International Pellet Watch has been analyzing polyethylene (PE) pellets because of their sorptive nature.  However, the present study focused on polypropylene (PP) pellets, because PP is less resistant to weathering and more UV stabilizers could be compounded to PP than PE.  We analyzed 10 benzotriazole UV stabilizers (BUVSs) including UVP, UVPS, UV329, UV9, UV320, UV350, UV326, UV327, UV328, UV234 in 36 PP pellet samples (each sample consists of basically 50 pellets) collected from beaches across the globe (Europe, Africa, middle east, Asia, Oceania, north, middle and south America).  Among them, 17 samples collected from remote islands were included to examine potential of microplastic-mediated long-range transport of the additives.  In the 36 PP pellet samples, 14 samples showed extremely high concentrations of BUVSs over 1000 ng/g (sum of the 10 BUVSs : total BUVSs), while 20 samples showed trace levels of BUVSs below 200 ng/g, as shown in Fig.1 and Fig.2.

The highest one was up to 70000 at Belize. Higher concentrations of BUVSs than sorption-derived maximum concentrations of BUVSs (~4000 ng/g) which were established based on total BUVSs concentrations for PE pellets from world beaches (78 ng/g to 3981 ng/g; Fig.3), were observed for 10 samples.  Thus, the sporadic high concentrations of BUVSs observed in the 10 locations are likely to be derived from additives industrially compounded to the pellets. Interestingly, such sporadic high concentrations of BUVSs were found in pellets even from the remote islands, i.e., Macquarie Island, Hawaii Island, Ogasawara Island, and Hachijo Island.  The concentrations of BUVSs in the remote island were in similar orders of magnitude to those observed in coastal areas where is close to industrial areas such as Sydney or Tokyo.  These means that BUVSs are long-range-transported across the borders for thousands kilometers without drastic desorption or degradation.  The sporadic high concentrations were observed only for single or two BUVS compounds for individual samples. This pattern is consistent with their origin of industrial compounding.  Based on the compound-specific relation of BUVSs concentrations in PP pellets with those in PE pellets, the following compounds were suspected to be derived from industrially-compounded additives, as shown in Fig.4.  They include UV326 at Macquarie Island, Ogasawara Island, and Kenya; UV327 at Hachijo Island, Belize, and Kenya; UV329 at Oahu Island, Malaysia, Japan (Fujisawa); UV328 at Mexico (PunTa Herradura). The present analysis demonstrated that microplastics long-range-transport hydrophobic additives across the borders and the international regulation on plastics and associated chemicals is necessary.

Our paper entitled “International pellet watch: Global monitoring of polybrominated diphenyl ethers (PBDEs) in plastic resin pellets” has been online published in an international journal “Environmental Monitoring and Contaminants Research” (EMCR)↓

https://emcr-journal.org/

It’s open-access and the paper (PDF) and SI can be downloaded in the following site.

DOI: https://doi.org/10.5985/emcr.20210002

We really appreciate world volunteers who collected and sent pellets to us.

We still receive and analyze pellets across the world.  Analysis is still on going.  More papers on IPW and related activities will come.

Our paper entitled “Monitoring of polycyclic aromatic hydrocarbons, hopanes, and polychlorinated biphenyls in the Persian Gulf in plastic resin pellets” has been published in Marine Pollution Bulletin.  It’s available online https://doi.org/10.1016/j.marpolbul.2021.112052

Our paper entitled “Monitoring of polycyclic aromatic hydrocarbons, hopanes, and polychlorinated biphenyls in the Persian Gulf in plastic resin pellets” has been accepted in Marine Pollution Bulletin.  It demonstrates petroleum pollution in the Persian Gulf through the analysis of PAHs and hopanes in pellets collected on 19 beaches in the Gulf.

Shige Takada delivered online presentations on UV-328, a kind of UV stabilizers used for plastics, on Pre-meeting for Sixteenth meeting of the Persistent Organic Pollutants Review Committee (POPRC.16) on Dec.2^nd and 3^rd.  He utilized data obtained through International Pellet Watch.  His conclusion is that pellets and similar size of plastic fragments undergo long range transport with hydrophobic additives such as UV-328, which are finally transferred and accumulated into seabird tissues through ingestion of plastics by seabirds on remote and desert islands.  We hope that IPW contribute to proper management of plastic additives and to the solution of plastic problem. (website of POPRC : http://chm.pops.int/Home/tabid/2121/Default.aspx)

Pellet sample from Anglet, France has just arrived Today.  It was collected by a Belgian based NGO (Save the plastic) focusing on marine plastic pollution.   Their website is as follows : https://savetheplastic.org.

Our IPW activities demonstrated that microplastics are transport media of POPs and endocrine disrupting chemicals (EDCs) in marine environments and their exposure source to marine organisms.  Our message to the society is that reduction of single-use plastics is one of the most efficient solutions for the problem.  Actions to reduce single-use plastics have started in various sectors in the society.  These have been introduced by a newspaper (The Japan News by The Yomiuri Shinmbun).  Our university (Tokyo University of Agriculture and Technology) also started action to reduce plastics and to promote researches for sustainable society free from petroleum-based plastics (TUAT 5R Plastic-free Initiative : Reduce, Reuse, Recycle, Renewable, and Research) in August 2019.  TUAT installed 18 free water dispensers in our campus to reduce PET bottle consumption.

Analytical results on PCBs in pellets from Congo, Guinea, Kenya, Morocco, Nigeria, Senegal, Tanzania, Tunisia have just come.  These samples were collected by IPEN (International Pollutants Elimination Network; https://ipen.org/) with whom IPW has been collaborating since last year.  PCB concentrations (sum of 13 congeners) ranged from 5 to 3384 ng/g-pellets. Except for Kenya, PCB concentrations for all the African countries (18 ng/g – 3384 ng/g) exceeded global background level (10 ng/g).  Especially, samples from Senegal and Tunisia were higher or comparable to pollution levels for industrialized countries such as western European countries, USA, and Japan.  There must be local sources of PCBs in the countries.  They did not produce nor use PCBs for their economic growth.  As we previously demonstrated in the case study in Ghana¹⁾, PCBs could be derived from e-waste scrapyard.  Another potential source is leakage of PCBs from second-hand electric equipment imported from industrialized countries.  We need more samples from each country.

1) Hosoda, J., Ofosu-Anim, J., Sabi, E.B., Akita, L.G., Onwona-Agyeman, S., Yamashita, R., and Takada, H., 2014. “Monitoring of organic micropollutants in Ghana by combination of pellet watch with sediment analysis: E-waste as a source of PCBs.” Marine Pollution Bulletin  86, 575-581.http://dx.doi.org/10.1016/j.marpolbul.2014.06.008

To help understanding how IPW contributes to the solution of plastic problem, presentation file (pdf) on International Workshop “The Science of Microplastics in the World Ocean” held in Woods Hole Oceanographic Institution on Oct. 16, 2019 has been uploaded here.

Takada_WoodsHoleMPWSForSllide

IPW’s analytical activity has just recovered from lock-down of laboratory due to COVID19 pandemic.  Pellets from Greece are now under analysis.