Occurrence and effects of plastic additives on marine environments and organisms: A review

TL;DR: This work identified polybrominated diphenyl ethers (PBDE), phthalates, nonylphenols (NP), bisphenol A (BPA) and antioxidants as the most common plastic additives found in marine environments and transfer of these plastic additives to marine organisms has been demonstrated both in laboratory and field studies.

About: This article is published in Chemosphere.The article was published on 2017-09-01 and is currently open access. It has received 671 citations till now. The article focuses on the topics: Microplastics.

Summary

2. Chemicals used as plastic additives

• The type of additive depends on the plastic polymer and the requirements of the final product (Table 1 ).
• Hazardous substances refer to chemicals that pose a risk to the environment and to human health as defined by the REACH regulation in the European Union according to the European Chemical Agency (2017).

2.3. Bisphenol A

• 6623) is the most representative chemical of the bisphenol group and is one of the most commonly produced chemicals worldwide, with over three million tons produced annually (Laing et al., 2016), also known as BPA (Pubchem ID.
• BPA is mainly used as a monomer for polycarbonate (PC) plastics (65% of volume used) and epoxy resins (30% of volume used), which are for instance the main component of the lining layer of aluminum cans (Crain et al., 2007; ICIS, 2003) .
• Leaching of BPA can occur (Sajiki and Yonekubo, 2003) , leading to the release of this additive from food and drink packaging, which is considered as a source of exposure for human beings (Vandermeersch et al., 2015) .
• 2009) , BPA is still allowed in the European Union for use in food contact material (European Council Regulation, 2011) .
• Other bisphenol analogs, such as bisphenol B, bisphenol F and bisphenol S are used in plastics and may represent a threat to the environment even though their toxicity is still unknown (Chen et al., 2016) .

2.4. Nonylphenols

• Nonylphenols (NP) are intermediate products of the degradation of a widely used class of surfactants and antioxidants: nonylphenol ethoxylates (NPE) (Engler, 2012) .
• NP and NPE are organic chemicals used for many applications such as paints, pesticides, detergents and 13/45 personal care products (US Environmental Protection Agency, 2010a).
• They can also be used as antioxidants and plasticizers for the production of plastics (Rani et al., 2015; US Environmental Protection Agency, 2010a) .
• Moreover, effluents from wastewater treatment plants are the major source of NP and NPE in the environment (Soares et al., 2008) .
• NP are considered as endocrine disruptors and their use is prohibited in the European Union due to their effects on the environment and human health (Rani et al., 2015) .

3.2. Sediment

• As for marine waters, sediments are also affected by anthropogenic discharges and chemicals including plastic additives.
• Regarding BFRs, multiple BDE congeners have been found in marine sediments with BDE-209 being the major PBDE quantified in most studies at concentrations ranging from ng/kg to mg/kg (Table 7 ).
• Like BFRs, NP and phthalates, BPA has also been found worldwide in sediments (Table 8 ).

4.2.1. Evidence from laboratory experiments

• During exposure, fish exposed to microbeads spiked with PBDEs showed higher concentrations than the two controls, and lower brominated congeners were better transferred in fish tissues than higher brominated congeners.
• More realistic experiments have been performed using plastics incubated or collected in natural environments.
• For instance Rochman et al. (2013) used low-density polyethylene (LDPE) pellets deployed in seawater for two months and showed that the LDPE pellets adsorbed chemicals from the surrounding environment.
• Another laboratory study demonstrated that the transfer of nonylphenol, triclosan and PBDE-47 can occur via MP ingestion in the lugworm (Arenicola marina) with possible effects on lugworm behavior (Browne et al., 2013) .

4.3. Toxicity of plastic additives demonstrated by leaching experiments

• Evidence for plastic toxicity has been rising in the last years.
• While direct toxicity can occur due to the physical impacts of plastic ingestion (for a review, see Wright et al. (2013) ), indirect toxicity may be observed in relation to the release of hazardous chemicals from plastics.
• Recent studies demonstrated, using leaching experiments, that various plastics are toxic to a wide range of organisms (Table 9 ). ) , PET and PS) to quantify the impact of their leachate on the survival and settlement of barnacle Amphibalanus amphitrite larvae.
• Similarly, Bejgarn et al. (2015) exposed the copepod Nitocra sinipes to the leachate of weathered or non-weathered plastics.
• Here, leaching experiments were performed with leachates prepared with 10 g of each plastic placed in 100 mL of brackish seawater from the Baltic rotating at 6-21 rpm for 72h in the dark (Bejgarn et al., 2015) .

4.4. Relative importance of HOC in comparison with plastic additives: case of modelling studies

• The high affinity of plastic polymers for HOC has been demonstrated in numerous laboratory experiments (Bakir et al., 2014; Teuten et al., 2007) , and an increasing number of studies have focused on the role of MP as a vector for HOC in marine organisms (Besseling et al., 2013; Rochman et al., 2013) .
• Moreover, Koelmans et al. (2016) suggested that MPs ingestion by marine biota does not increase their exposure to HOCs and could have a cleaning effect while concerns have arisen regarding risk due to plastic additives.

Figures

Table 2: List of common plastic additives and their associated functions and potential effects 107

Table 5: Concentrations of phthalates in seawater in µg L-1 239

Table 7: Concentrations of polybrominated diphenyl ether (PBDE) in marine sediments in µg kg-1 dry weight 261

Table 4: Concentrations of polybrominated diphenyl ether (PBDE) in seawater in ng L-1 234

Table 3: Plastic additives and their associated octanol-water partition coefficients (Log Kow). Data were extracted 114 from the following reviews: Bergé et al. (2012), Espinosa et al. (2016), Net et al. (2015) and Oehlmann et al. (2008) 115

Table 9: list of aquatic species, plastic polymer types, exposure times and endpoints used in various leaching experiments 427

Table 8: Ranges of concentrations of nonylphenol and BPA in marine sediments in µg kg -1 dry weight. nd: not 281 detected. 282

Table 1: List of the most commonly produced polymers and their associated plastic additives. Adapted from Hansen et al. (2013) 101

Table 6: Ranges of concentrations of nonylphenol and BPA in seawater in µg L-1 245

Frequently asked questions

Q1. What have the authors contributed in "Occurrence and effects of plastic additives on marine environments and organisms: a review" ?

This work identified poly-brominated diphenyl ethers ( PBDE ), phthalates, nonylphenols ( NP ), bisphenol A ( BPA ) and antioxidants as the most common plastic additives found in marine environments. Upcoming research focusing on the toxicity of microplastics should include these plastic additives as potential hazards for marine organisms, and a greater focus on the transport and fate of plastic additives is now required considering that these chemicals may easily leach out from plastics.