UNAIR NEWS – Heavy metal is a group of metal elements with a density greater than 5gr / cm 3 , which at a certain level capable of being a poisonous material and is very dangerous for living organisms. Furthermore, heavy metals are also pollutants often identified in the aquatic environment.
Explained by a researcher of Faculty of Science and Technology (FST) UNAIR, Prof. Dr. Agoes Soegianto, Ir., DEA., in a team, based on a biological point of view, heavy metals can be divided into two categories, essential and non-essential. The presence of heavy metals in the aquatic environment can also come from a variety of sources, including industrial waste, domestic waste, agricultural waste, release of contaminated sediment or from the atmosphere.
“There are quite a lot of heavy metals in the category, but some known as a source of water pollutants is Cadmium (Cd) and Copper (Cu),” he said.
Prof. Agoes continued, copper is included in essential heavy metals, and is a micronutrient that is important for the growth and metabolism of various algae, cyanobacteria, and other organisms.
“However, at high concentrations and long exposure, copper can affect photosynthetic activity and inhibit metabolic processes associated with organism growth,” he explained.
While Cadmium is a type of non-essential heavy metal whose benefits for organisms are not yet known. On the other hand, Cadmium is used as a metal or electroplating material, stabilizer, plastic coloring and industrial batteries.
“In an aquatic environment, cadmium will undergo biotransformation and bioaccumulation in living organisms. Then, the metal content in these organisms will increase (biomagnification), and the biota that occupies the highest trophic position in the food chain will experience the largest accumulation, “he added.
To deal with this problem, Prof. Agoes and his team managed to find one type of plankton that could remediate or reduce the concentration of cadmium and copper heavy metals in the aquatic environment, the microalgae Chaetoceros calcitrans .
The method, testing Chaetoceros calcitrans that it is able to remediate heavy metals, was by exposing it to Cadmium and Copper for 96 hours with different concentrations, starting from the control treatment (without heavy metals); with 0.7 concentration; 1.3 concentration; and 1.9 concentration; with 3 replications.
“The results showed that heavy metal exposure can significantly reduce microalgae density. That is, the body of the microalgae is able to absorb the content of heavy metals, so the concentration of heavy metals in water is reduced, “he explained.
Furthermore, the growth of microalgae has decreased with increasing concentrations of heavy metals. The final density of microalgae showed that copper is more toxic than cadmium. It can be seen from the IC50 value of copper heavy metals which is lower than Cadmium, which were 0.384 and 0.409 ppm, respectively.
Author: Bastian Ragas
Editor: Nuri Hermawan
Pratiwi D.C, Pratiwi N, Guntur, Dyah K.R, Soegianto Agoes. Potential Heavy Metals Remediation Test On Chaetoceros calcitrans. Poll Res. 38 (August Suppl. Issue) : S18-S21 (2019) ISSN 0257–8050.