School of Civil, Environmental and Mining Engineering

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Contact

Sobia Ahmed

Phone: (+61 4) 6961 5361


Supervisors

Start date

Jan 2015

Submission date

Jan 2019

Sobia Ahmed

Thesis

Links between chemical composition of dissolved organic nitrogen and its bio availability in groundwater

Summary

Dissolved organic nitrogen (DON) is an important constituent for groundwater quality. While DON concentrations may be low (Lapworth et al. 2008), DON may be the dominant form of bioavailable nitrogen in groundwater (Kroeger et al. 2006a; Wiegner et al. 2006; Lapworth et al. 2008; Barron et al. 2009). Previous research has concluded that insufficient understanding of DON’s molecular structure (Westerhoff and Mash 2002; Jones et al. 2009; Huo et al. 2014), reactivity and bioavailability (Seitzinger et al. 2002; Wiegner and Seitzinger 2004; Filep and Rékási 2011; Tiemeyer and Kahle 2014), and relatively few direct measurements, makes it difficult to predict DON sources and therefore challenging to recommend preventive measures and removal techniques (Westerhoff and Mash 2002; Matilainen and Sillanpää 2010; Liu et al. 2012).

Some previous work has investigated the concentration and bioavailability of DON in Perth’s surface waters, drains and streams (Petrone et al. 2009, 2010; Petrone 2010; Fellman et al. 2011) however little is known about DON in groundwater. It has been suggested that DON concentrations have increased in both surface and groundwater under land use change and urbanization (Smith and Shams 2002; Barron et al. 2009; Barron and Donn 2010; Petrone et al. 2010). The impact of DON increases on nitrogen bioavailability in the receiving waters is unknown.

This study aims to a) identify chemical structure and composition of groundwater DON across the Perth metropolitan area (PMA), b) develop predictive mapping of DON bioavailability across the PMA, c) at specific locations across the PMA, determine DON bioavailability and therefore validate the predictive mapping and d) assess the effects of land use change and urbanization on groundwater DON composition and bioavailability. Ultimately this work will facilitate a better understanding of possible preventive and treatment measures of groundwater DON.

Why my research is important

Dissolved organic nitrogen (DON) is an important constituent for groundwater quality. While DON concentrations may be low (Lapworth et al. 2008) however it may be the dominant form of bioavailable nitrogen in groundwater (Kroeger et al. 2006a; Wiegner et al. 2006; Lapworth et al. 2008; Barron et al. 2009). Insufficient understanding of DON’s molecular structure (Westerhoff and Mash 2002; Jones et al. 2009; Huo et al. 2014), reactivity and bioavailability (Seitzinger et al. 2002; Wiegner and Seitzinger 2004; Filep and Rékási 2011; Tiemeyer and Kahle 2014), and relatively few direct measurements, makes it difficult to predict DON sources and therefore challenging to recommend preventive measures and removal techniques (Westerhoff and Mash 2002; Matilainen and Sillanpää 2010; Liu et al. 2012).

Characterization of DON can lead to its sources and bioavailability will disclose the lability of DON in natural water systems. DON bioassay procedure is quite lengthy; therefore it is important find to links between DON chemical structure and bioavailability. This research will (a) characterize groundwater DON composition to identify its sources across the PMA and (b) develop correlation between DON chemical structure and bioavailability (with the help of published chemical structure to bioavailability data) and generate a predictive map showing DON bioavailability across PMA. Such a correlation between DON chemical composition and bioavailability has never investigated in past. The last part of this research is (c) DON bioavailability analysis at specific locations across the PMA to determine DON lability and therefore validate the predictive mapping developed in second part. This study will also assess the effects of land use change and urbanization on groundwater DON composition and bioavailability. Ultimately this work will facilitate a better understanding of possible preventive and treatment measures of groundwater DON.

Funding

  • CRC for Water Sensitive Cities

 

School of Civil, Environmental and Mining Engineering

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Last updated:
Thursday, 19 September, 2013 11:39 AM

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