Original scientific paper
https://doi.org/10.33765/thate.15.4.1
Published in: Holistic Approach Environ. 15(2025) 4, pp. 137 – 149
Paper reference number: HAE-24112
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COMPARING THE ENVIRONMENTAL IMPACTS AND TOXICITY OF LAUNDRY DETERGENTS WITH SOAPNUTS AND OTHER TREE-BASED NATURAL SURFACTANTS

Archana Waran^*, Syamkumar Reghunandan Pillai^*, Swati Kulkarni^*, Preethy Chandran^*

^* Cochin University of Science and Technology, School of Environmental Studies, Kalamassery, Kochi, Kerala, India

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ABSTRACT

The extensive production of petroleum-based synthetic detergents worldwide presents a huge challenge to sustainability and environmental safety. Efforts are being made to find alternatives from the nature. The study tested plant-based surfactants including soapnut from Sapindus mukorossi and Sapindus trifoliatus and soapbark extract from Quillaja saponaria with anionic surfactants (sodium lauryl sulphate and linear alkyl benzene sulphonate) and commercial detergents (powder and liquid) through wastewater quality analysis and toxicity tests on zebrafish (Danio rerio). A wastewater quality index was used to compare the physicochemical properties of laundry wastewater. Wastewater from all the surfactants tested were acceptable, but acute toxicity tests confirmed that soapnuts and anionic surfactants are more toxic than commercial detergents and Quillaja. Aerobic treatment using microbial consortia neutralises saponins three times more efficiently than natural biodegradation, with up to 60 % saponin degradation within 15 – 30 days. Soapnuts are a proven source of natural surfactant, with applications in industry, animal husbandry, and agriculture, and they have the potential to meet the demand for green detergents and net-zero carbon emission goals. For soapnuts to be environmentally acceptable, the wastewater generated from them and their products must be treated with a combination of aerobic degradation, adsorption and filtration until the saponins are adequately removed.

Keywords: saponin, toxicity, soapnuts, detergent, Danio rerio, LC₅₀
This work is licensed under a Creative Commons Attribution 4.0 International License.
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