Coupled processes involving ammonium inputs, microbial nitrification, and calcite dissolution control riverine nitrate pollution in the piedmont zone (Qingshui River, China).

Rivers in agricultural countries widely suffer from diffuse nitrate (NO) pollution. Although pollution sources and fates of riverine NO have been reported worldwide, the driving mechanisms of riverine NO pollution associated with mineral dissolution in piedmont zones remain unclear. This study combined hydrogeochemical compositions, stable isotopes (δO-NO, δN-NO, δO-HO, and δH-HO), and molecular bioinformation to determine the pollution sources, biogeochemical evolution, and natural attenuation of riverine NO in a typical piedmont zone (Qingshui River).

The variations of heavy metals sources varied their aggregated concentration and health risk in sediments of karst rivers - A case study in Liujiang River Basin, Southwest China.

The sources and health risk variation of heavy metals (HMs) in sediments of Liujiang River Basin were investigated seasonally to clear the control of HMs contamination in karst rivers. The results revealed the exogenous input of HMs should be more prominent in wet season, due to the higher concentration and EF values. PMF identified HMs were mainly from natural, mining and industrial sources.

The distribution, sources and health risk of polycyclic aromatic hydrocarbons (PAHs) in sediments of Liujiang River Basin: A field study in typical karstic river.

The accumulation of PAHs in sediments of Liujiang River Basin were investigated to disclose the sources, input processes and toxicity risk of PAHs in a typical karstic river. The results revealed the concentrations of ∑PAHs are ranging from 111.97 to 593.

Health Risk Assessment Based on Source Identification of Heavy Metal(loid)s: A Case Study of Surface Water in the Lijiang River, China.

In this study, 24 surface water samples were collected from the main trunk/tributary of the Lijiang River during the wet season (April) and the dry season (December) in 2021. The total concentration of 11 heavy metal(loid)s (Al, Cu, Pb, Zn, Cr, Ni, Co, Cd, Mn, As, and Hg) was determined to investigate their physicochemical properties and spatial-temporal distribution characteristics. The heavy metal evaluation index (HEI) and the positive matrix factorization (PMF) model were employed to evaluate water quality and to reveal quantitatively identified pollution sources for further investigation to obtain a health risk assessment using the hazard index (HI) and carcinogenic risk (CR) of various pollution sources.

The Influence of the Reduction in Clay Sediments in the Level of Metals Bioavailability-An Investigation in Liujiang River Basin after Wet Season.

The seasonal elevation of metals' bioavailability can aggravate the threat of metal contamination in the aquatic environment. Nevertheless, their regulations have rarely been studied, particularly the connections between metals' transformation and environmental variations. Therefore, the catchment area of Liujiang River was taken as an example in this study, their seasonal variations in metals' bioavailability in sediments, especially during the wet season, was investigated to recover the processes associated with metals' speciations and multiple environmental factors.