From Street Stains to Sequencing: Uncovering the Cause of Urban Blackening

Brief

A large industrial facility faced claims from nearby residents who alleged that a dark-coloured fungus was colonising their properties as a result of emissions from the site. The reported blackening was said to have caused aesthetic damage and raised concerns about environmental responsibility, the potential for future claims, and possible regulatory action.

HKA worked with the industrial facility owner (“the client”) to determine whether the blackening was caused by emissions from the facility, and if so, to what extent.

What we did

To support the client in responding to these claims, HKA conducted a comprehensive investigation that combined spatial analysis, environmental sampling, and advanced scientific techniques. The HKA team mapped blackening across several hundred locations adjacent to the facility to assess its distribution and any correlation with proximity to the site. These locations were revisited to evaluate seasonal variation. In parallel, samples were collected from both the site and surrounding areas for optical microscopy, and an additional samples for advanced DNA sequencing to help identify the fungal species involved. The multi-layered approach enabled HKA to develop a robust and scientifically grounded understanding of the issue.

Outcomes

DNA sequencing provided deeper insight into the origin of the fungus and its relationship to site emissions.

HKA’s approach, which combined multiple lines of evidence and sophisticated sequencing techniques, demonstrated our ability to deliver practical, evidence-based solutions to complex environmental challenges. This helps clients manage risk, respond to claims, and engage confidently with regulators and stakeholders