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Environment International
journal homepage: www.elsevier.com/locate/envint

Review article

Black plastics: Linear and circular economies, hazardous additives and
marine pollution
Andrew Turner
School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK

A R T I C LE I N FO

A B S T R A C T

Handling Editor: Robert Letcher

Black products constitute about 15% of the domestic plastic waste stream, of which the majority is single-use
packaging and trays for food. This material is not, however, readily recycled owing to the low sensitivity of black
pigments to near infrared radiation used in conventional plastic sorting facilities. Accordingly, there is mounting
evidence that the demand for black plastics in consumer products is partly met by sourcing material from the
plastic housings of end-of-life waste electronic and electrical equipment (WEEE). Inefficiently sorted WEEE
plastic has the potential to introduce restricted and hazardous substances into the recyclate, including brominated flame retardants (BFRs), Sb, a flame retardant synergist, and the heavy metals, Cd, Cr, Hg and Pb. The
current paper examines the life cycles of single-use black food packaging and black plastic WEEE in the context
of current international regulations and directives and best practices for sorting, disposal and recycling. The
discussion is supported by published and unpublished measurements of restricted substances (including Br as a
proxy for BFRs) in food packaging, EEE plastic goods and non-EEE plastic products. Specifically, measurements
confirm the linear economy of plastic food packaging and demonstrate a complex quasi-circular economy for
WEEE plastic that results in significant and widespread contamination of black consumer goods ranging from
thermos cups and cutlery to tool handles and grips, and from toys and games to spectacle frames and jewellery.
The environmental impacts and human exposure routes arising from WEEE plastic recycling and contamination
of consumer goods are described, including those associated with marine pollution. Regarding the latter, a
compilation of elemental data on black plastic litter collected from beaches of southwest England reveals a
similar chemical signature to that of contaminated consumer goods and blended plastic WEEE recyclate, exemplifying the pervasiveness of the problem.

Keywords:
Black plastic
Food packaging
Waste electrical and electronic equipment
Recycling
Brominated flame retardants
Heavy metals

1. Introduction
Because of their ease of manufacture, low cost, strength, versatility,
inertness and insulating properties, plastics have become an invaluable
commodity in a range of sectors, including packaging, construction,
agriculture, healthcare, transport, clothing, communication and electronics (PlasticsEurope, 2016; Van Eygen et al., 2017). With such a
diversity of applications, plastics may be tailored to precise needs
through the addition of specific substances during manufacturing. Additives include materials and chemicals introduced intentionally for
colour, heat stabilisation, plasticising, filling, impact modification, internal lubrication and flame retardancy, as well as catalytic residues
arising from the polymerisation process itself (Hansen et al., 2013).
Both in spite of and because of their versatility and widespread use,
plastics also pose a number of environmental threats. Thus, although
most plastics are, in theory, recyclable, technological and economic
constraints and the presence of additives that are harmful should they

E-mail address: aturner@plymouth.ac.uk.
https://doi.org/10.1016/j.envint.2018.04.036
Received 1 February 2018; Received in revised form 16 April 2018; Accepted 20 April 2018

migrate from the polymeric matrix preclude the recycling of many
products, at least into general consumer goods; as a consequence, a
significant fraction of the plastic stream ends up in landfill or incinerated (Ignatyev et al., 2014). Moreover, through poor management
and disposal practices from an individual level to an institutional basis,
plastic littering has become a pervasive problem in the marine environment (Sheavly and Register, 2007). Here, not only do primary
plastic objects and secondary plastic fragments have an aesthetic impact, they pose significant threats to wildlife (Li et al., 2016). Incidental
or deliberate ingestion of plastic is a particular concern because it occurs across a wide range of organisms and may result in blockage of or
damage to the digestive tract (Santos et al., 2015; Jovanovic, 2017) as
well as act as a vehicle for the bioaccumulation of chemical additives or
pollutants adsorbed to the plastic surface (O'Connor et al., 2016; Massos
and Turner, 2017).
Among these issues, black plastics pose a unique series of challenges
and problems that have recently emerged. Thus, while there is a

 A. Turner

requirement for black products in various sectors, recycling of end-oflife black plastic is hampered by the availability of suitable technology
to sort this material efficiently (Dvorak et al., 2011). As a consequence,
the demand for black plastic appears to be met, in no insignificant part,
by the recycling of plastic from waste electronic and electrical equipment (WEEE) (Chen et al., 2010; Haarman and Gasser, 2016). The
presence of restricted chemical additives, residues or contaminants in
WEEE plastic that cannot be identified or removed readily, however,
has resulted in the appearance of potentially harmful chemicals in new
black plastic consumer products intended for the preparation or storage
of food or as toys for children (Chen et al., 2009; Kuang et al., 2018).
The present paper reviews the contemporary literature on the
characteristics, life-cycles and environmental impacts of black plastics,
and examines relevant regulations and conventions relating to the recycling and disposal of plastics that contain restricted chemical additives. The discussion is aided and directed by measurements of additives in black plastic electrical and non-electrical consumer products
and in black plastic marine litter that have been garnered by the author's research group over the past few years or that have been undertaken for the specific purposes of the current review.
2. Nature and uses of black plastic
Most black plastics are coloured with carbon black, a group of industrial carbons created by the partial combustion of various hydrocarbons. Characterised by a small particle size and high oil absorption,
carbon black is cheap to produce and has excellent colour strength,
hiding power, solvent resistance and ultraviolet stability (Brewer,
2004). Addition of about 1% is usually sufficient as a colourant in
unpigmented polymers but higher quantities (up to 40%) may be added
to modify mechanical and electrical properties (Pfaff, 2017). The precise characteristics of plastic can be further refined by adjusting the
size, morphology and dispersion of the particles within the polymeric
matrix.
The properties of carbon black render it suitable for a wide range of
plastics but it is particularly favourable for products used outdoors or
where strength, conductivity or thermal stability is required. Items
employing carbon black therefore include automobile components,
mouldings and piping, ready meal trays, refuse bags, tarp and mesh,
and housings and insulation for electrical and electronic equipment
(EEE). Carbon black is also used in products where colour is the principal concern from an aesthetic perspective, like replica toys, jewellery
and food packaging (Plasticseurope.com, 2016).
In Table 1, a more specific list of consumer products that are wholly
or partly constructed of black plastic is given. Here, products are classified as follows: ‘food-contact’, where plastic is in direct or indirect
contact with food or beverages; ‘storage and construction’, with a range
of applications in the household but excluding storage of food; ‘clothing
and accessories’, including articles that are in direct contact with the
skin or that are handled regularly; ‘toys and hobbies’, including objects
potentially mouthable by young children; ‘office and garden’ and other
products used in the workplace or outdoors; and ‘EEE’, or plastic casings of products that are battery- or mains-operated and that have the
propensity to generate heat (and including electrical varieties of products categorised elsewhere such as toys, tools and sports equipment).
3. Challenges for the recycling of black plastic
3.1. Non-EEE plastic
Efficient recovery and recycling of non-EEE plastics relies on sorting
into monopolymeric fractions (and according to resin identification
codes) that can be performed cheaply, reliably, safely and automatically (Bezati et al., 2011). Currently available technology is based
on spectral signatures derived from near infra-red (NIR) reflectance
spectroscopy (0.8 to 2.5 μm) where plastics are identified according to

