SEPHIRA ENVIRONMENTAL LIMITED - Key Persons


Christopher Brett Mongillo

Job Titles:
  • Principal Environmental Scientist, Chemist, Compliance Specialist
Christopher, who formerly went by "Brett", has 35+ years of professional experience in identifying, remediating and managing contaminated land, water and air issues. He is valued by his clients for his quick and clear-minded decision-making, and for his ability to communicating clearly about contaminated land risks. Christopher served as a Principal Contaminated Sites Advisor for Environment Canterbury for over five years. In this role he experienced the regulation and management of contaminated land issues at every level of government, including serving on an advisory council to MfE for the development of the National Environmental Standard for Assessing and Managing Contaminants in Soil for the Protection of Human Health which came into effect in January 2012. Prior to his time with Environment Canterbury he was employed as a consulting environmental scientist by various consultancies in the United States. This combination of consulting and New Zealand based government experience affords him the ideal set of skills to provide sound advice and educational services on contaminated land management. He is a specialist in asbestos, lead and coal tar asphalt investigation, and has extensive experience with a wide range of other contaminants.​

Helen Mongillo

Job Titles:
  • Principal Environmental and Engineering Manager, Hydrogeologist
Helen has 35+ years of experience in contaminated land, water and sediment investigation and remediation. Since her arrival in Christchurch in 2008, Helen has worked for south island developers, quarries, farms, councils, New Zealand Defence force and the mining industry. She worked for 20 years in the USA, specialising in contaminated site investigation, risk assessment, remedial options assessment, remediation oversight and sediment projects.

Sebastian Küng

Job Titles:
  • Environmental Scientist / Engineer
Sebastian supports the contaminated sites team by doing preliminary and detailed site investigations, groundwater and surface water quality monitoring. He is also skilled at stormwater and waste water assessments, erosion and sediment control plans, and completing resource consent application and assessments of environmental effects. Sebastian's dual science and engineering degrees are an asset to to the multi-disciplinary projects we deliver at Sephira Environmental. Sebastian started with Sephira Environmental in 2022, bringing over six years of experience as an environmental consultant. He has worked with with a range of clients across New Zealand. He completed a Master of Engineering Studies at the University of Auckland in July 2015, and previously completed a Bachelor of Science in Environmental Science overseas. Sebastian has specialty skills including ultra-trace sampling for PFAS.

Sylvia Wilson

Job Titles:
  • Accounts Manager
  • Environmental Scientist, Accounts Manager, Safety Administration Manager
Sylvia is an essential part of the contaminated sites team, undertaking preliminary and detailed site investigation field assessments and reporting. She identifies MfE HAIL activities, collects soil samples, and is an excellent client liaison, managing a range of small projects. She has specialty experience in investigation of sites with asbestos in soil or building materials. Sylvia started with Sephira Environmental in 2016 after completing her Bachelor of Science in Chemistry at the University of Canterbury. At the beginning of 2018 she left to explore other passions, including spending five months gaining analytical experience at an asbestos testing laboratory, but returned to Sephira Environmental towards the end of 2019. Sylvia is the Accounts Manager for Sephira Environmental, balancing the books and managing a variety of administrative tasks. She is also the company Safety Administration Manager. She established new safety systems for Sephira Environmental based on the latest government recommendations and ensures that we stay compliant with the safety requirements of our major construction sector clients, and all jobs. Her organisational abilities are a strong asset to the company. Sylvia will be going on Maternity leave at the end of April 2022. She plans to return to Sephira when the time is right for her family and herself.

Thaddeus Mongillo


Tom Wilson

Job Titles:
  • Environmental Engineer, IT Specialist
  • Specialist
Tom is a lead in our contaminated land team, working on preliminary and detailed site investigations. He is also a critical resource in our soil remediation team. He helps our clients identify historic contaminating activities on their properties and provides advice on how to clean up contaminated soil. He oversees earthworks contractors to bring properties into a condition suitable for a variety of residential or commercial/industrial uses. Tom has specialty experience in investigation and remediation of soil contaminated with asbestos, coal tar asphalt, and heavy metals. He also leads our consent groundwater monitoring team. Tom started with Sephira Environmental in 2017 upon finishing his Bachelor of Engineering (Hons) in Electrical and Electronics Engineering at the University of Canterbury. Tom is the IT specialist for Sephira Environmental facilitated by his education in Electrical Engineering. He is excellent with databases, web applications and basic circuitry. Education: MEngSt (Hons) Engineering Studies, University of Auckland, MSc Environmental Sciences, University of East Anglia, UK, BSc Environment: Atmospheric Environment and Air Quality, Chemistry, McGill University, Canada; Site Safe Consultant Certified; First Aid Trained