
• Radionuclides.
• Source regions for these contaminants include industrial and agricultural areas in Eurasia, North, and Central America due to long-distance transport.
• High energy radioactive waste has been dumped in the arctic.

Persistent Organic Pollutants (POPs)

• POPs are carbon-based chemical compounds and mixtures, including industrial chemicals like PCBs, pesticides like DDT, and unwanted wastes like dioxins.
• They are synthetic products and by-products of industrial processes.
• POPs are persistent and resistant to degradation due to chlorination/bromination.
• They are chlorinated or halogenated compounds, lasting a long time in the environment because they resist biological breakdown.
• Legacy POPs are chemicals included in the original Stockholm Convention.
• New POPs are chemicals listed under the Stockholm Convention between 2005-2019.

POP Transport Pathways to the Arctic

• POPs are found even in the most remote places in the Arctic, with most transport occurring in the winter when winds are higher.
• Atmospheric transport is the fastest route for these contaminants to reach the Arctic.
• POPs are found in every part of the Arctic.
• Moderate degree of chlorination and moderate lipophilic properties are key chemical characteristics.

Global Distillation Model

• Organochlorines (OCs) evaporate in warm temperatures.
• OCs move via winds to colder places.
• OCs condense and fall to Earth in cold temperatures.
• Volatilization is when substances transition into gaseous phase and Avection relates to transport in wind patterns.
• Condensation occurs when meeting colder temperatures, transitioning from gaseous to liquid phase.
• The grasshopper effect involves multiple jumps for chemicals to reach the Arctic.
• More volatile POPs take fewer jumps to transport and reach their destination.

Global Distillation Model – Key Points

• POPs migrate from source regions to colder climates.
• POPs migrate in a few "jumps" – the grasshopper effect.
• At higher temperatures, they are picked up by wind as gases and condense when temperatures drop.
• They re-volatilize when weather changes.
• POPs of different volatilities migrate at different velocities.
• The composition of contaminant mixtures changes along a latitudinal gradient.
• PCBs in sediments have decreased around the time these compounds were banned in North America.

Transport Within the Arctic Ocean

• Ice acts as an important vehicle, entrapping and transporting POPs.
• Ice melting coincides with the period of maximum primary biological productivity.

POP Accumulation

• Tissue concentrations of POPs in biota occur.
• Legacy POPs are decreasing, but unfortunately, new POPs are increasing, though the extent of information is limited.
• Recent biomonitoring studies indicate POPs impair immune response capacity, cause oxidative stress, and endocrine disruption (thyroid and steroid hormone imbalance) in Arctic mammals.
• POPs exposure causes growth and metabolic disruption, and reproductive impairments in arctic mammals and humans.

Understanding Biomarkers

• Biomarkers are biological, molecular, and chemical indicators or signals that can predict what can happen due to exposure.
• Predictive biomarkers indicate future effects.
• Reactive biomarkers indicate current effects.

Risk Assessment

• Risk Quotient (RQ) = Body Residue (BR) / Critical Body Residue (CBR).

Human Exposure to POPs

• Humans are exposed to legacy POPs.