Article pubs.acs.org/est
Effects of Toxic Leachate from Commercial Plastics on Larval Survival and Settlement of the Barnacle Amphibalanus amphitrite Heng-Xiang Li,†,‡ Gordon J. Getzinger,§ P. Lee Ferguson,§,∥ Beatriz Orihuela,‡ Mei Zhu,‡ and Daniel Rittschof*,‡ †
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China ‡ Duke Marine Laboratory, Nicholas School of the Environment, Duke University, Beaufort, North Carolina 28516, United States § Nicholas School of the Environment, Duke University, Durham, North Carolina 27701, United States ∥ Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina 27701, United States S Supporting Information *
ABSTRACT: Plastic pollution represents a major and growing global problem. It is well-known that plastics are a source of chemical contaminants to the aquatic environment and provide novel habitats for marine organisms. The present study quantified the impacts of plastic leachates from the seven categories of recyclable plastics on larval survival and settlement of barnacle Amphibalanus (=Balanus) amphitrite. Leachates from plastics significantly increased barnacle nauplii mortality at the highest tested concentrations (0.10 and 0.50 m2/L). Hydrophobicity (measured as surface energy) was positively correlated with mortality indicating that plastic surface chemistry may be an important factor in the effects of plastics on sessile organisms. Plastic leachates significantly inhibited barnacle cyprids settlement on glass at all tested concentrations. Settlement on plastic surfaces was significantly inhibited after 24 and 48 h, but settlement was not significantly inhibited compared to the controls for some plastics after 72−96 h. In 24 h exposure to seawater, we found larval toxicity and inhibition of settlement with all seven categories of recyclable commercial plastics. Chemical analysis revealed a complex mixture of substances released in plastic leachates. Leaching of toxic compounds from all plastics should be considered when assessing the risks of plastic pollution.
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INTRODUCTION Plastics are the most common particulate pollutants in marine environment and a source of growing concern.1,2 Global plastic production was an estimated 299 million tons in 2013, a 3.9% increase from 2012.2 Mismanagement of municipal solid waste in coastal regions represents a dominant source of plastic debris into the marine environment. In 2010, 192 coastal countries generated approximately 275 million metric tons of plastic waste, of which 4.8−12.7 million metric tons were predicted to enter the ocean.3 Concomitant with increases in global use and disposal of plastic materials, plastic pollution in the oceans is significant and growing.4−6 Recent estimates predict that more than 5 trillion plastic pieces weighing over 250 000 tons are currently afloat at sea.4 Monitoring efforts reveal the ubiquitous occurrence of plastics in nearly all marine habitats including coasts, open ocean, sea floors, and remote islands.7 Concerns over the distribution of plastics in marine environments center largely on potential adverse outcomes for human and ecological health associated with the transfer of contaminants, either added during manufacturing or accumulated from the ambient environment, to higher organisms.8−17 © XXXX American Chemical Society
Numerous studies have investigated the occurrence and trophic transfer potential of plasticizers, stabilizers, antioxidants, and catalysts, and emerging pollutants like alkylphenols, phthalate esters, halogenated diphenyl ethers, biphenyl, and organochlorine pesticides.18−30 However, comparatively fewer studies have focused on the potential impacts of plastics and their associated chemistries, on microorganisms and dispersal stages of hydrozoans, bryozoans, and arthropods, which colonize plastic debris.31−34 Biofouling of plastics may play a key role in determining the environmental fate and effects of plastic debris.35−37 Physical disruption by wave action and embrittlement by photocatalyzed polymer autoxidation are the primary drivers of plastic weathering in marine environments.38−40 Such processes lead to the fragmentation of macro plastic debris into smaller and more bioavailable microplastic particles.18,39 Biofouling may Received: June 7, 2015 Revised: November 24, 2015 Accepted: December 14, 2015
