Friday Cat-erpillar Blogging: Silkworms Get the Lead Out

Silkworm

Silkworm, Bombyx mori

Lead is a toxic metal with detrimental effects on human development and is found in numerous contaminated industrial sites . Removal of toxic metals from contaminated sites is problematic and costly. Phytoremediation, the use of plants to remove toxins from the soil is one potential solution.

A group of Chinese scientists* explored adding an insect component to phytoremediation of sites contaminated by lead. Mulberry trees planted in lead contaminated soils removed lead from the soil. The majority of the lead was bound in the root tissue, but some lead was translocated to the leaves. Lead in mulberry leaves is primarily bound to cell walls.

Mulberry leaves can be fed to silkworms as part of the silk production process. The scientists found that silkworms are lead tolerant and can survive on contaminated leaves. Much of the lead consumed by silkworms is passed in the frass without being absorbed by the gut. Absorbed lead stimulates production of metallothioneins, detoxification enzymes that bind to lead and transport it into the urine for elimination.

Potentially, the mulberry could be planted on lead contaminated soil, fed to silkworms, and the frass with concentrated lead collected for proper disposal.

*Lingyun Zhou, Ye Zhao, Shuifeng Wang, Shasha Han, Jing Liu. 2015. Lead in the soil–mulberry–silkworm food chain: Translocation and detoxification. Chemosphere. 128: 171-177. http://dx.doi.org/10.1016/j.chemosphere.2015.01.031

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in by jjneal, Caterpillar Blogging, Environment. Bookmark the permalink.

One Response to Friday Cat-erpillar Blogging: Silkworms Get the Lead Out

  1. Pingback: Friday Cat-erpillar Blogging: Silkworms Get the Lead Out | Living With Insects Blog

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s