Raphaëlle Roffo | University College London (original) (raw)

Papers by Raphaëlle Roffo

Science of The Total Environment

Scientific Reports, 2020

Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) pea... more Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus considered extracellular (median 96.9%). ΔTLF was only significant in more urbanised study areas where TLF was greatest. Beneath Dakar, Senegal, ΔTLF was significantly correlated to total bacterial c...

UCL Geography, MSc Dissertation, Poster

Each day, 1.8 billion individuals around the world drink water contaminated with faeces (WHO, 201... more Each day, 1.8 billion individuals around the world drink water contaminated with faeces (WHO, 2017). In sub-Saharan Africa alone, this represents a leading cause of mortality, as diarrhoeal diseases killed 643,000 people in 2015 (WHO, 2016). In the coastal megacity of Dakar, Senegal, the Thiaroye shallow aquifer is a complex system in which multiple sources of pollution and a lack of sufficient sanitation infrastructure have contributed to an extreme degradation of groundwater quality. This study is an investigation of faecal contamination patterns across the aquifer. It is based on data collection conducted in the greater Dakar region under the Dakar urban observatory of the AfriWatSan project, in June-July 2018. Within the AfriWatSan framework, this study seeks to explore faecal contamination patterns across the Thiaroye aquifer, based on standard culture-based methods and tryptophan-like fluorescence (TLF). TLF is a fluorescence based method currently being developed by the British Geological Survey for real-time screening of faecally contaminated drinking water in urban Africa. The method offers several key advantages over traditional methods as it is portable, real-time and easy to use.
97 samples were collected with 48 parameters including hydrochemical parameters and environmental risks. This study first seeks to explore the relationships between different variables, with a specific focus on TLF performance as a faecal matter detection method. It then explores spatial patterns of contamination, before adopting an unsupervised machine learning approach to classification with Agglomerative Hierarchical Clustering (HAC).
While TLF fails to accurately predict current contamination across the Thiaroye aquifer, this data exploration and modelling exercise provides additional information about the Thiaroye aquifer groundwater quality. In order to achieve a more accurate representation of the contamination, further research will need to incorporate groundwater flow modelling, and to investigate vertical contamination flows.
Research was conducted under the AfriWatSan project, funded by The Royal Society (UK) and Department for International Development (DFID), and supported by the British Geological Survey (BGS), currently developing portable, UV-based fluorimeters for real-time screening of faecally contaminated drinking water in urban Africa.

This paper is an attempt to explain how the multi-faceted role of Chinese central government is m... more This paper is an attempt to explain how the multi-faceted role of Chinese central government is mediated by economic interests and clientelist relations, as we argue that the ambiguous “One country two systems” framework has, at the turn of the century, accelerated a deeper penetration of mainland China’s politico-economic influence in the HKSAR.

The Istanbul field trip, which took place in January 2013, provided us the opportunity to see in ... more The Istanbul field trip, which took place in January 2013, provided us the opportunity to see in action urban governance, the subject of our studies. As Governing the Large Metropolis students, we were eager to raise, through an in situ case study, the sensitive issues surrounding Istanbul’s governance that we had gleaned from an academic perspective during our first semester of our masters programme. Meetings and conferences with key stakeholders in, for instance, the water and housing sectors, were unique opportunities to challenge discourses and confront the complex interactions that shape a city’s identity, social structures, economic orientations, and even physical forms.

We will try in this paper to uncover the role of various local, national and international stakeh... more We will try in this paper to uncover the role of various local, national and international stakeholders in fostering the rebirth of PPWSA, as well as in resisting the change. This paper argues that the key for success was an acute vision of water management, with rational articulation of the three strategic stakes that need to be combined to foster sustainable development of a water network, with significant support from multilateral and bilateral development agencies.

In an age of access, as immediacy of information has become the standard in all spheres of our so... more In an age of access, as immediacy of information has become the standard in all spheres of our societies thanks to new information and communication technologies, transparency is more than ever at the heart of the reflection on democracy. Obviously, accountability is not a new requirement for governments. However it has gained unprecedented importance, as those in charge of managing public affairs are increasingly expected to be able to provide information on their action and to receive citizens’ feedback at any stage of the policy continuum. In this context, lack of transparency generates suspicion and potentially distrust in the political personnel which undermines the democratic system as a whole. Citizen involvement in administrative decision-making and management processes can remedy this loss of public trust and actually reinforce governments’ legitimacy.

Over the last few decades, China has gone through an incredibly rapid path of urbanization and in... more Over the last few decades, China has gone through an incredibly rapid path of urbanization and industrialization, inducing a whole range of issues and potential harms to its population. The opening of the economy tremendously accelerated this trend and, more specifically, environmental pollution has recently become the focus of all attention, as scandals outbreaks increased and damages acquired more visibility. The notion of risk is essential to whom wants to get an insight of pollution-related issues; we tend indeed to consider as self-evident the existence of a link between air quality and deterioration of human health, and to use the notion of risk as a bridge between the two. However, risk is a social construct. Its manipulation can hence be extremely revealing to the observers, regarding the tensions and struggles underlying risk management and relationships of the actors involved in governance.

Among the most striking features of this city, any foreigner who ever travelled or stayed in Beij... more Among the most striking features of this city, any foreigner who ever travelled or stayed in Beijing would immediately mention its incredibly high levels of pollution and its infamous fog. The city’s reputation being seriously damaged, action must be taken to preserve not only the populations from tremendous risks, but also maintain attractiveness for foreign entrepreneurs and improve competitiveness. The bottom line of our recommendations therefore stays in the absolute necessity for Beijing Municipality to increase transparency and implement serious environmental quality assessment mechanisms, in order to develop partnerships and benefit from international cooperation.

Thesis Chapters by Raphaëlle Roffo

UCL Geography, MSc Dissertation, 2018

Science of The Total Environment

Scientific Reports, 2020

UCL Geography, MSc Dissertation, Poster

UCL Geography, MSc Dissertation, 2018