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DOI: 10.1021/acs.est.5b02781 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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harvested at the Duke University Marine Laboratory. The assay consisted of adding a drop of newly hatched nauplii (20 μL, 30−60 larvae) to each test tube and incubating at 28 °C in darkness without feeding for 24 h, before scoring nauplii for mortality. Mortality was determined as the proportion of immotile nauplii. The assay was repeated and data were combined for statistical analysis. Settlement Inhibition Assays. Barnacle nauplii were collected from adult barnacles and cultured in a clean bucket containing 8 L of FASW maintained at 28 °C and a 12:12 lightdark cycle using fluorescent lights. Larvae were feed 500 mL brown algae Skeletonema costatum daily and constantly aerated. No water changes were performed during the culture period. After 4 days, larva that had metamorphosed into cyprids were collected with nylon sieves and held at 6 °C for 3 days until testing. Triplicate settlement tests were conducted in combusted borosilicate glass vials (Wheaton Scientific) containing 3 mL of FASW or plastic leachate dilution prepared identically to those described above for nauplii tests. Ten cyprids were added to each vial and incubated at 28 °C with a 12:12 h light-dark cycle using fluorescent lamps. After 24 h, settlement inhibition was determined as the percent of larvae that had not attached to the surface of glass vials and metamorphosed. The assays were repeated and data were combined for statistical analysis. Settlement on Plastics. Settlement of barnacle larvae directly onto plastic surfaces was assayed using 4 cm2 pieces of plastic. Control surfaces consisted of clean glass coverslips (Corning #583396) and polystyrene Petri dishes (Falcon #1006). Flaming prior to testing removed hydrophobic coatings from the glass coverslips, which necessitated the use of a small wax circle drawn with a wax pen to control the spread of water on the flamed glass coverslips. The glass coverslip, polystyrene Petri dish and wax were tested after Rittschof et al. to ensure they were not toxic (Supporting Information, Figure S1).50 For settlement assays, three pieces of each plastic were placed in a glass bowl lined with moist paper toweling and fitted with a transparent lid to prevent evaporation of the water drops containing cyprids. Ten cyprids in 1 mL FASW were added to each test surface before incubating in 100% humidity at 28 °C with a 12:12 h light-dark cycle using fluorescent lamps. Settlement and metamorphosis were recorded after 24, 48, 72, and 96 h. The assays were repeated three times. Leachate Screening. Plastic leachates, PS Petri-dish controls and filtered aged seawater blanks were syringe filtered (0.2 μm, PTFE) and screened for organic substances by large volume direct aqueous injection (1 mL) onto a highperformance liquid chromatograph (HPLC, Dionex UltiMate 3000) equipped with a 100 × 2.1 mm Hypersil aQ reversed phase column (Thermo Scientific) coupled by an electrospray ionization (ESI) source to an LTQ Orbitrap Velos highresolution accurate-mass mass spectrometer (HR/AM MS, Thermo Scientific). Analyses were performed in both positive and negative polarity ESI. HPLC mobile phases consisted of ultrapure water (A) and acetonitrile (B) both containing 0.1% (v/v) formic acid and isopropanol (C). To limit ionization suppression and source contamination, samples were injected under 100% aqueous conditions and the column rinsed to waste for 5 min before beginning gradient elution (gradient conditions can be found in the Supporting Information, Table S3). Throughout the entire chromatograph, full-scan HR/AM spectra (mz 50−2000, R = 60 000 at m/z 400) were acquired along with data-dependent HR/AM MS2 spectra (R = 7500 at
retard the weathering of plastics by directly shielding materials from ultraviolet radiation and by limiting exposure to euphotic zones by changes in debris buoyancy.36,41,42 Bioadhesion and biofilm formation are known to be sensitive to both surface chemistry and additives substances.43−46 However, to our knowledge, no studies have investigated the impact of plastics and their associated chemistries on the settlement of common fouling organisms. Such knowledge is essential for advancing the mechanistic understanding of the environmental fate and effects of plastics. Barnacles are a well-developed animal model for studying marine fouling on surfaces.47−49 Due to the negative impact of barnacles on economically important marine infrastructures like ships, naval operations, navigation aids, and cooling water intakes, there is an extensive literature on barnacle fouling. Barnacles settle on plastic debris, making them an environmentally relevant model for studying the impacts of plastics and plastic leachates on fouling organisms. In the present study, our objective was to quantify the effects of common recyclable plastics and their leachates on larval survival and settlement of a common marine barnacle Amphibalanus (=Balanus) amphitrite.
