Toxicant extraction efficiency and branchial NaCl fluxes in lampreys exposed to kepone�

Abstract

Freshwater fish (larval lampreys Petromyzon marinus) occupied plastic tubes and ventilated aqueous solutions (around 1.0 mg/L) of the organochlorine pesticide Kepone at 13 degrees C. The efficiency with which Kepone was extracted from solution during a single pass through the pharynx, and the effect of Kepone on fluxes of Na+ and Cl- across the gills were measured. The efficiency with which lampreys extracted Kepone from local tap water averaged 55-66%, confirmed by measuring Kepone accumulation within the lampreys (as 14C-equivalents), using a mass-balance approach. The extraction efficiency matches predictions based on studies using teleosts. Extraction efficiencies declined slowly throughout the exposure period and related inversely to ventilatory rates. In ion-flux measurements, Kepone produced a 40% decline in the rate of influx of Cl- across the pharynx. Effluxes of Na+ and Cl- were not affected, nor was influx of Na+. These latter findings are difficult to reconciliate with accepted theories of Kepone's toxic action; they may relate to the fact that lampreys are unusually tolerant to Kepone poisoning.

HISTOPATHOLOGICAL CHANGES IN LIVER AND GILLS OF Odontesthes bonariensis INHABITING A LAKE WITH HIGH CONCENTRATIONS OF ARSENIC AND FLUORIDE (CHASICÓ LAKE, BUENOS AIRES PROVINCE)

“…All these actions are closely related to gill chloride cells (Mallatt 1985, Mallatt andStinson 1990) and they are one of the entryways for toxins in fish (Hughes 1984). Once the gills are damaged, the gas exchange and osmotic regulation functions could be affected, resulting in physiological and histological changes in fish (Haque et al 2012).…”

Toxicidade dos sedimentos da Bacia Hidrográfica do Rio Monjolinho ( São Carlos - SP): ênfase nas substâncias cobre, aldrin e heptacloro

“…Alguns estudos têm demonstrado que a perda na integridade das brânquias pode estar relacionada a uma deficiência na concentração de eletrólitos no sangue, como sódio, cloreto e cálcio, a qual vem sendo observada depois da exposição de peixes de água doce à pesticidas, à metais, tais como mercúrio, cromo, zinco, cobre e cádmio (FU; LOCK; WENDELAAR BONGA, 1989; LOCK; CRIJSEN; VAN OVERBEEKR, 1981;MALLATT;STINSON, 1990;REID;McDONALD, 1988;SPRY;WOOD, 1985). Isto ocorre, porque em relação aos metais os mesmos podem afetar a permeabilidade da brânquia, uma vez que eles deslocam os íons cálcio das membranas, estabilizando-se em locais das brânquias McDONALD, 1985).…”

“…Ainda, deve-se considerar que a intensidade das lesões em tecidos branquiais varia em função do nível de poluição dos ambientes (ANDRADE, 2003;FRACÁCIO et al, 2003;GERNHÖFER et al, 2001;MELETTI, 2003;PAWERT;TRIEBSKORN, 1998;TRIEBSKORN et al, 2003) KARINO;NAKASHIMA, 2000), demonstrando a importância de estudos sobre os efeitos no crescimento de organismos. Kristensen (1994) MALLATT; STINSON, 1990;REID;McDONALD, 1988;SPRY;WOOD, 1985). …”