DDT contamination in water resources of some African countries and its impact on water quality and human health

Multigenerational exposure to trace concentrations of DDT residues in Wistar rats: Effects on biometric development and biochemical parameters

The Organochlorine Dichlorodiphenyltrichloroethane (DDT) and its residues, Dichlorodiphenyldichloroethane (DDD) and Dichlorodiphenyldichloroethylene (DDE), are Persistent Organic Pollutants (POPs) that bioaccumulate, persist in the environment, and magnify through the food chain. Chronic exposure is linked to oxidative stress and mitochondrial dysfunction, emphasizing the need to study its multigenerational impacts on health and development. This study investigated the effects of multigenerational exposure to DDT residues in Wistar rats. Pregnant females were provided water containing trace concentrations of p,p'-DDD (0.015 µM) and p,p'-DDE (0.006 µM) from the first day of gestation (PD0) until the end of the life cycle of two generations (F1 and F2). Biometric and biochemical evaluations were conducted at PND35 and PND105, including weight, naso-anal length, and abdominal circumference. Hepatic, renal, and adipose tissues were analyzed macro- and microscopically, along with biochemical analyses. Statistical analyses included ANOVA and generalized linear models. The hypothetical model confirmed that no significant variations occurred between generations, indicating that effects were driven by group, age, and sex differences. The analysis revealed that DDD/DDE synergism and female sex significantly influenced hepatic, renal, cerebral, and white adipose tissues. DDD/DDE exposure increased hepatic enzyme activity, reduced cerebral cholinesterase and renal antioxidants, and altered adipocyte mass. Age also influenced enzymatic activity and development, with notable differences between PND35 and PND105 in tissues and biometric indices. In conclusion, DDD/DDE exposure, particularly in females, significantly impacted hepatic, renal, cerebral, and adipose tissues. The results highlight that observed effects depend on group, age, and sex, emphasizing the risks associated with environmental contamination.

MicroRNA expression in response to environmental hazards: Implications for health

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally and are increasingly recognized as sensitive biomarkers of environmental exposure. This review explores how various environmental hazards-including radiation, air pollutants, heavy metals, pesticides, phthalates, and pathogens-alter both cellular and circulating miRNA expression, influencing phenotypic plasticity and contributing to disease development. Environmental hazards can induce epigenetic modifications in miRNA profiles, disrupting key biological processes such as inflammation, oxidative stress, apoptosis, and DNA repair. These alterations are associated with a wide range of diseases. The review outlines miRNA biogenesis, function, and extracellular transport, highlighting their stability and tissue specificity as biomarkers of exposure and disease. It also examines the complexity of exposure-specific miRNA signatures, shaped by factors such as genetic background, co-exposures, and exposure duration, and discusses current challenges in their validation and clinical application. Overall, this review underscores the pivotal role of miRNAs in cellular responses to environmental hazards and their potential as diagnostic and therapeutic tools, with broad implications for environmental health and disease prevention.

Bioaccessibility of p,p'-DDT and p,p'-DDE in tropical soil ecosystems: a model based on pollutant speciation coefficients and the desorption free energy of adsorbed speciation forms

The bioaccessibility of organic pollutants in the environment depends on the nature and speciation of the contaminants and is determined using in vitro methods that simulate gastro-intestinal digestion. The objectives of the present study were to study the bioaccessibility coefficients of p,p'-DDT and p,p'-DDE in tropical soils based on the physico-chemical properties of the contaminant. The behavior of organic contaminants in soil ecosystems is characterized by their speciation and persistence, both of which depend on the extent to which the contaminant adsorbs to particulates in the soil matrix, as revealed in the characteristic persistence curve of the contaminant. Data are presented showing that the bioaccessibility coefficient of soil contaminants can be represented by a model based on the contaminant's speciation coefficients in the sample matrix, the desorption free energy of contaminant adsorbed speciation forms and temperature, provided its dissipation conforms to the multi-phase pseudo-zero order rate law. When the model was applied to determine the bio-accessibility coefficients of p,p'-DDT and p,p'-DDE in tropical soils based on previously published data from the literature, mean bioaccessibility coefficient values of 0.30 ± 0.21 (n = 8) and 0.35 ± 0.13 (n = 9) (p,p'-DDT), and 0.43 ± 0.05 (n = 4) and 0.20 ± 0.01 (n = 2) (p,p'-DDE), were obtained depending on whether determinations were carried out using chromatographic or radiotracer methods. The results fall within the range of literature values obtained using in vitro methods, thus attesting to the potential of the model presented for predicting the bioaccessibility coefficients of persistent organic pollutants in soil ecosystems.

