IPB University Experts in Pollution and Ecotoxicology Reveal the Dangers of Volcanic Ash to Water and Fish
Eruptions of several volcanoes in Indonesia not only affect the areas surrounding the mountains but can also threaten water sources and aquatic ecosystems. Volcanic ash carried by the wind or rainwater runoff can enter rivers, lakes, reservoirs, shallow wells, storage tanks, and even aquaculture ponds.
IPB University Pollution and Ecotoxicology Expert, Prof Etty Riani stated that the level of threat volcanic ash poses to water sources depends on the thickness and composition of the ash, the distance from the volcano, the volume of water, as well as pH and alkalinity levels.
“The threat posed by volcanic ash to water, especially in open water sources such as rivers, lakes, reservoirs, shallow wells, storage tanks, and rainwater catchments, must certainly be taken into account,” said Prof Etty.
According to her, an eruption does not immediately cause water to become contaminated with hazardous metals. The more immediate effects are increased turbidity and total suspended solids (TSS).
“Very fine ash particles can persist in water for a long time, clogging filters, damaging pumps, and reducing the effectiveness of disinfection processes,” she explained.
In addition, she said that volcanic ash also contains various minerals that have the potential to release sulfates, chlorides, fluorides, aluminum, iron, manganese, calcium, magnesium, sodium, and potassium. Testing for toxic elements such as arsenic, lead, cadmium, and mercury is also necessary if large amounts of ash are present.
Clear Doesn’t Necessarily Mean Safe
Prof Etty emphasized that water that looks clear isn’t necessarily safe to drink. Water that has settled may still contain dissolved elements. Therefore, water contaminated with ash should be analyzed and treated first.
“Boiling water only kills microorganisms, but it does not remove fine ash, fluoride, dissolved salts, or heavy metals. In fact, evaporation during boiling can potentially concentrate dissolved chemicals,” she explained.
Dangerous to Fish?
Volcanic ash can also disrupt fish life. Physically, ash particles can adhere to gills, causing inflammation, hindering oxygen exchange, and triggering respiratory stress. High turbidity also reduces light penetration, thereby decreasing photosynthesis in phytoplankton and aquatic plants.
“If exposure is very high, fish may experience physiological disturbances, tissue damage, behavioral changes, stunted growth, and even death,” she said.
The risk of immediate fish mortality is particularly high in small, shallow, densely stocked aquaculture ponds with limited water exchange. A drop in dissolved oxygen (DO), sudden changes in pH, and blockages in aerators and pumps can exacerbate the situation.
Therefore, Prof Etty recommends covering wells, basins, reservoirs, and water storage containers. The first rainwater after an eruption should not be collected, while roofs and gutters need to be cleaned before being used again.
“The public should not dispose of ash into drains, rivers, or ponds. For drinking and cooking, it is best to use bottled water or official water supplies,” she said.
For fish farmers, she recommends partially covering ponds with tarps without obstructing air exchange, increasing aeration, and regularly monitoring dissolved oxygen (DO), pH, turbidity, temperature, and fish behavior.
“If fish are gasping for air or losing their balance, immediately take rescue measures and use replacement water that has been confirmed safe,” she added. (AS) (IAAS/KQA)