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MATERIALS AND METHODS Plastic Selection. New plastic products, representing each of the seven recycling categories defined by the Society of Plastics Industry (SPI), were purchased from commercial sources. Plastic types were identified by the recycling category printed on the product and included vinyl polymers (highdensity polyethylene, HDPE; low-density polyethylene, LDPE; polypropylene, PP; polyvinyl chloride, PVC), polyesters (polycarbonate, PC; polyethylene terephthalate, PET) and aromatic polymers (polystyrene, PS). Each of the plastic types investigated are commonly detected in the marine environment,1,5 and account for 80−90% in global plastic demand.2 Information on the source and charcteristics of the tested plastics can be found in the Supporting Information, Table S1. Leachate Preparation. Plastic leachates were prepared from 10 × 10 cm subsamples cut from each plastic product, avoiding areas where labels were affixed. The samples were further subdivided into 1 × 1 cm sections to be convenient for leaching in glass tube. No washing was conducted in order to test the first leaching. Leachates for each plastic category were prepared in duplicate. To prepare leachates, plastic pieces were contacted for 24 h at 28 °C with 20 mL filtered aged seawater (FASW) in covered clean glass test-tubes, giving a final concentration of 0.50 m2 area of plastic in 1 L filtered seawater (0.50 m2/L, solid-to-liquid ratio). Filtered seawater was from the dock of Duke University Marine Laboratory (Beaufort, NC). Salinity and pH were measured before and after each experiment (Supporting Information, Table S2). After 24 h, the leachates were transferred to a clean tube and used as stock solution for preparation of serial dilutions. Four leachate concentration levels from 0.004 to 0.5 m2/L were prepared by diluting the appropriate amount of leachate stock with FASW. Solutions were prepared immediately before toxicity and settlement assays, which followed the well-established protocols in our lab as reported elsewhere.50 Surface energy of recycling plastic was measured by a standardized harmonic mean (SHM) method.51 Nauplii Toxicity Assays. Duplicate toxicity tests were conducted in combusted glass culture tubes containing 3 mL of either FASW or leachate dilution using naupliar larvae collected less than 3 h after release from adult barnacles (A. amphitrite) B
DOI: 10.1021/acs.est.5b02781 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology m/z 400) for the top-four most intense ions in each full-scan. Resultant data were subjected to a nontargeted screening workflow consisting of peak picking, adduct and isotope detection using Compound Discover (Thermo Scientific), molecular formula assignment and fragment tree annotation by SIRIUS (Version 3.0),52 and spectral library searching using the mzCloud mass spectral database.53 Statistical Analysis. One-way analysis of variance (ANOVA) was used to test differences in nauplii mortality between plastic leachates and FASW controls, and cyprid settlement between plastics and controls. The percentage of larval mortality and settlement in response to each experimental treatment was arcsine-transformed before the statistical analysis as this transformation could normalize the data and increase homoskedasticity. Replicates without no mortality or settlement were assigned a value of 1/4n and replicates with 100% of mortality or settlement were assigned the value of 1-(1/4n), where n indicated the number of larvae in a replicate. However, the data presented in the figures and tables were not transformed. Data were tested for normality and equal variance before the ANOVA (SPSS statistics 22.0 software). The relationships between surface energy (SHM values) and nauplii mortality, and between surface energy and cyprid settlement at the highest concentration (0. 50 m2/L) of plastic leachates were assessed using Spearman’s correlation test. In all cases, p < 0.05 was defined as a statistically significant difference.
