Sublethal effects of pulp and paper mill effluent on two commonly cultured carps: a SEM- and EDS-based hematological biomarker analysis

Abstract

Blood being a vehicle for the transport of industrial pollutants in living system, fish hematology is considered as potent biomarker. In the present study, we investigated respective sublethal effects of pulp and paper mill effluents on hematology of two commonly cultured carps, Cyprinus carpio and Ctenopharyngodon idella, using optical, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Irrespective of species, results showed significant decrease in erythrocyte, hematocrit and hemoglobin contents while an increase in white blood cell counts (P < 0.05). We observed an increasing trend of MCV (170.0 ± 3.07 to 193.16 ± 2.5) and MCH (34.31 ± 1.89 to 38.71 ± 3.61) up to 28th day in C. carpio (P < 0.05), while, in C. idella, the highest percent increase in MCV (180.8 ± 2.19) and MCH (32.9 ± 0.62) was observed on seventh exposure day, which subsequently declined, respectively, to 173.1 ± 17.1 and 27.9 ± 2.45 on 28th day. Unlike C. carpio, significant and progressive MCHC declining trend (18.23 ± 0.28 to 16.13 ± 0.31) was observed in C. idella. The most commonly observed abnormalities under SEM include echinocytes, cytoplasmic blebbing, cytoplasmic ring, spherocytes, lobopodial projections and acanthocytes in red blood cells of exposed fishes. EDS further revealed the presence of aluminum, antimony, arsenic, cadmium, mercury, tungsten, zinc and titanium; some of these metals were not even detected in the effluent samples, suggesting the probable metal bio-concentration in fish tissue, and subsequent jeopardization is a major concern particularly in the industrial area. Our study further suggested the use of sensitive and specific techniques like SEM and EDS in fish hematological biomarker analysis along with the conventional approach.

Bisphenol A induced toxicity in blood cells of freshwater fish Channa punctatus after acute exposure

“…SEM studies of erythrocytes revealed various abnormalities such as irregular shape, notched, elongated cells, cytoplasmic bleb in C. punctatus . Various researchers observed different abnormalities in erythrocytes of fish exposed to different xenobiotics ( Dey et al, 2016 , Kaur and Kaur, 2015 , Mehra and Chadha, 2021 ). Changes in the morphology of erythrocytes of fish exposed to xenobiotics indicate the poor health status of the fish ( Sawhney and Johal, 2000 ).…”

Visualization of poikilocytosis as an emerging erythrocytic biomarker for fish health assessment

“…Elliptocyte (EL, El): [30,47,49,87,93,126,129,130,140,152]. Dacrocyte (Da, Tr): [4,47,77,87,96,129,140,152,153]. Schistocyte (Sch, Sh): [5,69,77,130,154,155].…”

“…Acanthocytosis has been associated with liver dysfunction [29], suggesting a possible link between drug administration, organ damage, and poikilocytosis. In fish, acanthocytes have been observed during hemolytic, microcytic, and normocytic anemia induced by heavy metal intoxication, paper mill effluents, pharmaceutical application, pesticide application, and many more [50,75,96,100], but their pathological significance has not been studied yet. Acanthocytes have been observed in every reported case of poikilocytosis in fish (Table 2).…”