The surface of the Earth contains a plethora of both natural and manmade structures that all interact with each other. The lands, forests, water and mountains are all connected, and over time these interactions shape our environment. The Earth’s soil contains an array of materials, the result of geological events from millions of years ago and modern mining activities. The entire world now finds itself amid a grave environmental threat, and scientists need to determine the effect of chemical and biological processes and chemical elements on the Earth’s surface.
China is a huge country with lots of natural resources and different soil types. Recent studies show, however, that the arable land in southwest China contains high concentrations of heavy metals. The mining in the area was thought to be the cause, but it may not be that simple.
Researchers from the Chinese Academy of Geological Sciences and China Geological Survey published a study in Earth Science Frontiers on their findings in the mountainous region of Zhaotong-Bijie-Yibin-Leshan-Luzhou. In addition to mountains, this region also has forest, farmlands, and mining for lead, zinc, and silver. Dr. Hangxin Cheng, lead study author, explains, “Research in this area can reveal the driving mechanisms behind changes in the content and macroscopic distribution of elements in soil, thereby providing scientific solutions for the rational exploitation and utilization of natural resources."
The researchers set out to understand which factors are responsible for the distribution of chemical elements. 100 researchers gathered more than 110,000 topsoil and deep soil samples from all over the region and analyzed the chemical composition of the samples. They found that four main factors can explain the current chemical element distribution. First, the topmost material dictates the distribution of chemicals found in the earth. Second, geochemical processes shape how the elements are distributed. Third, biogeochemical processes drive the evolution of land quality, and lastly, activities like mining disrupt the natural distribution of elements.
This study provides some insight into how different dynamic processes can determine the distribution of chemical elements. Further studies should be conducted to analyze a variety of landscapes, including forests and swampy landscapes, low mountains, and alpine lakes, to represent considerable advances in epigenetic geochemical dynamics and help us establish a foundation for the development of scientific theories of Earth's systems," explains Dr. Cheng.