This paper provides a detailed description of the findings and methodology related to the monitoring of microplastics in three lakes and one river of the Akmola Region in Kazakhstan. The concentration of microplastic particles and the analysis of water and sediment quality of the Yesil River and Kopa, Zerendinskoye, and Borovoe lakes have been analyzed. A total of 64 water samples were collected across the spring, summer, and autumn seasons, with subsequent analysis revealing a seasonal increase in microplastic concentrations. The average microplastic content ranged from 1.2 × 10⁻¹ particles/dm³ in spring to 4.5 × 10⁻¹ particles/dm³ in autumn. Lakes exhibited higher concentrations compared to the Yesil River. Correlation analysis highlighted a connection between microplastic content and turbidity, particularly notable during the spring season. Analysis of sediments revealed a decrease in microplastic concentrations from the coastal zone toward open waters sediments. Microplastic fibers were predominant in sediments (69.6%), followed by fragments (19.1%), films (7.4%), and granules (3.9%). Larger particles (>500 µm) were found in beach sediments, constituting an average of 40.5% of the total plastics found. This study contributes valuable insights into the spatial and temporal distribution of microplastics, emphasizing the need for ongoing monitoring and management strategies to address this environmental concern.

Microplastics are increasingly recognized as contaminants of emerging concern in wastewater systems, where treatment plants act both as sinks and as point sources. However, Central Asian wastewater infrastructures are under-represented in the literature, and global syntheses are hindered by strong methodological heterogeneity (sampling regimes, size cut-offs, QA/QC). This PRISMA-guided critical review compiles and harmonizes data from 63 WWTP studies worldwide (402 matrix-stage observations), including the few available case studies from Kazakhstan and neighboring countries, to benchmark Central Asian plants against a global envelope and identify methodological and infrastructure gaps. Globally, influent concentrations cluster around a median ≈65 particles/L, while final/tertiary effluents show a median ≈2.2 particles/L. Median removal efficiency is 85.5% for secondary and 95.0% for tertiary/advanced trains, with ≈10³–10⁵ particles/kg DW typically retained in sludge. Across influent, effluent and sludge, fibers and fragments of PE, PP and PET dominate polymer morphology patterns, with similar PET/PE/PP signatures also reported in downstream river water. Central Asian influents fall within global interquartile ranges, but secondary-only facilities tend to yield effluents in the upper half of the global distribution. Overall, the review provides a first integrated, methodologically explicit assessment of WWTP microplastics in Central Asia and underscores the need for protocol harmonization, longitudinal monitoring, and targeted upgrades of polishing steps and sludge management in arid hydrosystems.

This research presents a detailed numerical modeling study focused on estimating the concentration of microplastics (MPs) in freshwater ecosystems. This research covers three lakes (Kopa, Zerendinskoye, and Borovoe) and the Yesil River, applying differential equations to model the spatial distribution and seasonal variations in MP concentrations. The methodology integrates field survey data collected during three different seasons (spring, summer, and autumn) from both sediment and water samples. The MP concentrations were found to follow an exponential decay pattern from the shore toward the center of the lakes, with higher concentrations near the shoreline. The modeling framework is calibrated using regression analysis, which provides the best-fit parameters for the distance–concentration curves. This study employs sensitivity analysis to justify the decay coefficient, resulting in a selected value of k = 0.09. Model performance is assessed using statistical metrics such as the root mean square error (RMSE) and the coefficient of determination (R²), ensuring accuracy in predicting MP concentrations across different environmental compartments. This work represents a novel contribution to the field by applying numerical modeling techniques to an understudied geographical area. The findings highlight significant seasonal and spatial variations in MP concentrations, emphasizing the need for comprehensive monitoring. This study’s results contribute valuable insights into the environmental behavior of MPs in freshwater systems and support efforts to develop effective management strategies to mitigate pollution.

This article highlights the technology of processing organic waste in order to obtain biohumus. The varietal composition of urban organic waste has been studied. The technology of preparation of raw materials for obtaining a high-quality substrate for further processing, which provides for the purification of the total mass of organic waste from particles of plastic, glass metal, etc., is considered. An experiment was carried out to determine the optimal composition of the substrate for «California» worms (E. Andrei), which have a high productivity. The optimal parameters of humidity and ambient temperature for the vital activity of worms are considered. In the experiment, three experimental groups were formed, which differed in the composition of organic waste. All three groups contained 40% food waste; 10% – branches, wood cuttings, grass; 10% – tea bags, coffee waste, paper and cardboard; 10% soil and 30% animal waste. In each group, animal waste was different: cattle manure, bird droppings and horse manure. The effectiveness of the varietal composition of the substrate was assessed by the increase in the productivity of «California» worms. The highest results were shown by the substrate in which cattle manure was introduced, the growth of worms in which increased by 6.5 times, the lowest results were in a mixture with the addition of bird droppings – by 5.1.

This research presents a detailed numerical modeling study focused on estimating the concentration of microplastics (MPs) in freshwater ecosystems. The research covers three lakes (Kopa, Zerendinskoye, and Borovoe) and the Yesil River, applying differential equations to model the spatial distribution and seasonal variations of MP concentrations. The methodology integrates field survey data collected during three different seasons (spring, summer, and autumn) from both sediment and water samples.The MP concentrations were found to follow an exponential decay pattern from the shore toward the center of the lakes, with higher concentrations near the shoreline. The modeling framework is calibrated using regression analysis, which provides the best-fit parameters for the distance-concentration curves. The study employs sensitivity analysis to justify the decay coefficient, resulting in a selected value of k = 0.09. Model performance is assessed using statistical metrics such as the root-mean-square error (RMSE) and the coefficient of determination (R²), ensuring accuracy in predicting MP concentrations across different environ-mental compartments.The findings highlight significant seasonal and spatial variations in MP concentrations, emphasizing the need for comprehensive monitoring. The study's results contribute valuable insights into the environmental behavior of MPs in freshwater systems and support efforts to develop effective management strategies to mitigate pollution.

The effects of polymer type, particle size, leaching temperature, and duration on leachate bioactivity from polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) were examined with a framework for screening human-health implications. Fractions spanning 0.175–3.0 mm were leached for 30 days. Phytotoxicity was assessed in wheat and lentil with leachates prepared at 25 °C, 37 °C, and 60 °C; sperm motility and dermal irritation were assessed at 40 °C using bull semen and rabbits. Higher temperature significantly inhibited germination parameters (p < 0.001), and 0.175–0.3 mm fractions produced the strongest effects. Phytotoxicity ranked PP > PET > PE, whereas spermatotoxicity ranked PET > PP > PE. The lowest scenario-specific Germination Index (GI) dropped to 38.20%, sperm-motility deviation reached 29.1%, and the responses were inversely correlated (Pearson’s r = −0.547, df = 13, p = 0.035). Compared with previous 1-day data, 30-day leaching increased mean sperm-motility deviation 2.5–4.1-fold. One dermal application caused no visible irritation (index = 0). Across 45 scenarios, the Total Risk Index ranged from 0.012 to 0.400, whereas limiting-factor assessment assigned high-risk classes where endpoint-specific responses were diluted by averaging. The framework supports conservative hazard screening but does not establish human toxicity or exposure thresholds.