Toxic assessment of the leachates of paddy soils and river sediments from e-waste dismantling sites to microalga, Pseudokirchneriella subcapitata

• The growth inhibition of the algae was aggravated with the increase of leachate dilution ratio.
• The sediment leachate was more toxic than that from paddy soils.
• Oxidative stress in the algae may related to the PBDEs and copper level in the leachate.
• The leachate decreased the amount of PSII active reaction centers and photosynthesis performance.
• APX, SOD and GST were induced at high concentrations of leachate.

The potential adverse effects of e-waste recycling activity on environment are getting increasing concern. In this work, a model alga, Pseudokirchneriella subcapitata, was employed to assess the toxic effects of the leachates of paddy soils and river sediments collected from e-waste dismantling sites. Chemical analysis of the paddy soils and river sediments and their leachates were carried out and the growth rate, chlorophyll a fluorescence and anti-oxidative systems of the alga were measured. Results showed that two leachates decreased the amount of PSII active reaction centers and affected photosynthesis performance, interfered with chlorophyll synthesis and inhibited algal growth. Some chemical pollutants in the sediments and soils such as polybrominated diphenyl ethers (PBDEs) and metals derived from e-waste recycling activity may impose oxidative stress on algae and affect the activity of anti-oxidative enzymes such as GST, SOD, CAT and APX. The leachates of both river sediments and paddy soils are potentially toxic to the primary producers, P. subcapitata and the leachate from sediments was more deleterious than that from soils.