Abstract:
Nanoparticles are an emerging class of pollutants due to their extensive use in different
products. They enter the environment directly or indirectly during the manufacturing
lifecycle as well as by-products that contain nanoparticles, for example,sunscreens and
paints. Nano zinc oxide and titanium dioxide are extensively utilized worldwide, and
their production is expected to increase further. The study evaluates the toxicity of nano
zinc oxide individually and in combination with nano titania in common carp. This fish
species is economically valued worldwide as it is a source of protein and easily
available. It is also susceptible to a wide range of water contaminants. Titanium dioxide
nanoparticles enhanced the lethality of zinc oxide nanoparticles as the LD50 reduced
from 351 to 326 mg/L. Zinc oxide nanoparticles accumulation was found to be
augmented in the presence of titanium dioxide nanoparticles. The maximum
accumulation was observed in the intestine of fish, while the lowest was observed in
the muscle of fish. Initially, zinc oxide nanoparticle reduces the ROS in the fish body
however with increasing dosage and time, defense mechanism suppresses, and an
increase was found in the ROS and a direct increase was found in the ROS in the
presence of titanium dioxide nanoparticles (p<0.05). The maximum histopathological
lesions were observed in co-exposure treatment group and the most common alterations
were the shortening and curling of secondary lamella, partial fusion of lamella, and
edema. The biochemical indices glucose, triglycerides and alanine transaminase
significantly increased due to TiO2 NPs. However, total protein decreased in the
combined exposure group. The findings highlight the significance of considering the
co-occurrence and interplay of nanoparticles in comprehending their toxicity in
organisms.
