Optimizing health risk assessment for soil trace metals under low-precision sampling conditions: A case study of agricultural soil.

Cost limitations often lead to the adoption of lower precision grids for soil sampling in large-scale areas, potentially causing deviations in the observed trace metal (TM) concentrations from their true values. Therefore, in this study, an enhanced Health Risk Assessment (HRA) model was developed by combining Monte Carlo simulation (MCS) and Empirical Bayesian kriging (EBK), aiming to improve the accuracy of health risk assessment under low-precision sampling conditions. The results showed that the increased sampling scale led to an overestimation of the non-carcinogenic risk for children, resulting in potential risks (the maximum Hazard index value was 1.08 and 1.64 at the 500 and 1000 m sampling scales, respectively). EBK model was suitable for predicting soil TM concentrations at large sampling scale, and the predicted concentrations were closer to the actual value. Furthermore, we found that the improved HRA model by combining EBK and MCS effectively reduced the possibility of over- or under-estimation of risk levels due to the increasing sampling size, and enhanced the accuracy and robustness of risk assessment. This study provides an important methodology support for health risk assessment of soil TMs under data limitation.

Human health risks of heavy metal(loid)s mediated through crop ingestion in a coal mining area in Eastern China.

The heavy metal(loid)s (HMs) in soils can be accumulated by crops grown, which is accompanied by crop ingestion into the human body and then causes harm to human health. Hence, the health risks posed by HMs in three crops for different populations were assessed using Health risk assessment (HRA) model coupled with Monte Carlo simulation. Results revealed that Zn had the highest concentration among three crops; while Ni was the main polluting element in maize and soybean, and As in rice. Non-carcinogenic risk for all populations through rice ingestion was at an "unacceptable" level, and teenagers suffered higher risk than adults and children. All populations through ingestion of three crops might suffer Carcinogenic risk, with the similar order of Total carcinogenic risk (TCR): TCRAdults > TCRTeenagers > TCRChildren. As and Ni were identified as priority control HMs in this study area due to their high contribution rates to health risks. According to the HRA results, the human health risk was associated with crop varieties, HM species, and age groups. Our findings suggest that only limiting the Maximum allowable intake rate is not sufficient to prevent health risks caused by crop HMs, thus more risk precautions are needed.

Improving prediction of soil heavy metal(loid) concentration by developing a combined Co-kriging and geographically and temporally weighted regression (GTWR) model.

The study of heavy metal(loid) (HM) contamination in soil using extensive data obtained from published literature is an economical and convenient method. However, the uneven distribution of these data in time and space limits their direct applicability. Therefore, based on the concentration data obtained from the published literature (2000-2020), we investigated the relationship between soil HM accumulation and various anthropogenic activities, developed a hybrid model to predict soil HM concentrations, and then evaluated their ecological risks. The results demonstrated that various anthropogenic activities were the main cause of soil HM accumulation using Geographically and temporally weighted regression (GTWR) model. The hybrid Co-kriging + GTWR model, which incorporates two of the most influential auxiliary variables, can improve the accuracy and reliability of predicting HM concentrations. The predicted concentrations of eight HMs all exceeded the background values for soil environment in China. The results of the ecological risk assessment revealed that five HMs accounted for more than 90% of the area at the "High risk" level (RQ ≥ 1), with the descending order of Ni (100%) = Cu (100%) > As (98.73%) > Zn (95.50%) > Pb (94.90%). This study provides a novel approach to environmental pollution research using the published data.

Hormetic effect of a short-chain PFBS on Microcystis aeruginosa and its molecular mechanism.

Short-chain Perfluorinated compounds (PFCs), used as substitutes for highly toxic long-chain PFCs, are increasingly entering the aquatic environment. However, the toxicity of short-chain PFCs in the environment is still controversial. This study investigated the effects of short-chain perfluorobutanesulfonic acid (PFBS) at different concentrations (2.5, 6, 14.4, 36, and 90 mg/L) on M. aeruginosa growth under 12-day exposure and explored the molecular mechanism of toxicity using transcriptomics. The results showed that M. aeruginosa exhibited hormetic effects after exposure to PFBS. Low PFBS concentrations stimulated algal growth, whereas high PFBS concentrations inhibited it, and this inhibitory effect became progressively more pronounced with increasing PFBS exposure concentrations. Transcriptomics showed that PFBS promoted the pathways of photosynthesis, glycolysis, energy metabolism and peptidoglycan synthesis, providing the energy required for cell growth and maintaining cellular morphology. PFBS, on the other hand, caused growth inhibition in algae mainly through oxidative stress, streptomycin synthesis, and genetic damage. Our findings provide new insights into the toxicity and underlying mechanism of short-chain PFCs on algae and inform the understanding of the hormetic effect of short-chain PFCs, which are crucial for assessing their ecological risks in aquatic environments.

