Assessing the risk of contaminant spreading through sediment production in a tropical environment

Abstract

Agricultural sites have been of great concern for decades due to rainfall-induced soil
detachment and transport of sediment materials, and their associated chemicals and/or
nutrients, away from those sites during wet days resulting in significant environmental
problems. The same phenomena could also be expected from bare contaminated site exposed
for a long time before remediation. Exposed topsoil material which is disturbed by various
land operations is much more prone to erosion. All of these problems are more pronounced
when such land is situated in a tropical environment and especially during rainy seasons. This
is because tropical storms are quite intense in nature, frequent and variable. Hence,
contaminated sites in those regions should be given the same importance as agricultural land
when addressing problems resulting from soil erosion. This paper attempts to highlight such
problems through studying the impact of tropical monsoon data collected from India on the
risk of soil erosion which could also be relevant to assessing risk of contaminant spreading
from surface soil through erosion and transportation of the detached material to downstream.
The most well known and most frequently used soil loss model, the Revised Universal Soil
Loss Equation 2 (RUSLE2), was used for that purpose. It was found that soil erosion in this
region is very high and does go far beyond the threshold suggested by the USDA and that the
erosion process is very much sensitive to the climatological variabilities.