Edited by: Karen A. Kidd, McMaster University, Canada
Reviewed by: Chelsea Marina Rochman, University of California, Davis, United States; Franco Teixeira de Mello, Centro Universitario de la Regiónal del Este (CURE), Universidad de la República, Uruguay
*Correspondence: Montserrat Filella
This article was submitted to Freshwater Science, a section of the journal Frontiers in Environmental Science
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Over 3,000 samples of plastic litter have been retrieved from 12 pebble beaches around the shores of Lake Geneva. The plastic stock consisted of identifiable objects of various size and color, including bottles, bottle tops, cotton buds, pens, toys, and straws, an heterogeneous assortment of fragments whose origin was either discernible or unknown, and pieces or blocks of expanded polymer (polystyrene or polyurethane foam). Analysis of 670 samples by portable x-ray fluorescence (XRF) spectrometry revealed high concentrations of hazardous elements or compounds among many plastics. These included Cd, Hg, and Pb (with maximum concentrations of 6,760, 810, and 23,500 ppm, respectively) as stabilizers in PVC-based materials and/or brightly-colored sulfide or chromate pigments in primary and secondary plastics, and Br (with a maximum concentration of 27,400 ppm) as a proxy for brominated flame retardants (BFRs) in both plastics and foams. The abundance of hazardous elements in beached plastics that have been restricted or banned reflect the age and residence time of the plastic stock in the lake, coupled with a relatively high length of shoreline to surface area of the system. The migratability of hazardous elements from the polymeric matrix is likely to determine their environmental impacts and is recommended as a future area of research.
香京julia种子在线播放
The accumulation and impacts of anthropogenic litter in marine environments has been well-documented and publicized over the past few decades. In contrast, and despite often easier and more ready access, littering in the freshwater environment has received far less attention, with systematic investigations of rivers and lakes appearing in the literature only recently (Eriksen et al.,
Regardless of their precise source, plastics deposited on the shores and beds of lakes and suspended in the lentic water column are likely to pose the same problems to wildlife as marine plastics. In this respect, entanglement and ingestion are of greatest concern, with the former having the propensity to suffocate, impair mobility, disrupt feeding and maim, and the latter posing a significant risk of obstruction or damage to the linings of digestive tracts and, through reduced feeding drive, starvation (Gregory,
In order to improve our understanding about potentially toxic elements present in plastics in the lentic environment, the present study determines their concentrations in plastic litter collected from 12 beaches around Lake Geneva (or Lac Leman), one of western Europe's largest bodies of freshwater. Selected samples are analyzed by portable x-ray fluorescence (XRF) spectrometry using established and validated protocols (Turner and Solman,
Lake Geneva is an elongated, mesotrophic, perialpine lake at an altitude of 372 m above mean sea level whose catchment area of 8000 km2 (including the lake itself) houses a resident population of about 1.1 M according to 2011 data (CIPEL,
Twelve pebble beaches along the Swiss and French shores of Lake Geneva (Figure
Location of the 12 beaches sampled in Lake Geneva.
Name and location of each beach and information about the number (and average weight) of samples retrieved and the number of XRF analyses performed.
