Australian Industries Affected by Ototoxic Chemicals

Ototoxic ChemicalsIn Australia, workplace health and safety has stringent guidelines to manage workplace noise as it’s recognised that excessive noise exposure above certain levels will cause significant hearing loss. 

It is known that ototoxic chemicals, including many medications and common industrial chemicals, can cause hearing loss and even exacerbate the effects of ongoing noise exposure. 

Today, we will define what ototoxicity is, the issues surrounding ototoxic chemicals and examine the different effects of some of them. 

What Is Ototoxicity?

Ototoxicity is the term given to chemicals that are toxic to the ear because they cause damage to the different mechanisms involved in hearing. 

Increasing evidence has shown that exposure to certain chemicals, including medications and industrial chemicals, can increase noise-induced hearing loss acquired in the workplace. 

More specifically, different chemicals damage different parts of the hearing system. Research has shown that ototoxic chemicals easily enter the bloodstream and affect the working of the inner ear and the connecting pathways from the cochlea, including the auditory nerve. 

At present, over 750 chemical groups are thought to be ototoxic. However, not all have been studied at length.

It appears that hearing thresholds that are poorer than what would be expected for a person’s age is the key symptom of toxicity. Other symptoms include tinnitus and vertigo.

Ototoxic Agents of Concern and the Industries Involved

Industries Involved

Ototoxic chemicals can be divided into two general classes, medications and workplace chemicals.

Ototoxic medication

More than 200 medications on the market are ototoxic, including:

  • Aminoglycosides
  • Antibiotics 
  • Antimalarials
  • Anti-inflammatories 
  • Cancer medications (cisplatin and carboplatin)
  • Loop diuretics

More specifically, these medications treat cancer, heart disease and significant infections. 

The first sign of ototoxicity while undergoing medical treatment is tinnitus onset, followed by hearing loss. Sometimes, balance issues can develop. Through that, ototoxic medications cause the hair cells in the cochlea to die. In some cases, the problems experienced resolve after treatment has been completed, though the hearing loss is permanent in many cases. 

It is important to discuss the potential side effects with your medical practitioner to make an informed choice. 

Sometimes, when a patient undergoes medical treatment, an audiologist monitors the hearing throughout the process. The audiologist then reports back to the doctor and patient, who can then use the information to decide whether to continue with the medication or change it. 

Workplace substances 

Workplace substances

As mentioned earlier, there are many substances that cause and exacerbate hearing loss in the workplace. 

There are three main groups of workplace chemicals, including solvents, heavy metals and asphyxiants. 

Solvents 

Solvents are of concern as they affect all parts of the hearing pathway. Specifically, solvents affect the cochlea hair cells, leading to permanent hearing loss. 

Solvents used in the workplace that have known ototoxic effects include:

  • Toluene
  • Styrene
  • Ethylbenzene 
  • Ethanol
  • N-heptane
  • N-hexane

Some industries that use these solvents include chemical labs, paint manufacturing, pharmaceutical manufacturing, fibreglass manufacturing and the furniture and leather industries. 

Heavy metals 

High levels of heavy metals found in the bloodstream have been associated with hearing loss. Some heavy metals are ototoxic and cause the death of hair cells in the cochlea. These heavy metals include:

  • Copper
  • Lead
  • Zinc
  • Lithium
  • Arsenic
  • Manganese

The industries that use these heavy metals include power stations, plumbing, car battery manufacturing, chemical and pesticide manufacturing and fertiliser manufacturing. 

Asphyxiants 

This chemical class acts on the cochlea by depriving the cells of oxygen, leading to their death.

Asphyxiants and pesticides in this particular group include:

  • Carbon monoxide
  • Hydrogen cyanide
  • Acrylonitrile 
  • Organophosphates 

The industries that use this class of chemicals include pharmaceutical and pesticide manufacturing. 

Effect of Noise Exposure Combined with Ototoxic Chemicals 

It’s important to note that ototoxic chemicals have also demonstrated in the presence of noise exposure to have an additive impact resulting in further damage to a person’s hearing. 

If you work in an industry where you are exposed to noise and use any of the chemicals listed above, there should be mechanisms to help mitigate these risks. In addition, regular hearing tests with an audiologist are advised to ensure that any changes in your hearing are detected early, and further precautions are taken if necessary.

Ototoxic chemicals are seen in the medical and manufacturing industries in Australia. While we have been educated in the effects of excessive noise exposure, and it’s been recognised by workplace health and safety, ototoxic chemicals impact on hearing loss is less known. 

At present, we know that there are potentially over 750 chemicals that can cause issues with hearing, whether it’s permanent hearing loss or problems with the auditory system. 

In Summary 

With the information obtained so far about ototoxic chemicals, patients undergoing medical treatment must understand the impact of the medication on their hearing. 

If you think you have developed hearing loss as a side effect of certain medications, you should think about getting a hearing test and hearing aids.

At EarDeals, we offer a wide range of different hearing aids that are high quality and affordable. 

Visit our website to browse our range of hearing aids or contact us for more information. 

Previous article

What is a Balance Disorder?

Next article

The Top 8 Hearing Aid Myths

1