stretching vibration modes of CH, CH2 and CH3 groups (Becker et al.,
2017). Plastics coloured with carbon black and other black pigments,
however, exhibit very low reflectance of light in the NIR spectral region
and the signal-to-noise ratio of present sensors is insufficient to allow
classification according to polymer type (Rozenstein et al., 2017);
identification may be hampered further by the presence of additional
additives and lacquer films (Becker et al., 2017). Consequently, black
plastics with no specific provision for recycling are typically confined to
a linear economy in which end-of-life material enters the unsorted residue of reprocessing facilities before being sent for landfill or incineration and energy recovery rather than being reconstituted into
pellets for the production of new goods.
Alternative technologies to identify black plastics have recently
been investigated that are based on mid-wave infra-red spectroscopy (3
to 12 μm) but thus far these have not proved to be feasible on a commercial scale (Becker et al., 2017; Rozenstein et al., 2017). A review
into the problem by the UK government-funded recycling group, WRAP
(Waste Resources Action Programme), concluded that, in combination
with existing NIR technology, either alternative colourants or the addition of fluorescent markers would be the most suitable option to
achieve a sufficient throughput of materials at a recovery or reprocessing facility (Dvorak et al., 2011). To this end, the PRISM project
(Plastic Packaging Recycling using Intelligent Separation technologies
for Materials) has recently secured funding to develop fluorescent
materials from metal oxides for marking and coding plastics that are
identified though an ultraviolet light source (Moore, 2016). In the
meantime, WRAP has advised local UK authorities to check with their
processor if black plastics are recycled and, if not, update their communications with householders stating clearly that black products are
on the ‘not recycled’ list (Letsrecycle.com 1).
3.2. EEE plastic
Although plastic used for housing or insulation of EEE may be a
variety of (mainly neutral) colours, black is the dominant colour employed for appliances smaller than white goods such as fridges and
washing machines (UNIDO, 2017). Unlike more general black household waste, the majority of which is food packaging, the disposal of
end-of-life black plastic used in, for example, televisions, computers,
phones, power tools, lighting equipment and electrical toys, is embraced by specific, existing legislation in the European Union that is
outlined below. Typically, plastics used in such equipment, like high
impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS) and
polycarbonate (PC), have better mechanical and electrical properties
than those used in most other consumer products (e.g. polyethylene
terephthalate, PET, used in food packaging) but recycling is confounded
by a number of additional challenges, including the potential environmental and health impacts associated with the presence of hazardous additives (Haarman and Gasser, 2016).
4. Regulations relevant to EEE plastic
In order to better manage waste from EEE, contribute to a circular
economy and enhance resource efficiency, the Directive on waste
electrical and electronic equipment (WEEE) (Directive 2002/96/EC;
European Parliament and Council, 2003a) and the Directive on the
restriction of the use of certain hazardous substances in electrical and
electronic equipment (RoHS) (Directive 2002/95/EC; European
Parliament and Council, 2003b) were introduced by the European
Union and became effective from 2003 and 2005, respectively. The
former directive focused on the creation of collection schemes for WEEE
and was revised with effect from 2014 in order to tackle a rapidly
growing and diversifying waste stream (Directive 2012/19/EU;
European Parliament and Council, 2012). The latter directive deals
with the restriction and replacement of hazardous metals and specific
brominated flame retardants (BFRs) in EEE and was recast with effect

 A. Turner

Table 1
Categorisation and inventory of common consumer products that are constructed in part or in whole of black plastic.
Food-contact

Storage and construction

Clothing and accessories

Toys and hobbies

Office and garden

EEE

Drinks stirrers
Coffee cup lids
Straws
Kitchen utensils
Thermos mugs and flasks
Food presentation trays
Ready meal trays
Cutlery
Coffee plungers
Bottles and bottle tops
Coffee pods
Ice cream carton lids
Draining boards
Tupperware lids
Lunch boxes
Stoppers and caps

Coat hangers and sizer labels
Bottles and lids
Tubes and caps
Spectacle cases
Rucksacks
Cases
Luggage tags
Carrier bags
Folders
Refuse sacks
Boxes and crates
CD and DVD cases
Ink cartridges
Suckers
Cable ties and strapping
Piping
Caistors
Tool grips

Buttons and toggles
Spectacle frames and sunglasses
Beads and necklaces
Bracelets and brooches
Watch straps
Masks
Protective clothing and guards
Shoes and boots
Hair bands and clips
Strapping and cord
Shoehorns
Keyfobs
Umbrella grips
Hair brushes and combs
Belts
Wallets and purses

Car chassis and wheels
Caterpillar tracks
Figures and animals
Toy guns
Trains and tracks
Balls and marbles
Games icons and figures
Magnetic counters
Trophy bases
Tripods
Musical instruments
Xmas cracker toys
Xmas decorations
Photo frames and book covers
Tweezers
Printing sets
Building blocks
Fidget spinners

Stapler and scissor grips
Seating and handles
Tarping and mesh
Lawnmower blades
Wire ties
Bins and butts
Pens and lids
Taping
Hosing
Furniture
Trolley wheels
Rivets
Foot pumps and adaptors
Plant pots
Garden tools
Signage
Parcel packaging

Televisions
Mobile phones
Laptops and tablets
Cameras and lenses
Games consoles
Media storage
Wire insulation
Chargers, plugs and transformers
Remote controls
Electrical toys
Radios
Domestic appliances
Power tools
Printers and copiers
Projectors
Calculators
Lighting equipment
DVD players

