Team:Buenos Aires/ motivaciones

Contamination is a mayor and continuously growing global problem. As only 2.5 percent of the water is freshwater and of all that the total usable supply for ecosystems and humans is less than 1 percent, contamination of natural water springs is a central issue to work in. Sanitary problems in developing derive many times from non-proper water supply and treatment. Waterborne diseases are still a concern and cause of death in many regions.

Limited access to clean water is problem that tends to worsen. Depending on the type of contamination (complexity and abundance), making the water to be drinkable could be easy and inexpensive. Even if it wasn't possible to make it drinkable, information on pollutant levels could be easily used to modify consumption patterns and to seek alternative sources of water. At present, the spatial and temporal quantification of contaminants is limited by the difficulty in processing the samples, the remoteness of many locations and its associated costs. Moreover, the lack of centralization and systematization of data makes very difficult the mission to obtain the information. Our central aim is to help solving this situation.

So, we thought of a biosensor device that was cheap and easy to use and understand for people without any type of previous knowledge or equipment.

There are many types of contamination and correspondingly decontamination processes. The pollution that converts water in non-drinkable can vary from just a single toxic (eg arsenic) to a highly complex mixture of types of substances such as those found in various river basins (eg Sali-Dulce, Matanza-Riachuelo among others). Heavy metals, such as mercury or arsenic, and nitrites derivate from agriculture runoff are two world spread examples of groundwater contamination. Because of that, we decided to make an Arsenic and a Nitrite biosensor as a first model. However, we have made our design modular so that it could be easy to change the contaminant to which it responds.

Nitrites are an essential component of fertilizers applied in harvests. When fertilizers are inappropriately applied the excess of these chemicals ends up in nearby rivers or lakes. This additional amount of nutrients provokes the overgrowth of certain plants, algae which are then support of many microorganisms which produces an ecological misbalance, hypoxia and death of other organisms. This process is called eutrophication and implies not only an ecological misbalance but also the loose of a usable fresh water source.

On the other hand, Arsenic is naturally present in soil and ground water in certain regions. Argentina, US, Bangladesh and Chile are top on the list of countries with high natural arsenic concentration in certain zones. Population without access to treated water living in these areas is many times exposed to chronic consumption of Arsenic. This derives in certain health complications such as skin lesions, cancer of the skin, lung and bladder, and gastro-intestinal and pulmonary conditions. The arsenic guideline values (GV) is 10 ppb (parts per billion), also expressed as 10 μg/L (micrograms per liter). National standards for arsenic vary, in many countries it is the same as the WHO GV but in others – including in China, India and Bangladesh – it is 50 ppb.