Persistent Organic Pollutants (POPs)

Question 1

Definition of POPs

Answer 1

POPs are man-made organic chemicals resistant to environmental degradation that accumulate through food chains, posing toxic effects on humans and wildlife.

Question 2

Characteristics of POPs

Answer 2

• Persistence in the environment
• Adverse effects
• Potential for long-range environmental transport
• Bioaccumulation in the food chain

Question 3

Adverse effects of POPs

Answer 3

• Endocrine disruption leading to reproductive, neurological, and immune system disorders
• Cancers such as prostate, pancreatic, and breast cancer
• Cardiovascular diseases and diabetes
• Other effects like obesity and chloracne

Question 4

Examples of POPs

Answer 4

DDT (Dichlorodiphenyltrichloroethane)
PCBs (Polychlorinated Biphenyls)
PFCs (Perfluorinated Compounds)

Question 5

Stockholm Convention

Answer 5

Global treaty to protect human health and the environment from POPs
Bans and restricts production, use, and import/export of POPs
Aims for safe management of POP-containing stockpiles and wastes

Question 6

Cycling of POPs in the marine environment

Answer 6

• Sources include fossil fuel combustion, industrial effluents, and microplastics
• Transported through atmospheric and oceanic currents
• Bioaccumulation occurs in marine food chains
• Slow degradation and accumulation in sediments

Question 7

What contributes to high concentrations of DDT in the Indian Ocean and South Asia?

Answer 7

High concentrations of DDT in the Indian Ocean and South Asia are attributed to its use for anti-malarial and crop pest control, which is still authorized by the Stockholm Convention.

Question 8

What do the temporal trends of b-HCH in air at Alert and Storhofi indicate?

Answer 8

The temporal trends of b-HCH in air at Alert and Storhofi, as shown in the study by Hung et al. (2017), suggest the presence and transport of persistent organic pollutants (POPs) in the Arctic atmosphere.

Question 9

How do POPs interact with sediment in aquatic environments?

Answer 9

POPs adsorb onto water particles, influenced by their chemical structures. Sediment can act as both a sink and source of POPs, with activities like dredging and storms increasing their release into water and air. Storms, intensified by climate change, elevate sediment resuspension, releasing more POPs. Additionally, sediment can transport POPs to deeper waters via submarine canyons and adjacent transport.

Question 10

How are POPs monitored in the marine system?

Answer 10

Monitoring shows a non-continuous decrease in all compounds, termed “legacy pollutants.” Techniques like solid-phase extraction followed by gas chromatography reveal very low concentrations, sometimes below detection limits. POP profiles resemble those of other oceans, with peaks observed around 500 meters, indicating release from remineralization of sinking organic matter.