Rainfall Influences Occurrence of Pharmaceutical and Personal Care Products in Landfill Leachates: Evidence from Seasonal Variations and Extreme Rainfall Episodes

Abstract

Unused or expired pharmaceutical and personal care products (PPCPs) are usually discharged into municipal solid wastes, then travel to landfills, and eventually percolate into leachates. However, knowledge of their occurrence and temporal dynamics in leachates is limited, making landfill leachate an underappreciated emission source of PPCPs. Furthermore, the differences in PPCP variations in landfill leachates emphasize the necessity for identifying the influencing factors and elucidating the mechanisms for PPCP fluctuations. In this study, successive monthly monitoring of PPCPs in leachates throughout an entire year was performed to determine their seasonal variations and identify their influencing factors. Furthermore, five pairs of additional sampling campaigns were conducted before and after rainfall events during wet seasons to elucidate the influencing mechanisms. The results showed that there was a distinct seasonal variation in PPCPs in landfill leachateselevated levels during the wet period (from April to September, with a mean concentration of 17.0 μg/L for total monitored PPCPs)when compared to other months (mean concentration of 3.8 μg/L). Rainfall played a considerable role in mediating PPCP concentrations in leachates. The PPCP responses to five rainfall episodes further verified the influence of rainfall and demonstrated that the tendency to PPCP concentration increase was related to rainfall precipitation. Torrential rain events (i.e., 24 h cumulative precipitation of 50–99.9 mm) led to the most significant increases in PPCP concentrations in landfill leachates. In addition, the hydrophilicity of PPCPs contributed to the different fluctuations during the 1 year investigation and different responses to rainfall. To the best of our knowledge, this study provides the first direct evidence supporting the influence of rainfall on PPCPs in landfill leachates, which can help better understand the occurrence and behavior of emerging contaminants in this underappreciated emission source.

Estimating the Mass of Pharmaceuticals Harbored in Municipal Solid Waste Landfills by Analyzing Refuse Samples at Various Ages and Depths

“…Once entering the landfill, pharmaceuticals might be placed or bounded in their layers and exhibit concentration variation owing to varying content in the original MSW disposed in the landfill. During the landfilling process, either driven by rainfall or naturally percolated into landfill leachates, pharmaceuticals experience water (or rainwater) leaching and are released from the refuse, transferred to deeper layers by landfill leachate, and redistributed between refuse and leachates . Pharmaceuticals with high sorption potential could be bounded in the refuse to a great extent.…”

“…During the landfilling process, either driven by rainfall or naturally percolated into landfill leachates, pharmaceuticals experience water (or rainwater) leaching and are released from the refuse, transferred to deeper layers by landfill leachate, and redistributed between refuse and leachates. 55 Pharmaceuticals with high sorption potential could be bounded in the refuse to a great extent. In that case, their initial random content in different landfill layers might be maintained, leading to large concentration variations among refuse layers.…”

Surrogate-based follow-up of activated carbon adsorption preceded by ozonation for removal of bulk organics and micropollutants from landfill leachate

“…According to our previous study, less than 40% removal of ozone-recalcitrant MPs were obtained during the ozonation of leachate samples. Three ozone-recalcitrant compounds (k O3 < 10 M −1 •s −1 , see Table 1) which have been widely detected in landfill leachate or other aquatic environments (Masoner et al, 2016;Qi et al, 2018;Yu et al, 2021) were selected in this study, i.e. atrazine, alachlor and primidone.…”

“…In general, natural organics account for the bulk of leachate organics, which can be quantitated by the measurement of general organic parameters such as chemical oxygen demand (COD) or dissolved organic carbon (DOC). In recent years, MPs have been of increasing concern because of their ubiquity in leachate and their worrying features related to toxicity, carcinogenicity, bacterial resistance and bioaccumulation, even at low concentrations (ng/L-μg/L) (Qi et al, 2018;Yu et al, 2021). The removal of MPs from landfill leachate is a new challenge because the high and variable concentration of bulk organics in leachate can have a significant impact on the removal of MPs (Guillossou et al, 2020b).…”

The Effect of Salinity on Oxygen Transfer Process in Leachate With a Low Initial Cod Concentration

“…The concentration of leachate produced in the dry season is twice as large as that of leachate produced during the rainy season (Kawai et al, 2012). The occurrence of rainwater percolation in landfills can decompose the elements present in the leachate so that the leachate concentration decreases (Yu et al, 2021).…”