Role of Sediments in Insecticide Runoff from Urban Surfaces: Analysis and Modeling

Abstract

Insecticides, such as pyrethroids, have frequently been detected in runoff from urban areas, and their offsite transport can cause aquatic toxicity in urban streams and estuaries. To better understand the wash-off process of pesticide residues in urban runoff, the association of pyrethroids with sediment in runoff from residential surfaces was investigated in two watersheds located in Northern California (Sacramento County). Rainfall, flow rate, and event mean concentrations/loads of sediments and pyrethroids, collected during seasonal monitoring campaigns from 2007 to 2014, were analyzed to identify relationships among stormwater quality and rainfall characteristics, primarily using Principal Component Analysis (PCA). Pyrethroid wash-off was strongly related to sediment wash-off whenever sediment loads exceeded 10 mg; this value was conveniently selected as a threshold between dissolved and particle-bound control of off-site pyrethroid transport. A new mechanistic model for predicting pyrethroid wash-off profiles from residential surfaces at basin-scale was implemented in the Storm Water Management Model (SWMM). The accuracy of the model predictions was estimated by evaluating the root mean square error (RMSE), Nash–Sutcliff efficiency (NSE), and Kling–Gupta efficiency (KGE) for each pyrethroid detected (RMSEtot = 0.13; NSEtot = 0.28; KGEtot = 0.56). The importance of particle-bound transport revealed in this work confirms previous field investigations at a smaller scale, and it should be a key consideration when developing policies to mitigate pesticide runoff from urban areas.

Using Principal Components Analysis and IDW Interpolation to Determine Spatial and Temporal Changes of Surface Water Quality of Xin’anjiang River in Huangshan, China

“…It is a difficult and complicated process to know the water quality status of the whole river basin, determine the influencing factors of water quality, and improve the water environment quality of the river basin [26]. To provide a holistic vision of all the variables involved in the system, PCA was used on the Xin'anjiang River [27,28].…”

Enhancing Physical Similarity Approach to Predict Runoff in Ungauged Watersheds in Sub-Tropical Regions

“…Once the data points begin to be grouped into clusters, the similarity is computed between the groups as well. Several metrics could be used to calculate it, and the choice of the similarity measure could influence the results [47]. This technique also requires a prior choice of the number of groups (k) that is arbitrary.…”

“…The numerical values for this final stage (regional model calibration) are reported in Table 9. Considering that in the 56 iterations, x 2 and x 3 were varying in the ranges [−1.5, −0.5] and [47,67] respectively, it is worth remarking that the following outcomes correspond to the best values of x 2 = −1.5 and x 3 = 59. Table 9.…”

Sustainable Management and Successful Application of Constructed Wetlands: A Critical Review

“…Agricultural and urban runoff represent the two most common polluted storm waters that threaten the quality of surface waters [68][69][70][71]. For this reason, many studies have classified stormwater runoff from urban regions as a contribution to non-point source pollution to surface water [72,73]. An example of HSSF CWs used to treat agriculture stormwater runoff was reported by Zhou et al [74].…”