br Conclusions br Funding This work was supported

Conclusions
Funding This work was supported by a Finnish government subsidy for health science research [grant numbers TYH2012141, TYH 2013218, and TYH 2014216]; the SSAC Foundation [grant numbers SLS-504141 and SLS-693781]; and the Paulo Foundation. The funding sources had no involvement in study design, data collection, analysis, or interpretation, writing the manuscript, or the decision to submit the article for publication.
Authors’ contributions
Potential conflicts of interest
Acknowledgements
Introduction During the last 60 years, plastic production increased considerably from around 0.5 million tonnes in 1950 to 311 million tonnes in 2014 (Thompson et al., 2009; Plastics, 2015), which accompanied by increasing release of plastic waste to the environment. It is estimated that 4.8–12.7 million tonnes of plastic waste washed offshore in 2010 alone (Jambeck et al., 2015). Recently, microplastics (MPs) with particle size in the micrometer range have become the focus of study due to their potential toxic impact to aquatic ecosystems. MPs have been detected in surface water (Zhao et al., 2015), water column (Nel and Froneman, 2015), and bottom sediments (Browne et al., 2011). Previous studies have showed that polyethylene (PE), polystyrene (PS), polypropylene (PP), polyamide (PA), and polyvinyl chloride (PVC) are the most frequently detected MPs in the aquatic environment (Hidalgo-Ruz et al., 2012; Fok et al., 2017). It is believed that MPs can accumulate various hygromycin b synthesis and chemical pollutants and serve as a carrier for long-range transport (Guo et al., 2012; Turner and Holmes, 2015; Hueffer and Hofmann, 2016). Studies have been conducted on the adsorption behaviors of organic pollutants or heavy metals onto different types of MPs (Bakir et al., 2014a, 2014b, Velzeboer et al., 2014; Wang et al., 2015; Hueffer and Hofmann, 2016; Wu et al., 2016) as well as the effects of plastic types and environmental factors (e.g., ionic strength and pH) on pollutants adsorption processes (Wang et al., 2015). Both the sorbent and the sorbate properties can influence the adsorption extent significantly. For instance, properties of MPs such as polarity, abundance of rubbery, and degree of crystalline have great impacts on adsorption capacities of pollutants (Guo et al., 2012; Wang et al., 2015; Brennecke et al., 2016). The hydrophobicity of organic contaminants is also important in determining their adsorption on MPs (Hueffer and Hofmann, 2016). Furthermore, adsorption of organic pollutants on MPs varied in the seawater and the freshwater (Velzeboer et al., 2014), which may be due to the impacts of salinity. As reported by Wang et al. (2015), perfluorooctanesulfonate (PFOS) adsorption on PE and PS increased with increasing of ionic strength, while ionic strength had no effect on perfluorooctanesulfonamide (FOSA) adsorption. As a class of emerging contaminants, antibiotics have received increasing attention due to their impacts on the microbial community as well as the generation of resistance genes (Le et al., 2005; Yang et al., 2017). A large number of antibiotics are released into the environment every year. As evaluated by Zhang et al. (2015), only in China, 53,800 tonnes of antibiotics discharged into the receiving environment in 2013. Studies reported that tetracyclines, macrolides, fluoroquinolones, and sulfonamides are the frequently detected antibiotics in the aquatic environment worldwide (Kolpin et al., 2002; Watkinson et al., 2009; Jiang et al., 2011; Li et al., 2012). Antibiotics such as trimethoprim, fluoroquinolones, and sulfonamides were found to be stable in surface water (Lunestad et al., 1995; Lin et al., 2010). More importantly, the residual antibiotics may pose relatively high ecological risk to the relevant aquatic organisms (Xu et al., 2013). If antibiotics can be absorbed by MPs, both could have higher toxic effects on aquatic life due to the combined pollution. There is evidence that persistent organic pollutants (POPs) can transfer from MPs to Artemia nauplii and further to zebrafish via a trophic food web (Batel et al., 2016). Thus, understanding the possible reactions between different kinds of antibiotics and MPs is warranted for the evaluation of their environmental risks.