Impact of economic development on soil trace metal(loid)s pollution: A case study of China.

Recently, intensive anthropogenic activities, while promoting economic growth, have also exacerbated soil trace metal(loid) (TM) pollution. To explore the impact of economic development on soil TM pollution, a time-weighted method was introduced to calculate the average concentrations of eight TMs in Chinese topsoil from 2001 to 2020, and panel data on TMs and economic factors of 31 provinces were used for regression analysis. The results revealed that the average concentrations of soil TMs all exceeded their respective soil background values. Meanwhile, the spatial distribution of soil TMs was characterized by obvious regional heterogeneity, with economically developed areas being heavily polluted and having high ecological risks. In addition, the results derived from panel data models showed that the relationship between soil TM pollution and economic development in China presented a continuous growth curve, but with an N-shaped pattern in eastern China, a U-shaped pattern in central China, and a positive linearity in western China. Four control variables were also introduced to evaluate their impact on TM pollution, and the results indicated that the proportion of secondary industry and the road area per capita were the major influencing factors. Ultimately, the inflection point estimation results suggested that the soil TM pollution level will increase in eastern China, central China and western China with ongoing economic growth. Our findings contribute to the current understanding of the relationship between soil TM pollution and anthropogenic activities, and provide a scientific basis for adjusting and planning industrial development and layout according to the characteristics of soil TM pollution.

Effect and mechanism of microplastics exposure against microalgae: Photosynthesis and oxidative stress.

The occurrence of microplastics (MPs) within aquatic ecosystems attracts a major environmental concern. It was demonstrated MPs could cause various ecotoxicological effects on microalgae. However, existing data on the effects of MPs on microalgae showed great variability among studies. Here, we performed a meta-analysis of the latest studies on the effects of MPs on photosynthesis and oxidative stress in microalgae. A total of 835 biological endpoints were investigated from 55 studies extracted, and 37 % of them were significantly affected by MPs. In this study, the impact of MPs against microalgae was concentration-dependent and size-dependent, and microalgae were more susceptible to MPs stress in freshwater than marine. Additionally, we summarized the biological functions of microalgae that are primarily affected by MPs. Under MPs exposure, the content of chlorophyll a (Chl-a) was reduced and electron transfer in the photosynthetic system was hindered, causing electron accumulation and oxidative stress damage, which may also affect biological processes such as energy production, carbon fixation, lipid metabolism, and nucleic acid metabolism. Finally, our findings provide important insights into the effects of MPs stress on photosynthesis and oxidative stress in microalga and enhance the current understanding of the potential risk of MPs pollution on aquatic organisms.

Human activities contributing to the accumulation of high-risk trace metal(loid)s in soils of China's five major urban agglomerations.

Rapid urbanization has accelerated the accumulation of trace metal(loid)s (TMs) in soils, but the relationship between this accumulation and human activities remains largely unknown. Therefore, based on 775 published literatures (2001-2020), this study aimed to identify the influence of human activities on TM accumulation. Results showed that all soil TM concentrations were higher than their corresponding Chinese soil background values. The pollution risk assessment indicated that the soil TMs in the study area were at moderate levels, and the value of Pollution load index was 2.10. According to the assessment of health risks, the non-carcinogenic risks for adults were at the "Negligible risk" level; while the carcinogenic risk was not negligible for all populations, with children being more susceptible than adults. Meanwhile, six high-risk TMs were identified based on the grading of Contaminating factors (CF ≥ 3) and contribution to health risk (≥ 75%), including four high pollution risk TMs (Cd, Hg, Cu, and Pb) and two high health risk TMs (Cr and As) . In addition, in accordance with the results of the Random forest model, the accumulation of soil high-risk TMs was closely related to influencing factors associated with human activities. The accumulation of Hg and Cr among five major urban agglomerations had the same influencing factors (the number of industrial companies and the amount of industrial wastewater discharge for Hg; the amount of pesticide application and highway mileage for Cr). However, there were significant differences in the factors influencing the accumulation of the other four high-risk TMs (including Cd, As, Cu and Pb), due to the different characteristics of each urban agglomeration. Our results provide new insights into the relationship between human activities and soil TM accumulation.

