To investigate the dynamic variation patterns of leachate levels within the landfill mound, source leakage, and groundwater contamination plumes, a one-hydrologic-year monitoring was conducted at a landfill site in southern China. The results indicated a significant positive correlation between leachate levels and rainfall. Levels at monitoring points SW1-1, SW1-2, ZS1-2, and ZS1-3 ranged from 4.4m to 5.8m, 6.7m to 11.0m, 4.3m to 6.3m, and 4.0m to 6.8m, respectively, exhibiting annual fluctuations of 1.4m to 4.3m. The estimated source leakage rate of leachate ranged from 9.49m3/d to 10.90m3/d. The areas close to the landfill dam were significantly impacted by leakage. NH4+-N concentrations at the landfill dam shoulder monitoring well QC1-19 increased with rising leachate levels but attenuated rapidly downstream. The spatial extent of the contamination plume exhibited seasonal variability. During wet seasons, plume migration was dominated by source leakage, extending the plume boundary beyond 120m from the landfill dam. Conversely, during dry seasons, natural attenuation mechanisms, such as biodegradation, became dominant, confining the plume boundary near the leakage source. Mn concentrations were generally elevated and demonstrated an inverse relationship with ORP. Conversely, Fe concentrations exhibited no clear discernible trend. NH4+-N concentrations increased with decreasing pH. The relationships between CODCr and pH, as well as the dynamic interactions among CODCr, NH4+-N, NO3-, and ORP, were observed to be complex.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |