title: Sensitivity of a tropical micro-crustacean (Daphnia lumholtzi) to trace metals tested in natural water of the Mekong River.
abstract: Metal contamination is one of the major issues to the environment worldwide, yet it is poorly known how exposure to metals affects tropical species. We assessed the sensitivity of a tropical micro-crustacean Daphnia lumholtzi to three trace metals: copper (Cu), zinc (Zn) and nickel (Ni). Both, acute and chronic toxicity tests were conducted with metals dissolved in in situ water collected from two sites in the lower part of the Mekong River. In the acute toxicity test, D. lumholtzi neonates were exposed to Cu (3-30μgL-1), Zn (50-540μgL-1) or Ni (46-2356μgL-1) for 48h. The values of median lethal concentrations (48h-LC50) were 11.57-16.67μg Cu L-1, 179.3-280.9μg Zn L-1, and 1026-1516μg Ni L-1. In the chronic toxicity test, animals were exposed to Cu (3 and 4μgL-1), Zn (50 and 56μgL-1), and Ni (six concentrations from 5 to 302μgL-1) for 21days. The concentrations of 4μg Cu L-1and 6μg Ni L-1enhanced the body length of D. lumholtzi but 46μg Ni L-1and 50μg Zn L-1resulted in a strong mortality, reduced the body length, postponed the maturation, and lowered the fecundity. The results tentatively suggest that D. lumholtzi showed a higher sensitivity to metals than related species in the temperate region. The results underscore the importance of including the local species in ecological risk assessment in important tropical ecosystems such as the Mekong River to arrive at a better conservational and management plan and regulatory policy to protect freshwater biodiversity from metal contamination.
authors.affiliation: Hochiminh City University of Technology, Vietnam National University - Hochiminh City, 268 Ly Thuong Kiet Street, District 10, Hochiminh City, Vietnam. Electronic address: dao.son@hcmut.edu.vn.
authors.forename: Thanh-Son
authors.initials: TS
authors.lastname: Dao
authors.affiliation: University of Science, Vietnam National University - Hochiminh City, 227 Nguyen Van Cu Street, District 5, Hochiminh City, Vietnam.
authors.forename: Vu-Nam
authors.initials: VN
authors.lastname: Le
authors.affiliation: Institute for Environment and Resources, Vietnam National University - Hochiminh City, 142 To Hien Thanh Street, District 10, Hochiminh City, Vietnam.
authors.forename: Ba-Trung
authors.initials: BT
authors.lastname: Bui
authors.affiliation: National Institute of Aquatic Resources, Technical University of Denmark, 2920 Charlottenlund, Denmark; Department of Freshwater Aquaculture, Nha Trang University, Nha Trang City, Vietnam.
authors.forename: Khuong V
authors.initials: KV
authors.lastname: Dinh
authors.affiliation: University Rennes1, UMR 6553 ECOBIO, Campus de Beaulieu, 35042 Rennes Cedex, France.
authors.forename: Claudia
authors.initials: C
authors.lastname: Wiegand
authors.affiliation: Institute for Environment and Resources, Vietnam National University - Hochiminh City, 142 To Hien Thanh Street, District 10, Hochiminh City, Vietnam.
authors.forename: Thanh-Son
authors.initials: TS
authors.lastname: Nguyen
authors.affiliation: Hochiminh City University of Technology, Vietnam National University - Hochiminh City, 268 Ly Thuong Kiet Street, District 10, Hochiminh City, Vietnam.
authors.forename: Cong-Thanh
authors.initials: CT
authors.lastname: Dao
authors.affiliation: University of Science, Vietnam National University - Hochiminh City, 227 Nguyen Van Cu Street, District 5, Hochiminh City, Vietnam.
authors.forename: Van-Dong
authors.initials: VD
authors.lastname: Nguyen
authors.affiliation: University of Science, Vietnam National University - Hochiminh City, 227 Nguyen Van Cu Street, District 5, Hochiminh City, Vietnam.
authors.forename: Thi-Hien
authors.initials: TH
authors.lastname: To
authors.affiliation: University of Science, Vietnam National University - Hochiminh City, 227 Nguyen Van Cu Street, District 5, Hochiminh City, Vietnam.
authors.forename: Ly-Sy-Phu
authors.initials: LS
authors.lastname: Nguyen
authors.affiliation: University of Science, Vietnam National University - Hochiminh City, 227 Nguyen Van Cu Street, District 5, Hochiminh City, Vietnam.
authors.forename: Truong-Giang
authors.initials: TG
authors.lastname: Vo
authors.affiliation: Hochiminh City University of Technology, Vietnam National University - Hochiminh City, 268 Ly Thuong Kiet Street, District 10, Hochiminh City, Vietnam.
authors.forename: Thi-My-Chi
authors.initials: TM
authors.lastname: Vo
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects*; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000633:toxicity*; D045483:Rivers; D023382:Toxicity Tests, Acute; D036401:Toxicity Tests, Chronic; D014744:Vietnam; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: Acute toxicity; Life history traits; Mekong River water; Sensitivity; Trace metals