Coastal sediment heavy metal(loid) pollution under multifaceted anthropogenic stress: Insights based on geochemical baselines and source-related risks.

Contamination and risk assessments generally ignore the potential bias in results caused by the variation of background values at different spatial scales due to the spatial heterogeneity of sediments. This study aims to perform quantitative source-ecological risk assessment via establishing geochemical baselines values (GBVs) of heavy metal(loid)s (HMs) in Daya Bay, China. Cumulative frequency distribution (CFD) curves determined the GBVs of 12.44 (Cu), 30.88 (Pb), 69.89 (Zn), 0.06 (Cd), 47.85 (Cr), 6.80 (As), and 0.056 mg kg-1 (Hg), which were comparable to the background values of Guangdong Province surface soils, and implied a potential terrestrial origin of the coastal sediments. Principal component analysis (PCA) and positive matrix factorization (PMF) identified three sources (F1: natural processes; F2: anthropogenic impacts; F3: specific sources) with contributions of 51.7%, 29.2%, and 19.1%, respectively. The source-specific risk assessment revealed an ecological risk contribution potential of 73.8% for the mixed anthropogenic sources (F2 + F3) and only 26.2% for natural processes. Cd and Hg were the priority management of metallic elements, occupying 63.5% and 72.5% of the contribution weights of F2 and F3, respectively, which showed multi-level pollution potentials and ecological risk levels. The spatial distribution patterns demonstrated the hotspot features of HM pollution, and priority concerns should be given to the management of marine traffic and industrial point source pollution in Daya Bay. The results of the study provide a scientific approach and perspective for pollution treatment and risk management in the coastal environment.

New insights into health risk assessment on soil trace metal(loid)s: Model improvement and parameter optimization.

Trace metal(loid)s (TMs) in soils may pose potential health risks to humans. Due to model uncertainty and variability of exposure parameters, the traditional health risk assessment (HRA) model may lead to inaccurate risk assessment results. Therefore, this study developed an improved HRA model to assess health risks by combining two-dimensional Monte Carlo simulation (2-D MCS) with a Logistic Chaotic sequence based on published data from 2000 to 2021. The results showed children and adult females were the high-risks populations for Non-carcinogenic risk and Carcinogenic risk, respectively. Meanwhile, children's Ingestion rate (IngR < 160.233 mg/day) and adult females' Skin adherence factor (0.026 mg/(cm2•d) < AF < 0.263 mg/(cm2•d)) were used as recommended exposure to make the health risk within acceptable range. Additionally, when performing risk assessment using actual exposure parameters, priority control TMs were identified, with As being the priority control TM for Southwest China and Inner Mongolia, whereas Cr and Pb for Tibet and Yunnan, respectively. Compared to health risk assessment, improved models increased risk assessment accuracy and provided recommended exposure parameter for high-risk populations. This study will provide new insights for soil-related health risk assessment.

Toxic effects of three perfluorinated or polyfluorinated compounds (PFCs) on two strains of freshwater algae: Implications for ecological risk assessments.

Perfluorinated or polyfluorinated compounds (PFCs) continue entering to the environmental as individuals or mixtures, but their toxicological information remains largely unknown. Here, we investigated the toxic effects and ecological risks of Perfluorooctane sulfonic acid (PFOS) and its substitutes on prokaryotes (Chlorella vulgaris) and eukaryotes (Microcystis aeruginosa). Based on the calculated EC50 values, the results showed that PFOS was significantly more toxic to both algae than its alternatives including Perfluorobutane sulfonic acid (PFBS) and 6:2 Fluoromodulated sulfonates (6:2 FTS), and the PFOS-PFBS mixture was more toxic to both algae than the other two PFC mixtures. The action mode of binary PFC mixtures on Chlorella vulgaris was mainly shown as antagonistic and on Microcystis aeruginosa as synergistic, by using Combination index (CI) model coupled with Monte Carlo simulation. The mean risk quotient (RQ) value of three individual PFCs and their mixtures were all below the threshold of 10-1, but the risk of those binary mixtures were higher than that of PFCs individually because of their synergistic effect. Our findings contribute to enhance the understanding of the toxicological information and ecological risks of emerging PFCs and provide a scientific basis for their pollution control.

