Assessment Of Cesium Formate's Aquatic Impact
As caesium formate is a popular choice in wells located in the North Sea, it’s vital that an assessment of its aquatic impact is conducted. Various studies, looking at different marine species, have demonstrated that this compound is, at worst, mildly toxic for aquatic organisms.
Both marine and fresh water species can withstand caesium formate concentrations up to 500 mg/L, but higher doses (over 1000 mg/L) over a prolonged period may cause increased pigmentation, loss of equilibrium, lethargy and death.
Even in the case of brown shrimp, a particularly sensitive species, a high dose is required before any harmful effects are visible. Studies have led to the classification of caesium formate as low to moderately toxic for both marine and freshwater invertebrate species, after some animals experienced restricted mobility following exposure to concentrations above 100 mg/L.
Similarly to previous examples, algae are not severely disturbed by caesium formate, but freshwater species seem to be more affected than their seawater counterparts. As caesium formate dissociates in water, the formate ion establishes links with calcium and magnesium. Researchers believe in freshwater these weak complexes become inaccessible to algae, which can be deprived of an important source of nutrients. In contrast, in sea water the concentration of these minerals is so much higher, that algae are not affected even in the presence of formate-calcium/magnesium complexes.
Testing the ability of embryos to develop in the presence of caesium formate, studies revealed that, in accordance with previous results from other aquatic species, molluscs are not strongly affected by this compound, even during a crucial period of development. Tests showed that concentrations above 1200 mg/L over a prolonged period are needed to prevent embryo development.
What Happens To Cesium Formate In Water?
Under normal aquatic conditions, caesium formate dissociates into cation caesium (Cs+) and anion formate (CHOO-). The caesium element will remain in the water, but there is no indication of bioaccumulation or any detrimental health effects for marine species. In contrast, any harmful impact caused by caesium formate is believed to be consequence of anion formate accumulation. However, with low doses, this compound is unlikely to provoke any serious reactions, as it never accumulates for long and is quickly biodegraded to carbon dioxide. In conclusion, this compound is considered safe to use in an water environment, such as the North Sea oil rigs, and only minimal protection is needed to handle this chemical.
So in summary, it is not just a matter of chemical dilution, but Cesium Formate has a low environmental impact as well.