Abstract
4-Methylcyclohexanemethanol (or 4-MCHM) is a toxic chemical used in coal power plants. A 2014 chemical spill released a crude form of 4-MCHM, greatly affecting the surrounding community and environment. This chemical is often used in factories to clean coal, and was thought to be safe to use. After the spill, 4-MCHM has been tested on mammals such as rats and guinea pigs, causing decreased activity and mortality. In humans it has caused skin irritation and gastrointestinal symptoms (nausea, diarrhea), and damage to DNA in human cells. The purpose of this experiment is to investigate the effect of 4-MCHM (a coal cleaning agent) on the population change in Daphnia magna. Experimenting with Daphnia magna will show the effect of 4-MCHM on a very crucial part of aquatic ecosystems. Since 4-MCHM was not available for purchase, a very similar compound was used. This compound, called 1,4-Cyclohexanedimethanol (or 1,4-CHDM), is closely similar in structure and toxicity. If the chemical 1,4-CHDM (as a substitute for 4-MCHM) is related to mortality, then increasing concentrations will decrease Daphnia magna population size over a period of 26 days. This experiment was divided into three parts due to time constraints. In the first and second part, Daphnia magna were contained in 4 plastic containers, each filled with 100 ml of spring water. In the first part, the containers had concentrations of 1%, 0.1%, 0.01%, and 0%(control) of 1,4-CHDM. The concentrations for the 2nd part were 0.001%, 0.0005%, 0.0001%, and 0%(control) of 1,4-CHDM. The concentrations for the third part, which used three containers per concentration, were 0.064 g/L, 0.069 g/L, 0.074 g/L, and 0 g/L (control) of 1,4-CHDM. These third set of concentrations were ranged around the estimated amount of 4-MCHM that was originally released into the river. Since the concentrations were very small, they were prepared in a one-liter solution, from which 100 ml was taken for each container. 10 Daphnia magna were used for the first and third part, and 12 were used for the second part. The population size is recorded and fed every 72 hours, for 26 days in the first part, 14 days for the second, and 23 days for the third (due to time constraints). It can be concluded from the data that the addition of 1,4-CHDM caused a decrease in the population of Daphnia magna. This was shown in both the first and second parts, as the Daphnia magna had a high mortality rate, while the control group multiplied quickly. In the third part, the population fluctuated due to an initial error of uneven distribution of pregnant Daphnia magna over the habitats. However, after 23 days, the control group multiplied quickly while the other concentrations had an increasing mortality rate or their population stayed relatively constant. 1,4-CHDM, and therefore 4-MCHM, has a dangerous effect on the population of Daphnia Magna over a period of time. This could be caused by effects on reproductive health, egg development, respiratory damage, or other health problems contributing to the mortality of Daphnia Magna. From this study and further investigation it can possibly be observed that 4-MCHM causes serious health problems, and with further investigation, a safe limit can be applied to many industries.