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RESULTS AND DISCUSSION Toxicity to Nauplii. Figure 1-A depicts the toxicity of plastic leachates to barnacle nauplii. At all concentration levels, naupliar mortality was less than 30%. Compared to FASW controls, leachates from all seven plastic categories had statistically significant toxicity to nauplii larvae at 0.50 m2/L. Significant mortality was observed in all leachates except PS at 0.10 m2/L. At 0.50 m2/L, PVC, LDPE and PC had the most toxic leachates while leachates from PP and PS were the least toxic. Differences in biological response to the complex chemical mixtures present in leachates is expected to vary with specific chemicals leached and the species specific susceptibility of the exposed animal model.8,9 Plastic leachate composition is impacted by the physicochemical properties of both the applied additives and the polymer matrix.8 The heterogeneity of plastic and additive properties are reflected in our results, which showed that the toxicity of leachates to barnacle nauplii was variable and material-dependent. For instance, rank-order of toxicity varied among plastic types between leachate concentrations. However, at all test concentrations, PVC was found to be the most toxic to barnacle nauplii, consistent with the known properties of that material. Namely, the presence of residual vinyl chloride monomers and other substances known to be found in PVC polymers (e.g., Pb, Cd, dibutyltin dilaurate, phthalates),14 which are likely to act as broad-spectrum biocides.54,55 At the highest concentration level, LDPE was the second most toxic plastic leachate. LDPE also represents the softest material tested in this study, which may indicate higher loading of plasticizers to impart flexibility.54 Phthalate esters are a commonly applied plasticizer and endocrinedisrupting compounds that may cause adverse reproductive and developmental effects.8 Like many plastic additives, phthalates are noncovalently associated with the polymer matrix and therefore leach into media contacted with plastic where they
Figure 1. A-C: Impacts of commercial plastics on larval survival and settlement of barnacle Amphibalanus Amphitrite. A, B: Nauplii mortality (A) and cyprid settlement (B) after 24 h exposed to filtered aged seawater (FASW) controls and different concentrations of plastic leachates. “*” indicate significantly higher than FASW controls (ANOVA, p < 0.05). C: Cyprid settlement on glass and polystyrene Petri-dish control surfaces and seven categories of plastic surfaces after 24−96 h. “**” indicate significantly lower than both Glass and PS Petri-dish controls, and “*” indicate only significantly lower than Glass controls (ANOVA, p < 0.05).
may impart toxicity in exposed organisms.8,9 While our chemical screening (vide infra) did not identify phthalates in the plastic leachates, the analysis of such compounds is often complicated by persistent and elevated laboratory blanks. Given the known biological activity and widespread application of this class of plastic additive, we are undertaking a targeted analysis to better understand the potential role of endocrine disrupting chemical additives in the toxicity of plastic leachates to barnacle nauplii. Settlement on Glass with Plastic Leachates. Figure 1B depicts the inhibition of barnacle cyprid settlement on glass vials by plastic leachates. Settlement was significantly inhibited by leachates from all categories of plastics at all tested concentrations. Similar to the leachate toxicity results, the rank-order of settlement inhibition varied between concentration levels. However, LDPE, PET, and HDPE consistently exhibited the greatest percent inhibition. HDPE completely C
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Environmental Science & Technology inhibited settlement at three of the four concentrations tested. PP, PVC and PS leachate consistently showed the lowest percent inhibition of settling. Interestingly, no material-specific relationship between leachate settlement inhibition of barnacle cyprids and mortality of barnacle nauplii could be established, suggesting that the underlying mechanisms exhibiting adverse outcomes in this model are life-stage dependent. Settlement on Plastics. Compared to PS Petri-dish and glass controls, cyprid settlement on the tested plastic materials was significantly depressed after 24 h for all material types, as shown in Figure 1C. Furthermore, settlement inhibition persisted through 96 h in all by three materials. After 48 h all plastics had lower settlement than the glass control, and six of seven types of plastic surfaces had lower settlement than both glass and PS Petri-dish controls. After 72 h settlement on PP, PVC, and PS was statistically similar to the glass and PS Petridish controls. However, settlement on the other four categories of plastic was significantly lower than glass and PS Petri-dish controls. In the case of HDPE, no settlement was observed until 96 h. At the end of the experiment, four plastics exhibited significant inhibition of settlement in the order: HDPE > PC > LDPE > PET. Settlement after 96 h on PS, PVC and PP was not statistically different from the controls. Toxicity and Settlement in Relation to Surface Energy. Surface energy was determined as SHM values for each of the seven categories of recyclable plastics. SHM values were low and in a narrow range from 15.18 to 19.95 on plastic surfaces, and high (51.43) on glass surface (Table 1). No
Figure 2. Relationships between the surface energy (SHM values) of plastics and nauplii mortality (A) or cyprid settlement (B) of barnacle Amphibalanus amphitrite at the highest concentration (0.5 m2/L) of plastic leachates.
