Mechanical

Cars, trucks, tractors, slashers, bicycles and even lawnmowers break up waste and move it through the environment.

For example, collection of kerbside waste bins by rubbish trucks can result in plastic bags, paper and other items blowing out and contributing to residential and roadside litter[3]. It highlights the importance of roads in the mechanical distribution of waste pollution[1].

Quick facts

Litter falling from vehicles is dangerous

to other motorists, cyclists and pedestrians, and can result in property damage.

Mechanical

• Overview
• Actions

Mechanical processes transport waste pollution through the environment, and together with wind, water (i.e. rain) and sunlight (i.e. breakdown of materials making them more transportable), they they also tend to break up persistent material (like plastic) into smaller pieces. These pieces remain in the environment as they do not break down into organically usable forms. For example, a plastic water bottle fragments into smaller and smaller pieces, going from macroplastics, to microplastics and nanoplastics. At each stage, these pose different threats to animals and ecosystems.

A study found the presence of microplastics in road dust along an urban to rural transect within South-East Queensland. Concentrations ranged from ~0.5 mg/g in a rural site to 6 mg/g in Brisbane city, with 29% each consisting of polyvinyl chloride and polyethylene terephthalate. There was a strong relationship between the concentration of microplastics in road dust and the volume of vehicles on the road[2].

Waste made of bio/photodegradable material breaks down completely and decomposes into natural elements.

References

1. ^ Gregory, MR (1978), 'Accumulation and distribution of virgin plastic granules on New Zealand beaches', New Zealand Journal of Marine and Freshwater Research. [online], vol. 12, no. 4, pp. 399-414. Available at: https://doi.org/10.1080/00288330.1978.9515768.
2. ^ O’Brien, S, Okoffo, ED, Rauert, C, O’Brien, JW, Ribeiro, F, Burrows, SD, Toapanta, T, Wang, X & Thomas, KV (August 2021), 'Quantification of selected microplastics in Australian urban road dust', Journal of Hazardous Materials. [online], vol. 416, p. 125811. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0304389421007755 [Accessed 9 April 2025].
3. ^ Richards, G (2019), '3,100 littering tickets - an how many went to garbage trucks: Roadshow', The Mercury News. [online] Available at: https://www.mercurynews.com/2019/12/25/recycling-trucks-often-spew-trash-back-onto-freeways-roadshow/.

Last updated: 23 April 2025