from 2013 (Directive 2011/65/EU; European Parliament and Council,
2011) and subsequently amended with effect from 2019 (Directive
2011/65/EU Annex II amendment; European Parliament and Council,
2015) in order to encompass a broader array of equipment and improve
regulatory and legal clarity. Legislative or administrative procedures
based on or similar to these directives have since been adopted in regions outside of the European Union, including India, China, Japan,
Thailand, Latin America, Canada and various states in the US
(Tanskanen and Butler, 2007; Bandyopadhyay, 2009; Terazono et al.,
2015).
The production, use and processing of certain BFRs is also restricted
according to additional and more general international agreements. The
Stockholm Convention (Resource Futures International, 2001), which
came into effect in 2004 and is currently ratified by 181 parties, requires developed nations to resource the elimination of the production
and use of intentionally and unintentionally produced persistent organic pollutants (POPs) and manage and dispose of POPs by environmentally sound means. Although BFRs were not included in the
list of chemicals in the original convention, several of those encompassed by the RoHS Directive were added in modifications that
have since come into effect, albeit with exemptions relating to plastic
recycling (UNIDO, 2017). The Basel Convention on the Control of
Transboundary Movements of Hazardous Wastes and Their Disposal
(UNEP, 2014) has been effective since 1992 and is currently ratified by
185 parties (but not the US). This convention was designed to reduce
the movement of hazardous waste, particularly from developed to less
developed nations, and includes the BFRs embraced by the Stockholm
Convention. A critical and controversial loophole of the Basel Convention, however, is that exporters are able to designate WEEE as
products that are “repairable” or to be “reused” rather than as hazardous waste, thereby potentially exempting non-functional electronic
equipment from the obligations of the agreement (Perkins et al., 2014).
5. Hazardous additives in black plastics
Aside from pigments and dyes, additives are not necessarily specific
to plastics of particular colours. However, the dominant use of black in
food packaging and in EEE housings and insulation, coupled with the
constraints on recyclability outlined above, mean that certain additives
are likely to be more of an environmental and health concern when
associated with black products. Potentially ‘hazardous’ substances in
this context are the metalloid, antimony, and the four heavy metals and
two groups of BFR defined by the current RoHS Directive for WEEE
materials (European Parliament and Council, 2011).
Antimony (Sb) is often homogeneously dispersed in PET, a plastic of

high thermal stability and the most widely used for food packaging and
cooking, as catalytic residue from the polycondensation of ethylene
glycol and terephthalic acid. Its precise impacts on human health are
still unclear but a toxicological similarity with arsenic ensures that it is
gaining interest and remains a concern (Pierart et al., 2015). Because of
toxicities that are better understood, cadmium (Cd), chromium (Cr) in
its hexavalent form, mercury (Hg) and lead (Pb), and the polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE)
flame retardants, are restricted by the RoHS Directive on homogeneous
materials or components of EEE (including plastic housings and insulation) to concentrations of either 1000 ppm or 100 ppm (Cd only).
Note that four phthalate plasticisers are also to be added to the restricted list for EEE products placed on the market from 2019, and that,
despite compounds of Sb (and in particular, antimony trioxide, Sb2O3)
commonly used as a halogenated flame retardant synergist (Felix et al.,
2012), the metalloid itself has not been considered in the directive.
5.1. Measurement of hazardous additives in plastic
Determination of specific flame retardants and metals-metalloids in
plastics may be accomplished by, for example, gas chromatography–mass spectrometry (GC–MS) and inductively coupled plasma
mass spectrometry (ICP-MS), respectively, following decomposition of
the matrix in a suitable solvent or mineral acid. Although these techniques are extremely sensitive, sample preparation can be both timeand resource-consuming and may generate significant quantities of
hazardous waste (Chen et al., 2009; Mello et al., 2015). Accordingly,
increasing use has been made of energy-dispersive X-ray fluorescence
(XRF) spectrometry as a means of analysing plastics simultaneously for
Br, as a proxy for BFRs, and Cd, Cr, Hg, Pb and Sb (Furl et al., 2012;
Gallen et al., 2014; Aldrian et al., 2015; Massos and Turner, 2017). This
approach relies on irradiating a sample with a high intensity, collimated X-ray beam (typically up to 50 kVp and 100 μA) and deconvoluting a spectrum of secondary X-rays generated by the material
through a series of iterations. (Note that, unlike NIR, X-ray intensity is
not affected by colour). XRF cannot discriminate different brominated
compounds or oxidation states of Cr and detection limits on the order of
tens of ppm mean that low levels of BFRs and metals may not be reported. However, the technique has the advantages of being rapid, nondestructive and, with handheld devices and suitable X-ray shielding,
portable.
5.2. XRF-determination of black plastic additives for the present study
In the present study, concentrations of the elements listed above,

 A. Turner

plus Cl as a measure of chlorination and an indicator of polyvinyl
chloride (PVC; operationally defined as [Cl] > 15% for the purposes of
the XRF calibration), were determined in plastics using a Niton XL3t
950 GOLDD+ XRF according to protocols described in detail elsewhere
(Turner and Solman, 2016) and as summarised below. Data for old and
new black plastics, sourced from various households, offices, nurseries,
schools, stores and fast-food establishments, have been compiled both
from results of previous research into consumer plastics in general
(Turner and Filella, 2017a, 2017b) and from new measurements where
black products have been specifically targeted. Data for marine plastic
litter that is coloured black have been distilled from published and
unpublished results of several beach litter surveys undertaken around
the English Channel and Atlantic coasts of south west England (Turner,
2016; Massos and Turner, 2017).
Thus, plastic products or specific components thereof (‘samples’),
and excluding rubbers, foams and textiles, were analysed by XRF in situ
or in a laboratory test stand in a low density plastics mode with
thickness correction and using an excitation beam width of 8 mm or
3 mm depending on sample size and accessibility. Counting was performed for periods of between 30 s and 200 s (depending on sample
thickness, composition and analyte signal) that were equally distributed
between a low energy range (20 kV and 100 μA) and main energy range
(50 kV and 40 μA). X-ray spectra were quantified by fundamental
parameter coefficients to yield concentrations on a dry weight basis (in
ppm) and with a counting error of 2σ (95% confidence) that were
downloaded to a laptop using Niton Data Transfer (NDT) software. For
quality assurance purposes, reference discs supplied by the manufacturer and certified for concentrations of Cd, Cr, Hg, Pb and Sb in
polyethylene (PN 180-619, LOT#T-18), Cd, Cr, Hg, Pb and Br in
polyethylene (PN 180-554, batch SN PE-071-N) and Br and Sb in PVC
(PVC-4C80) were analysed throughout each measurement session,
while high quality virgin black pellets of various construction and with
no added components (supplied by Algram Group Ltd., Plymouth) were
used to check for false positives. Median detection limits under these
operating conditions were < 10 ppm for Br, Cr and Pb, about 20 ppm
for Hg and around 40 ppm for Cd and Sb, with precise values dependent
on the nature of the sample but that were generally inversely related to
material thickness.
6. Concentrations of hazardous additives in black consumer
plastics
Results arising from the XRF-analyses of black plastic electrical and
non-electrical consumer products are summarised in Table 2, where
samples have been grouped according to the categorisation given in
Table 1. Thus, in total, > 600 samples were tested, with at least 70
considered in each category and PVC encountered in 41 cases and
across all categories. In Fig. 1, examples of Br-positive samples among
non-EEE products and Pb-positive samples among both EEE and nonEEE products are photographed to illustrate the range of items in which
hazardous substances may be found.
Bromine was detected in almost one half of all black samples tested
and in at least 20% of samples from each category, with concentrations
overall ranging from 1.5 to 133,000 ppm and detection most frequent
(on a percentage basis) in the EEE category. By comparison, analysis of
samples coloured other than black and reported in Turner and Filella
(2017b) revealed variable concentrations of Br in various older (preRoHS) white EEE and in only a limited number of non-EEE that were
usually green and where the halogen is employed in phthalocyanine
pigments (Ranta-Korpi et al., 2014).
Lead and Sb were detected in about one quarter of all black samples
analysed and exhibited a more uniform distribution across the different
categories than Br. Lead was most commonly detected on a percentage
basis in the clothing and accessories and toys and hobbies categories
and least frequently in the food-contact category, and concentrations
above 5000 ppm were always associated with PVC products. Antimony