Table 1. Surface Energy of Samples Measured by SHM Methods samples
surface energy
PET HDPE PVC LDPE PP PS PC PS petri-dish glass
19.95 15.81 15.18 16.07 19.73 18.11 17.54 20.44 51.43
leachates in glass vials showed settlement inhibition at all concentrations. Therefore, we conclude that the observed settlement inhibition is likely associated with leaching chemicals that are not acutely toxic, but are nonetheless strongly biologically active. This result was consistent among all plastic types tested. However, all surfaces, including plastics, foul in a matter of days in natural waters, suggesting that materials that initially inhibit settlement by fouling organisms quickly lose their resistance under environmental conditions.58 Further work is needed to better understand what factors cause inhibition of barnacle settlement on plastics and which environmental factors might lead to the loss of that inhibition. Our results were similar to those reported for plastic leachates tested in marine and freshwater crustacean models.59−62 Bejgarn et al. (2015) examined 21 new plastic products and found leachates from eight (38%) plastics caused acute toxicity to marine copepod Nitocra spinipes.60 Using leaching methods in two assays, leachates from 9 of 32 and 11 of 26 unused plastics resulted in acute toxicity to Daphnia magna.61,62 Toxicity was documented in leachates from new plastics in 24 h to 3 day exposure to freshwater or seawater.60−62 Thus, we speculate the new plastic products are hazardous to aquatic environment. Toxicity of plastic leachates may also be related to procedures used to generate and test leachates, which vary dramatically among literature reports and thus limits our ability to directly compare our results to those reported by others. However, our results are generally consistent with previous investigations into the toxicity of plastic leachates to organisms. For instance, Lither et al. (2009, 2012) demonstrated that plastic leachates prepared by shaking plastics for 24 h where toxic to D. magna.61,62 Furthermore, Bejgarn et al. (2015) found that leachates prepared by shaking exposure for 72 h followed by simulated sunlight for an additional 96 h did not
correlation between SHM and recycle category could be established. However, we found a strong correlation between SHM and nauplius mortality (Spearman correlation test, p < 0.05, Figure 2A), and between SHM and cyprid settlement (Spearman correlation test, p < 0.05, Figure 2B) at the highest plastic leachate concentration. In general, the least wettable surfaces were the most toxic in the assays. Results showed that all plastics tested were strongly lipophilic, about half as hydrophilic as surfaces exposed to estuarine water for 4−5 days.56,57 We were surprised that over this range of surface energies that there was a strong negative correlation of toxicity with hydrophobicity. This suggests that the more lipophilic surfaces are less toxic in the short term tests. Longer-term studies are required to determine if relationships persists as plastics become weathered by environmental exposure. While material surface energy has been known to effect barnacle settlement,47,51 the narrow range of surface energies determined for the plastics in this work can also be detected by the barnacle cyprids. Furthermore, settlement tests with D
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Environmental Science & Technology significantly effect leachate toxicity in all of the studied plastics.60 Here we used static leaching for 24 h to reduce the loss of semivolatile and volatile organic additives (e.g., phthalates) and to limit photocatalyzed transformation of leachate constituents. Results in this study documented measurable leaching toxicity for all types of plastic products. HPLC-HR/AM MS Screening of Leachates. Analysis of plastic leachates revealed the presence of numerous ESI amenable organic substances. The number of unique chromatographic features detected (i.e., accurately measured mass and retention time pairs) varied greatly depending on the ESI polarity and the leachate source, but consistently showed higher counts for plastic leachates. Figure 3 depicts the detected chromatographic features for each plastic leachate.
