Toxic effect of cigarette butts leachates on blood markers of Periophthalmus waltoni species from the Persian Gulf region

Cigarette butts (CBs) are one of the most common, long-lasting, and toxic forms of marine and coastal area debris. Although the significance of CBs and the toxic contents of this waste items are well recognized, but there is still a lack of information about the effects of this waste on the aquatic organisms. Therefore in this study, the in-vivo toxic effects of various CBs leachates (smoked cigarette butts with tobacco [SCBs], smoked CBs without tobacco [SFs], and unsmoked filters [USFs]) on cellular and chemical hematologic markers in fish (Periophthalmus waltoni) were evaluated. In three acute, sub-acute, and sub-chronic exposure measurements, P. waltoni exposed to different CBs leachates showed a significant increase in white blood cells, creatine kinase, lactate dehydrogenase, alkaline phosphatase, alanine transaminase, and aspartate transaminase, as well as a decrease in hemoglobin (Hb) levels. The mean ± SD values of Hb in P. waltoni species exposed to different CBs leachates (control, SCBs, SFs and USFs) in acute (1 day) phase were 7.15 ± 0.34, 6.02 ± 0.29, 6.25 ± 0.25 and 6.89 ± 0.1 g/dl respectively. These values in subacute (28 days) phase were 6.70 ± 0.15, 5.19 ± 0.24, 5.67 ± 0.30 and 6.10 ± 0.24 g/dl and in sub chronic exposure (42 days) phase were 7.20 ± 0.40, 5.16 ± 0.30, 5.88 ± 0.34 and 6.60 ± 0.33 g/dl respectively. Our results showed that CBs leachates act as a stressor, leading to changes in some hematologic markers in P. waltoni species. Because of the continued deposition of CBs waste into global aquatic environments, policies to mitigate this waste in coastal areas are needed to prevent potentially negative effects on fish and other aquatic organisms.