Extraction activities can have serious negative impacts on river dolphins. These include, but are not limited to, creating pollution, underwater noise, and turbidity, as well as changing the structure and flow of riverbeds, and accidental dolphin injury and mortality via collisions with vessels. Best practices for extraction can be driven by legal or voluntary processes, including industry-led initiatives to promote sustainable practices. Environmental Impact Assessments are a key starting point.
- As top predators, river dolphins accumulate toxic pollutants associated with mining, such as heavy metals and oil, with potentially adverse impacts on their health.
- Taking measures to ensure these toxic pollutants do not enter the system is the only solution; developing alternative mining methods and avoiding mining in critical habitats are crucial for achieving this.
Sand and gravel extraction
- Sand and gravel extraction impact river dolphins by creating underwater noise, increasing turbidity, and changing the structure and flow of riverbeds.
- Sand is the second most used natural resource after water. Industries can reduce the use of sand in construction, recycle materials containing sand, and use alternative materials to create the aggregates needed for construction and road-building.
How do extractive industries like mining and extraction pose threats to river dolphins?
Gold and coal mining along river banks are known to be major sources of contamination to both soil and water1, 2. Water-borne pollution is known to have serious impacts on river dolphin health, with the potential to impact reproductive rates and cause population decline. Artisanal gold mining in rivers and on riverbanks is particularly problematic for river dolphin populations, as the process of separating gold from other minerals releases mercury into the soil and water, leading to serious health issues for the fish and dolphins, as well as for the local communities that depend on the rivers for their livelihoods, water and food36. Dolphins in both marine and riverine environments are prone to accumulating high levels of mercury as they become concentrated in the fish they eat, with those high mercury levels being associated with liver abnormalities and damage to the central nervous system in dolphins7, 8. Regarding oil and gas extraction, spills or other accidents can cause acute environmental disasters with long-term and far reaching chronic effects.
Sand is the second most used natural resource after water. Used primarily to create concrete for construction and for roads, the global rate of sand and aggregate extraction has increased three-fold in the last two decades, with over 40 billion tons currently being extracted every year9. Extraction of gravel and sand from river beds poses serious threats to river dolphins as it creates underwater noise pollution, increased turbidity of waters, and altered river topography and flows. These changes can have negative impacts on dolphins e.g. when noise generated by dredging/extraction activities masks their communication / echolocation, or when changes to the water quality, depths and flow impact their fish prey or the dolphins’ ability to move through the river1011.
How can the impacts of extractive industries on river dolphins be reduced?
- Legally enforceable regulations: A top-down approach to reducing or eliminating the threats from extractive activities is the implementation of legally enforceable regulations that prohibit the activity all together. This approach was used in the Ayeyarwady River in Myanmar, where a 2005 ban on artisanal gold mining along the river appeared to drastically reduce the number of mining operations13. However, legally enforceable, top-down measures require vigilance, surveillance and enforcement by authorities, and a 2019 survey found that gold mining activities had resumed in some of the core habitats used by Irrawaddy dolphins14. Regulations are also being used to prevent or limit industries from extracting sand and gravel from rivers in Europe, New Zealand and Viet Nam.
- Alternative, more sustainable practices: In the Mahakam river, where coal mining on the river banks, and transportation of coal down the river is leading to contamination of core Irrawaddy dolphin habitats, conservation teams have suggested that river pollution can be decreased by transporting the coal overland instead of along the river2. There are more sustainable alternatives to the extraction of sand and gravel from riverbeds, including extraction of gravel from terrestrial sources or crushing rock from mountains, as well as reducing and recycling concrete15, 16. Studies also indicate that non-toxic municipal waste, foundry sand waste17, rubber waste18, and tile waste 19 could be used as alternative aggregates for road construction. Other sand/aggregate alternatives include manufactured sand, coconut shells, sawdust, and fly ash waste 20.
- Industry-led best practices: Industry associations can take the lead on promoting best practices within their own ranks. For example, the Global Aggregates Information Network (GAIN) – a voluntary network of regional aggregates associations around the world – shares industry best practices to promote sustainability.
- Multi-stakeholder advisory groups: Advisory groups such as an Independent Scientific and Technical Advisory Panels (ISTAPs), can help avoid activities that negatively impact river dolphins. They can also help ensure the implementation of activities that have positive impacts. In some cases, banks and finance groups can play a catalysing role in demanding that extractive industries adopt and implement best practices such as ISTAPs. One such example is the establishment of the Western Gray Whale Advisory Panel (WGWAP) to oversee monitoring and reduction of the impacts of oil exploration and production on an Endangered population of gray whales off the coast of Russia’s Sakhalin Island. The Panel was formed in 2004 in response to a demand by financial institutions providing loans to Sakhalin Energy that activities be conducted in a manner that minimised impact on the whales. The resulting collaboration between the IUCN, WWF, Sakhalin Energy, and the Russian Government, led to the establishment of best practices, and appears to have contributed to a population increase, and the ‘downlisting’ of the population from Critically Endangered to Endangered in 2018. For more information see this detailed and inspiring report.
- Esdaile LJ, Chalker JM. The Mercury Problem in Artisanal and Small-Scale Gold Mining. Chemistry – A European Journal 2018;24:6905-16.
- Kreb D, Susanti I. PESUT MAHAKAM CONSERVATION PROGRAM TECHNICAL REPORT: Abundance and threats monitoring surveys during medium to low water levels, August/September & November 2007. Samarinda: Yayasan Konservasi Rasi; 2008.