was most frequently detected in the EEE plastics, where concentrations
spanned about three orders of magnitude, but was present across all
other categories and with concentrations that were greatest either in
the presence of high concentrations of Br or in PVC products. In the
food-contact category, Sb was detected in 12 out of 14 PET trays tested
(all of which were Br-negative) and at concentrations that were rather
uniform (344 ± 89.0 ppm). However, the metalloid was never detected in other plastic products at similar concentrations and in the
absence of Br, providing empirical evidence that black PET is not
widely recycled into consumer goods.
Cadmium and Cr were detected in fewer black samples than the
elements above but were present in items across all categories and, with
the exception of Cd in a plastic brooch (35,000 ppm), concentrations
spanned about two order of magnitude. On a percentage basis, Cd was
most frequently encountered among office and garden equipment while
Cr was most frequently detected in food contact items (including PET
food trays). In contrast, Hg was detected in only eight samples across
five categories and at concentrations that were always below 100 ppm.
Regarding black EEE plastics, 90 samples were identified from appropriate symbols and signage as post-RoHS Directive (or placed on the
market since 2005) and 32 as pre-RoHS, with the remaining samples
(unmarked components of absent larger items) unclear in this respect. A
comparison of the descriptive statistics for Br, Cd, Cr, Pb and Sb in postand pre-RoHS samples, shown in Table 3, indicates a similar percentage
frequency of detection in both categories for all elements with the exception of Cd and Pb, which were encountered in fewer cases postRoHS. Moreover, a series of non-parametric Mann-Whitney U tests,
performed in Minitab 17, revealed that, among the elements, only
concentrations of Pb were statistically different (α < 0.05) between
the two categories (and lower post-RoHS).
7. Sources of hazardous additives in black plastics
7.1. Additives in EEE plastics
Of the elements considered, Br was most commonly detected among
the black plastic samples analysed. Within the EEE category, its occurrence is attributed to the historical and contemporary use of brominated flame retardants in thermosetting plastic housing and casings
(Shaw et al., 2014). Halogenated materials act as efficient and costeffective flame retardants by interrupting the radical chain reaction in
the gas phase, and the variety of brominated compounds available allows specific needs to be met in different plastics with a range of applications. Commercial mixtures of deca- and octaBDE, tribromophenol
derivatives and brominated phosphates were commonly employed in
polymers for EEE before 2005 (UNEP, 2010), and usually in the presence of Sb2O3 as a synergist. The Sb2O3 to BFR ratio was generally in
the range of 0.2 to 0.5, or equivalent to a mass ratio of Sb to Br of about
0.3 to 0.5, except where the metalloid caused molecular weight degradation of the matrix (a particular problem in PC) (Papazoglou,
2004). Environmental concerns and implementation of the RoHS Directive, however, resulted in the subsequent development of alternative
brominated compounds that are supposed to be safer and the wider use
of halogen-free flame retardants like hydrated minerals of aluminium
and magnesium and phosphate esters (Liagkouridis et al., 2015).
The precise quantity of a compound or mixture required to achieve
adequate flame retardancy depends on the composition of the polymer,
the application of the product, the type and nature of retardant and its
compatibility with the polymeric matrix, and the efficiency of any synergist. Papazoglou (2004), however, suggest that a minimum of 3 to
5% by weight of a brominated compound is required in most plastics,
which is equivalent to a Br content of at least about 20,000 ppm. On
this basis, only four out of 32 pre-RoHS black EEE products analysed as
part of the present study, and each containing Sb, are sufficiently flame
retardant in terms of bromination, with a further four samples of high
Cl content likely to be retardant in terms of chlorination (Table 3).

 A. Turner

Table 2
Detection frequency and descriptive statistics for the elements determined by XRF in the different sample categories of black plastic. Concentrations are in ppm.
Element

Br

Cd

Cr

Hg

Pb

Sb

Descriptor

n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max

Food-contact

Storage and construction

Clothing and accessories

Toys and hobbies

Office and garden

EEE

(n = 129; PVC = 1)

(n = 112; PVC = 11)

(n = 71; PVC = 2)

(n = 86; PVC = 4)

(n = 97; PVC = 12)

(n = 133; PVC = 11)

29
594
56.3
2.6–6010
8
79.0
67.5
27.2–148
35
58.6
36.9
19.4–278
1
25.8

57
2800
142
3.4–94,500
7
77.5
56.3
18.6–209
15
41.3
36.2
18.3–99.4
1
6.8

49
1180
74.9
3.3–14,500
4
433
317
197–902
11
80.6
38.5
18.1–389
0

32
359
19.7
1.5–7000
10
502
246
21.1–1590
12
119
29.4
17.8–847
1
16

88
6280
244
1.8–133,000
8
84.0
52.9
18.8–287
20
108
61.1
16.4–478
1
91.7

18
40.5
44.5
5.9–101
20
560
342
137–3200

32
1170
48.5
4.3–16,500
30
2780
398
24.7–35,850

38
3850
53.9
1.5–92,200
6
6100
146
77.0–35,000
15
283
117
19.1–1800
4
18.4
12.8
4.8–43.4
25
473
50.6
5.2–4670
15
4740
240
29.5–48,600

29
629
76.3
5.6–9600
22
1490
447
52.9–9190

27
2220
103
4.1–14,100
15
2080
456
99.5–17,700

31
915
76.1
2.2–11,800
51
4760
600
38.8–56,900

Table 3
A comparison of detection frequency and descriptive statistics for the elements
determined by XRF in pre- and post-RoHS EEE black plastics. Note that Hg was
not detected in either category. Concentrations are in ppm.
Element

Br

Cd

Cr

Pb

Sb

Fig. 1. Examples of EEE and non-EEE samples that were Pb-positive (a) and
non-EEE samples that were Br-positive (b).

