Heavy metals and Nitrates: dangerous pollutants?
Heavy metals are generally defined as metals with relatively high densities. Some of them are essential for a proper functioning of the human metabolism. However, at high concentrations they can be toxic.
Nitrate is an inorganic compound composed of one atom of nitrogen (N) and three atoms of oxygen (O). It could be another problematic substance, whose presence at certain concentrations can cause a negative impact on the environment and human health. They are especially dangerous in the form of nitrites, because they are more reactive.
Nitrate is an inorganic compound composed of one atom of nitrogen (N) and three atoms of oxygen (O). It could be another problematic substance, whose presence at certain concentrations can cause a negative impact on the environment and human health. They are especially dangerous in the form of nitrites, because they are more reactive.
![](https://static.igem.org/mediawiki/2019/e/ed/T--UPNAvarra_Spain--MetalesYnitratos.png)
![](https://static.igem.org/mediawiki/2019/3/32/T--UPNAvarra_Spain--T_flecharojabajar.png)
Effects
Health
Prolonged exposure to heavy metals that are toxic or carcinogenic can cause deleterious health effects, while high concentrations of nitrate in blood can lead to diseases such as methemoglobinemia.
![](https://static.igem.org/mediawiki/2019/e/ef/T--UPNAvarra_Spain--T_humanheart.png)
Environment
The accumulation of these elements can lead to the degradation of the soil, decreasing its productivity, and in case of excessive pollution, it can even lead to desertification. In case of nitrates, its accumulation favors water eutrophication.
![](https://static.igem.org/mediawiki/2019/6/69/T--UPNAvarra_Spain--T_earth.png)
![](https://static.igem.org/mediawiki/2019/3/32/T--UPNAvarra_Spain--T_flecharojabajar.png)
What are biosensors?
Any device which converts certain biological processes into measurable signals, providing relevant information. As primitive concept of biosensor we have the example of canaries, that went down to work with miners to detect lethal gases in mines.
![](https://static.igem.org/mediawiki/2019/0/00/T--UPNAvarra_Spain--T_canariocantando.png)
![](https://static.igem.org/mediawiki/2019/1/1f/T--UPNAvarra_Spain--T_flechadelado.png)
![](https://static.igem.org/mediawiki/2019/0/07/T--UPNAvarra_Spain--T_canariojaula.png)
![](https://static.igem.org/mediawiki/2019/1/1f/T--UPNAvarra_Spain--T_flechadelado.png)
![](https://static.igem.org/mediawiki/2019/b/b9/T--UPNAvarra_Spain--T_canariomina.png)
The canary breathes dangerous gases like carbon monoxide.
When the canary is exposed to the gas, it has difficulty breathing and stops singing.
Miners know there is poisonous gas around and they should leave the mine, because it is dangerous.
![](https://static.igem.org/mediawiki/2019/3/32/T--UPNAvarra_Spain--T_flecharojabajar.png)
Our project
We are working to create bacterial biosensors for heavy metal and nitrate contamination. By means of already described parts (heavy metal and nitrate sensitive promoters) and other regulatory sequences, we are going to create different systems in order to analyze the presence and concentration of these substances in water. In this way, our bacteria will change their color depending on the detected substance and its quantity.
![](https://static.igem.org/mediawiki/2019/3/32/T--UPNAvarra_Spain--T_flecharojabajar.png)
![](https://static.igem.org/mediawiki/2019/9/97/T--UPNAvarra_Spain--T_bacteriacentroamarillo.png)
![](https://static.igem.org/mediawiki/2019/9/95/T--UPNAvarra_Spain--T_bacteriacentromorado.png)
![](https://static.igem.org/mediawiki/2019/a/a1/T--UPNAvarra_Spain--T_bacteriacentrorojo.png)
![](https://static.igem.org/mediawiki/2019/3/36/T--UPNAvarra_Spain--T_bacteriacentroazul.png)
![](https://static.igem.org/mediawiki/2019/3/32/T--UPNAvarra_Spain--T_flecharojabajar.png)