Leather is a common material used for the upper of modern day rock climbing shoes. As seen from the earlier post on the history of the rock climbing shoe, early mountaineering boots were even completely made out of leather. This material is typically favoured due to its breathability and durability, which provides climbers wearing comfort and resists wear-and-tear from from grazing against climbing walls. Additionally, the flexibility of leather allows climbers to achieve a close-fit to their shoe as the fabric moulds to fit their feet after several wears.
Despite the many advantageous characteristics of leather uppers, more companies have started to offer climbing shoes made with synthetic uppers, perhaps due to increasing awareness of the negative impacts of leather tanning. Tanning is a necessary process in the production of leather as it stabilises the raw animal skin and prevents it from putrefying (Hansen et al., 2020). The process has come under much scrutiny for its significant water consumption, heavy use of chemicals and discharge of toxic wastewater (Hansen et al., 2021). Chrome tanning is carried out with the use of a chromium sulphate, and the process contributes to the release of trivalent chromium ions (China et al., 2020). Since tanning chemicals are not fully absorbed by leather, this leads to the discharge of excess chemicals in tannery effluent (Hansen et al., 2020). Other pollutants such as pthalates, phenolic compounds and grease are also released in untreated wastewater which has been shown to inhibit seed germination, and root and shoot growth (Yadav et al., 2019).
Leather tanning can give rise to devastating environmental impacts. As the environment around leather tanneries deteriorate, impacts are also felt by people that live in the surrounding communities. Join me in the next post which will cover the health impacts of leather tanning.
References
China, C. R., Maguta, M. M., Nyandoro, S. S., Hilonga, A., Kanth, S. V., & Njau, K. N. (2020). Alternative tanning technologies and their suitability in curbing environmental pollution from the leather industry: A comprehensive review. Chemosphere, 254, 126804.
Hansen, É., de Aquim, P. M., Hansen, A. W., Cardoso, J. K., Ziulkoski, A. L., & Gutterres, M. (2020). Impact of post-tanning chemicals on the pollution load of tannery wastewater. Journal of Environmental Management, 269, 110787.
Hansen, É., de Aquim, P. M., & Gutterres, M. (2021). Environmental assessment of water, chemicals and effluents in leather post-tanning process: a review. Environmental Impact Assessment Review, 89, 106597.
Yadav, A., Raj, A., Purchase, D., Ferreira, L. F. R., Saratale, G. D., & Bharagava, R. N. (2019). Phytotoxicity, cytotoxicity and genotoxicity evaluation of organic and inorganic pollutants rich tannery wastewater from a Common Effluent Treatment Plant (CETP) in Unnao district, India using Vigna radiata and Allium cepa. Chemosphere, 224, 324-332.