Descriptor

n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max

Pre-RoHS

Post-RoHS

(n = 32; PVC = 4)

(n = 90; PVC = 7)

21
13,900
753
3.7–101,000
3
58.9
48.1
29.2–99.7
4
127
157
20.5–172
12
1990
101
8.0–11,800
15
9210
776
53.4–56,900

58
3930
214
1.8–133,000
4
52.1
52.9
18.8–83.9
15
106
52.2
16.4–478
18
245
28.9
2.2–1650
32
2920
552
38.8–30,100

Failure to detect Br in eleven pre-RoHS samples suggests that either
non-halogenated flame retardants were employed or the voltage of the
product was sufficiently low to circumvent retardant addition. In the
remaining samples, the presence of Br over a wide range of concentrations (from about 4 to 4000 ppm) that are too low to provide
retardancy, coupled with a co-association with Sb, raises possibilities
about material recycling.
A similar distribution of Br and Sb is evident in the post-RoHS
samples (Table 3). Thus, here, only two samples contained sufficient Br
(and Sb) to provide flame retardancy, presumably from unrestricted
brominated compounds, with 32 products containing no measurable Br
and probably attaining retardancy, where required, through non-brominated compounds. The remaining post-RoHS samples contained Br

 A. Turner

over a wide range of concentrations (from about 2 to 10,000 ppm) that
are too low for retardancy but that were often co-associated with Sb,
consistent with the material recycling assertion mentioned above.
Unlike Br and Sb, which have distinct functions in the manufacture
and protection of EEE plastics, the sources of Cd, Cr and Pb in a variety
of pre- and post-RoHS samples are less clear but likely to be more
varied. Regarding plastics themselves, compounds of both Cd and Pb
have been used as stabilisers in PVC (Titow, 2012) while Cr(VI) may be
present in some polyethylene as residual chromium trioxide catalyst
from the polymerisation process (Epacher et al., 2000). However, the
presence of these metals in a wider array of (non-PVC) EEE plastics
implies that many products may have been manufactured from a mixed
recyclate. For example, Dimitrakakis et al. (2009) found that WEEE
plastic may contain 15 or more different polymer types, with polymer
identification not always possible (especially for black materials that
evade NIR detection) and cross contamination during recycling inevitable. Regarding the present results, that Cd and Pb were always
associated with Cl in the EEE samples tested suggests traces of PVC may
have been recycled into new products. Alternatively (or additionally),
since Cd, Cr(VI) and Pb have a wide variety of uses in non-plastic
electronic equipment (as, for example, alloying elements, anticorrosion
agents and activators, and in components of batteries, bonding agents,
film pastes, solder, varnishes and ceramic capacitors), imperfect sorting
of WEEE materials during dismantling may result in contamination of
the plastic recyclate (Wäger et al., 2012). There also exists the possibility that the XRF results were skewed by secondary X-rays generated
by metallic parts in the vicinity of the plastic being probed. However,
where the co-existence of metallic and plastic components was evident
or suspected, potential interferences were minimised by probing the
edge of the sample using a 3-mm excitation beam width (Turner,
2018a); moreover, this effect would not explain the presence of Cd, Cr
and Pb in plastic components with no metallic attachments, like battery
compartment covers, support apparatus, protective caps, calculator
cases and audio docking station adaptors, as well as their occurrence in
the non-EEE samples reported in Table 2.
7.2. Additives in non-EEE plastics and evidence for the recycling of poorlysorted WEEE
In non-EEE black plastic samples, relatively high concentrations of
Cd and Pb may be attributed to the use of metal-based stabilisers in PVC
products, while smaller quantities of Cr and Sb are likely the result of
catalytic residues in polyethylene and PET, respectively. However, the
widespread detection of these elements, and in particular Pb, across a
broader range of materials, coupled with the extensive occurrence of Br
among the samples tested that require no flame retardancy (and at
concentrations insufficient to provide retardancy), calls for an alternative explanation.
Unlike other colours of plastic that can be readily identified by NIR
spectrometry, there are technological and economic difficulties in the
sorting and recycling of black plastics, as discussed earlier. With a high
demand for black plastics in various sectors, it is suspected that polymers of this colour are often sourced for new consumer goods from endof-life WEEE, and as implicated more specifically for both old and new
EEE plastic above. New goods may be constructed entirely from black
WEEE plastic, or may be blended with cleaner plastics (including those
of other colours) and re-pigmented black.
In theory, and because industry-scale technology does not exist for
removal of Br from plastic, sorting facilities should isolate plastics
containing BFRs for disposal by appropriate means or for energy recovery in the metal or cement industries according to best available
technologies (UNIDO, 2017). Although sorting may be accomplished
by, for example, density separation in fluids or manual inspection according to age or ISO signage, with occasional spot checks using portable XRF for validation, poor, low-cost or inefficient practices allow
materials impregnated with BFRs to re-enter the recyclate (Haarman

and Gasser, 2016). This is a particular problem in (but is not unique to)
less developed nations, like India, Pakistan, Nigeria and China, which,
despite the objectives of the Basel Convention, import significant
quantities of WEEE from Europe, North America, Australia and Japan
(Sepúlveda et al., 2010; Obaje, 2013), presumably as “used” or “repairable” goods. Here, large stockpiles that include older WEEE and
restricted BFRs may be processed by inexperienced operatives without
suitable screening technology at informal or unregulated facilities
(UNIDO, 2017; Ni et al., 2013). (At the time of writing, China, the
largest recipient of waste from overseas, has announced stringent restrictions on waste importation and introduced a licensing scheme that
targets facilities with clean records and full regulation compliance, a
system that will also allow the country to boost its own waste recycling
rate; Letsrecycle.com 2).
A consequence of this quasi-circular economy, coupled with imperfect international monitoring and regulatory loopholes, is that,
unaware to the consumer and, in many cases, the manufacturer and
retailer, BFRs and heavy metals like Pb end up in a heterogeneous assortment of items. These are exemplified in Fig. 1 and include the ring
of a baby's dummy, a disposable fork from a reputable supermarket,
various kitchen utensils, the wheels of toy cars, games marbles and
counters, necklace beads and pendants, clothes hangers, spectacle
cases, plant pots, lawnmower blades, coffee plungers, thermos flasks
and rawl plugs. Moreover, given the heterogonous mixture of EEE
plastic types and vintages apparently recycled, coupled with potential
blending with cleaner materials, concentrations of Br and Pb vary
widely, with identical looking products from different suppliers sometimes containing relatively high concentrations of these elements and
sometimes Br- and Pb-free. Significantly, consumer products analysed
by XRF that returned concentrations of either element above 1000 ppm
in the present study are RoHS non-compliant with respect to the heavy
metal or potentially non-compliant with respect to BFRs. That is, limits
designed for hazardous substances in WEEE are being breached for
goods beyond the scope of the legislation, including products in regular
contact with food, toys designed for young children, items of jewellery
and a range of handles and grips.
Further, empirical evidence for the recycling of BFRs into non-EEE
consumer goods is the co-existence and correlation of Sb with Br. Thus,
in Fig. 2, concentrations of the two elements are plotted against each
other for both EEE plastics, with pre- and post-RoHS samples discriminated, and non-EEE products, where each sample category is
discriminated. (Note that four highly chlorinated or PVC-based samples
have been omitted where Sb was evidently used as a synergist for
chlorine-based flame retardants.) Results of linear regression analysis of
the data sets, shown in Table 4, reveal significant relationships in all
cases, with slopes ranging from about 0.23 to 0.54 and that are consistent with the mass ratios of Sb-based synergists to BFRs in plastics
defined above. Significantly, once 95% confidence intervals had been
factored in, there was no statistical difference between the slope defining all non-EEE samples and that defining all EEE products.
A growing body of literature is reporting the occurrence of BFRs in a
range of products where they are neither needed nor expected and
present an unnecessary hazard to the consumer. For instance, Miller
et al. (2016) used XRF to demonstrate the widespread occurrence of Br
in plastic consumer goods that had been newly purchased on the US
market, with mass spectrometry performed on black necklaces and
garlands confirming the presence of several restricted BFRs. Samsonek
and Puype (2013) and Kuang et al. (2018) detected various restricted
BFRs in black thermos cups purchased in the EU and in black kitchen
utensils purchased in the UK, respectively, while Chen et al. (2009)
found several BFRs in toys bought on the Chinese market, including
PBBs that had never been produced in the country. Clearly, the reconstitution of WEEE into consumer products is a pervasive, global
issue affecting plastics across a multitude of sectors and that is likely to
have wide-ranging impacts on the environment and on human health.

