Analysis of the Migration Characteristics of Stormwater Runoff Pollutants on Different Underlying Surfaces in Guangzhou, China

Abstract

Stormwater runoff is identified as urban nonpoint source pollution that increasingly introduces contaminants to urban water bodies and impedes sustainable development. The pollution load of runoff varies due to the interception of different land cover types during the urban hydrological process. During the rainy season (June–August) in 2018, five different underlying surfaces (green roof, parking lot, urban road, parkway, and grassland) were selected in Guangzhou to analyze the migration characteristics of stormwater runoff pollutants. The concentrations of heavy metals, such as chromium (Cr), cadmium (Cd), lead (Pb), and mercury (Hg), as well as total nitrogen (TN), total phosphorus (TP), and polycyclic aromatic hydrocarbons (PAHs) were collected and analyzed on different underlying surfaces with the rainfall data at the beginning of a stormwater runoff event. The results showed that PAHs, heavy metals, and TP existed mainly in the form of particles; nitrogen was mainly present as ammonia and nitrate; and the TN, TP, PAHs, and heavy metal were significantly different in the stormwater runoff on each underlying surface. The pollutant concentration in urban road runoff was the highest, accounting for 40–70% of the total pollutant concentration in the stormwater runoff, and the pollutant concentration in green roof runoff was the lowest, accounting for 10–40% of the total pollutant concentration in the runoff. An obvious effect of initial rainfall erosion was observed during stormwater runoff from urban roads and parking lots, and the scouring effect on grasslands and green roofs was mainly due to the many factors affecting the underlying surface during the middle and late stages. The rates of reduction of heavy metals were the most significant. The effect of water purification was positively correlated with stormwater runoff duration. The rates of reduction of TN, heavy metals (Cr, Cd, and Hg), and PAHs in the grassland areas were 35.20 ± 26.28, 0.24 ± 10.13, 71.77 ± 10.97,32.62 ± 110.48, and 41.30 ± 8.78%, respectively. This study could provide a theoretical basis for preventing and managing pollutants in urban stormwater runoff.

Effect of Combinations of Green Roof Substrate with Vegetation Coverage on Rainwater Quality Improvement

“…A certain amount of glucose, potassium dihydrogen phosphate, ammonium chloride, ground and screened diatomite and potassium nitrate were added to tap water respectively to simulate the pollutants of chemical oxygen demand (COD), total phosphorus (TP), ammonium nitrogen (NH 4 + -N), suspended solids (SS) and total nitrogen (TN) in runoff. The average concentration of pollutants in rainwater was set by referring to the corresponding roof rainwater pollutant concentration and the actual situation of Jinan city, China [31][32][33][34][35][36]. The concentrations of SS, COD, TN, NH 4 + -N and TP were 351.5, 85.05, 6.27, 7.33 and 0.17 mg•L -1 , respectively.…”

Spatial Distribution, Risk Index, and Correlation of Heavy Metals in the Chuhe River (Yangtze Tributary): Preliminary Research Analysis of Surface Water and Sediment Contamination

“…The diverse pollution levels within the tributary could emanate from various sources, given its exposure to agricultural, residential, and anthropogenic activities. Elevated indices, especially in Samples 8-10, might be attributed to agricultural runoff, a common concern in surface water pollution, especially following rainfall events, due to the washing away of fertilizers and pesticides into water bodies [49]. September's climate context might be pivotal, as late summer and early autumn can introduce climatic variables influencing runoff and pollution levels.…”

“Green structures” for effective rainwater management on roads

“…As it is shown by the authors, green structures are the biotechnical mechanisms for rising environment-safety of buildings, which can connect technogenic and natural environment in cities. They can solve different problems (Andenaes et al, 2021;Bohan Shao, 2021;Bortolini et al, 2021;Fantozzi et al, 2021;Giacomello et al, 2021;Iffland et al, 2021;Juricic et al, 2021;Kaewpraek et al 2021;Lijiao Liu, 2021;Procaccini et al, 2021;Tkachenko, 2018;Tkachenko et al, 2019a;Tkachenko et al, 2019b;Tkachenko et al, 2020;Tkachenko et al, 2021;Yongjun Pan, 2021) including rising energy efficiency, sanitizing the interiors, exteriors and make them more comfort etc. We consider them as one of the most effective natural solutions for rainwater management, which should be used more widely on different types of city roads.…”