IS YOUR ROOFTOP WATER TANK A HIDDEN SOURCE OF MICROPLASTICS?

When we think of microplastics, images of polluted oceans and discarded plastic bags come to our mind. However, an overlooked source might be right above us—our rooftop water tanks.

The Summer Heat and Your Tank: A Dangerous Combo

The rooftop water tanks are generally made using plastics like polyethylene. These tanks endure intense sunlight, UV radiation, and thermal stress due to fluctuating temperatures daily. Over time, this exposure leads to its degradation, both at its outer and inner surfaces, causing them to shed tiny plastic particles—microplastics1—some of which does get into the stored water inside. A damaged water tank (once a crack appears, these tanks can’t be repaired!) or one exposed to fire can be even a larger source of microplastics.

How Bad Is It? Let’s Look at the Numbers

While exact figures can vary, degraded plastic containers do release significant amounts of microplastics into their contents. For instance, water in a 1 litre PET bottle can release as high as 325 microplastic particles. Extrapolating this, a 500-liter tank could potentially release:

•  Over 160,000 microplastic particles per day

•  @58 million particles annually

These microplastics find their way into household water systems, contact our skin, enter our body, thereby causing severe and apparently unexpected health issues like inflammation and endocrine disruption and so on.

What Can You Do About It?

To mitigate this issue, we can do the following:

• Install UV-reflective insulation sheets to reduce the tank's exposure to sunlight, slowing down plastic degradation.

• Inspect and clean tanks periodically to prevent buildup.

• If feasible, opt for tanks made from materials less prone to UV degradation.

Small steps can lead to significant impacts. Protect your health and the environment by addressing the hidden sources of microplastics in your daily life.

References

1. Z. Yao, H. J. Seong, Y.-S. Jang, Environmental toxicity and decomposition of polyethylene, Ecotoxicology and Environmental Safety 242 (2022) 113933.

2. S. A Mason, V. G. Welch, J. Neratko, Synthetic Polymer Contamination in Bottled Water, Front Chem, 6 (2018) 407.