Acute and Chronic Toxicity Effects of the Heptachlor Pesticide on Tilapia (Oreochromis mossambicus): Impact to Behavioral Patterns and Histopathological Responses

Analyzing the impact of pesticides on the indus river: contamination levels in water, sediment, fish, and associated human health risks

Pesticides are frequently used to protect crop yields and manage malaria vectors; however, their inadvertent transport into aquatic habitats poses a significant concern. Various anthropogenic activities influence the Indus River in Pakistan. This study aimed to assess the presence of eight pesticide residues at three different sites (Kalabagh, Kundian, and Chashma) in water, sediment, and the fish species (Labeo rohita) during both dry and wet seasons to measure the intensity of this pressure. Pesticide analysis was carried out using gas chromatography equipped with an electron capture detector. The results revealed the highest concentrations of pesticides during both dry and wet seasons at all sites, measuring 0.83 and 0.62 μg/l (water), 12.37 and 9.20 μg/g/dw (sediment), and 14.27 and 11.29 μg/g/ww (L. rohita), respectively. Overall, pesticide concentrations were higher in the dry season than in the wet season across all study sites. Based on detection frequency and concentration in both seasons at all sites, dominant pesticides included cypermethrin and carbofuran (in water), as well as endosulfan and cypermethrin (in sediment and fish tissue). Levels of endosulfan and cypermethrin exceeded standard limits. Moreover, principal component analysis (PCA) indicated no correlation among pesticides in fish tissue, sediment, and water. However, pesticides exhibited different behavior in different seasons. Furthermore, endosulfan and triazophos impose great human health risk, as indicated by the THQ value (> 1). The overall HI value was greater for site 1 in the dry season (8.378). The study concluded that the presence of agricultural pesticides in the Indus River poses a risk to aquatic life and has the potential to disrupt the entire food chain. This highlights the importance of sustainable practices for the study area and Pakistan overall agricultural and environmental sustainability. It is further recommended to strengthen regulations for reduced pesticide use and promote eco-friendly pest management.

Organochlorine, organophosphorus, and carbamate pesticide residues in an Ethiopian Rift Valley Lake Hawassa: occurrences and possible ecological risks

Currently, pesticide production and use are on the rise globally. This trend is certain to continue in the coming decades with residues posing risks to the environment and human health even at low levels. Although various aspects of pesticides and their possible implications have widely been studied, such studies have mostly been carried out in developed countries leaving the rest of the world with little scientific information. We present here the results of a study on the occurrences, concentrations, and ecological risks of 30 pesticide residues (PRs) in water and sediment samples from a tropical freshwater Lake Hawassa in the Ethiopian Rift Valley. A total of 54 composite samples of water and sediment were collected from three sampling sites on three occasions. The samples were prepared by quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique, and analyzed using GC-MS at Bless Agri Food Laboratory Service located in Addis Ababa, Ethiopia. The study applied the risk quotient (RQ) method to scrutinize the risks posed to aquatic biota by the detected PRs. The results showed occurrences of 18 and 20 PRs in the water and sediment samples, respectively. The majority, 78 and 75% of the detected PRs in water and sediment samples, respectively represent the organochlorine chemical class. Concentrations of heptachlor epoxide were significantly (p ≤ 0.001) higher than those of the remaining pesticides in both matrices. Of the pesticides detected, 77% were present in water and 83% in sediment samples and pose a serious risk (RQ ≥ 1) to the Lake Hawassa biota. This calls for further research to investigate the risks to human health posed by the PRs. The findings of this study can contribute to the development of global protocols, as they support the concerns raised about the ecological and public health impacts of PRs on a global level.

Diffusion of organochlorine (OCPs) and cypermethrin pesticides from rohu (Labeo rohita) internal organs to edible tissues during ice storage: a threat to human health

The migration of organochlorine pesticides (OCPs) and cypermethrin residues from internal organs to edible tissues of ice-held Labeo rohita (rohu) was investigated in this study. The liver (246 µg/kg) had the highest level of ∑OCP residues, followed by the gills (226 µg/kg), intestine (167 µg/kg), and muscle tissue (54 µg/kg). The predominant OCPs in the liver and gut were endosulfan (53-66 µg/kg), endrin (45-53 µg/kg), and dichloro-diphenyl-trichloroethane (DDT; 26-35 µg/kg). The ∑OCP residues in muscle increased to 152 µg/kg when the entire rohu was stored in ice, but they decreased to 129 µg/kg in gill tissues. On days 5 and 9, the total OCPs in the liver increased to 317 µg/kg and 933 µg/kg, respectively. Beyond day 5 of storage, total internal organ disintegration had led to an abnormal increase in OCP residues of liver-like mass. Despite a threefold increase in overall OCP residues by day 9, accumulation of benzene hexachloride (BHC) and heptachlor was sixfold, endrin and DDT were fourfold, aldrin was threefold, and endosulfan and cypermethrin were both twofold. Endosulfan, DDT, endrin, and heptachlor were similarly lost in the gills at a rate of 40%, while aldrin and BHC were also lost at 60 and 30%, respectively. The accumulation of OCP residues in tissues has been attributed to particular types of fatty acid derivatives. The study concluded that while pesticide diffusion to edible tissues can occur during ice storage, the levels observed were well below the allowable limit for endosulfan, endrin, and DDT.

