An important objective of aquatic ecotoxicology is to determine the effects of toxic compounds in organisms that play a central role in aquatic communities where rotifers have a large impact on several important ecological processes. The contribution of the rotifers to secondary production in many aquatic communities is substantial as they are often the larger fraction of zooplankton biomass at certain times of the year. In addition to the importance of their ecological roles in aquatic communities, the rotifers are attractive organisms for ecotoxicological studies by its short life cycles and rapid reproduction, their small size, and little volumes needed for culture and toxicity assays. The main end points used in ecotoxicological studies are mortality, reproduction, behavior, and biomarkers. Such parameters are included in international regulations from all over the world, where different species are used to evaluate the effect of environmental samples or chemical compounds. The high diversity of rotifers is an important issue because it can modify their relative susceptibility to toxicants. Thus, more studies are needed to know the relations and mechanisms involved in clonal variation, sensitivity, and development, which can be all assessed by state-of-the-art procedures.
Tourist growth in Quintana Roo, Mexico has brought with it an increase of pollution by sunscreens to aquatic ecosystems, which represents an environmental risk because of the chemical components of sunscreens that can negatively affect human health and aquatic ecosystems. However, the magnitude of pollution in aquatic environments is unknown. Consequently, we sought to estimate the contamination by sunscreens based on usage and tourism statistics. Our estimate indicates that the water in Quintana Roo will receive nearly 4367.25 tons of chemicals from sunscreens used by residents and tourists over a period of 18 years (2007 to 2025). On average, each tourist stays in Quintana Roo for 3.45 days, and 89.9% of these visitors apply sunscreen, although only the 83.7% engage in water activities. Additionally, 30.4% of residents engage in water activities for an average of 1.5 days/year. We considered direct sunscreen contaminant contamination, which occurs from the application of sunscreen and subsequent water activities, as well as indirect contamination, which occurs when people wash their skin with drinking water that then enters the drainage system. Our analysis indicated that the greatest contribution of sunscreen to the karst aquifer of Quintana Roo, is direct. Chemicals dissolved in water are a danger to aquatic life and human health.
Vinclozolin (VZ) is a dicarboximide fungicide widely used on fruits, vegetables and wines, effective against fungi plagues. In this study we characterized the effects of VZ using a 4-day reproductive chronic assay with the freshwater rotifer Brachionus calyciflorus. The assay included observations of several features of asexual and sexual reproduction. Our results indicate that VZ: (a) increased asexual and sexual reproduction, (b) caused severe abnormality in females and (c) these abnormalities were inherited by sexual and asexual reproduction. At 1.2 mg/L three abnormal females were found out of 457 total females (0.66 %). This low percentage is consistent and reproducible according to further analysis, where we increased the number of replicates and total females exposed to 1.2 mg/L of VZ, and found 18 abnormal females out of 2868 total females (0.63 % abnormality). Interestingly, abnormal females found at 5.6 mg/L VZ exposure, were able to show mating behavior. Our results suggest that VZ behaves as a strong endocrine disruptor whose effects show the characteristic inverted-U-shape exposure concentration response curve regarding the intrinsic population increase and the percentage of abnormalities as endpoints.
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