Magnetic polyamidoamine dendrimers for magnetic separation and sensitive determination of organochlorine pesticides from water samples by high-performance liquid chromatography

Organochlorine pesticides (OCPs) have received much attention due to their toxicity. Reliable methods to monitor their residues in the environment are needed. Here, magnetic polyamidoamine dendrimers were prepared by co-precipitation, Michael addition, and amidation. The magnetic polyamidoamine dendrimers demonstrated good adsorption ability for OCPs—this feature was utilized to construct a sensitive tool for monitoring OCPs in water samples. The proposed method provided remarkable linearity from 0.1 to 500 μg/L and satisfactory limits of detection from 0.012 to 0.029 μg/L. The spiked recoveries of the four target analytes were 91.8%?103.5% with relative standard deviations less than 4.5%. The magnetic materials had good reusability. The results indicated that the resulting method was an efficient, easy, rapid, economical, and eco-friendly tool for monitoring OCPs in aqueous samples.     

Neural stem cell-based in vitro bioassay for the assessment of neurotoxic potential of water samples

Intensive agriculture activities, industrialization and growing numbers of wastewater treatment plants along river banks collectively contribute to the elevated levels of neurotoxic pollutants in natural water reservoirs across Europe. We established an in vitro bioassay based upon neural stem cells isolated from the subventricular zone of the postnatal mouse to evaluate the neurotoxic potential of raw wastewater, treated sewage effluent, groundwater and drinking water. The toxic potential of water samples was evaluated employing viability, proliferation, differentiation and migration assays. We found that raw wastewater could reduce the viability and proliferation of neural stem cells, and decreased the neuronal and astrocyte differentiation, neuronal neurite growth, astrocyte growth and cell migration. Treated sewage water also showed inhibitory effects on cell proliferation and migration. Our results indicated that relatively high concentrations of nitrogenous substances, pesticides, mercuric compounds, bisphenol-A, and phthalates, along with some other pollutants in raw wastewater and treated sewage water, might be the reason for the neuroinhibitory effects of these water samples. Our model successfully predicted the neurotoxicity of water samples collected from different sources and also revealed that the incomplete removal of contaminants from wastewater can be problematic for the developing nervous system. The presented data also provides strong evidence that more effective treatments should be used to minimize the contamination of water before release into major water bodies which may be considered as water reservoirs for human usage in the future.     

Sources, distribution, and risk assessment of organochlorine pesticides in Nairobi City, Kenya

The distribution and sources of organochlorine pesticides (OCPs) in air and surface waters were monitored in Nairobi City using triolein-filled semipermeable membrane devices (SP-MDs).The SPMDs were extracted by dialysis using n-hexane,followed by cleanup by adsorption chromatography on silica gel cartridges.Sample analysis was done by GC-ECD and confirmed by GC–MS.Separation of means was achieved by analysis of variance,followed by pair-wise comparison using the t-test (p≤0.05).The total OCPs r...     

Effect of colloid-size copper-based pesticides and wood-preservatives against microbial activities of Gram-positive Bacillus species using five-day biochemical oxygen demand test

Copper-based pesticides and wood preservatives could end up in the environment during production, use, and end-of-life via different pathways that could cause unintended ecological and adverse health effects. This paper provides the effect of colloid-size Cu-based pesticides (CuPRO and Kocide), micronized Cu azole (MCA-1 and MCA-2) and alkaline Cu quaternary (ACQ) treated woods, Cu²⁺, Cu²⁺ spiked untreated wood (UTW), and CuCO₃ solutions against Gram-positive Bacillus species using five-day biochemical oxygen demand (BOD₅) standard test. The total Cu leached from MCA-1, MCA-2, and ACQ in Milli-Q water after 5 days were ~0.1, ~0.11, and ~0.64 g/kg of wood, respectively. However, the form of Cu leached from MCA woods was mostly ionic (> 90%). The total organic carbon (TOC) content of any tested wood (UTW/MCA-1/MCA-2/ACQ) was ~99% of its corresponding total carbon (TC) content, whereas the TOC of any tested wood sawdust exceeded that of its corresponding piece/block by > 300%. The dissolved oxygen (DO) consumption value in the presence of Cu²⁺, CuCO₃, CuPRO, and Kocide solutions was significantly influenced by Cu particles/ions. However, the DO consumption value in the presence of UTW/MCA-1/MCA-2/ACQ woods was significantly influenced by organics leached from woods. On the other hand, the DO consumption of MCA sawdust was greater than (300%) that of MCA pieces/block. The findings of this study provide more insight into how organics leached from woods significantly reduce the toxic effects of Cu ions against Gram-positive Bacillus species.     

Sources and health risks of PM2.5-bound polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in a North China rural area

Polychlorinated biphenyls(PCBs) and organochlorine pesticides(OCPs) are typical persistent organic pollutants(POPs),which have high toxicity,bioaccumulation and long-distance transfer capability.Daily variation,sources of PcBs and OcPs in PM_2.5 are rarely explored in polluted rural area.Here,the sources and health risks of the PcBs and OcPs were evaluated for 48 PM_2.5 samples collected in winter 2017 in Wangdu,a heavy polluted rural area in the North China Plain.The average...     