Source apportionment and human health risk of PAHs accumulated in edible marine organisms: A perspective of "source-organism-human".

Most PAHs produced by human activities can be absorbed and accumulated by edible organisms and pose a potential hazard to human health. However, the source apportionment and human health risk of PAHs accumulated in edible organisms remains largely unknown. Therefore, we conducted source analysis and health risk assessment based on the PAH concentrations in ten marine fish from coastal areas of Guangdong, China. Results showed that the pollution of PAHs in fish organisms was at "Minimally polluted" level, and that all marine fish had the ability to accumulate PAHs. Risk assessment indicated Carcinogenic risk of PAHs in four populations was at a "Cautionary risk" level, with urban children suffered the highest risk. Petroleum pollution, Coal and biomass combustion, and Marine transport emissions were identified as the main anthropogenic sources for PAHs in organisms, and Marine transport emissions accounted for the highest Carcinogenic risk. The Acceptable daily intake for all populations were far below their actual daily intake without causing "Cautionary risk". Our findings provide new insights into the source apportionment and health risk of PAHs from a "source-organism-human" perspective, and suggested that joint management of three anthropogenic sources would be an effective way to prevent the health risks of PAHs.

Spatio-temporal characteristics of soil Cd pollution and its influencing factors: A Geographically and temporally weighted regression (GTWR) method.

Soil Cd pollution is the result of the combined influence of various human activities over a long period of time, and then quantifying the influence is essential for the prevention and control. Based on published literature data during 2000-2020, this study investigated the pollution characteristics and influencing factors of soil Cd in the Yangtze River Delta. The results were as follows: (1) The average Cd concentration was higher than the Chinese soil criteria value (0.30 mg/kg), and the proportion of Cd concentration exceeding its background value was 87.43%. (2) The assessment results using Contamination factor (CF) and Geo-accumulation index (Igeo) indicated that the soil Cd pollution risk could not negligible in the study area. (3) The pollution center shifted significantly owing to the combined effect of human activities. (4) The main influencing factors of Cd pollution obtained by Geographically and temporally weighted regression (GTWR) model were GDP per capita, Consumption of chemical fertilizer, Output value of primary industry, and Output value of secondary industry, but there were significant differences in the dominant factors for different provinces. Our findings contribute to the current understanding of the relationship between Cd pollution and human activities, and provide a scientific basis for pollution control.

Acute effects of three surface-modified nanoplastics against Microcystis aeruginosa: Growth, microcystin production, and mechanisms.

As plastic pollution continues to increase and plastic waste is shredded to form smaller plastic particles, there is growing concern about the potential impact of nanoplastics (NPs) on freshwater ecosystems. In this work, the effects of three surface-modified NPs, including polystyrene (PS), PS-NH2, and PS-COOH, on the growth, photosynthetic activity, oxidative damage, and microcystins (MCs) production/release of Microcystis aeruginosa (M. aeruginosa) were investigated. Results indicated that all three NPs significantly inhibited the growth of M. aeruginosa after a 96 h exposure, and the growth inhibition followed the order of PS-NH2 > PS > PS-COOH (p < 0.05). Meanwhile, all three NPs at the concentration of 100 mg/L significantly increased the content of intra-MCs (115 %, 147 %, and 121 % higher than the control, respectively) and extra-MCs (142 %, 175 %, and 151 % higher than the control, respectively) after a 96 h exposure (p < 0.05). Moreover, our findings also suggested that the potential mechanisms of surface-modified PS NPs on M. aeruginosa growth and MCs production/release were associated with physical constraints, photosynthetic activity obstruct, and oxidative damage. Our findings provided direct evidence for different kinds of surface modifications of PS NPs on freshwater algae and improve the understanding of the potential risk of NPs in aquatic ecosystems.

Natural-anthropogenic environment interactively causes the surface urban heat island intensity variations in global climate zones.

