Assessment of microplastic-sorbed contaminant bioavailability through analysis of biomarker gene expression in larval zebrafish

“uPVC was selected as a model polymer because it is reported globally in themarine environment (Andrady, 2011), and because preliminary trials with unplasticized PVC showed that the MPs sank to the bottom.”

“A uPVC size of 200 – 250 μ m was selected and provided a high surface area for sorption (Teuten et al., 2009), is comparable with previous work (Bakir et al., 2012) and is representative of small MPs found in the environment (Thompson et al., 2004).”

“Plastic debris is present in numerous shapes and sizes and particles b 5 mm (MPs) in size are reported as the most abundant sizes detected in large-scale assessments of the oceans (Eriksen et al., 2014).”

“…of MPs and co-contaminants used in the present study were orders of magnitudes higher than what is found in the environment (Aris et al., 2014; Long et al., 1995; Lusher et al., 2014), and co-contaminant concentrations were deliberately tested at higher than environmentally relevant amounts.”

“One concern is the potential for MPs to transport harmful pollutants (termed here “ co-contaminants ” ) sorbed from marine environments (Holmes et al., 2012; Mato et al., 2001; Rochman et al., 2013a) into the food chain (Teuten et al., 2007).”

“Phenanthrene [Phe, (log 10 of the octanol:water partition coef fi cient (log 10 K ow ) = 4.57 (Miller et al., 1985)] is a simple three ringed polycyclic aromatic hydrocarbon (PAH) that has been frequently reported as a co-contaminant sorbed to MPs (Mato et al., 2001).”

“Plastic debris is accumulating in the environment on a global scale and the potential for negative effects on ecosystems has become a priority concern for environmental science and policy (Gregory, 2009).”

“Recently MPs have been shown to alter the bioavailability of pyrene and PCBs in vertebrates and invertebrates (Avio et al., 2015; Besseling et al., 2013; Oliveira et al., 2013; Rochman et al., 2013b).”

“The assumption of spherical shaped particles for determination of surface area by computation has been used previously (Goldstein et al., 2013; Nuelle et al., 2014;Rocha-SantosandDuarte,2014).”

“One concern is the potential for MPs to transport harmful pollutants (termed here “ co-contaminants ” ) sorbed from marine environments (Holmes et al., 2012; Mato et al., 2001; Rochman et al., 2013a) into the food chain (Teuten et al., 2007).”

“One concern is the potential for MPs to transport harmful pollutants (termed here “ co-contaminants ” ) sorbed from marine environments (Holmes et al., 2012; Mato et al., 2001; Rochman et al., 2013a) into the food chain (Teuten et al., 2007).”

“Previous studies measured the concentration of co-contaminants in different tissues after MP/co-contami-nant exposures (Besseling et al., 2013; Oliveira et al., 2013), and some previous work also used gene expression to indicate toxicological effects of MP/co-contaminant exposure (Avio et al.,…”

“One concern is the potential for MPs to transport harmful pollutants (termed here “ co-contaminants ” ) sorbed from marine environments (Holmes et al., 2012; Mato et al., 2001; Rochman et al., 2013a) into the food chain (Teuten et al., 2007).”

“SEM (JEOL JSM-6610LV) was used to investigate surface topography of particlesaccordingto standard procedure(Ashton et al., 2010) - sampleswere mountedontodisksof adhesive tapeand coated with a nano-layer of gold (EMITECH K550) to aid substrate conductivity.”

“Previous studies measured the concentration of co-contaminants in different tissues after MP/co-contami-nant exposures (Besseling et al., 2013; Oliveira et al., 2013), and some previous work also used gene expression to indicate toxicological effects of MP/co-contaminant exposure (Avio et al.,…”

“…MPs have been reported to have elevated amounts of polychlorinated biphenyls (PCBs) and other persistent organic contaminants (Colabuono et al., 2010; Tanaka et al., 2013), although whether the increased amounts of these contaminants is a consequence of desorption from ingested MPs is unknown.”

“…of MPs and co-contaminants used in the present study were orders of magnitudes higher than what is found in the environment (Aris et al., 2014; Long et al., 1995; Lusher et al., 2014), and co-contaminant concentrations were deliberately tested at higher than environmentally relevant amounts.”

“SEM analysis revealed detailed surface topography of uPVC particles, and, compared to images of micro-sized polyethylene previously published (Corcoran et al., 2009), the texture of the uPVC particles of the present study appeared to be more irregular and coarse.”

“The term bioavailability is de fi ned as the extent to which a compound enters tissue and reacts with biological molecules (Semple et al., 2004).”

“Various contaminants, with different physicochemical properties, have been shown to interactwithMPs in both the environment and laboratory, and co-contaminants that are more hydrophobic appear to be more strongly sorbed and likewise less likely to desorb (Bakir et al., 2012; Frias et al., 2010; Teuten et al., 2009).”

“Over the last decade, investigations have reported the presence of MPs in sediments (Reddy et al., 2006) and in pelagic zones (Collignon et al., 2012); however, the ecological implications of MPs are unknown.”

