Tabtoxin is produced by Pseudomonas tabaci that may cause toxic concentrations of ammonia to build up.

However, they are not convinced that the primary cause of this is toxic concentrations of aluminium released into the soil as acidity increased.

Now while a lethal level of morphine undoubtedly killed this woman, the source of that toxic concentration is not at all clear.

The threshold between essential and toxic concentrations of this element is rather narrow - the factor is in the range of 10-100.

When toxic concentrations are reached, there may be a delay of one or two days before maximum toxicity occurs.

"Do you remember the initial bioassays, which showed a small fish population with high heavy metal and toxic concentrations in their tissues?"

Was the drug detected in any body fluid in toxic concentrations?

Unfortunately for its therapeutic uses, the therapeutic concentration is very close to the toxic concentration.

It was proposed that the small thickness of silicon coatings presents minimal risk to a toxic concentration being reached.

It is considered very safe, with high differences between effective and toxic concentrations.