The inconstant climate change and rapid urbanization substantially disturb the global thermal balance and induce severe urban heat island (UHI) effect, adversely impacting human development and health. Existing literature has revealed the UHI characteristics and driving factors at an urban scale, but interactions between the main factors of a global grid scale assessment on the context of climate zones remain unclear. Therefore, based on the multidimensional climatic and socio-economic statistical datasets, the multi-time scale of surface urban heat island intensity (SUHI) characteristics was investigated in this study to analyze how natural-anthropogenic drivers affect the variance of SUHI and vary in their importance for the changes of other interaction factors. The results show that the mean value of SUHI in summer is higher than in winter, and in daytime is higher than in nighttime on a seasonal and daily scale. SUHIs in different global climate zones have significant differences. When analyzing drivers' contributions and interactions with LightGBM model and SHAP algorithm, we know that monthly precipitation (PREC), the estimated population (POP) and surface pressure (PRES) are the three major drivers of daytime SUHI. The nighttime SUHI is mainly PREC, POP and anthropogenic heat emission (AHE), the influence rules of the natural driversare mostly opposite to that of daytime. This study highlights the fundamental role of background climate for designing strategies. Irrigation or artificial rainfall will be effective to mitigate SUHI in low rainfall areas, while it is more effective to reduce AHE in high rainfall areas. In where greening can be difficult in the most developed cities, reducing AHE, increasing per capita GDP and controlling the population scale may also contribute to alleviating the SUHI. This study provides ideas for developing responsive urban heat island mitigation policies in a more realistic setting.

Insights into growth-promoting effect of nanomaterials: Using transcriptomics and metabolomics to reveal the molecular mechanisms of MWCNTs in enhancing hyperaccumulator under heavy metal(loid)s stress.

Carbon nanotubes present potential applications in soil remediation, particularly in phytoremediation. Yet, how multi-walled carbon nanotubes (MWCNTs) induced hyperaccumulator growth at molecular level remains unclear. Here, physio-biochemical, transcriptomic, and metabolomic analyses were performed to determine the effect of MWCNTs on Solanum nigrum L. (S. nigrum) growth under cadmium and arsenic stresses. 500 mg/kg MWCNTs application significantly promoted S. nigrum growth, especially for root tissues. Specially, MWCNTs application yields 1.38-fold, 1.56-fold, and 1.37-fold enhancement in the shoot length, root length, and fresh biomass, respectively. Furthermore, MWCNTs significantly strengthened P and Fe absorption in roots, as well as the activities of antioxidative enzymes. Importantly, the transcriptomic analysis indicated that S. nigrum gene expression was sensitive to MWCNTs, and MWCNTs upregulated advantageous biological processes under heavy metal(loid)s stress. Besides, MWCNTs reprogramed metabolism that related to defense system, leading to accumulation of 4-hydroxyphenylpyruvic acid (amino acid), 4-hydroxycinnamic acid (xenobiotic), and (S)-abscisic acid (lipid). In addition, key common pathways of differentially expressed metabolites and genes, including "tyrosine metabolism" and "isoquinoline alkaloid biosynthesis" were selected via integrating transcriptome and metabolome analyses. Combined omics technologies, our findings provide molecular mechanisms of MWCNTs in promoting S. nigrum growth, and highlight potential application of MWCNTs in soil remediation.

Risk assessment and driving factors of trace metal(loid)s in soils of China.

Recently, with the rapid development of China's economy, the pollution of trace metal(loid)s (TMs) in soils has become increasingly severe and attracted widespread attention. Based on 1,402 published papers from 2000 to 2021, this study aimed to analyze the pollution intensity, ecological risk and driving factors for eight TMs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in Chinese soils. Results showed that the average concentrations of eight TMs in Chinese soils all exceeded background values, and the pollution of Cd and Hg was the most serious. Based on Principal component analysis of pollution intensity and ecological risk, the priority control TMs were identified for the heavily polluted provinces. The results of Geo-detector model suggested that Urban development factors contributed most to the TM accumulation in Chinese soils. Further, spatial analysis using bivariate Moran's I indicated that industrial activities contributed most to soil TM accumulation in the middle and lower reaches of the Yangtze River, while soil TM pollution in the southwest and northwest provinces was mainly caused by mining and metal smelting. This study investigated the relationship between soil TM pollution and anthropogenic activities, thus providing a scientific basis for controlling soil TM pollution at a large-scale level.

Joint toxicity mechanisms of binary emerging PFAS mixture on algae (Chlorella pyrenoidosa) at environmental concentration.

