Effects of Diazinon on the Survival, Blood Parameters, Gills, and Liver of Grass Carp (Ctenopharyngodon idella Valenciennes, 1844; Teleostei: Cyprinidae)

Abstract

Diazinon (DZN) is a widely used pesticide that can affect the vital organs of non-target aquatic animals—mainly fish. This study evaluated the acute toxicity (LC50) of six DZN concentrations (0.5, 0.75, 1.5, 2, 2.5, and 3 mg·L−1) and, based on its evaluation after 24 h, 48 h, 72 h, and 96 h, two sublethal concentrations for chronic toxicity testing (0.01 and 0.05 mg·L−1) for 21 days of exposure to DZN on grass carp fingerlings (Ctenopharyngodon idella Valenciennes, 1844). The median lethal concentrations of DZN at 24, 48, 72, and 96 h were 1.83, 1.57, 1.35, and 1.12 mg·L−1, respectively. Next, histological observations after 96 h LC50 showed oedema of the primary lamellae of the gills at low pesticide concentrations (0.5 to 1 mg·L−1) and extensive necrosis of primary lamellae of the gills at higher concentrations (1.5 to 3 mg·L−1). Moreover, cytoplasmic vacuolation and extensive necrosis were observed in liver tissue. Increased skin mucus, unbalanced swimming on the water surface, and increased gill opercula movements were noted during chronic exposure. Haematological parameters such as haematocrit, red blood cell count, white blood cell count, haemoglobin, and mean corpuscular volume were significantly reduced after 21 days of exposure to 0.05 mg·L−1 of DNZ (p < 0.05). The present study shows that DZN has various toxic effects on grass carp, which may pose a potential risk for other fish species.

Evaluating Silymarin Extract as a Potent Antioxidant Supplement in Diazinon-Exposed Rainbow Trout: Oxidative Stress and Biochemical Parameter Analysis

“…Diazinon is an insecticide widely used to control pests in agriculture, on livestock farms, and in residential areas. However, its use has led to contamination of surface waters in many parts of the world, including the United States [ 1 , 2 , 3 ]. Studies have found traces of diazinon in streams, rivers, and lakes due to runoff from agricultural and residential areas [ 4 , 5 ].…”

Impact of Chlorpyrifos on Cytopathological Indices in Mangrove Crab, Episesarma tetragonum (Fabricius)

“…The insecticide chlorpyrifos is found in agricultural, industrial, and home waste and is considered a primary source of aquatic contamination [ 14 , 15 ]. Nutrient recycling in paddy soils is also threatened by disrupting interactions between micro- and macro-organisms [ 16 , 17 , 18 , 19 , 20 ]. The mangrove habitat is particularly vulnerable to agricultural effluents, mainly because of its location at the river’s mouth.…”

“…Cytopathological indicators are crucial for monitoring and evaluating the toxicity of aquatic ecosystems [20][21][22][23][24][25][26]. Prolonged exposure to toxic agents often does not cause death directly; however, the structure and function of vital organs are affected, jeopardizing the individual population.…”