Pollution in the interflow from a simple landfill in a mountainous and hilly area in Southwest China.

Simple landfills lack pollution prevention measures and therefore continuously release pollutants into the surrounding environment. There are a large number of simple landfills in the mountainous and hilly areas in China, and the interflow accounts for a large proportion of runoff. However, the pollution in the interflow stemming from the simple landfill has not been extensively studied. Here, the pollution of the interflow caused by the simple landfill near the Yunxi Town Landfill in the mountainous and hilly region in Southwest China was studied. The composition and pollution release potential of aged refuse in the landfill were determined, and the water quality of interflow around the landfill was monitored for five months. Seasonal changes in water quality of the interflow were observed, and the concentration of pollutants in the interflow around the simple landfill greatly exceeded the water quality standard for the local water function zoning throughout the sampling period. Specifically, the chemical oxygen demand concentrations of the interflow were 247.90 ± 81.57 mg/L, and more than 50 types of refractory organics were detected, with as many as 10 types of polycyclic aromatic hydrocarbons and Environmental Protection Agency priority pollutants. The total nitrogen concentration of the interflow was 132.45 ± 108.68 mg/L; organic nitrogen (53.27%) was the main component, followed by nitrate nitrogen (32.28%) and nitrous nitrogen and ammonia nitrogen (14.45%). The results highlight the need for the remediation of interflow around simple landfills in mountainous and hilly areas. Generally, the basic data could be used to aid the development of remediation technology.