 A. Turner

100000

100000

(a)

(b)

10000

Sb, ppm

Sb, ppm

10000
1000

100

1000
100

clothing and accessories

food-contact

10

storage and construction

10

pre-RoHS

toys and hobbies

1

office and garden

1

10

100

1000

10000 100000

Br, ppm

post-RoHS

1

1

10

100

1000

10000 100000

Br, ppm

Fig. 2. Concentrations of Sb versus concentrations of Br in non-EEE black plastic samples (a) and black plastic EEE casings (b).
Table 4
Results of regression analyses of Sb versus Br for the different black plastic
sample categories.
Category

n

Slope

Intercept, ppm

r2

p

Food-contact
Storage and construction
Clothing and accessories
Toys and hobbies
Office and garden
All non-EEE
Pre-RoHS EEE
Post-RoHS EEE
Pre- and post-RoHS EEE

8
25
11
20
6
70
12
24
36

0.477
0.377
0.526
0.542
0.480
0.451
0.464
0.229
0.342

−22.8
227
1.67
77.8
167
157
−822
695
562

0.939
0.998
0.999
0.930
0.919
0.968
0.726
0.966
0.705

< 0.001
< 0.001
< 0.001
< 0.001
0.003
< 0.001
< 0.001
< 0.001
< 0.001

8. Potential environmental and health impacts of hazardous
additives in black plastics
The environmental impacts of plastics in general arise from the
energy and resources involved in their production and transportation,
the presence of broadly-used organic additives (e.g., phthalates), and
the poor management of plastic waste and its disposal. With regard to
black plastics, impacts are compounded and diversified because of inefficient and inadequate recycling and the presence of a range of
harmful chemical additives.

8.1. PET packaging
Because of the potential toxicological profile of Sb (Gebel, 1997), its
occurrence in black PET used in food packaging or cooking has been
evaluated as a possible health hazard. Diffusible species of Sb are likely
to be the monodentate glycolate (eSbeOCH2CH2OH) and chelate ligand (eOCH2CH2Oe) complexes, with inorganic Sb probably making a
small contribution. Diffusion of Sb from the PET matrix depends on a
number of factors, like degree of crystallinity of the polymer, the molecular weight distribution of the Sb-glycol complexes and the presence
of additional additives that may act as sorbents for Sb (e.g. TiO2 microparticles), but is facilitated when the contents are heated, as in prepacked ready meals (Haldimann et al., 2013). In some food trays exposed to high temperatures, migratable concentrations have been found
to exceed the European Commission limit of 40 μg kg−1 but not the
WHO accepted tolerable daily intake of 6 μg kg−1 body weight per day
(Haldimann et al., 2007).
Black PET used for food packaging appears to be derived from virgin
stock, with few uses of the polymer in EEE (Bhaskar et al., 2010) and no
empirical evidence of recycling from this source (at least with respect to
detectable Br or Pb). Moreover, it is a highly significant contributor to
household plastic waste, with a recent study in Copenhagen finding that
between 10 and 15% of rigid material (excluding WEEE) was black and

largely derived from packaged food (Plastic Zero, 2014). In the UK
alone, industry estimates that there are between about 30,000 and
60,000 t per annum of rigid black plastic in the waste stream whose
principal use was the packaging of food (Dvorak et al., 2011). Based on
the mean concentration of Sb in PET trays (~350 ppm), it is estimated
that up to 20 t of the metalloid may also be disposed of annually via
landfill and incineration. Regarding the latter route, Sb is a problematic
element because of its propensity to leach from bottom ash at concentrations that exceed limit values for use in secondary materials but
through mechanisms that are currently unclear (Van Caneghem et al.,
2016).
Disposal of Sb is also at odds with the EU's raw materials initiative.
Thus, the metalloid is listed as one of the original fourteen critical raw
materials which display a particularly high risk of supply shortage over
the next decade and have a relatively high impact on the economy
(European Commission, 2011). Specifically, Sb has an “import dependency” (mainly from China) of 100% and low “substitutability” and
“recycling rate” scores. The recovery of Sb from various WEEE plastics
by centrifugation of residues arising from polymer dissolution has been
trialled in the laboratory but the upscaling necessary to attain a marketable secondary product is not currently feasible (Schlummer et al.,
2016).
8.2. WEEE plastic
WEEE plastic contains a wider array of hazardous chemical additives whose toxicities are relatively well-defined. Environmental impacts and human exposure arising from soil and water contamination
and release of semi-volatile BFRs may, therefore, be significant at dismantling, recycling and moulding facilities, and especially at those that
are unregulated or poorly managed (Zhang et al., 2012; Han et al.,
2017). Local contamination may also occur through landfilling, with
anaerobic conditions promoting the debromination of many highly
brominated PBDEs into more toxic congeners (Tokarz et al., 2008).
However, because black WEEE plastic appears to be ubiquitously recycled into components of toys, games and jewellery, products that are
used to store, dispense, strain, stir or mouth food, and items for the
storage and application of cosmetics, the wider population is exposed to
these chemicals through a variety of pathways.
Unfortunately, very few studies have examined the migration or
availability of additives from recycled WEEE plastic. Chen et al. (2009)
estimated the exposure of PBDE flame retardants to young children
from a number of hard plastic toys purchased in China (and using
empirical measurements and data for EEE plastics) through inhalation,
dermal contact and direct mouthing. Maximum total exposure was
about 10 ng kg−1 body weight per day, with mouthing the greatest
exposure contributor and comparable to that arising from human milk
consumption for toddlers and higher than that resulting from fish
consumption for infants. However, there was a significant degree of

