The toxic effects of chemicals from TFT-LCD manufacturing on aquatic organisms

The manufacture of thin film transistor liquid crystal displays (TFT-LCDs), used for television screens, computer monitors and mobile phone screens, has increased dramatically over the past twenty years. The volume of toxic chemical compounds discharged into the environment from TFT-LCD manufacturing has also risen significantly, but little is known about the impact of this pollution on living organisms.

Now, Izumi C. Mori and colleagues at Okayama University, together with scientists across Japan and Malaysia, have demonstrated the toxic effect of these chemicals on four aquatic organisms – the fish O.latipes, the micro-crustacean D. magna, the alga P.subcapitata, and the bacterium V.fischeri. Micro-crustaceans appear to be especially susceptible to toxicity – this could lead to a significant imbalance in the ecosystem as they have a predatory role.

The team investigated the effects of three main chemicals used in the process of making TFT-LCDs: solvents called tetramethylammonium hydroxide (TMAH), known to cause heart disease and respiratory failure in animals, iodine / potassium iodide solution (KI), and dimethyl sulfoxide (DMSO). The combined toxicity of these chemicals is unknown.

Mori and his team found that the micro-crustaceans were highly affected by the toxins, particularly TMAH. Both TMAH and KI are regularly produced by the same factories and released into the same water bodies. The researchers believe the combined toxicity of both chemicals would cause a three-fold increase in toxicity in micro-crustaceans. With TMAH and KI both highly water-soluble, the team also urge immediate research into the effect of combined chemicals on planktonic species.