Hi everyone, and welcome to our first post on land pollution! As usual, we’ll be using this first post to introduce the topic before going on to more case studies in the upcoming posts.

To begin, we’re sure many of you have come across signs like this on your holidays, especially when it’s a nature area:

This was taken by one of us (Joanna) on a school trip to Horton Plains in Sri Lanka way back in 2016. But have you ever wondered why the emphasis on having no litter and no dumping activities is always so great? How does litter, or any anthropogenic pollutive material, affect the land we walk on?

As we’ll explain below, it’s not just because it’s unsightly…

Culprit 1: Plastics

The main way we can pollute the land is through the plastics that we might unwittingly throw onto the ground when on holiday (admit it, if the wind accidentally blows some bits of packaging away, we don’t bother to pick them up as much as compared to when we’re back home here in Singapore). Without a doubt, plastics can become hazardous to the animals and creatures that come across it, whereby they consume the plastics and end up choking or even dying. In this post, however, we’re more concerned about the chemical effects that plastics can have on the soil.

One way plastics can pollute the soil is through the leaching of its components and additives into the soil. In a recently published paper by Machado et al. (2019), chemical components like phthalates and Bisphenol-A (BPA) can leach into the soil and poison animals, resulting in them experiencing endocrine malfunction and genetic alterations. Eventually, these poisoned animals might even end up on our plates – and we find ourselves on the receiving end of our own actions.

More fundamentally, however, the very same paper also explores the way in which plastics, when broken down into microplastics, change the properties of soil. Such an effect then causes a further alteration in soil microbial activity and plant biomass (where root and leaf traits are altered) – such a change at the basic level then has implications for wider processes such as water cycling and carbon-nitrogen ratios in the environment.

Culprit 2: Heavy metals

While plastic is the more ‘controllable’ form of pollution for us as tourists, it would be worth considering the pollution that occurs even before we set foot in our destination – pollution from heavy metals through construction of hotels and other tourist amenities.

Common heavy metals used in construction include lead, chromium and zinc, and the release of these metals during the construction process may lead to them slowly leaching into the soil. If these heavy metals stay in the soil, a variety of effects may ensue: it interferes with the degradation of organic contaminants, poisons humans when we drink from groundwater contaminated by it or eat food harvested on soil with it, and results in even wider problems like lowered land fertility (Wuana & Okieimen, 2011).

On top of all these problems is the issue of the heavy metals being transported into water bodies through events like rain – resulting in aquatic pollution. Sounds familiar? That’s because we covered it in an earlier post here, when we introduced aquatic pollution.

The usual suspects, actually…

Something might have been ringing in your head as we mentioned plastics and heavy metals in this post. Everything seems to sound a little familiar – and it is, because the pollutants that are responsible for pollution in water and on land are shared.

Yet, while the pollutants are shared, their circumstances are vastly different, as we will see in the upcoming post…

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References

Machado et al. 2019, ‘Microplastics can change soil properties and affect plant performance’, Environmental Science and Technology, vol. 53, no. 10, pp. 6044-6052, doi: https://doi.org/10.1021/acs.est.9b01339

Wuana, R & Okieimen, F.E 2011, ‘Heavy metals in contaminated soils: a review of sources, chemistry, risks and best available strategies for remediation’, International Scholarly Research Network (ISRN) Ecology, vol. 2011, doi: doi:10.5402/2011/402647
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