Assessment of organochlorine pesticide residues in agricultural soils of southern Nigeria and analysis of potential health risks

The use of pesticides in commercial farms can lead to exposure among various vulnerable groups. This study assessed the distribution, human health risks, and origins of 13 targeted organochlorine pesticides (OCPs) in soil samples from commercial farms in Southern Nigeria. Following a questionnaire survey on pesticide usage, soil samples were subjected to Soxhlet extraction and analyzed using gas chromatography-mass spectrometry. Results indicated that 31.6 % of farmers did not use personal protective equipment, and only 37.6 % had received training on safe pesticide application. While pyrethroids and organophosphates were commonly used, organochlorines were rarely applied. The detected levels of OCPs in the agricultural zones ranged from below detection limit (BDL) to 18.35 ± 13.83 µg/kg and were generally within the minimum risk level (MRL), except for α-HCH and β-HCH in Oron and Etinan zones. The estimated non-carcinogenic risk s from detected OCPs were insignificant at the time of the study, as the calculated Hazard Indexes (HIs) and Hazard Quotients (HQs) for ingestion, dermal absorption, and inhalation were all less than 1, indicating generally low risks. The carcinogenic risk assessment showed that the Incremental Lifetime Cancer Risk (ILCR) values ranged from 10-10 to 10-4, indicating a very low to low risk level according to the classification by the United States Agency for Toxic Substances and Disease Registry (US ATSDR). Source apportionment suggested that most OCP congeners were of historical origin, with only a few indicating recent use. In conclusion, organochlorine pesticide residues in the studied farms posed minimal health risks, with most originating from historical rather than recent use.

A shot in the foot: Could chemical control of malaria vectors threaten food security?

Overwhelmingly, contemporary malaria vector control equals the use of chemical pesticides (through insecticide-treated bednets or indoor residual spraying). Gradually, but surely, we have become enslaved to thinking that controlling malaria mosquitoes equals the use of chemical insecticides, and much of the vector control field today is dominated by scientists, lobbyists, chemical companies, funding agencies and (global) institutions that endlessly repeat this dogmatic belief. Although chemical control has undoubtedly saved millions of lives, which, morally speaking would immediately justify its continued use, it has many sides that may ultimately cost more lives than it saves. Not only the cyclical problems with insecticide resistance, but also our increased understanding of the human and environmental health impacts of these chemicals, continue to raise red flags. Furthermore, the millions of kilogrammes of annual bednet waste (polyethylene, polypropylene) and bednet packaging material cannot be ignored. In recent years, an abundance of evidence that the use of chemical pesticides is a prime cause for the global decline in insect biodiversity and abundance has surfaced. The rate at which this decline is happening is frightening and may sooner rather than later threaten food production on a global scale. Should we opt for saving lives in the short term by using chemicals and face devastating and irrevocable long-term consequences or become wise(r) in the way we control malaria mosquitoes?

Agricultural Pest Management: The Role of Microorganisms in Biopesticides and Soil Bioremediation

Pesticide use in crops is a severe problem in some countries. Each country has its legislation for use, but they differ in the degree of tolerance for these broadly toxic products. Several synthetic pesticides can cause air, soil, and water pollution, contaminating the human food chain and other living beings. In addition, some of them can accumulate in the environment for an indeterminate amount of time. The agriculture sector must guarantee healthy food with sustainable production using environmentally friendly methods. In this context, biological biopesticides from microbes and plants are a growing green solution for this segment. Several pests attack crops worldwide, including weeds, insects, nematodes, and microorganisms such as fungi, bacteria, and viruses, causing diseases and economic losses. The use of bioproducts from microorganisms, such as microbial biopesticides (MBPs) or microorganisms alone, is a practice and is growing due to the intense research in the world. Mainly, bacteria, fungi, and baculoviruses have been used as sources of biomolecules and secondary metabolites for biopesticide use. Different methods, such as direct soil application, spraying techniques with microorganisms, endotherapy, and seed treatment, are used. Adjuvants like surfactants, protective agents, and carriers improve the system in different formulations. In addition, microorganisms are a tool for the bioremediation of pesticides in the environment. This review summarizes these topics, focusing on the biopesticides of microbial origin.

A new insight into the mechanism of dichlorodiphenyltrichloroethane-induced hepatotoxicity based on GSDME-mediated pyroptosis

There have been persistent concerns about the safety risks associated with DDT residues in the environment. Studies have shown that exposure to DDT or its metabolites can cause various liver diseases. However, the mechanisms of liver toxicity haven't been well studied. In our current investigation, we observed that DDT triggers pyroptosis in human liver cells (HL-7702), representing a novel form of programmed cell death. Our results delineated DDT (0-100 μM) induced pyroptosis in HL-7702 cells, which was confirmed through morphological changes, lactate dehydrogenase (LDH) release, gasdermin E (GSDME) cleavage and Annexin-V/PI staining. Knockdown of GSDME reduced cell death and transferred the mode of cell death from pyroptosis to apoptosis. Notably, DDT exposure markedly increased reactive oxygen species (ROS) production, concurrent with c-Jun N-terminal kinase (JNK) phosphorylation. Intervention with a ROS inhibitor or JNK inhibitor SP600125 restored cell viability and hindered GSDME-mediated pyroptosis. Our results firstly demonstrate that DDT suppresses HL-7702 cells growth by inducing pyroptosis mainly through the ROS/JNK/GSDME pathway. These findings not only contribute to an in-depth understanding of DDT toxicity but also open avenues for gaining valuable insights into potential mitigation strategies and therapeutic interventions.