title: Fish eyes and brain as primary targets for mercury accumulation - a new insight on environmental risk assessment.
abstract: Fish eyes and brain are highly susceptible to environmental Hg exposure but this issue is still scarcely investigated, mainly regarding methylmercury (MeHg) accumulation. Yet, Hg levels in fish lens have not been previously examined under field conditions. Total Hg (tHg), MeHg and inorganic Hg (iHg) levels were assessed in the brain, eye wall and lens of the golden grey mullet (Liza aurata) from an Hg contaminated area, both in winter and summer, together with water and sediment levels. Sampling was performed at Aveiro lagoon (Portugal) where a confined area (LAR) is severely contaminated by Hg. Fish brain, eye wall and lens accumulated higher levels of tHg, MeHg and iHg at LAR than the reference site, reflecting faithfully environmental spatial differences. The brain and eye wall responded also to the winter-summer changes found in water and sediment, accumulating higher levels of MeHg (and tHg) in winter. Contrarily, lens was unable to reflect seasonal changes, probably due to its composition and structural stability over time. The three neurosensory structures accumulated preferentially MeHg than iHg (MeHg was higher than 77% of tHg). Lens exhibited a higher retention capacity of MeHg (mean around 1 μg g(-1) at LAR), accumulating higher levels than the other two tissues. Interestingly, MeHg and iHg levels were significantly correlated for the brain and eye wall but poorly associated within the two analysed eye components. The high levels of MeHg found in the brain, eye wall and lens could compromise their functions and this needs further research.
authors: Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; IPMA - Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3Bs, PT Government Associated Laboratory, Braga/Guimarães, Portugal. Electronic address: ppereira@ipma.pt.
authors: Patrícia
authors: P
authors: Pereira
authors: IPMA - Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, 4050-123 Porto, Portugal.
authors: Joana
authors: J
authors: Raimundo
authors: IPMA - Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal.
authors: Olinda
authors: O
authors: Araújo
authors: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors: João
authors: J
authors: Canário
authors: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3Bs, PT Government Associated Laboratory, Braga/Guimarães, Portugal.
authors: Armando
authors: A
authors: Almeida
authors: Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Mário
authors: M
authors: Pacheco
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004784:Environmental Monitoring / Q000379:methods*; D005123:Eye / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism*; D008628:Mercury / Q000378:metabolism*; D011174:Portugal; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Bioaccumulation; Environmental contaminant biomonitoring; Fish; Inorganic mercury; Methylmercury; Neurosensory structures