Table 2. Number of Chromatographic Features Detected in Plastic Leachates, FASW and PS Petri-Dish Controls, And the Percent of Peaks Detected in That Sample ionization modes
a
samples
ESI(+)
ESI(−)
features unique to samplea (%)
FASW PS petri-dish HDPE PET PS LDPE PP PVC PC
52 59 113 120 139 148 150 158 165
0 0 3 2 4 5 7 2 5
11 10 8 10 4 18 31 38 18
Data from ESI(+) only.
to barnacles, the resultant toxicity likely represents the sum of the chemical stressors unique to that plastic material. Chromatographic features were assigned best-fit molecular formula based on detected pseudomolecular-ions, isotopic abundances and tandem mass spectra using the SIRIUS algorithm.52 Spectral library searching was conducted using the mzCloud mass spectral database, which contains spectral data for >3000 substances relevant to metabolomics, toxicology and environmental sciences.53 Even with the depth and breadth of the applied spectral library, only one compound, N,Ndiethyl-meta-toluamide (DEET), was returned with a confident spectral match score (>80%). This result indicates that, while the leachates were rich in ESI amenable organic substances, those detected are not among commonly monitored organic chemical contaminants. Further analysis of the detected features revealed several series of polyethoxylated surfactants as evidence by repeating mass differences corresponding to −C2H4O− moieties. Interpretations of tandem mass spectra for these compounds lead to the tentative identification of C6 and C8 alcohol polyethoxylates and polyethylene glycol. Both the number of detected peaks and the total number of detected polyethoxy homologues were poorly correlated with the observed toxicity (Spearman correlation test, p > 0.01). Given the relatively high number of peaks detected in the plastic leachates and the small number of identifications made, further work is needed to better characterize chemical exposures occurring at marine plastic debris. To that end, we are undertaking a study to elucidate the identity of toxicants leaching from the studied materials by combining effect directed analysis, nontargeted analysis by HPLC-HR/AM MS and targeted quantitative analysis of commonly applied inorganic and organic polymer additives. Environmental Implications. This work adds to a growing literature on the toxicity of plastic and their associated leachates to aquatic organisms. In particular, we demonstrate that for barnacles, the toxicity of plastics is life-stage dependent, which may have important implications for the fouling of plastics in the marine environment. For instance, our data suggests that barnacle nauplii exposed to plastics in confined environments will experience an acute toxic response to leached chemicals from plastic materials. Such conditions would be expected in tidal environments where nauplii may become constrained with plastic debris in shallow and stagnated tidal pools. Alternatively, our results show that plastic debris in near-surface environment may resist settlement by barnacle cyprids, which may have important implications for the fate of plastics in the near-shore
Figure 3. Molecular weight versus retention time plots for plastic leachates and controls (FASW and PS Petri-dish). Horizontal axes depict chromatographic retention time (min.) while ordinate axis show the accurately measured molecular weight (Da). Circles represent detected chromatographic features scaled by the area counts of that feature relative to all peaks detected in a given sample.
