Bioconcentración de metales pesados (Zn, Hg, Pb) en tejidos de Ariopsis felis y Diplodus annularis en el río Ranchería, norte de Colombia / Bioconcentration of heavy metals (Zn, Hg, Pb) in tissues of Ariopsis felis and Diplodus annularis in the Ranchería river, Northern Colombia

RESUMEN La contaminación por metales pesados en los ecosistemas acuáticos en el planeta es una de las más severas problemáticas que comprometen la seguridad alimentaria a nivel local, regional y global. En este estudio, se aborda el problema específico de la bioconcentración de mercurio (Hg), plomo (Pb) y Zinc (Zn) en los tejidos orgánicos de 2 de las especies de peces (Ariopsis felis y Diplodus annularis) de mayor importancia alimenticia para los pobladores rivereños del río Ranchería, al norte de Colombia. Las muestras de tejido orgánico se sometieron a una digestión ácida (HNO3 y HClO 4 en relación 3:1) y la cuantificación de los metales se realizó por espectrofotometría de absorción atómica. Adicionalmente, se midieron los niveles de los metales en el sedimento, con el objeto de determinar índices de calidad medioambientales, lo que permitió determinar que los metales pesados no presentan riesgo para los organismos acuáticos que habitan en esta zona. Se encontraron diferentes valores de concentración de metales pesados: en orden decreciente, Zn > Hg > Pb, en sedimento, y Hg > Zn > Pb, en el tejido biológico. Los resultados muestran que las concentraciones de los metales pesados presentes en el tejido de los peces y en el sedimento guardan una correlación positiva y una regresión lineal estadísticamente significativa (p = 0,001, p < 0,05). La presencia de metales pesados en el sedimento del río y de bioconcentrados en los peces podría derivarse de fuentes puntuales y difusas relacionadas con actividades agrícolas, pecuarias, mineras y aguas residuales.

ABSTRACT Heavy metal pollution in aquatic ecosystems in the area is one of the most severe problems that compromise food security at the local, regional and global levels. In this study, the specific problem of the bioconcentration of mercury (Hg), lead (Pb), and Zinc (Zn) in 2 of the higher nutritional importance fish species (Ariopsis felis and Diplodus annularis) for the riverside inhabitants of the Ranchería river, in northern Colombia, is addressed. The organic tissue samples were subjected to acid digestion (HNO3 and HClO4 in a 3:1 ratio), and the quantification of metals was carried out by atomic absorption spectrophotometry. Additionally, the levels of metals in the sediment were measured, in order to determine environmental quality indices. This allow to determine that heavy metals do not present a risk to the aquatic organisms that inhabit this area. Different heavy metal concentration values were found: in decreasing order, Zn> Hg> Pb in sediment, and Hg> Zn> Pb in biological tissue. The results reveal that the concentrations of heavy metals present in fish tissue and sediment show a positive correlation, and a statistically significant linear regression (p = 0,001, p < 0,05). The presence of heavy metals in river sediment and bioconcentrates in fish could derive from point and diffuse sources related to agricultural, livestock, mining and wastewater activities.

Studies on persistent organic pollutants residue in water, sediment and fish tissues of river Sutlej, India

Aim: To study the level of persistent organic pollutants in the environment of River Sutlej and rule out its detrimental effects on aquatic fauna. Methodology: Two different sites were selected for the study, one was before the confluence of a polluted tributary (Site I) another was after the confluence of polluted tributary (Site II). Analysis of water, sediment, gills and muscles of selected fish species was done to detect the level of persistent organic pollutants using Gas Chromatography. Results: Among POP's, PCB-28 was detected during monsoon period(0.55 ng ul-1) at Site I, while as it was detected both during monsoon (0.65 ng ul-1) and post-monsoon (0.49 ng ul-1) period at Site II in the water samples. Similarly, PCB-28 was detected in gills of Cirrhinus mrigala during pre (0.26 ng g-1) and post-monsoon (0.27 ng g-1) periods at Site I, while at Site II it was detected only during monsoon period (0.17 ng g-1). In Aoricthysaor gills, only PCB-28 was detected during pre-monsoon (0.34 ng g-1) and monsoon periods (0.19 ng g-1) at Site II. In Heteropneustes fossilis PCB-28 was detected during pre-monsoon period (0.26 ng g-1) at Site I, while at Site II it was found during pre-monsoon (0.21 ng g-1) and monsoon (0.17 ng g-1) periods. In Catla Catla gill samples among PCB's only PCB-28 was detected during pre-monsoon (0.32 ng g-1), monsoon (0.29 ng g-1) and post-monsoon periods (0.24 ng g-1) at Site II while Mirex (0.01 ng g-1) was detected at Site I during post-monsoon period. Interpretation: The study concluded that continuous monitoring of pesticide residue is warranted in the river Sutlej to rule out any detrimental effect of pesticide pollution on aquatic fauna.

Toxicity of zinc on the biochemical contents of certain tissues of freshwater fish, channa gachua (HAM.).

Industrial effluent containing heavy metals, on entering aquatic environment causes biochemical disturbances in the fish. The present study deals with the toxicity of Zinc as (ZnSO4), as a component of industrial waste and its effect on tissue glycogen and protein level at 24, 48, 72 & 96 hrs respectively .The estimated glycogen and protein concentration in the tissues- gills, liver, kidney, ovary and testis were found to be reduced during the exposure periods.