- Hacon, S. D. S., Oliveira-da-Costa, M., Gama, C. D. S., Ferreira, R., Basta, P. C., Schramm, A., & Yokota, D. (2020). Mercury exposure through fish consumption in traditional communities in the Brazilian Northern Amazon. International Journal of Environmental Research and Public Health, 17(15), 5269.
- Lacerda LD, Salomens W (1998) Mercury from Gold and Silver Mining: A Chemical Time Bomb. Springer-Verlag., International Journal of Surface Mining, Reclamation and Environment 13:2; https://doi.org/10.1080/09208119908944205 [Online April 27, 1998]
- Mosquera-Guerra, F., Trujillo, F., Parks, D., Oliveira-da-Costa, M., Usma, S., Willems, D., … & Marmontel, M. (2018). Presence of mercury in river dolphins (Inia and Sotalia) in the Amazon and Orinoco basins: evidence of a growing threat for these species. In Scientific Committee, Meetings, SC67B, Slovenia.
- Mosquera-Guerra, F., Trujillo, F., Parks, D., Oliveira-da-Costa, M., Van Damme, P. A., Echeverría, A., … & Armenteras-Pascual, D. (2019). Mercury in populations of River Dolphins of the Amazon and Orinoco Basins. EcoHealth, 16(4), 743-758.
- Augier H, Park WK, Ronneau C (1993) Mercury Contamination of the Striped Dolphin Stenella coeruleoalba Meyen from the French Mediterranean Coast. Marine Pollution Bulletin 26:306– 311; https://doi.org/10.1016/0025-326x(93)90572-2 [Online June 1, 1993]
- Cardellicchio N, Decataldo A, Di Leo A, Giandomenico S (2002) Trace elements in organs and tissues of striped dolphins (Stenella coeruleoalba) from the Mediterranean Sea (Southern Italy). Chemosphere 49:85–90; https://doi.org/10.1016/s0045-6535(02 )00170-4 [Online October 01, 2002]
- Bhatawdekar, R. M., Singh, T. N., Mohamad, E. T., Armaghani, D. J., & Hasbollah, D. Z. B. A. (2020). River Sand Mining Vis a Vis Manufactured Sand for Sustainability. In Proceedings of the International Conference on Innovations for Sustainable and Responsible Mining (pp. 143-169). Springer, Cham.
- Araújo R.N., Pastana, J.M.D.N.D. and Costa Neto, M.C.D., 2020. Areia e seixo na região de Ourém-Capitão Poço, nordeste do Pará: estado do Pará.
- Drifting sand: Mitigating the impacts of climate change in the Mekong Delta through public and private sector engagement in the sand industry, Vietnam
- Santos, G.M.A. 2013. Ecologia e comportamento do boto-vermelho Inia geoffrensis (Cetacea, Iniidae) e dos golfinhos do gênero Sotalia (Cetacea, Delphinidae) no Estuário Amazônico. (Masters Dissertation, Dissertação de Mestrado, Programa de Pós-graduação em Zoologia, Museu Paraense Emílio Goeldi/Universidade Federal do Pará – UFPA, Belém -PA).
- Smith BD, Tun MT. Review of the status and conservation of Irrawaddy dolphins Orcaella brevirostris in the Ayeyarwady River of Myanmar. In: Smith BD, Shore RG, Lopez A, eds. Status and Conservation of Freshwater populations of Irrawaddy dolphins: Wildlife Conservation Society; 2007:21-40.
- Wang Z-T, Duan P-X, Akamatsu T, Wang K-X, Wang D. Passive acoustic monitoring of the distribution patterns of Irrawaddy dolphins (Orcaella brevirostris) in the middle reaches of the Ayeyarwady River, Myanmar. Marine Mammal Science 2020;36:1241-53.
- NBM&CW (2015). C&D Waste Processing in India – Delhi Shows the Way. nbmcw.com/report/crushing-screening/34365-c-d-waste-processing-in-india-delhi-shows-the-way.html.
- Roychowdhury et al., 2020Roychowdhury, A., Somvanshi, A., & Verma, A. (2020). Another Brick off the Wall: Improving Construction and Demolition Waste Management in Indian Cities, Centre for Science and Environment, New Delhi.
- Siddique, R., Singh, G., Belarbi, R., Ait-Mokhtar, K., & Kunal (2015). Comparative investigation on the influence of spent foundry sand as partial replacement of fine aggregates on the properties of two grades of concrete. Construction and Building Materials 83 (May 2015), 216–22. https://doi.org/10.1016/j.conbuildmat.2015.03.011.
- Thomas, B.S., Gupta, R.C., Kalla, P., Cseteneyi, L. (2014). Strength, abrasion and permeation characteristics of cement concrete containing discarded rubber fine aggregates. Construction and Building Materials 59 (May 2014), 204–12. https://doi.org/10.1016/j. conbuildmat.2014.01.074.
- Singh, P., & Singla, R. (2015). Utilization of waste ceramic tiles as coarse aggregate in concrete Journal of multidisciplinary engineering science and technology (JMEST) (November 2015) 2(11). http://www.jmest.org/wp-content/uploads/ JMESTN42351216.pdf.
- UNEP (2019). Sand and sustainability: Finding new solutions for environmental governance of global sand resources. GRID-Geneva, United Nations Environment Programme, Geneva, Switzerland.