Jardin Botanique, Geneva, CH | 46°13N, 6°08′E | 17 March 2016 | 168 | 24 | 1.4 |
Crans-près-Céligny, CH | 46°36N, 6°22′E | 15 March 2016 | 18 | 4 | 1.2 |
Gland, CH | 46°25'N, 6°17′E | 15 March 2016 | 170 | 48 | 1.2 |
Rupalet, CH | 46°27'N, 6°21′E | 15 March 2016 | 34 | 13 | 3.0 |
Pêcherie, CH | 46°27'N, 6°22′E | 15 March 2016 | 804 | 109 | 0.76 |
Budaz, CH | 46°29'N, 6°44′E | 15 March 2016 | 71 | 14 | 2.8 |
Maladaire, CH | 46°26'N, 6°52′E | 15 March 2016 | 544 | 88 | 0.90 |
Les marines, Villeneuve, CH | 46°24'N, 6°55′E | 15 March 2016 | 152 | 41 | 1.2 |
Bret-Locum, F | 46°24'N, 6°45′E | 16 March 2016 | 262 | 55 | 1.6 |
Chauffours, F | 46°24'N, 6°41′E | 16 March 2016 | 630 | 149 | 1.4 |
Petite Rive, F | 46°24'N, 6°37′E | 16 March 2016 | 320 | 79 | 1.1 |
St-Disdille, Thonon-les-Bains, F | 46°24'N, 6°30′E | 16 March 2016 | 166 | 46 | 2.1 |
Selected samples of various size, color, and texture from each location were analyzed by energy-dispersive XRF using a battery-powered Niton analyser (model XL3t 950 He GOLDD+) for a suite of elements, of which As, Br, Cd, Cl, Cr, Hg, Pb, Sb, and Se are the focus of the present study, under operating conditions described and validated elsewhere (Turner and Solman,
For quality assurance purposes, two Niton reference plastics (PN 180-619, LOT#T-18, and PN 180-554, batch SN PE-071-N) were analyzed likewise and at regular intervals during each measurement session. A comparison of mean measured concentrations and certified values, shown in Table
A comparison of measured and certified concentrations of elements in two Niton reference plastic discs, with errors representing two standard deviations about the mean in all cases.
PN 180-619, LOT#T-18 | Measured ( |
48 ± 8 | 264 ± 22 | 114 ± 12 | 97 ± 12 | 143 ± 8 | 80 ± 13 | 238 ± 16 | |
Certified | 51 ± 7 | 292 ± 20 | 106 ± 10 | 101 ± 10 | 155 ± 12 | 94 ± 10 | 207 ± 15 | ||
PN 180-554, PE 071-N | Measured ( |
154 ± 36 | 524 ± 78 | 974 ± 89 | 908 ± 34 | 949 ± 81 | |||
Certified | 150 ± 6 | 495 ± 20 | 995 ± 40 | 1000 ± 40 | 1002 ± 40 |
Measurement limits of detection of the Niton XL3t are dependent on a number of factors, including analyte fluorescence intensity, mode of instrument application, counting time, and sample density, composition and thickness. For the samples considered here and under the operating conditions described above, detection limits were generally lowest and below 10 ppm for As, Br, Cr, and Pb and highest and above 70 ppm for Ba, Sb, and Sn. Note that in the case of As, overlap of its Kα fluorescence peak with the Lα peak of Pb coupled with the relatively low intensity of the As-Kβ line means that concentrations cannot be effectively calculated for samples with Pb:As ratios in excess of about 10 (Environmental Protection Agency,
Fourier transform infra-red (FTIR) spectroscopy was employed to obtain a high resolution infrared spectrum of absorbance by the samples that identifies the type of polymer/s present. Thus, based on the XRF results, selected samples (
Data from the XRF were converted to Excel files using Niton Data Transfer (NDT) software. Regressions and correlations were performed in Excel 2010 using the data analysis ToolPak add-in, with an alpha level of 0.05 adopted as a measure of defining statistical significance.
The majority of anthropogenic material observed on each beach was plastic, with manufactured wooden and metallic debris present in lesser quantities and glass entirely absent. The plastic items retrieved from the 12 locations are illustrated in Figure
The number of items retrieved and the distribution of items in terms of classification and size varied considerably among the beaches and with no clear geographical pattern. For instance, the plastic stock at Petite Rive was dominated by primary plastics but at Rupalet comprised a high proportion of secondary fragments, and while foams were absent from Crans-près-Céligny and comprised a low proportion of the plastic pool at La pêcherie they were abundant on the beaches at Rupalet and Les marines; plastics at La pêcherie were also dominated by a high number of small items whereas those at Rupalet comprised far fewer items that, on average, were considerably larger. Variations in the amount and type of plastic accumulated among the beaches may be attributable to many factors, including proximity to inhabited areas and tributaries, recent history of beach cleaning, circulation, and currents in the lake and beach aspect and slope, but a detailed analysis and source apportionment was not the objective of the present study.
