Effec t s of h e avy m e t al con t a min a tion in s al t m a r s h a n d

r e e d b e d on c a r bo n s e q u e s t r a tionE nya, Osim, Lin, C a n d Jam e s, P

Tit l e Effec t s of h e avy m e t al con t a min a tion in s al t m a r s h a n d r e e d b e d on c a r bo n s e q u e s t r a tion

Aut h or s E nya, Osi m, Lin, C a n d Ja m e s, P

Typ e Confe r e nc e o r Works ho p It e m

U RL This ve r sion is available a t : h t t p://usir.s alfor d. ac.uk/id/e p rin t/42 8 3 0/

P u bl i s h e d D a t e 2 0 1 7

U SIR is a digi t al collec tion of t h e r e s e a r c h ou t p u t of t h e U nive r si ty of S alford. Whe r e copyrigh t p e r mi t s, full t ex t m a t e ri al h eld in t h e r e posi to ry is m a d e fre ely availabl e online a n d c a n b e r e a d , dow nloa d e d a n d copied for no n-co m m e rcial p riva t e s t u dy o r r e s e a r c h p u r pos e s . Ple a s e c h e ck t h e m a n u sc rip t for a ny fu r t h e r copyrig h t r e s t ric tions.

For m o r e info r m a tion, including ou r policy a n d s u b mission p roc e d u r e , ple a s econ t ac t t h e Re posi to ry Tea m a t : u si r@s alford. ac.uk .

Effects of heavy metal contamination in Saltmarsh and Reed bed on Carbon Sequestration

Osim Enya, Chuxia Lin and Philip James School of Environment and Life Sciences, University of Salford, Great Manchester M5 4WT, United Kingdomo.enya@edu.salford.ac.uk

ABSTRACT

Assessing stabilization of soil organic matter (SOM) with heavy metalcontamination is one factor that will invariably provide an answer towhether heavy metal contamination affects the storage of soil organicmatter/carbon. The transformations of SOM will bring about changes infunctional group chemistry during decomposition/mineralization. Theeffects of heavy metal contamination level under different land use type oncarbon sequestration were investigated. Results indicated that, theconcentration of heavy metal under different land use affects thetransformation of soil organic matter. This will have implication on carbonstorage/Sequestration.

A study of heavy metals in surface sediments of the Mersey, monitoredover a period of 25 years (Harland, Taylor, & Wither, 2000), has shown thatheavy metal concentrations are strongly correlated with organic matter andsoil particle size, resulting in distribution patterns which reflect sedimentcharacteristics and dynamics rather than the position of input sources.

Hsu and Lo (1999), reported that transformations of SOM throughdecomposition and mineralization brings about changes in functional groupchemistry, such as the relative increase in aromatic to aliphatic groupsduring decomposition. By quantifying relative changes in functional groups,Fourier Transform Infrared (FTIR) spectrometer can be used to help explainSOM transformations and stabilization.

Research linking the effect of heavy metal contamination under differentland use type and carbon sequestration is scare. The content of this studyrelate to one of my PhD research objectives.

OBJECTIVE• To assess the effects of heavy metal contamination under different

land use type on the transformation of soil organic matter.

METHODS• The study was conducted in the Upper Mersey Estuary, northwest

England (Photo 1).

• Thirty (30) representative soil samples were collected within 30 cmdepth from experimentally designed plots (Fig 1)

• Soil samples were air dried, crush and passed through 63µm and 2mmsieve for analysis of heavy metal concentration by ICP-OES, and soilorganic carbon content/characterization using FT-IR Spectrometer,Nuclear Magnetic Resonance (NMR) Spectrometer and loss on ignitionmethod. Statistical analysis was by IBM SPSS 20 version.

RESULTS

• Results indicated that the concentration of heavy metal affects thetransformation of soil organic matter/carbon.

• Inorganic phosphate, aliphatic primary amines and aliphatichydrocarbons functional groups were observed in grazing saltmarshwhile inorganic phosphate and aliphatic primary amines functionalgroups were found in un-grazing location (Figs 2&3).

• Soil organic carbon content was statistically significantly higher at 0.05level of confidence in the grazing saltmarsh as compared to un-grazedlocation (Fig 4). This may be due to the grazing activities.

• The proton spectra indicated that aliphatic hydrocarbon and aromaticprotons are present in different humic substances (Fig 5).

• The soil that were less contaminated with heavy metal contains morefunctional groups (Fig 6).

INTRODUCTION

.

CONCLUSIONS

• Concentration levels of heavy metal in saltmarsh and reed bed have an effect on the transformation of soil organic matter.

• Less contaminated sites show more functional groups indicating higher rates of decomposition or transformation of soil organic matter.

• Significantly more soil organic carbon was stored within the cattle grazing area than un-grazing.

Photograph 1 showing aerial photograph of the upper Mersey estuary Fig 1 Sampling design

SM= Salt Marsh, GSM= Grazing Salt Marsh, GSM-N= Non-Grazing Salt Marsh, RB= Reedbed, WD= Woodland, NGD= Natural Grassland,

RGD = Rough Grassland

ReferencesHarland, B. J., Taylor, D., & Wither, A. (2000). doi: http://dx.doi.org/10.1016/S0048-9697(00)00374-0Hsu, J. H., & Lo, S. L. (1999). Chemical and spectroscopic analysis of organic matter transformations during composting of pig manure. Environmental Pollution, 104(2), 189-1969326/2/4/045024

Fig 6 Showing effect of concentration on functional group

Fig 2 FT-IR Spectra showing different functional groups within GSM

Fig 3 FT-IR Spectra showing different functional groups within GSM-N

Fig 4 Showing the storage of soil organic carbon under differentland use type

Fig 5 1H-NMR spectra of humic substances with different carbon species (Humic +1 = acid hydrolysis before extraction Humic -1 is without acid hydrolysis before extraction)

Further ResearchLaboratory incubation experiment is ongoing using three levels of heavy metal contamination (high, medium and low) with six treatments (control, As, Cr, Cu, Pb and Zn) to assess their effects on soil organic matter content/functional group.