What happens when pharmaceuticals meet colloids

Abstract

Pharmaceuticals (PCs) have been widely detected in natural environment due to agricultural application of reclaimed water, sludge and animal wastes. Their potential risks to various ecosystems and even to human health have caused great concern; however, little was known about their environmental behaviors. Colloids (such as clays, metal oxides, and particulate organics) are kind of substances that are active and widespread in the environment. When PCs meet colloids, their interaction may influence the fate, transport, and toxicity of PCs. This review summarizes the progress of studies on the role of colloids in mediating the environmental behaviors of PCs. Synthesized results showed that colloids can adsorb PCs mainly through ion exchange, complexation and non-electrostatic interactions. During this process the structure of colloids and the stability of PCs may be changed. The adsorbed PCs may have higher risks to induce antibiotic resistance; besides, their transport may also be altered considering they have great chance to move with colloids. Solution conditions (such as pH, ionic strength, and cations) could influence these interactions between PCs and colloids, as they can change the forms of PCs and alter the primary forces between PCs and colloids in the solution. It could be concluded that PCs in natural soils could bind with colloids and then co-transport during the processes of irrigation, leaching, and erosion. Therefore, colloid-PC interactions need to be understood for risk assessment of PCs and the best management practices of various ecosystems (such as agricultural and wetland systems).

Effect of Clay Colloid Particles on Formaldehyde Transport in Unsaturated Porous Media

“…Many studies have focused on colloid and colloid facilitated contaminant transport in porous media [2][3][4][5]. Several studies have focused specifically on colloid transport in the presence of metals [6], pesticides [7,8], and pharmaceuticals [9][10][11]. Some other studies have examined the co-transport of colloids with bio-colloids experimentally [12][13][14][15], and numerically [16].…”

Sulfamethoxazole/Trimethoprim ratio as a new marker in raw wastewaters: A critical review

“…The solid fraction can therefore play a key role in the transport of organic contaminants especially if the organic molecules display particular affinity with inorganic/organic surfaces (i.e. hydrophobic contaminants) (Quesada et al, 2014;Xing et al, 2015). Organic and/or mineral suspended solids often present a significant cation exchange capacity (Barron et al, 2009;Hyland et al, 2012;Thiebault, 2019), therefore presenting a potential high affinity with cationic compounds.…”

Processes of distribution of pharmaceuticals in surface freshwaters: implications for risk assessment

“…Colloids are formed and transported to surface waters by weathering and biological processes. Their large specific surface area and sorption capacity play a crucial role in the speciation, bioavailability and transport of substances in the aquatic environment (Zhou et al 2007;Xing et al 2015).…”