Skin inflammation and psoriasis may be linked to exposure of ultrafine carbon particles

<正>Air pollution has become the largest environmental risk to human health,estimated to kill seven million people worldwide every year.Data from the World Health Organization (WHO)showed that 91%of the world population was exposed to air contamination with air quality not meeting the WHO guidelines in 2016.A number of adverse health consequences have     

Occurrence and ecotoxicological risk assessment of pesticides in sediments of the Rosetta branch, Nile River, Egypt

This study aimed to (1) monitor the occurrence and spatiotemporal variations of 100 pesticides in sediments collected monthly from July 2018 to June 2019 from sampling sites in El-Rahawy, Sabal, and Tala, along the Rosetta branch of the Nile River, Egypt, and (2) perform an ecological risk assessment for aquatic organisms upon exposure to the detected sediment pesticides based on the risk quotient (RQ) method. Out of the 100 pesticides monitored, 16 pesticides belonging to seven chemical families were detected, and 55% of the sediment samples were contaminated with one or more pesticide residues. The mean concentration (mg/kg dry weight (dw)) and detection frequency (%) of the four most frequently detected pesticides in the sediment samples were as follows: chlorpyrifos (0.18 mg/kg dw and 34%), p,p′-DDE (0.018 mg/kg dw and 30%), cypermethrin (0.03 mg/kg dw and 14%), and deltamethrin (0.026 mg/kg dw and 13%). The spatial distribution exhibited that El-Rahawy had the highest pesticide load (2.86 mg/kg dw) among the studied sites, whereas the temporal variations revealed that the highest total pesticide concentrations were detected in winter season (1.73 mg/kg dw). Meanwhile, 12 pesticides showed high RQs (>1), posing a potential ecological risk to aquatic species that live and feed on such sediments.     

The risks of sulfur addition on cadmium accumulation in paddy rice under different water-management conditions

Recently, the application of sulfur (S) has been recommended to control the accumulation of cadmium (Cd) in rice in contaminated paddy soil. However, the effects of exogenous S on Cd transfer in paddy rice systems under different water-management practices have not been systematically investigated. Pot experiments were performed to monitor the composition of soil pore water and the Cd accumulation in iron plaque and rice tissue were compared under different S (0 and 200 mg/kg Na₂SO₄) and water (continuous and discontinuous flooding) treatments. Sulfur application significantly increased Cd concentrations in soil pore water under discontinuous flooding conditions, but slightly reduced them under continuous flooding. Moreover, the oxidation/reduction potential (Eh) was the most critical factor that affected the Cd levels. When the Eh exceeded −42.5 mV, S became the second critical factor, and excessive S application promoted Cd dissolution. In addition, S addition elevated the Cd levels in iron plaque and reduced the Cd transfer from the iron plaque to rice roots. In rice, S addition inhibited Cd transfer from the rice roots to the straw; thus, more Cd was stored in the rice roots. Nevertheless, additional S application increased the Cd content in the rice grains by 72% under discontinuous flooding, although this effect was mitigated by continued flooding. Under simulated practical water management conditions, S addition increased the risk of Cd contamination in rice, suggesting that S application should be reconsidered as a paddy fertilization strategy.     

The profiles of chiral pesticides in peri-urban areas near Yangtze River: Enantioselective distribution characteristics and correlations with surface sediments

Chiral pesticides account for 30% of pesticides. Pesticides are inevitably leached into the groundwater by runoff. At the watershed level, the distribution characteristics of enantiomers in sediments collected from the river network of an agricultural area near the middle and lower reaches of the Yangtze River were tested, and their potential correlations with the physicochemical properties and microbial communities of the sediments were analyzed. The sediment pollution was serious at sites 8 and 9, with their pollution source possibly being agricultural or industrial sewage. Moreover, there were higher cumulative contents of pesticide residues at sites 4, 8, and 9. Specifically, Cycloxaprid was the most detected chiral pesticide in the study area, followed by Dinotefuran and Diclofop-methyl. Additionally, Ethiprole and Difenoconazole had strong enantioselectivity in the study area. Interestingly, the enantiomers of some chiral pesticides, such as Tebuconazole, had completely different distributions at different sites. Pearson correlation analysis showed that sediment catalase and microbial biomass carbon were important factors for enantioselectivity of chiral pesticides. The effect of sediment physicochemical properties on enantioselective distribution was achieved by influencing the microorganisms in the sediment. Furthermore, the enantioselective distribution of Tebuconazole was closely related to the genus Arenimonas. Overall, the enantioselective distribution of most of the chiral pesticides was positively correlated with the prokaryotic microbial community. This study provides empirical support for agricultural non-point source pollution caused by chiral pesticides, and also lays a research foundation for exploring the factors that affect the fate of chiral pesticides in the environment.