Polluted water from a storage dam (Villa Victoria, méxico) induces oxidative damage, AChE activity, embryotoxicity, and behavioral changes in Cyprinus carpio larvae.

The Villa Victoria dam is one of the most important storage reservoirs in Mexico since it distributes water to more than 20 million inhabitants in the Metropolitan Zone of Mexico City. In this dam, the common carp (Cyprinus carpio) is an important food resource for the inhabitants, so the aim of this work was to evaluate the oxidative damage (lipoperoxidation, oxidized proteins, antioxidant enzymes activity and gene expression), AChE, embryotoxicity and behavioral changes in C. carpio embryos and larvae exposed to water from Villa Victoria dam for 24, 48, 72 and 96 h. The embryotoxicity was evaluated trough the General Morphology Score (GMS) and the teratogenic index. Behavioral changes in basal locomotor activity and thigmotaxis were evaluated in a DanioVision, Noldus ™. An increase in lipid and protein oxidation as well as modification of CAT, SOD and GPx enzymatic activity was observed during the exposure times. The GMS indicated a low development in the embryos, the teratogenic index was less than 1, however teratogenic effects as yolk edema, fin malformation, head malformation and scoliosis were observed. In parallel, an increase in AChE activity and gene expression was observed reflecting changes in distance traveled of the basal locomotor activity and thigmotaxis at the sampling points. In conclusion, pollutants in water from Villa Victoria dam caused oxidative damage, changes in SOD, CAT, GPx and AChE activity as well as embryotoxicity and modifications in the behavior of C. carpio larvae. This study demonstrates the need to implement restoration programs for this reservoir since, contamination in the Villa Victoria dam could eventually endanger aquatic life and human health.

Ecotoxicological evaluation of chitosan biopolymer films particles in adult zebrafish (Danio rerio): A comparative study with polystyrene microplastics.

To mitigate the environmental impact of microplastics (MPs), the scientific community has innovated sustainable and biodegradable polymers as viable alternatives to traditional plastics. Chitosan, the deacetylated form of chitin, stands as one of the most thoroughly investigated biopolymers and has garnered significant interest due to its versatile applications in both medical and cosmetic fields. Nevertheless, there is still a knowledge gap regarding the impact that chitosan biopolymer films (CBPF) may generate in aquatic organisms. In light of the foregoing, this study aimed to assess and compare the potential effects of CBPF on the gastrointestinal tract, gills, brain, and liver of Danio rerio against those induced by MPs. The findings revealed that both CBPF and MPs induced changes in the levels of oxidative stress biomarkers across all organs. However, it is essential to note that our star plots illustrate a tendency for CBPF to activate antioxidant enzymes and for MPs to produce oxidative damage. Regarding gene expression, our findings indicate that MPs led to an up-regulation in the expression of genes associated with apoptotic response (p53, casp3, cas9, bax, and bcl2) in all fish organs. Meanwhile, CBPF produced the same effect in genes related to antioxidant response (nrf1 and nrf2). Overall, our histological observations substantiated these effects, revealing the presence of plastic particles and tissue alterations in the gills and gastrointestinal tract of fish subjected to MPs. From these results, it can be concluded that CBPF does not represent a risk to fish after long exposure.

The evaluation of liver dysfunction and oxidative stress due to urban environmental pollution in Mexican population related to Madin Dam, State of Mexico: a pilot study.

One of the most important causes of disease and premature death in the world is environmental pollution. The presence of pollutants in both water and air contributes to the deterioration of the health of human populations. The Mexico City Metropolitan Area is one of the most populous and affected by air pollution worldwide; in addition, in recent years there has been a growing demand for water, so urban reservoirs such as the Madin dam are vital to meet the demand. However, this reservoir is highly polluted due to the urban settlements around it. Therefore, the aim of the present study was to evaluate oxidative stress in clinically healthy subjects by means of the degree of lipoperoxidation, as well as the modification of serum enzyme levels, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase associated with air and drinking water pollutants from three zones of the Mexico City Metropolitan Area, two of them related to Madin Dam. This descriptive cross-sectional study was conducted between March 2019 and September 2021 in 142 healthy participants (age range 18-65 years). Healthy subjects were confirmed by their medical history. The results showed that chronic exposure to air (SO2) and water pollutants (Al and Fe) was significantly associated with elevated levels of lipoperoxidation. There was evidence that contamination from the Madín dam can generate oxidative stress and affect the health status of people who receive water from this reservoir or who consume fish that inhabit it.

Polystyrene microplastics mitigate the embryotoxic damage of metformin and guanylurea in Danio rerio.

Microplastics (MPs) alone may endanger the health and fitness of aquatic species through different mechanisms. However, the harmful effects of these when mixed with other emerging contaminants require additional research. Herein, we aimed to determine whether a mixture of MPs with metformin (MET) or guanylurea (GUA) might induce embryotoxicity and oxidative stress in Danio rerio. Upon exposure to mixtures, our results showed MPs reduced the mortality rate of MET and GUA in embryos. Moreover, the severity and the rate of malformations were also decreased in all mixtures with MPs. Concerning oxidative stress, our findings indicated MET, GUA, MPs, and the mixtures increased the levels of lipoperoxidation, hydroperoxide content, and protein carbonyl content in D. rerio larvae. However, the oxidative damage induced in all mixtures was lower than that produced by both drugs alone. Thus, it is likely that the accumulation of MPs avoided the entrance of MET and GUA into the embryos. Once the embryo hatched, MPs did only remain accumulated in the yolk sac of larvae and did not translocate to other organs. Our risk assessment analysis confirmed that MPs shrunk the damage produced by MET and GUA. In a nutshell, MPs mitigate the embryotoxic damage of metformin and guanylurea in D. rerio by blocking their entrance.