Nitrate Pollution and Preliminary Source Identification of Surface Water in a Semi-Arid River Basin, Using Isotopic and Hydrochemical Approaches

Abstract

Nitrate contamination in rivers has raised widespread concern in the world, particularly in arid/semi-arid river basins lacking qualified water. Understanding the nitrate pollution levels and sources is critical to control the nitrogen input and promote a more sustainable water management in those basins. Water samples were collected from a typical semi-arid river basin, the Weihe River watershed, China, in October 2014. Hydrochemical assessment and nitrogen isotopic measurement were used to determine the level of nitrogen compounds and identify the sources of nitrate contamination. Approximately 32.4% of the water samples exceeded the World Health Organization (WHO) drinking water standard for NO 3´-N. Nitrate pollution in the main stream of the Weihe River was obviously much more serious than in the tributaries. The δ 15 N-NO 3´o f water samples ranged from +8.3 to +27.0. No significant effect of denitrification on the shift in nitrogen isotopic values in surface water was observed by high dissolved oxygen (DO) values and linear relationship diagram between NO 3´-N and δ 15 N-NO 3´, except in the Weihe River in Huayin County and Shitou River. Analyses of hydrochemistry and isotopic compositions indicate that domestic sewage and agricultural activities are the main sources of nitrate in the river.

Phytoplankton Response to Anthropogenic and Recreational Activities in The Watershed of a Resort Centre in Edo State, Southern Nigeria

“…The low phosphate concentrations recorded in this study is indicative of a lack of industrial effluent, agricultural run-off and domestic sewage (which are possible sources of phosphate) in the environment around the two stations while possible nitrate sources like industrial waste water, nitrogen chemicals, fertilizers and plant humus may have been lacking or reduced in the environment, hence, the low nitrate concentrations observed. 20 The difference in the phytoplankton abundance observed in the two stations could be as a result of the local conditions peculiar to the two stations. Station I is close to the market area which makes it an immediate recipient of most waste materials generated in the market.…”

Novel Photocatalytic NH3 Synthesis by NO3− Reduction over CuAg/TiO2

“…Therefore, the reaction system of the photocatalytic NO 3 − reduction to NH 3 over metal-doped TiO 2 may be significant as a green process for the photocatalytic NH 3 synthesis by the reduction of NO 3 − in the lower energy without using fossil fuel. As the source of N 2 , NO 3 − has attracted attention by the recent studies because it is the very toxic pollutant in the waste water and gives the very harmful effect to human health [13]. Therefore, the NH 3 synthesis by using NO 3…”

The Risk Assessment of River Water Pollution Based on a Modified Non-Linear Model

“…Meanwhile, in recent years, the fuzzy theory was increasingly applied for decision-making and assessment processes in imprecise situations. For example, the fuzzy logic and fuzzy set theory-based evaluation models have been established to deal with uncertainty problems and to describe characters of classified water quality bounds reflecting the actual water quality [27,28]. Overall, those methods/approaches are better for the risk assessment of water pollution in small-scale rivers.…”

“…Apart from this, in previous studies [13,[28][29][30], the variation of the composite index formula was used and it can improve the gap between the calculation results of the pollution index and the water quality standard. However, it does not directly determine the water quality grade from the relationship between the calculation results and the standard.…”