Five phenolic compounds in water and sediment of Yinma River Basin were investigated. The average concentration of phenol was the highest in water samples as well as in sediment samples during the wet season, 101.68 ng/L and 127.76 ng/g, respectively. 2,4,6-Trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) was not detected in some sampling sites. Shitou Koumen Reservoir and the neighboring area were the severest areas of phenolic pollution. The lower reach was more polluted in three water seasons than the middle reach and upper reach. Phenol had ecological risks in sediment during three water seasons. 2-Nitrophenol (2-NP) and 2,4-dichlorophenol (2,4-DCP) had ecological risks in sediment in both the normal and wet season. The concentrations of five phenolic compounds from high to low were in the wet season, normal season, and dry season in water and sediment, respectively. There were middle risks in water of total concentrations for five phenolic compounds in several sampling sites. Total concentrations for five phenolic compounds in sediment had high ecological risks in all sampling sites. However, there was no human health risk in the Yinma River Basin.

Reference evapotranspiration (ET0) plays an important role in regional dry/wet conditions. Based on the Food and Agriculture Organization of the United (FAO) Penman-Monteith method and daily climate variables, ET0 was calculated for 21 stations in and around the Songnen Grassland, northeast China, during 1960–2014. The temporal and spatial variations of ET0 and precipitation (P) were analyzed in the annual, seasonal, and growing season (from April to October) time series using the Mann-Kendall test, Sen’s slope estimator, and linear regression coupled with a break trend analysis. A sensitivity analysis was used to detect the key climate parameter contributing to ET0 change. By linear regression analysis on the relationship between ET0, P, and the aridity index (AI), the role of ET0 in determining regional wet/dry conditions was analyzed. Results show a higher ET0 in the southwest and a lower ET0 in the northeast, but P was opposite to that of ET0. Evident decreasing trends of ET0 in the annual, seasonal, and growing season time series were detected in almost the entire region by the trend analysis methods. For the entire region, the decreasing trend of ET0 can be linked to the relative humidity and maximum air temperature. The positive contribution of increasing temperature to ET0 was offset by the effect of the significantly decreasing relative humidity, wind speed, and sunshine duration at the 0.05 level during 1960–2014. In addition, the value of ET0 was higher in drought years and lower in wet years.

In recent decades the Yinma River Basin has been receiving increasing pollution from industrial and domestic wastewater, agriculture, and livestock production – which are all potential 4-NP pollution sources. Thus, this work investigated spatial-seasonal distribution, risks, and seasonal variations of 4-nonylphenol in the aquatic environment of the Yinma River Basin. The results indicated that the highest concentrations in water and sediment occurred in livestock-production, industrial, and domestic-wastewater areas, and the lowest occurred in agricultural areas; a seasonal variation in 4-NP concentrations in water was observed, with the highest concentrations occurring in the dry season and the lowest concentrations in the wet season. The results for risk quotient indicated that in three water seasons, low ecological risks of 4-NP in water primarily occurred in agricultural areas, and high ecological risks occurred downstream of domestic-wastewater drainage; the ecological risks of 4-NP in sediment from all the sampling sites were exposed to moderate or high ecological risks. Based on the results for hazard quotient, a seasonal variation in human health risks of 4-NP in water was observed; except for a sampling site located downstream of domestic wastewater drainage, human health risks of 4-NP in water were low.