Results for the FASW and the PS control Petri dish demonstrated relatively few detectable features with approximately 50 and 0 peaks detected by ESI(+) and ESI(−), respectively. This was consistent with the low mortality and settlement inhibition observed for those materials. In contrast, plastic leachates exhibited consistently higher peak counts (Table 2). In ESI(+) the number of detectable chromatographic features ranged from 113 to 165, while only two to seven peaks were detected by ESI(−). Based on these results we focused our analysis on peaks detected in ESI(+). The occurrence of chromatographic features in the leachates varied greatly between plastic types. For instance, 61 of the 158 peaks detected in the PVC leachate by ESI(+) occurred only in that sample. This result may explain the variable rank-order of plastic leachate toxicity and settlement inhibition. Namely, the unique chemical composition of each plastic type, as reflected by the HR/AM MS analysis, suggests that while leachates exhibit similar levels of acute toxicity and settlement inhibition E
DOI: 10.1021/acs.est.5b02781 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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be gratefully acknowledged. We are deeply indebted to Gordon J. Getzinger and P. Lee Ferguson for chemical analysis and comments.
marine environment by limiting plastic weathering and subsequently increasing plastic persistence in the marine environment. This result suggests that life stage-specific sensitivity to plastic toxicity may drastically affect the ability of organisms to utilize plastics as habitats in the marine environment. Furthermore, our results highlight challenges associated with assessing potential effects associated with exposure of marine fauna to plastic debris. In particular, our inability to explain the material dependent biological effects observed in our results by identification of discrete chemical toxicants suggests that the toxicity associated with these materials may be the result of a mixture-effect that would likely elude conventional single chemical toxicity assessments. The potential physical impacts of plastics are becoming well documented in marine ecosystems, including entanglement, smothering, hangers-on, hitch-hiking, and alien invasions.63 However, the chemical impact of environmental plastics, though reported for over 20 years, remains poorly understood.1,64,65 The present report along with a number other works demonstrate that plastics in all recycling categories each leach a unique and complex mixture of chemicals, many of which may not be commonly monitored environmental contaminants. The paucity of data regarding the chemical composition and toxicological effects to ecological relevant model organisms of those leached substances currently limits comprehensive risk assessment of the environmental impacts of plastic debris in aquatic environment. Furthermore, the fact that all plastics leach chemicals in most any environment suggests that improvements in waste management may mitigate direct inputs of plastic debris and their associated leachates, but would not stem the flow of leached chemicals from plastics into the environment. Given the ever increase demand for plastic products, a more holistic approach, based on principles of Green Chemistry, for limiting the environmental effects of plastics is necessary. Such an approach may require abandoning established industrial processes and chemistries in favor of those which produce plastic products with minimized environmental impact.