 A. Turner

uncertainty in the calculations and it was predicted that exposure could
be enhanced substantially for toys with higher BFR concentrations (the
median value for PBDEs in the study was 53 ppm) and for longer
mouthing periods or occasional swallowing of pieces that had been
chewed off. More recently, Kuang et al. (2018) estimated the exposure
of BFRs from black kitchen utensils purchased in the UK that had been
in contact with food fried in oil at 160 °C. Daily exposures of up to 6 μg
for total BFRs and 4 μg for total PBDEs were reported, with the latter
considerably exceeding corresponding UK exposure estimates determined independently for dust ingestion (up to 0.4 μg day−1) and the
diet (up to 0.075 μg day−1) (Besis and Samara, 2012).
An additional problem associated with plastic products containing
BFRs is the presence and formation of highly toxic polybrominated
dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs).
These compounds may be present in technical mixtures of PBDEs as
impurities but can be formed in significantly greater quantities during
low temperature (< 500 °C) thermolysis (Wang et al., 2010). Here,
many BFRs, including PBDEs and PBBs, act as precursors for the formation of PBDDs and, in particular, PCDFs, through debromination and
hydrogenation reactions, with the yield increasing in the presence of
Sb2O3 (Weber and Kuch, 2003). The mild thermal stress involved in the
production, moulding or recycling of plastics may be sufficient to
produce PBDD/Fs under many circumstances (Ebert and Bahadir,
2003), resulting in calls from some (now historical) sources for plastics
containing PBDEs not to be recycled (Meyer et al., 1993). PBDD/Fs are
also formed under conditions employed during the incineration of
municipal waste. Here, generation is greatest in the economiser, where
temperatures are reduced from those in the combustion chamber and
superheater to values optimal for PBDD/F formation (250 to 450 °C)
(Wang et al., 2010). The presence and formation of PBDD/Fs in plastic
goods poses a risk of exposure to consumers while their generation
during processing or combustion presents an occupational risk and has
adverse impacts on local air quality. Significantly, UNEP (2010) assert
that the formation of PBDD/Fs is the most important contributor to the
total health impacts arising from the recycling of PBDEs.
9. Marine pollution
Where plastic waste has captured the attention of the public and
scientific community to the greatest extent over the past few years is the
marine environment. Here, plastic has impacts that are many and
varied, ranging from aesthetics to the local economy, and from vessel
damage to wildlife entanglement. Additives and contaminants in plastics beached around the coasts of southwest England have recently been
investigated by XRF (Turner, 2016; Massos and Turner, 2017) allowing
a direct a comparison to be made of black consumer goods in current or
recent use with black plastic objects and fragments of less well-defined
origin and age.
Published and unpublished data generated by our research group
indicate that beached plastic that is black constitutes < 5% of the total
population sampled on a number basis, a value that is considerably
lower than estimates of black plastic in domestic waste stream after
exclusion of WEEE (up to about 15%; Plastic Zero, 2014). The discrepancy may be partly attributable to the difficulty in detecting black
objects against a dark background or where black stones or macroalgae
are present. However, in our experience there were no clear differences
in the relative abundance of black plastics retrieved from a variety of
beaches, including those that were composed only of fine, pale sand. It
is more likely that a higher proportion of black plastic has a density
greater than that of sea water (1.03 g cm−3) and a propensity to sink
rather than be washed up in the coastal zone. For example, the density
of PET is about 1.4 g cm−3 while the densities of materials commonly
employed in EEE range from around 1.05 g cm−3 for ABS and HIPS to at
least 1.3 g cm−3 for PVC; higher values also arise in the presence of
residues and functional additives.
The occurrence and concentrations of hazardous elements in beached

Table 5
Detection frequency and descriptive statistics for the elements determined by
XRF in beached black plastic litter. Note that Hg was not detected in any sample
category. Concentrations are in ppm.
Element

Br

Cd

Cr

Pb

Sb

Descriptor

n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max
n
Mean
Median
Min-max

Objects

Fragments

Pellets

Total

(n = 17;
PVC = 1)

(n = 10;
PVC = 0)

(n = 108;
PVC = 0)

(n = 135;
PVC = 1)

9
26.2
13.0
9.2–94.7
1
123

4
245
185
16.9–591
1
79.8

5
47.3
43.2
24.1–70.1
7
47.1
35.7
8.5–109
1
6260

7
40.9
33.6
24.3–81.7
5
71.2
37.7
11.0–149
2
340
340
150–531

46
298
26.5
4.5–4590
8
85.6
76.1
63.1–139
56
53.9
41.5
21.5–538
34
77.8
35.8
11.2–941
10
784
327
74.0–2720

59
253
25.6
4.5–4590
10
88.8
80.4
63.1–139
68
52.1
41.5
21.5–538
46
72.4
35.9
8.5–941
13
1140
364
74.0–6260

black plastics from southwest England are summarised in Table 5. Here,
samples have been categorised as primary objects that were recognisable
(mainly bottle tops), secondary fragments that were not identifiable, and
plastic pellets that are used as feedstock by the plastic manufacturing industry or as biobeads in wastewater treatment (Cornish Plastic Pollution
Coalition, 2017). In total, 135 samples from over 2000 retrieved were black,
with the relative abundance of this colour greatest among pellets. Only one
black sample was constructed of PVC, with all of those identified by Fourier
Transform Infrared spectrometry (n ~ 50) as polyethylene (PE) or polypropylene (PP) and whose densities (0.90 to 0.97 g cm−3, respectively) are
consistent with the sorting of marine plastics on this basis as asserted above.
Among the elements analysed, Hg was never detected and Br, Cr
and Pb were most frequently encountered, with detection frequencies of
the latter elements similar across each sample category and comparable
with corresponding frequencies for non-WEEE products shown in
Table 2. Thus, despite a narrower range of plastic types and potential
alteration of the chemical makeup by aging and weathering, the hazardous element signature of beached samples in terms of detection
frequency (and concentration range) is comparable to that of non-EEE
consumer goods and blended WEEE plastic. Significantly, the common
occurrence of Br, Pb and Sb in black pellets (but not in pellets of other
colours), which are likely derived from a multitude of local, regional
and distant sources, confirms the pervasive, widespread use of recycled
EEE by the global plastics industry.
The similarities of black plastic in marine waste and consumer
goods are illustrated more specifically in Fig. 3 where the concentration
of Sb is plotted against the concentration of Br for beached samples
(and with the exception of a single object of PVC where Sb was employed as a synergist in the highly chlorinated matrix). Thus, a significant relationship is evident that yielded a slope of about 0.6 and an
intercept of around 70 ppm. Although the estimate of the gradient was
associated with a relatively high degree of uncertainty, a value greater
than estimates for the slopes defining the SbeBr relationships for all
categories of non-EEE and EEE in Table 4 suggests that brominated
compounds may have a greater propensity for mobilisation into sea
water from the aging matrix than compounds of Sb (Turner, 2018b).
With a higher frequency of hazardous elements (and in particular Br, Pb
and Sb) than other colours of beached plastic litter, black items pose greater
risks of chemical exposure to organisms that inadvertently or incidentally