“The concentrations of MPs and co-contaminants used in the present study were orders of magnitudes higher than what is found in the environment (Aris et al., 2014; Long et al., 1995; Lusher et al., 2014), and co-contaminant concentrations were deliberately tested at higher than environmentally…”

“The sorption of Phe to uPVC MPs was previously characterized in our laboratory (Bakir et al., 2012), and the following sorption equation was obtained: y ¼ 0 : 51 x − 0 : 14 (where y =concentration of Pheleft in thepelagic scenario and x = the initial concentration of Phe).”

“Phenanthrene [Phe, (log 10 of the octanol:water partition coef fi cient (log 10 K ow ) = 4.57 (Miller et al., 1985)] is a simple three ringed polycyclic aromatic hydrocarbon (PAH) that has been frequently reported as a co-contaminant sorbed to MPs (Mato et al., 2001).”

“Over the last decade, investigations have reported the presence of MPs in sediments (Reddy et al., 2006) and in pelagic zones (Collignon et al., 2012); however, the ecological implications of MPs are unknown.”

“A recentarticle suggeststhat MPs ingested byseabirds act as passive samples of the persistent organic pollutants (POPs) that have accumulated within the animal rather than contributing to the accumulation of POPs (Herzke et al., 2016).”

“The assumption of spherical shaped particles for determination of surface area by computation has been used previously (Goldstein et al., 2013; Nuelle et al., 2014;Rocha-SantosandDuarte,2014).”

“Around 300 million tonnes of plastic are produced every year (Browne et al., 2011; Shim and Thomposon, 2015), and disposal of many of these plastic products leads directly or indirectly to their arrival in aquatic environments.”

“Relatively low (compared to other cyp1A inducers) level of induction of cyp1A by Phe is consistent with previous reports (Fent and Bätscher, 2000).”

“…that have ingested MPs have been reported to have elevated amounts of polychlorinated biphenyls (PCBs) and other persistent organic contaminants (Colabuono et al., 2010; Tanaka et al., 2013), although whether the increased amounts of these contaminants is a consequence of desorption from…”

“The concentration-related induction of vtg with EE2 was consistent with our previous work (Henry et al., 2009; Park et al., 2010; Reinardy et al., 2013), and other reports (Bowman et al., 2000; Solé et al., 2000).”

“1) (Henry et al., 2009; Park et al., 2010; Reinardy et al., 2013).”

“After sample homogenization (3–5 s of sonication) and tissue disaggregation (QiaShredder column, Qiagen), total RNA was extracted (RNeasy MiniKit for animal tissue, Qiagen, West Crawley, UK) from zebrafish larvae (35 fish in each sample) as previously described (Henry et al., 2009; Park et al., 2010; Reinardy et al.,…”

“Analytical chemistry was not used to characterize sorption of EE2 to uPVC particles due to dif fi culty in detecting such low concentrations; however, previous studies have demonstrated EE2 has a strong sorption af fi nity to plastic (Han et al., 2012; Walker and Watson, 2010).”

“PAHs are of concern due to their persistence in the environment as well as their carcinogenic and mutagenic properties (Jennings, 2012; Teranishi et al., 1975).”

“PAHs are of concern due to their persistence in the environment as well as their carcinogenic and mutagenic properties (Jennings, 2012; Teranishi et al., 1975).”

“…concentration and target gene expression indicated that measurement of the expression of these genes is a useful approach for evaluation of changes in co-contaminant bioavailability during sorption reactions with particles as we have demonstrated previously (Henry et al., 2013; Park et al., 2011).”

“The concentration-related induction of vtg with EE2 was consistent with our previous work (Henry et al., 2009; Park et al., 2010; Reinardy et al., 2013), and other reports (Bowman et al., 2000; Solé et al., 2000).”

“The concentrations of each substance were selected as they are the highest non-lethal concentrations which allowed for high gene expression whilst avoiding mortality (Gündel et al., 2012; Henry et al., 2009).”

“Analytical chemistry was not used to characterize sorption of EE2 to uPVC particles due to dif fi culty in detecting such low concentrations; however, previous studies have demonstrated EE2 has a strong sorption af fi nity to plastic (Han et al., 2012; Walker and Watson, 2010).”

“When NPs with sorbed Hg 2+ sedimented to the bottom of beakers, Hg 2+ exposure in fi sh at the bottom of the beaker increased (Henry et al., 2013).”

“The improvement observed in the number of MPs held in thewater column within thechamber is consistentwith that observed for engineered nanoparticles in a chamber of similar design (Boyle et al., 2015).”

“Relative quanti fi cation of gene expression was by the comparative C T method, in which the change in expression of the gene of interest is normalized to that of an internal housekeeping gene (Park et al., 2006).”

“A few studies on larval and adult zebrafish showed that microplastics were first ingested, became accumulated, and consequently caused alternations in locomotion, intestinal damage, and change in metabolic profiles (Lu et al., 2016; Chen et al., 2017; Sleight et al., 2017; Lei et al., 2018).”

“Recent investigations indicate that microplastics can alter the bioavailability of heavy metals in aquatic environments (Brennecke et al., 2016), PAHs (Karami et al., 2016; Oliveira et al., 2013), and PCBs (Sleight et al., 2017), thereby causing complex changes in physiological processes such as protein synthesis, ene…”