TT Talk - transport of plastic pellets
Focus in maritime transport has been turned towards the safe transport of microplastic pellets following well-publicised incidents. While the debate rages as to how to mitigate the risks to the maritime ecosystem, those arising through the entire freight supply chain need to be recognised.
Microplastic pellets, often referred to as nurdles, form the building blocks used in the production of most plastic products. They typically measure just a few millimetres in diameter – about the size of a lentil. The release of nurdles into the sea, other waterways or the environment in general have severe ecological implications, since the pellets may be eaten by fish or other sea creatures, as well as by birds and small mammals.
By accumulating in the stomach of the creature consuming it, the plastic has an impact on nourishment. Additionally, these pellets may, due to their unique chemical composition, also absorb toxins from the environment, presenting additional risks to the food chain. Further, reports have surfaced recently of insects and microbes that have evolved to consume plastic, but may naturally be consumed by birds and small mammals.
focusing only on … maritime incidents understates the scope of the risk involved in the end-to-end supply chain of microplastics
Once a spill has taken place, nurdles can rapidly be dispersed in water due to their small size, resulting in complex and costly clean-up efforts. The maritime industry is rightly focused on ways to make such events less likely, although there are uncertainties over how this can best be done. However, focusing only on these maritime incidents understates the scope of the risk involved in the end-to-end supply chain of microplastics. There are also significant and diverse landside risks involved in the packaging, handling and packing of this type of cargo. Additionally, many of the same environmental risks that occur in the oceans are also present on land.
Common packaging solutions
There are several different packaging methods used to ship nurdles.
- Tank containers
- Dry bulk containers
- Cardboard boxes with plastic lining
- Polypropylene sacks (25kg-1,000kg)
- Large Cloth Bags
- Intermediate bulk containers and drums
Each of these has its own unique characteristics and benefits, presenting opportunities for the varied stakeholders involved.
Source: Josh Finch, TT Club
Supply chain risks
Apart from the risks to the marine environment, other risks exist through the transport and storage supply chain.
Certain packagings, in particular large bags stored on pallets, can become unstable and have a tendency to shift during transit, including during sea voyages. Additionally, bags often split due to the shifting weight of the pellets inside them and there is currently no standard to which bags must be maintained. Unstable cargo, shifting weight and collapsing packages present challenges at all stages of the supply chain.
Unstable cargo, shifting weight and collapsing packages present challenges at all stages of the supply chain
- Weight distribution
When weight is unevenly distributed, there are increased risks of vehicle overturns. However, such dangers also extend to the warehouse operations through which the cargo passes, as bags may shift during packing or unpacking, endangering workers. Where cargo has shifted, simply opening the doors of a container, with weight pressed against them, may be highly dangerous.
- Environmental risk
At whatever point of transit, including handling and transport over land, the occurrence of a spill necessitates adequate containment and clean-up. By some estimates, as many as one in ten containerised consignments experiences a spill. Additionally, packing of bulk road and rail tank containers, often undertaken outside, often incurs incidental spillages.
While acknowledging that supply chain operators may have limited control over the types of packaging used, the use of cardboard boxes, large supersacks and ton bags should be discouraged. Spillages and instances of collapsing cargo using these types of packaging are alarmingly common, putting the workforce at risk, regardless of environmental hazards. If packed and secured correctly, smaller 25kg sacks are less likely to shift and the quantity of nurdles to clean up when a sack is damaged or otherwise splits is far less than with larger bags. It would also be helpful if a minimum standard of quality was established to limit the use and subsequent impact of poor quality sacks.
the use of cardboard boxes, large supersacks and ton bags should be discouraged
Supply chain workers should be made aware of the risks. Where spillages have happened in a container or in the yard, every attempt should be made to prevent plastic pollution from entering the environment. Nurdles should never be allowed to enter the water supply, either intentionally or as natural runoff. Where there is a danger of this happening, spillage equipment such as socks and filters that fit over drains should be used to prevent it.
Where tank containers are filled and emptied, operators should consider the use of pellet catching pans and mobile barriers to limit the chance of spillages entering the local environment, most especially the water supply.
When handling smaller sacks, workers should be alerted to exercise caution and use proper manual handling techniques. Because they shift easily, it is not unusual for the centre of gravity to shift unexpectedly while handling a sack of nurdles. Indeed, manual handling injuries are common in the plastics industry.
Load Restraint recommendations
Due to the way that nurdles shift inside their packaging, safely restraining cargoes of nurdles can prove challenging. However, there are solutions that provide an adequate measure of restraint and prevent collapses.
- Large sacks should be banded to the pallets on which they sit. Where such pallets are double stacked, the weight should be spread by using a plywood board between the stacked pallets.
- The use of an adaptive lashing solution, capable of re-tensioning itself, is recommended to prevent loads collapsing due to shifting. Any transversal gap should be closed with dunnage.
- Where pallets are secured to the bed of a curtain-sided vehicle using over-pallet strapping, prevent the strap from damaging the bag by using a pallet protection solution that sits between the strap and the bags. Even a wide strip of cardboard can be adapted for this purpose, though commercial products also exist, including wide strap solutions.
- Where 25 kg bags are palletised, ensure that bags are stacked in staggered layers to create a stable pallet load. Consider using corner protection to increase the stability of the pallet and to provide protection from damage to the bags.
There are no easy solutions to the challenges presented by the transport and storage of plastic pellets. Tank containers are costly. Bags split and shift. The world is still grappling with the challenge of transporting nurdles safely to prevent serious ecological consequences.
However, it is worth noting that the challenge is larger than is commonly understood and impacts on the safety and efficacy of every stage of the supply chain. The environmental repercussions are not limited to events at sea.
the challenge … impacts on the safety and efficacy of every stage of the supply chain
It is worth considering the full scope of the challenge, not least the safety of the workers in the supply chain, as the industry considers how to address it, particularly at the IMO. A proactive approach to risk mitigation is advisable.
If you would like further information, or have any comments, please email us, or take this opportunity to forward to any others who you may feel would be interested.