Researchers from the Kansas State University have now found what might be a sidekick of arsenic in the realm of heavy metal poisoning. The sidekick element mandates in-depth investigation in order to acquire knowledge of its impact on health of the humans.
A research work reported in the journal Frontiers in Environmental Science notes that manganese, which is a trace mineral good for human health when taken in lesser amounts but potentially hazardous in high doses, is related to organic matter dissolved in groundwater in a different way than its cancer-causing counterpart, that is, arsenic. Despite the difference, Researchers from the Kansas State University who led the study indicated that they believe that there might be a relation between the two metals that may turn out to be hazardous to the health of humans.
Professor of Geology Saugata Datta and Michael Vega, 2016 bachelor’s Graduate in Geology and Chemistry, Overland Park, discovered elevated levels of both these metals in drinking water in India. Datta and Vega also established that the properties of dissolved organic matter, that is, organic compounds contained in water, related to sediments, and derived from microbes or plants, were greatly in correspondence with arsenic dissolved in groundwater, and not to that extent with manganese.
We sampled 51 wells in the Bengal Basin and more than 90 percent of them were contaminated with arsenic, manganese or both. We saw this distinct relationship with arsenic and dissolved organic matter, and we think that processes between manganese and dissolved organic matter may contribute to the distribution of arsenic in groundwater.
Michael Vega, 2016 bachelor’s Graduate in Geology and Chemistry
Datta said that although many research works have focused on the impact of arsenic on the health of humans and on the remedial measures, an in-depth understanding of the link between arsenic and elevated levels of manganese is lacking. Just as arsenic at levels above 10 micrograms per liter in drinking water is considered a public health concern, so should maganese at levels above 0.4 milligrams per liter in drinking water because so little is known, he said.
“We need further studies to ascertain reports that increased infant mortality rates might be linked to high levels of manganese in drinking water,” stated Datta. “The joint effect of manganese and arsenic is definitely causing a level of harm that should be under deep scrutiny for the near future not just in India, but in other parts of the world where drinking water quality is an issue.”
Maganese can be in drinking water and air particulates and absorbed by crops, leading to overexposure, Datta said. For this reason, he said, manganese needs to be better monitored and studied.
In 2011, the World Health Organization removed the maximum contaminant limit for manganese, which was 0.4 milligrams per liter, from the ‘WHO Guidelines for Drinking Water Quality. But manganese is often found alongside arsenic in drinking water and scientists haven’t looked into that in as much detail.
Professor of Geology Saugata Datta
Datta and Vega gathered samples of water from wells along either sides of the Ganges River in West Bengal, India, and discovered higher levels of arsenic, iron and manganese on the eastern side of the river. Although the concentrations of arsenic and iron on the western side of the river were very low, the levels of manganese were high. According to Vega, the reason for this is the difference in dissolved organic matter as well as soil chemistry.
“We wanted to understand how dissolved organic matter was affecting manganese, whether the manganese release mechanism was affecting arsenic and how the distribution of arsenic and manganese varies spatially,” stated Vega.
Vega and Datta are assessing the organic matter types in regions that have high manganese concentrations since specific types of dissolved organic matter may react with manganese and arsenic in a manner that they remain in the water supply. The samples of groundwater gathered on each side of the river had visible dissimilarities in the dissolved organic matter type.
Highly protein-based organic matter was noticed in the groundwater on the western side of the river, where there were higher levels of manganese, probably due to microbes. More land-derived or humic organic matter was observed in the eastern side, where all three metals were present in elevated levels, possibly from plants and soil.
This is the first study to relate dissolved organic matter type with manganese in groundwater. We can’t say the same type of dissolved organic matter that is enhancing arsenic release is enhancing manganese, but we can say that both types of dissolved organic matter are associated with high concentrations of manganese in the water. A lot more work needs to be done.
Michael Vega, 2016 bachelor’s Graduate in Geology and Chemistry
Datta—newly elected as chair of the Division of Geology and Health of the Geological Society of America—stated that elevation in the levels of manganese may be caused naturally due to the weathering of rocks worldwide, and also in Kansas. While water quantity is a major cause of worry in various parts of Kansas, Datta stated that investigating for the occurrence of manganese in well water and the Ogallala Aquifer in rural Kansas is highly indispensable to ascertain the quality of water.
Vega and Datta gathered the samples at the time when Vega was an Undergraduate Researcher at the University. At present, he is a Graduate Student at Colorado School of Mines. Ganga Hettiarachchi, Professor of Agronomy; Joseph Weeks, Doctoral Student in Agronomy; Madhubhashini Galkaduwa, Postdoctoral Researcher in Agronomy; and Harshad Kulkarni, 2016 Doctoral Graduate in Civil Engineering are the additional Kansas State University contributors. Natalie Mladenov, San Diego State University; Karen Johannesson, Tulane University; Prosun Bhattacharya, KTH Royal Institute of Technology, Sweden; and Naresh Kumar, Stanford University are other contributors.
The study was funded by the National Science Foundation, Sigma Xi Honor Society, and Kansas State University College of Arts and Sciences.
Datta plans to continue the research on manganese as visiting Michel T. Halbouty chair at Texas A&M University for his 2017-2018 sabbatical.