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(1) Moore, C. J. Synthetic polymers in the marine environment: A rapidly increasing, long-term threat. Environ. Res. 2008, 108 (2), 131− 139. (2) PlasticsEurope. Plastics the facts 2014−2015. http://www. plasticseurope.org/Document/plastics-the-facts-2014-2015.aspx. (3) Jambeck, J. R.; Geyer, R.; Wilcox, C.; Siegler, T. R.; Perryman, M.; Andrady, A.; Narayan, R.; Law, K. L. Plastic waste inputs from land into the ocean. Science 2015, 347 (6223), 768−771. (4) Eriksen, M.; Lebreton, L. C. M.; Carson, H. S.; Thiel, M.; Moore, C. J.; Borerro, J. C.; Galgani, F.; Ryan, P. G.; Reisser, J. Plastic pollution in the world’s oceans: More than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea. PLoS One 2014, 9, (12).e11191310.1371/journal.pone.0111913 (5) Depledge, M. H.; Galgani, F.; Panti, C.; Caliani, I.; Casini, S.; Fossi, M. C. Plastic litter in the sea. Mar. Environ. Res. 2013, 92, 279− 281. (6) Law, K. L.; Thompson, R. C. Microplastics in the seas. Science 2014, 345 (6193), 144−145. (7) Barnes, D. K. A.; Galgani, F.; Thompson, R. C.; Barlaz, M. Accumulation and fragmentation of plastic debris in global environments. Philos. Trans. R. Soc., B 2009, 364 (1526), 1985−1998. (8) Teuten, E. L.; Saquing, J. M.; Knappe, D. R. U.; Barlaz, M. A.; Jonsson, S.; Bjorn, A.; Rowland, S. J.; Thompson, R. C.; Galloway, T. S.; Yamashita, R.; Ochi, D.; Watanuki, Y.; Moore, C.; Pham Hung, V.; Tana, T. S.; Prudente, M.; Boonyatumanond, R.; Zakaria, M. P.; Akkhavong, K.; Ogata, Y.; Hirai, H.; Iwasa, S.; Mizukawa, K.; Hagino, Y.; Imamura, A.; Saha, M.; Takada, H. Transport and release of chemicals from plastics to the environment and to wildlife. Philos. Trans. R. Soc., B 2009, 364 (1526), 2027−2045. (9) Engler, R. E. The complex interaction between marine debris and toxic chemicals in the ocean. Environ. Sci. Technol. 2012, 46 (22), 12302−12315. (10) Rochman, C. M.; Manzano, C.; Hentschel, B. T.; Simonich, S. L. M.; Hoh, E. Polystyrene plastic: A source and sink for Polycyclic Aromatic Hydrocarbons in the marine environment. Environ. Sci. Technol. 2013, 47 (24), 13976−13984. (11) Rochman, C. M.; Hoh, E.; Hentschel, B. T.; Kaye, S. Long-term field measurement of sorption of organic contaminants to five types of plastic pellets: Implications for plastic marine debris. Environ. Sci. Technol. 2013, 47 (3), 1646−1654. (12) Cole, M.; Lindeque, P.; Halsband, C.; Galloway, T. S. Microplastics as contaminants in the marine environment: A review. Mar. Pollut. Bull. 2011, 62 (12), 2588−2597. (13) Mato, Y.; Isobe, T.; Takada, H.; Kanehiro, H.; Ohtake, C.; Kaminuma, T. Plastic resin pellets as a transport medium for toxic chemicals in the marine environment. Environ. Sci. Technol. 2001, 35 (2), 318−324. (14) Thompson, R. C.; Moore, C. J.; vom Saal, F. S.; Swan, S. H. Plastics, the environment and human health: Current consensus and future trends. Philos. Trans. R. Soc., B 2009, 364 (1526), 2153−2166. (15) Setala, O.; Fleming-Lehtinen, V.; Lehtiniemi, M. Ingestion and transfer of microplastics in the planktonic food web. Environ. Pollut. 2014, 185, 77−83. (16) Seltenrich, N. New link in the food chain? Marine plastic pollution and seafood safety. Environ. Health Perspect. 2015, 123 (2), A34−A41. (17) Rochman, C. M.; Browne, M. A.; Halpern, B. S.; Hentschel, B. T.; Hoh, E.; Karapanagioti, H. K.; Rios-Mendoza, L. M.; Takada, H.; Teh, S.; Thompson, R. C. Classify plastic waste as hazardous. Nature 2013, 494 (7436), 169−171. (18) do Sul, J. A.; Costa, M. F. The present and future of microplastic pollution in the marine environment. Environ. Pollut. 2014, 185, 352− 364.
ASSOCIATED CONTENT
* Supporting Information S
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.est.5b02781. Information on the sources of new plastic products (Table S1). The water quality measured before and after leaching (Table S2). Gradient elution conditions for HPLC-HR/AM MS (Table S3). The nauplii mortality and cyprid settlement in different leachates from glass coverslip, polystyrene Petri dish, and wax (Figure S1) (PDF)
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REFERENCES
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This publication was supported by the National Natural Science Foundation of China (41206133) and the State Scholarship Found of China (201308440115), which should F
DOI: 10.1021/acs.est.5b02781 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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DOI: 10.1021/acs.est.5b02781 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
