Effects of tungsten on environmental systems

Area of Science:

• Environmental Science
• Ecotoxicology
• Soil Science

Background:

• Tungsten is widely used in industry and military applications, particularly in munitions.
• The environmental impact of tungsten, despite its prevalence, remains largely uncharacterized.
• This study investigates the ecological effects of tungsten from munitions in soil ecosystems.

Purpose of the Study:

• To assess the environmental effects of particulate and soluble tungsten, and tungsten alloys.
• To understand the impact of tungsten on soil chemistry, microbial communities, and soil fauna.
• To explore the potential for tungsten bioaccumulation and phytoremediation.

Main Methods:

• Investigated soil acidification caused by tungsten powder dissolution.
• Analyzed changes in soil microbial communities (bacteria and fungi) and biomass.
• Examined the effects on earthworms (red worms) and plants.
• Measured tungsten uptake by plants and soil enrichment in the rhizosphere.
• Assessed the impact of dissolved tungsten on microbial yields and biomass production.

Main Results:

• Tungsten powder dissolution significantly acidifies soils.
• Tungsten concentrations above 1% (mass basis) alter soil microbial communities, increasing fungal biomass and reducing bacterial populations.
• Tungsten exposure led to the mortality of red worms and plants, linked to soil acidification.
• Dissolved tungsten species reduced microbial yields by up to 38% and plant biomass by 8% at low concentrations.
• Significant uptake of tungsten by plants and worms was observed, with rhizosphere enrichment.

Conclusions:

• Tungsten contamination poses ecological risks to soil ecosystems, affecting microbial life, invertebrates, and plants.
• Soil acidification is a key mechanism driving tungsten's toxicity.
• Tungsten can enter the food chain through plant and worm uptake.
• Phytoremediation technologies show promise for cleaning tungsten-contaminated sites.