Since traditional Per- and polyfluoroalkyl substances (PFAS) were banned in 2009 due to their bioaccumulation, persistence and biological toxicity, the emerging PFAS have been widely used as their substitutes and entered the aquatic environment in the form of mixtures. However, the joint toxicity mechanisms of these emerging PFAS mixtures to aquatic organisms remain largely unknown. Then, based on the testing of growth inhibition, cytotoxicity, photosynthesis and oxidative stress, and the toxicity mechanism of PFAS mixture (Perfluorobutane sulfonate and Perfluorobutane sulfonamide) to algae was explored using the Gene set enrichment analysis (GSEA). The results revealed that all three emerging PFAS treatments had a certain growth inhibitory effect on Chlorella pyrenoidosa (C. pyrenoidosa), but the toxicity of PFAS mixture was stronger than that of individual PFAS and showed a significant synergistic effect at environmental concentration. The joint toxicity mechanisms of binary PFAS mixture to C. pyrenoidosa were related to the damage of photosynthetic system, obstruction of ROS metabolism, and inhibition of DNA replication. Our findings are conductive to adding knowledge in understanding the joint toxicity mechanisms and provide a basis for assessing the environmental risk of emerging PFAS.

Heavy metal(loid)s in multiple media within a mussel mariculture area of Shangchuan Island, China: Partition, transfer and health risks.

Limited research has been conducted on the heavy metal (loid) (HM) exchanges among seawater, sediments and cultured mussels in mariculture areas. To determine the impacts of mussel mariculture on the transfer and risks of HMs in coastal environments, samples of seawater, sediments and cultured mussels from a typical mariculture area in the South China Sea were analysed. The logarithmic partition coefficients of sediment/water indicated that HMs were preferentially retained by sediments. There were relatively low ecological risks in mussel raft mariculture areas. Principal component analysis and correlation analysis revealed the influences of terrestrial input and ocean circulation on the HMs in seawater, and the bioaccumulation factors reflected the possible accumulation of HMs in seawater by cultured mussels. Mussel farming was the indirect source of HMs in sediments, and the biochemical processes of cultured mussels promoted the transfer and accumulation of HMs into sediments. Health risk assessment revealed that children were more susceptible than adults, and Cd, As and Cr were among the threatening elements. Nonetheless, the health risks that were possibly caused by the daily consumption of farmed mussels were still within safe limits. Thus, the potential pollution remediation and biomonitoring functions of mussel aquaculture in coastal water environments will be further studied in the future.

Seasonal Variation and Contamination Risk Assessment of Heavy Metals in Surface Sediment of an Estuary Alluvial Island in Eastern China.

The heavy metal pollution of estuary wetlands caused by industrial and agricultural production activities has aroused widespread concern. The Hakanson Pollution index, Geo-accumulation index (Igeo) and Redundancy analysis were used to explore the seasonal variation and contamination risk of heavy metals in surface sediments. Results showed that the heavy metal concentrations were ranked in descending order: Cd > Cu > Zn > Pb > Cr. The analysis result of HPI and Igeo showed that there was a low level of heavy metal contamination both in summer and winter. Redundancy analysis showed that the correlation between heavy metals and physicochemical properties of sediment was significantly different in winter and summer. Our findings provide scientific support for the prevention of heavy metal pollution in estuary wetlands.

Toxicity mechanism of Nylon microplastics on Microcystis aeruginosa through three pathways: Photosynthesis, oxidative stress and energy metabolism.

Nylon has been widely used all over the world, and most of it eventually enters the aquatic environment in the form of microplastics (MPs). However, the impact of Nylon MPs on aquatic ecosystem remains largely unknown. Thus, the long-term biological effects and toxicity mechanism of Nylon MPs on Microcystis aeruginosa (M. aeruginosa) were explored in this study. Results demonstrated that Nylon MPs had a dose-dependent growth inhibition of M. aeruginosa at the initial stage, and the maximum inhibition rate reached to 47.62% at the concentration of 100 mg/L. Meanwhile, Nylon MPs could obstruct photosynthesis electron transfer, reduce phycobiliproteins synthesis, destroy algal cell membrane, enhance the release of extracellular polymeric substances, and induce oxidative stress. Furthermore, transcriptomic analysis indicated that Nylon MPs dysregulated the expression of genes involved in tricarboxylic acid cycle, photosynthesis, photosynthesis-antenna proteins, oxidative phosphorylation, carbon fixation in photosynthetic organisms, and porphyrin and chlorophyll metabolism. According to the results of transcriptomic and biochemical analysis, the growth inhibition of M. aeruginosa is inferred to be regulated by three pathways: photosynthesis, oxidative stress, and energy metabolism. Our findings provide new insights into the toxicity mechanism of Nylon MPs on freshwater microalgae and valuable data for risk assessment of MPs.