Toxicological effect of endocrine disrupting insecticide (deltamethrin) on enzymatical, haematological and histopathological changes in the freshwater iridescent shark, Pangasius hypothalamus

This study investigated the deltamethrin (DMN) induced harmful effects on Pangasius hypophthalmus using enzymatic activity, haematological, and histopathological changes. LC₅₀ value was 0.021mg/L at 96h, and sublethal toxicity was tested for 45 days at two `concentrations (i.e., 1/5^th and 1/10^th of LC₅₀). Haematological parameters and enzymatic activities significantly changed between DMN-exposed and control groups (p<0.05). Histopathologically, both DMN doses induced liver hyperemia, hepatic cell rupture, necrosis, hypertrepheoid bile duct, shifting nuclei, vascular haemorrhage, and hepatocyte degeneration, while in gill, secondary lamellae destruction, a fusion of adjacent gill lamellae, hypertrophy, hyperplasia, adhesion, and fusion were noticed. Kidney developed melanomacrophages, increased periglomerular and peritubular space, vacuolation, decreased glomerulus, hyaline droplets in tubular cells, loss of tubular epithelium, distal convoluted segment hypertrophy, and granular layer in brain pyramid and Purkinje cell nucleus. But, limiting pesticide impacts on freshwater fish and their habitat requires a holistic, cradle-to-grave approach and toxicological studies.

Toxicological effect of endocrine disrupting heavy metal (Pb) on Mekong silurid Pangasius catfish, Pangasius hypophthalmus

The current study aimed to investigate the effects of lead nitrate exposure on the enzymatical, haematological, and histological changes in the gill, liver, and kidney of Pangasius hypophthalmus. The fish were divided into six groups and treated with different Pb concentrations. The LC₅₀ value of Pb was 55.57 mg/L at 96 h for P. hypophthalmus, and sublethal toxicity was assessed for 45 days at 1/5th (11.47 mg/L) and 1/10th (5.57 mg/L) of LC₅₀ concentration. Enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels, alkaline phosphate (ALP), and lactate dehydrogenase (LDH) content increased significantly during sublethal toxicity of Pb. The reduction of HCT and PCV indicates an anemic condition due to the toxicity of Pb. Differential leucocytes, lymphocytes, and monocytes and their % values significantly decreased, indicating Pb exposure. The main histological changes observed in the gills were the destruction of secondary lamellae, the fusion of adjacent gill lamellae, primary lamellae hypertrophy, and severe hyperplasia, while in kidney exposed to Pb showed melanomacrophages, increased periglomerular, peritubular space, vacuolation, shrunken glomerulus, destruction of tubular epithelium, and hypertrophy of distal convoluted segment. The liver showed severe necrosis and rupture of hepatic cells, hyper trepheoid bile duct, shifting of nuclei, and vascular hemorrhage, while in the brain, binucleus, mesoglea cells, vacuole, and ruptured nucleus were observed. In conclusion, P. hypophthalmus, which has been exposed to Pb has developed a number of toxicity markers. Consequently, prolonged exposure to higher Pb concentrations may be harmful to fish health. The findings strongly suggest that the lead had a detrimental impact on the P. hypophthalmus population, as well as on the water quality and non-target aquatic organisms.

Bioaccumulation of organochlorine pesticide residues (OCPs) at different growth stages of pacific white leg shrimp (Penaeus vannamei): First report on ecotoxicological and human health risk assessment

Pesticide residues (PRs) in farmed shrimps are concerning food safety risks. Globally, India is a major exporter of pacific white leg shrimp (P. vannamei). This study was undertaken to analyze PRs in the water, sediments, shrimps, and feed at different growth stages to evaluate the ecotoxicological and human health risks. PRs in the seawater and sediments ranged from not detected (ND) to 0.027 μg/L and 0.006-12.39 μg/kg, and the concentrations were within the maximum residual limits (MRLs) and sediment quality guidelines prescribed by the World Health Organization and Canadian Environment Guidelines, respectively. PRs in shrimps at three growth stages viz. Postlarvae, juvenile, and adults, ranged from ND to 0.522 μg/kg, below the MRLs set by Codex Alimentarius Commission and European Commission. Most of the PRs in water, sediments, and shrimps did not vary significantly (p > 0.05) from days of culture (DOC-01) to DOC-90. The hazard quotient (HQ) and hazard ratio (HR) were found to be < 1, indicating that consumption of shrimps has no noncarcinogenic and carcinogenic risks. PRs in shrimp feed ranged from ND to 0.777 μg/kg and were found to be below the MRLs set by EC, which confirms that the feed fed is safe for aquaculture practices and does not biomagnify in animals. The risk quotient (RQ) and toxic unit (TU) ranged from insignificant level (ISL) to 0.509 and ISL to 0.022, indicating that PRs do not pose acute and chronic ecotoxicity to aquatic organisms. The study suggested no health risk due to PRs in shrimps cultured in India and exported to the USA, China, and Japan. However, regular monitoring of PRs is recommended to maintain a sustainable ecosystem.