Highlights
- • Distribution of Cu in different binding phases of sediments changes with changing pH of the surrounding environment.
- • Association of Cu organic matter increases at higher pH with sedimentary increases at higher pH.
- • Cu-SOM complexes may disaggregate and increase mobility at higher pH.
- • Increasing pH decreases lability of Cu complexes and increase mobility of Cu-complexes in sediments.
- • Concentration Cu in residual phases remains unchanged under varying pH.
Abstract
Impact of pH variation of overlying water column on transport and transformation of Cu-sediment complexes in the bottom mangrove sediments was investigated by using different metal extraction studies. The total Cu concentration in the studied sediments varied from ~64 ± 1 to 78 ± 2 mg·kg−1. The sequential extraction study showed that a major part of the sedimentary Cu (85–90% of the total sedimentary Cu) was present within the structure of the sediments with minimum mobility and bioavailability. The redistribution of non-residual Cu among the different binding phases of the sediments was observed at different pH. It was found that Cu shifted from the different non-residual binding phases to the organic binding phase of the sediments at higher pH. Partial leaching of sedimentary Cu-SOM complexes (with increasing stability as determined by kinetic extraction study) was observed at higher pH. This study infers that increase in pH of overlying water column may release Cu-SOM complexes and increase the mobility of Cu-complexes in mangrove systems.
Jayachandran S., Chakraborty P., Ramteke D., Chennuri K. & Chakraborty S., 2018. Effect of pH on transport and transformation of Cu-sediment complexes in mangrove systems. Marine Pollution Bulletin 133: 920-929. Article (subscription required).
