G. Pollutants

Question 1

What is the difference between macr-, meso- and micro- plastics?

Answer 1

Macroplastics are larger than 25mm
Mesoplastics are between 5mm - 25mm
Microplastics are smaller than 5mm

(NB: Nanoplastics are smaller than 0.1mm down to 20nm ???)

Question 2

What is the difference between Primary and Secondary microplastics?

Answer 2

Primary microplastics are pellets / granules / microbeads manufactured to a specific size. Directly released into the environment.

Secondary microplastics are fragments of larger plastic items degraded once exposed to the marine environment.

Question 3

What is an Endocrine Disruptor?

Answer 3

Direct Interference:
Mimics or blocks chemicals that are found naturally in the body.
Alters hormonal levels so affects the functions these hormones control.

Less direct interference:
Alters body’s ability to produce hormones.
Interfers with the way hormones travel through body.
Changes the number of hormone receptors in the body

Question 4

List 3 methods by which microplastics may be removed from the oceans:

Answer 4

1. Drones (with small-meshed nets)
2. Ships (with nets or extraction systems)
3. Booms & Collection devices

Question 5

What are the key factors of microplastics removal by Boom or Collection Device?

Answer 5

Booms capture floating litter of various sizes
Collection devices can capture litter throughout the water column
Relatively low cost BUT need frequent maintenance
Can be connected to litter traps
Can be powered by sunlight or water currents
Passive systems

Question 5

What are the pros and cons of mircoplastics removal by drone?

Answer 5

Pros:

1. Autonomous operation    2. Power supply by PV systems (eventually)

Cons:

1. Expensive
2. Limited battery capacity (currently)
3. Reduced field efficiency

Question 6

What are the key factors of microplastics removal by Ship / Vessels?

Answer 6

On-site collection + storage (temporary) + transportation
Modified ships equipped with nets
Skimmer vessels for floating litter
Fishermen collect plastic litter in exchange for a reward

Question 7

How effective is microplastics recovery by Boom / Collection Device?

Answer 7

29 locations in North Pacific Gyre

42% cleanup efficiency in 10 years

Question 8

What are the two main families of plastics found in the oceans?

Answer 8

1. Thermoplastics: become pliable at certain temperatures and set upon cooling.
2. Thermoset: a polymer obtained by irreversibly hardening a soft solid or liquid.

Question 9

What are the 7 key types of plastics?

Answer 9

1. PE
2. PET
3. PVC
4. Polyester
5. Polyamide
6. Epoxy resins
7. Rubber derivates from tyre abrasion

Question 10

Plastic Bags: on average how many are used and how long for?

Answer 10

More than 1 million bags are used every minute.

Average working life of 15 minutes.

Question 11

How many plastic bottles are used worldwide?

Answer 11

100 million plastic bottles per day.

Question 12

How much plastic is single-use?

Answer 12

50% of plastic is used just once and thrown away.

Question 13

How much plastic is thrown away each year?

Answer 13

Enough to circle the Earth 4 times.

Question 14

What are the 3 potential biological risks from microplastics?

Answer 14

1. Ingestion
2. Translocation (possibly into organs)
3. Intracellular absorption

Question 15

How much plastic enters the oceans annually?

Answer 15

Approximately 8 million tons of plastic emters the oceans annually.

Question 16

What are the most significant poperties of plastics as a pollutant?

Answer 16

1. Tough - microbeads are made from Polyethelyne (bulletproof vests etc.)
2. Bioaccumulation - can collect in the bodies of fish, shellfish, seabirds etc.
   Especially true for POPs (Persistent Organic Pollutants)
3. Absorbtion - can absorb and concentrate chemicals dissolved in seawater.
4. Leaching - chemicals in plastics can leach into water and sediments