UNAIR NEWS – It is known well that mercury is a dangerous heavy metal because as an ion or compound it is easily absorbed by cells and tissues in the body. In research entitled “Mercury’s Effects on Sperm Quality and Goldfish Fertility”, Dr. Alfiah Hayati M. Kes explained that mercury is often regarded as an aquatic pollutant with bad impacts to aquatic organisms, especially fish.
The presence of mercury in the waters can occur due to natural factors such as volcanic activity carried by rain water into rivers or from weathering rocks. In addition, there are human factors, as a result of anthropogenic activities (human activities, ed), such as gold mining, fossil fuels burning, paper processing plants, and other human activities.
“The source of mercury pollution flows into the river, from upstream to downstream towards the sea through the coast,” she explained.
According to Dr. Alfiah, changes occur in the reproductive system of fish contaminated with mercury. She explained that the structure of the testicular tubules becomes irregular, the quality of fish sperm is low and the success rate of fertilization of fish sperm and egg cells is low and the development of embryos in fish eggs is inhibited.
Dr. Alfiah revealed that mercury enters the body of the fish through the process of absorption of water through the gills and the process of the food chain, then accumulates through the process of bioaccumulation and biomagnification in the body’s tissues. The existence of these metals, she continued, can disrupt the fish’s reproductive system by reducing the quality of sperm, especially the speed and duration of movement (motility, ed) and sperm fertility.
“With the change in membrane structure in sperm cells, it can cause various metabolic disorders, damage and death of fish sperm cells,” she explained.
In her research, Dr. Alfiah explained that at 0.5 ppm, mercury compounds can reduce the time of group motility and individual fish sperm because sperm membranes which are rich in unsaturated fatty acids are very vulnerable to free radical attack.
“High levels of radicals can also damage sperm DNA (40%) and affect the integrity of sperm mitochondria which play an important role in the metabolic process to produce ATP energy supplies,” she said.
Not only that, she continued, mercury also affects the viability of fish sperm. High levels of mercury increase toxicity causing a lack of nutrition for sperm to survive.
“The existence of this radical compound also stimulates the occurrence of sperm death (apoptosis), which is preceded by the activation of the caspase enzyme which can reduce sperm survival. Moreover, the presence of mercury also decreases the ability of fish sperm to fertilize eggs, ” she continued.
In the end, Dr. Alfiah also explained the results of the research that 0.5 ppm mercury had reduced the success of sperm fertilization. When mercury levels are increased (5 ppm), the results showed that the percentage of sperm fertility and embryo development in fish eggs is very low compared to the control group (without mercury) indicating a high success rate of fertilization (96%). (*)
Author : Asthesia Dhea Cantika
Editor : Nuri Hermawan
Details of the research available at:
https://www.sciencedirect.com/science/article/pii/S1687428519300391
