Environmental accumulation of preservative adjacent to a chromated copper arsenate (type C)–treated wetland boardwalk was evaluated. The site is considered a realistic “worst case” because of the large volume of treated wood, low current speeds, high annual rainfall, and environmental sensitivity. Soil and sediment samples were collected before construction and 0.5, 2, 5.5, 11, 24, 60, and 131 months (11 y) after construction and analyzed for total chromium, copper, and arsenic concentrations. This article updates the findings after 11 years of exposure. Environmental concentrations varied with time, with proximity to the treated wood, and between riparian and aquatic locations. Concentrations of leached components in the soil developed slowly, were greatest at the 60-month sampling, and declined at the 131-month inspection. Soil samples with elevated levels of copper and chromium were confined to directly under the drip line of the boardwalk, and arsenic appeared to be limited to within 0.3 m (1 ft) of the structure. Concentrations of leached components in the sediments increased more quickly than those in the soil and tended to reach maximum or near maximum levels within the first year. However, concentrations of arsenic and copper in sediments directly under the walkway reached maximum levels after 60 months, before declining at the 131-month sampling. Elevated concentrations of copper, chromium, and arsenic were occasionally found in sediments as much as 3 m (10 ft) from the boardwalk.