Central Asia is the global hotspot resulting from either a scarcity of natural resources or environmental degradation. Tajikistan, however, is called the “central Asian water tower”, is rich in water and minerals and plays a very important role in the ecology of Central Asia. Given the soil contamination issues in Tajikistan, the spatial distributions and sources of n-alkanes and heavy metals in surface sediments of Tajikistan were investigated. The evaluation of n-alkane and elemental indices helped to elucidate the origins of complex pollutants. The n-alkane indices were allowed to identify biogenic and petrogenic sources, and statistical methods were used to identify natural and anthropogenic sources of heavy metals. Enrichment factors were used to assess the contamination statuses of heavy metals. The results indicated that n-alkanes in the cluster I (sample 23) and II (samples 1, 5, 12, 14, 18, 22, 29, and 30) samples were affected by crude oil or incomplete fossil fuel combustion. Biomarker indices indicated strong contributions of petroleum sources to the n-alkanes in samples 14, 18, 23, and 29, but that n-alkanes in the other samples were mainly derived from higher plant waxes. Statistical analyses showed that cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) were originated from industrial activities. Phosphorus (P) was closely related to local agricultural activities. Manganese (Mn) was derived from mining activities and industrial wastewater. The enrichment factors indicated that sediment was zero to minor contamination with Cr, Cu, Ni, and Pb, but moderate contamination with Cd and significant contamination with Zn. Interestingly, the samples contaminated with Cd included the cluster I and II samples, meaning the source of Cd contamination had agreed with the results of n-alkanes. The combined evaluation of n-alkanes and heavy metals suggested that their pollutant sources were crude oil contamination.
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