Dissolved Organic Matter and Lead Nanoparticles

One of the biggest advancements made by science over the last century has been in nanotechnology. Being able to manipulate and understand materials at such a small scale has led to vast advances in science and technology that help make many of the things taken for granted today possible. However, the other side of the story is that with the rise of nanotechnology, the presence of nanomaterials has also risen, which poses a problem due to the inherent toxicity in many of the substances used to make these nanomaterials. The problem gets worse when considering that these materials often find their way into natural habitats, particularly bodies of water. To give an idea, it is estimated that 66,000 tons of nanomaterials are directly released into surface waters each year. This is just an estimate, though, and it is possible the number is much larger. One particular nanoparticle (NP) receiving a lot of attention is lead oxide (nPbO₂), largely because of its use in large-scale water treatment and distribution systems that use chlorine as the disinfectant. Normally this causes few problems, but the possibility of disaster does exist. For example, when the city of Washington D.C. changed its disinfectant to chloramines, the lead solids subsequently chlorinated, which contaminated the water. Because of this obvious danger to living things, as well as the heavy presence of nPbO₂ in the world, researchers are curious to understand any impact these NPs have on aquatic life systems.

This was the focus of the study conducted by Chiang et al. from the National Taiwan University. They wanted to understand how organic matter would interact with the presence of nPbO₂ to determine the impacts on its bioavailability and toxicity. Since lead is known to cause neurotoxicity, nephrotoxicity, deleterious effects on the hematological and cardiovascular systems, and even some forms of cancer, it is important to know if lead oxide nanoparticles can have the same effect. To do this, Chiang and his team of researchers set out to test a variety of different life systems within the medaka fish, including acetylcholinesterase (AChE) activity, since this is related to the onset of certain neurological disorders. Measuring AChE was an essential component to determining the toxicity of these lead oxide NPs and was done using the Amplite Colorimetric Acetylcholinesterase Assay Kit, which uses DTNB to quantify the thiolcholine produced from the hydrolysis of acetylthiolcholine by AChE and is known for producing valid and reliable readings.

The results of this study indicated that lead oxide does in fact have an effect on several biological factors inside fish when combined with organic matter in water. This has huge implications, as new regulatory policies will be needed, as well as mitigation strategies to reduce and alleviate the effects. Studies like this go a long way towards helping humans understand and minimize their impact on the natural environment. Without quality, reliable tools such as the Amplite Colorimetric Acetylcholinesterase Assay Kit, conclusions like this would remain clouded in doubt, preventing urgent and needed action to help protect the natural environment from human activity.

References

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1. Chiang, Chun-Wei, et al. "Dissolved organic matter or salts change the bioavailability processes and toxicity of the nanoscale tetravalent lead corrosion product PbO2 to medaka fish." Environmental Science & Technology 50.20 (2016): 11292-11301.