 A. Turner

10000

Sb , p p m

1000

100
pellets
fragments

10

10

100

1000

10000

Br, ppm
Fig. 3. Concentrations of Sb versus concentrations of Br in beached black
plastics. Note that Sb was not detected in distinct objects that were non-PVCbased.

ingest plastics (including invertebrates, fish, birds, crustaceans and cetaceans; Law, 2017). Few investigations have been performed in respect of
chemical additives (for any colour of plastic), partly because the significance of restricted elements incorporated into the matrix of plastic litter
(rather than being adsorbed to its surface) has only recently been demonstrated (Nakashima et al., 2012; Turner and Solman, 2016). Nevertheless, in
a study of PBDEs in the abdominal adipose of twelve Pacific short-tailed
shearwaters, Tanaka et al. (2013) found accumulation of both lower- and
higher-brominated congeners. Accumulation of the former were attributed
to exposure through the diet since similar congeners were present in natural
prey (pelagic fish), while accumulation of the latter was attributed to exposure from ingested plastics since these congeners were absent from its

disposal via
controlled
combus!on

10. Concluding remarks and recommendations
While environmental and health impacts arise from the production
and use of plastics in general, black plastics pose greater risks and hazards because of technical and economic constraints imposed on the
efficient sorting and separation of black waste for recycling, coupled
with the presence of harmful additives required for black plastic production or applications in the EEE and food-packaging sectors. By
comparison, for example, while historical white EEE may contain restricted chemical additives, end-of-life white plastic in general is more
readily sorted and, therefore, sourced more safely for recycling.

energy recovery for
metal and cement
industries

Br present
EEE
black
plas!c

prey but more typical of flame-retarded plastics retrieved from its digestive
tract. Of significance in the context of the present discussion, photographs of
the ingested plastic captured by the authors reveal a relatively high proportion (and significantly > 5%) of black fragments. Tanaka et al. (2015)
provided further evidence for the accumulation of PBDEs by procellariiform
seabirds from ingested plastics by conducting leaching experiments on
materials compounded with deca-BDE. Thus, while small quantities of the
BFR were mobilised by sea water and acidified pepsin, up to 40% was
released in a solution containing fish oil, a component of stomach fluid
while feeding.
More recently, a kinetic study of the mobilisation of hazardous
elements from microplastics into a digestive fluid that simulates the
chemical conditions in the gizzard-proventriculus of the northern
fulmar has been undertaken (Turner, 2018b). Cadmium, Cr, Pb and Sb
release could be modelled using a pseudo-first-order diffusion equation
with rate constants ranging from of 0.02 to 0.5 h−1, while bioaccessibilities (as a percentage of total elemental content) ranged from < 1 for
Cd in PE to > 20% for Pb in PVC. Nakashima et al. (2016) have also
shown that up to about 0.1% of Pb in PVC can leach into sea water, and
that further leaching is possible should the surface become damaged by
abrasion such as might happen when beached. While not all plastics
tested in these studies were black, the more frequent occurrence of
hazardous elements in black materials is of relevance in the context of
the current synopsis.

test for Br
end-of-life

wildlife
exposure to
Br, Pb, Sb
inadequate
tes!ng or
sor!ng

occupa!onal
exposure to
Br, Pb, Sb
marine
pollu!on

recyclate

Br absent

end-of-life

recyclate
consumer goods

landfill
end-of-life

construc!on
and transport
sectors

end-of-life
human
exposure to
Br, Pb, Sb

energy from
waste

genera!on
of PBDD/Fs

Fig. 4. The life cycle of black plastic used in EEE. Solid lines represent the preferred pathways based on adequate testing for Br, while broken lines represent the nonpreferred pathways along with exposure routes and environmental impacts of hazardous additives (brominated compounds, Pb and Sb).

 A. Turner

Black PET, the most common component of black plastic in household waste, is not generally recycled and therefore sits within a linear
economy. Suggestions made to improve its recyclability include technologies that better label or identify black materials or the use of different black pigments (Dvorak et al., 2011; Plastic Zero, 2014) but a
more sustainable option would be to use lighter coloured (and preferably clear) plastic to package food, and especially where thermal
stress is not a constraining factor. This could be accomplished by
making the public more aware of the problems associated with black
plastic recycling and subsequently pressuring retailers and manufacturers for change. To this end, and at the time of writing, one of the
largest supermarket chains in the UK has announced plans to phase out
black plastic food packaging from their own products by the end of
2019 (Moore, 2018).
In contrast, black EEE plastic is contained within a complex, poorly
quantified and largely undesirable and unregulated quasi-circular
economy. The life cycle of this material is conceptualised in Fig. 4,
along with some of the key environmental impacts and exposure
pathways associated with the disposal and recycling of restricted additives (of which brominated compounds, Pb and Sb are conceived as
the most problematic). Thus, here, the demand for black plastic from
the manufacturing industry is at least partly met from recycled WEEE
plastic that should be free of restricted additives like BFRs and heavy
metals. However, poor or inefficient isolation of compliant material has
resulted in such a wide and uncontrolled dispersion of contaminants in
black plastics that their eradication is now only possible through the
manufacture of black goods from virgin materials. Realistically, the
most acceptable immediate objective would be a reduction in the impacts of hazardous additives through the recycling of black plastic into
goods where human exposure is minimal (e.g. pallets, lumber, communal refuse bins, guttering, road signs).
Given the nature and scale of these challenges and the long-term,
widespread contamination of multi-use black plastics, it is recommended that future scientific research focus on the behaviour and
migration of additives that have been recycled into sensitive consumer
goods like food-contact items, drinks vessels and small toys. While a few
publications have recently addressed restricted BFRs in this respect,
there is a complete lack of information on the migratability of heavy
metals, and in particular, Pb.
Acknowledgements
Angelo Massos and Logan Holliday (PU) are acknowledged for
providing access to unpublished data on marine plastic litter and
Montserrat Filella (University of Geneva) is thanked for engaging in
enthusiastic discussions about the subject. The author is grateful for the
constructive and insightful comments from three anonymous reviewers.
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