Jeff Johnson is a senior aquatic toxicologist and ecological risk assessment specialist with more than 25 years of experience leading complex investigations at contaminated sediment sites. He provides strategic technical direction for projects conducted under CERCLA, RCRA, and state voluntary remediation programs, developing defensible investigation and risk assessment approaches that integrate sediment, surface water, and groundwater-to-surface water interaction (GSI) pathways using weight-of-evidence methodologies. Jeff’s expertise includes contaminated sediment assessment and monitoring, Natural Resource Damage Assessments, in-situ toxicological and biological studies, ecological community assessments, and comprehensive sediment and water quality evaluations. Jeff supports environmental compliance initiatives, including NPDES permitting and selenium fish tissue assessments. He brings a collaborative approach to project management, guiding multidisciplinary teams, and mentoring staff to deliver high-quality, science-based solutions in complex regulatory environments