Table
Frequency of detection and summary statistics for the hazardous elements in beached Lake Geneva plastics.
Antimony | 73 (10.9) | 183 | 33.1 | 27100 | 87.2 | 655 |
Arsenic |
63 (9.4) | 6.3 | 1.7 | 26.4 | 3.9 | 11.2 |
Bromine | 146 (21.8) | 64.6 | 2.9 | 27400 | 18.2 | 314 |
Cadmium | 107 (15.9) | 1120 | 23 | 6760 | 224 | 2320 |
Chromium | 326 (48.6) | 48.8 | 17.0 | 77100 | 27.7 | 183 |
Lead | 153 (22.8) | 585 | 5.9 | 23500 | 48.6 | 2390 |
Mercury | 17 (2.5) | 68.6 | 3.3 | 810 | 17.1 | 510 |
Selenium | 34 (5.1) | 394 | 156 | 1670 | 244 | 808 |
Bromine was detected in over 20% of the samples analyzed, with concentrations ranging from about 3 to 27,000 ppm. Concentrations of total Br exceeding 1,000 ppm were encountered in 21 items that are photographed in Figure
Cadmium was detected in about 16% of lake samples analyzed by XRF, with concentrations ranging from about 20 to 7,000 ppm, and exceedance of the RoHS limit for Cd in plastics of 100 ppm occurred in 57 samples which are photographed in Figure
The present study appears to be the first to provide systematic data on Hg in plastic litter in the aquatic environment. Thus, while traces of the metal were detected in various samples, concentrations above 100 ppm, and as photographed in Figure
Lead was detected in almost one quarter of all samples analyzed, encompassing a wide variety of primary and secondary plastics in terms of size, color and polymer, and in fragments of polyurethane foam. Concentrations ranged from about 5 to 24,000 ppm, with exceedance of the RoHS for the metal of 1,000 ppm occurring in 65 cases and as illustrated in Figure
The present study is one of only a limited number that have published information on plastics in western Europe's largest lake (Faure et al.,
Compared with equivalent studies conducted on marine beaches (Turner,
The impacts of hazardous elements and compounds in plastics are largely related to their propensity to migrate from the polymeric matrix and accumulate in biota and there are three potential means by which this may take place. Thus, first, a chemical may slowly leach into the surrounding aqueous medium while plastic is suspended in the water column, providing a general increase in its concentration and availability. Since additives, including pigments, are not designed to leach from plastics, this process is predicted to be slow and of limited importance in circulating water, even after the surface has become weathered and abraded (Nakashima et al.,
The present study is among the first to describe both the type and characteristics of beached plastics in Lake Geneva and the occurrence of hazardous elements in fresh water plastic litter. The results reveal the ubiquity of restricted hazardous elements and compounds, including BFRs, often in association with antimony-based synergists, and cadmium-, mercury-, and lead-based stabilizers and/or pigments, among primary and secondary plastics and fragments of foam. The abundance of hazardous elements in beached lake plastics may be attributed to the decadal residence times of low density material in the lake, the age of the plastic stock in the system and the relatively high length of shoreline to surface area of the enclosed water body. The impacts of plastic-bound toxic elements on lake wildlife are unknown but should form the basis of future empirical investigations.
MF: sampling, analysis, writing paper; AT: analysis, writing paper.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We thank Juan Carlos Rodríguez-Murillo (CSIC, Spain) for invaluable help in the sampling campaign and Laia Bonet (ETHZ, Switzerland) for the processing of the photographs. Mr. Rupert Goddard (PU) is acknowledged for technical assistance with the portable XRF.
The Supplementary Material for this article can be found online at:
This figure is a photographic catalog of the beaches and samples retrieved from Lake Geneva.