Patterns of mercury and methylmercury bioaccumulation in fish species downstream of a long-term mercury-contaminated site in the lower Ebro River (NE Spain)

► We study the bioavailability and bioaccumulation capacities of THg and MeHg in fish. ► MCA and MLR explain the associations among Hg in fish and distribution in the river. ► Hg pollution (levels in fish) increases progressively downstream of the hot spot. ► Transport of MeHg and Hg bioavailability explain the higher levels downstream. ► Single measurements of THg leads to under- or overestimation of pollution levels.