Bioaccumulation and elimination of Hg in the fireworm Eurythoe complanata (Annelida: Polychaeta) from Mazatlan, Mexico.
Mercury accumulation and elimination by Eurythoe complanata were evaluated through two laboratory bioassays in the absence (bioassay A) and presence (bioassay B) of sediment. Ten individuals per treatment (three replicates) were exposed to Hg in solution (0, 1.5, 1.7, 3, 7.4, 8.7, 9, and 11 microg/L) for an 8-day exposure period. At the beginning of the elimination period, the solutions (both bioassays) and sediments (bioassay B) were replaced by seawater only and clean sediment, respectively. This period lasted 8 days. The effect of Hg concentrations on Hg accumulation by worms from bioassay A was confirmed by the Kruskal-Wallis test (H = 19.43, df = 7, chi(2) = 18.475, p = 0.01), whereas this effect was nonsignificant for bioassay B. Specimens from bioassay A accumulated about double the Hg than those of bioassay B. This indicates that sediment plays an important role in the bioaccumulation process. Mercury elimination was observed only on specimens from bioassay B, where 25% to 36% of the total Hg was eliminated during 8 days. This suggests that worms need a longer period of time to completely depurate the accumulated Hg. The Hg balance was performed at the beginning and end of the experimental periods. The total Hg percentage per aquarium decreased at the end of the experiment, which suggests that a considerable amount of Hg was evaporated or adhered to the aquarium walls. This first approach points out that experimental studies using E. complanata as a test species can be useful to evaluate the potential risk produced by Hg or other toxicants on marine biota inhabiting zones subjected to anthropogenic activities.
Vázquez-Núñez
Ramón
R
Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av Joel Montes Camarena s/n, Col Centro Mazatlán, Sinaloa, México.
Méndez
Nuria
N
Green-Ruíz
Carlos
C
D000818:Animals; D019015:Geologic Sediments / Q000032:analysis; D008628:Mercury / Q000032:analysis / Q000493:pharmacokinetics*; D008800:Mexico; D011077:Polychaeta / Q000378:metabolism*; D014873:Water Pollutants / Q000032:analysis / Q000493:pharmacokinetics*
D014873:Water Pollutants; D008628:Mercury