title: Bioconcentration of methylmercury in microzooplankton in a temperate river.
abstract: To understand the bioconcentration of methylmercury (MeHg) at the base of the riverine food chain, we determined levels of dissolved organic carbon, microseston, Hg, and MeHg in surface water in relation to the microzooplankton MeHg from Yeongsan River. The spatial distribution of unfiltered Hg (0.29-3.1 ng/L) and dissolved Hg (0.15-0.74 ng/L) closely followed the microseston distribution. The spatial distribution of unfiltered MeHg (0.0078-0.077 ng/L) and dissolved MeHg (0.0069-0.018 ng/L) increased with increasing distance from the river mouth and appeared to arise from the shallow wetlands surrounding the upper riverbanks and then to be transported downstream. The logarithm of the MeHg bioconcentration factor for microzooplankton ranged from 5.3 to 6.0 (5.7 ± 0.18), and for microseston ranged from 4.0 to 5.4 (4.9 ± 0.35). Linear correlation statistics comparing microzooplankton MeHg and river water characteristics revealed that microzooplankton MeHg concentration was most significantly correlated with unfiltered MeHg (r = 0.83) and particulate MeHg (r = 0.80) levels. This result suggests that MeHg in unfiltered river water, which is relatively easy to determine, can be used as a surrogate for MeHg in microzooplankton that may influence MeHg levels in higher-trophic-level organisms.
authors.affiliation: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
authors.forename: Hyunji
authors.initials: H
authors.lastname: Kim
authors.forename: Seam
authors.initials: S
authors.lastname: Noh
authors.forename: Eunhee
authors.initials: E
authors.lastname: Kim
authors.forename: Rama Krishnan
authors.initials: RK
authors.lastname: Poopal
authors.forename: Hak Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Seunghee
authors.initials: S
authors.lastname: Han
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D020387:Food Chain; D008628:Mercury / Q000378:metabolism; D008767:Methylmercury Compounds / Q000378:metabolism*; D056910:Republic of Korea; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D015048:Zooplankton / Q000378:metabolism*
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury