In the past, lead was cited as coming from:
1. Combustion of leaded fuels.
2. Lead pipes.
3. Paints containing lead.
4. Lead batteries (improper disposal/recycling/manufacture).
Since 1 - 3 have been all but phased out in the region, what would a student write as a second source of lead.
Currently, lead pollution worldwide comes from include smelters and electric utilities. Three years ago, a study in Japan added plastics to the list. The material which follows is taken from:
Quantification of Toxic Metals Derived from Macroplastic Litter on Ookushi Beach, Japan
Center for Marine Environmental Studies, Ehime University, 2-5, Bunkyo-cho, Matsuyama, 790-8577, Japan
Environ. Sci. Technol., 2012, 46 (18), pp 10099–10105
Publication Date (Web): August 23, 2012
Copyright © 2012 American Chemical Society
"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."
The highest metal concentrations were of lead, which they estimated made up more than 300 g of the 500 kg of plastic trash on Ookushi Beach. Most of the lead came from PVC; manufacturers often use the metal to stabilize PVC.
So now, we can safely use PVC as
a source of lead pollution.