Spatial variation of hydrocarbons in surface sediments from markanda river in northern India:

Abstract

Hydrocarbons in aquatic sediments preserve organic matter sources and are thus frequently utilised to interpret both natural and human input, as well as to estimate pollution levels. Surface sediments were collected from Markanda river over a stretch of 80 km and were analyzed for aliphatic and polar hydrocarbons distribution. The n-alkanes, isoprenoid alkanes, linear alkyl benzenes (LABs), phthalates, and polycyclic aromatic hydrocarbons (PAHs) were among the identified hydrocarbons. These identified compounds were used to track both biogenic (terrestrial plants and microbial inputs) and anthropogenic (petroleum/ petroleum products, fossil fuel or biomass burning, and waste disposal) inputs. In order to quantify the degree of petroleum pollution in the aquatic system, various indices were computed (carbon preference index, pristane/phytane, lower molecular weight/higher molecular weight chemicals, PAHs indices). The biomarkers analysis show that the anthropogenically derived hydrocarbons were the most common in the river system. The spatial distribution of different hydrocarbon abundances exhibited a changing pattern downstream the river, resulting in the classification of the investigated region into anthropogenically impacted zones. The land use pattern was examined in order to discover the probable causes of hydrocarbon spatial variance. The physico-chemical characteristics of the river as well as the grain size distribution of the surface sediments were also taken into account while determining the monitoring variables. The current study provided policymakers with a starting point for reducing anthropogenic impacts and improving river ecosystem health.