Article pubs.acs.org/est
Quantification of Toxic Metals Derived from Macroplastic Litter on Ookushi Beach, Japan Etsuko Nakashima,* Atsuhiko Isobe, Shin’ichiro Kako, Takaaki Itai, and Shin Takahashi Center for Marine Environmental Studies, Ehime University, 2-5, Bunkyo-cho, Matsuyama, 790-8577, Japan S Supporting Information *
ABSTRACT: The potential risk of toxic metals that could leach into a beach environment from plastic litter washed ashore on Ookushi Beach, Goto Islands, Japan was estimated by balloon aerial photography, in situ beach surveys, and leaching experiments in conjunction with a Fickian diffusion model analysis. Chromium (Cr), cadmium (Cd), tin (Sn), antimony (Sb), and lead (Pb) were detected in plastic litter collected during the beach surveys. Polyvinyl chloride (PVC) fishing floats contained the highest quantity of Pb. Balloon aerial photography in conjunction with a beach survey gave an estimated mass of Pb derived from plastic litter of 313 ± 247 g. Lead leaching experiments on collected PVC floats showed that Pb in the plastic litter could leach into surrounding water on the actual beach, and that plastic litter may act as a “transport vector” of toxic metals to the beach environment. Using the experimental data, the total mass of Pb that could leach from PVC plastic litter over a year onto Ookushi Beach was estimated as 0.6 ± 0.6 g/year, suggesting that toxic metals derived from plastic beach litter are a potential “pathway” to contamination of the beach environment due to their accumulation in beach soil over time.
1. INTRODUCTION The global production of plastic items reached 265 million tons per year in 2010,1 increasing exponentially over the past 70 years.2 Plastics provide substantial benefits because they are lightweight, durable, low cost, and have wide range of applications. Unfortunately, marine and beach environments are subjected to “plastic pollution” due to the same properties that provide these benefits.3 For example, plastic products that reach the ocean as litter are able to travel long distances for long periods because of their light weight and durability. Plastics are currently the most common type of marine/beach litter globally, and are a serious threat to marine wildlife due to ingestion of plastic litter and entanglement in nets.3 Even remote islands such as Goto Islands, Japan (Figure 1a), have a large amount of plastic litter (Figure 1b), originating primarily from China, Korea, Taiwan, and Japan, being washed ashore.4,5 This plastic litter eventually fragments into smaller pieces in the marine environment, and fragments of plastic less than 1 mm (defined as microplastic) have accumulated in the open ocean such as eastern North Atlantic.6,7 Furthermore, recent studies have indicated that microplastics (
