Environmental Chemistry and Ecotoxicology最新文献

Environmental Pollution due to the unprecedented inundation of microplastics (MPs) released from various sources is a major concern for most of the environmental & material scientists in today's world. Millions of tons of microplastics are produced each year and alarmingly enter the environment and up to 14 million tons of plastic waste are thought to enter into the ocean annually. The precarious results of it show a paramount imbalance in the natural ecosystem of many living beings. Such a devastating and toxic effect on our surroundings requires a long-lasting solution to safeguard its inhabitants. Additionally, studies have shown that MPs are consumed by a variety of organisms. It is precisely the combination of ingestion and chemical interaction that lends support to the idea that MPs could potentially influence the availability and harmfulness of both naturally occurring and externally introduced co-contaminants. Microbial remediation principally by bacterial and fungal populations has been an emerging trend for improving the microplastic pollution from the environment. This review paper delves into the ecotoxicological effects of microplastic pollutants on the environment and various microbial remediation technologies used by microorganisms for the degradation. It has been proven to be a key advancement as an environmentally friendly way of decomposing MPs than that of the traditional one. Plastic degradation and bioremediation potential of these microorganisms has aroused the interest of many, in eliminating the non-biodegradable plastics from the surroundings.

Heavy metal (HM) contamination in the atmosphere poses substantial threats to ecosystems. Traditional methods for the removal of HM-contaminated sites, such as physical and chemical treatments, often have limitations in terms of efficiency, cost, and potential negative impacts on the environment. As a result, there is growing interest in exploring alternative and sustainable approaches, such as bioremediation. Bioremediation is a promising technology that utilizes the inherent abilities of microorganisms to degrade or transform pollutants into less harmful forms. Microbial exopolysaccharides have gained attention as potential tools in bioremediation strategies due to their unique physicochemical properties and their ability to interact with heavy metals. This work aims to provide an overview of the role of microbial extracellular polymeric substances (EPS) in the bioremediation of HM-contaminated sites. First, the mechanisms by which EPS facilitates heavy metal sequestration are discussed. EPS can form metal-complexing agents, such as chelators and ion-binding sites, which enhance the immobilization and precipitation of heavy metals, reducing their bioavailability and toxicity. EPS can act as a protective barrier, shielding microorganisms from heavy metal stress and facilitating their survival and growth. Additionally, EPS production can be induced or enhanced in response to heavy metal exposure, potentially increasing the efficiency of bioremediation processes.

Nanomaterials (NMs) have acquired a place of prominence in scientific innovations due to their unique and tunable physicochemical properties. This versatility enables them to be employed in multitude of applications. Nano/ nanobiotechnology, consequently, has become a very research intensive field over past few years and accordingly, there has been a noticeable increase in nano enabled products in the market. Downsides of this, however has started catching everyone's attention recently as overuse of these particles from research labs to industries to consumer products, without proper care and caution has exposed both the workers and consumers to unknown risks and hazards. For one, it is important to understand that properties of engineered nanomaterials (ENMs) are entirely different from bulk counterparts and hence cannot be compared. Secondly, there are few unanimous guidelines on handling, safe exposure limits and disposal methods for a worker. Consumers, similarly, are unaware of the long term exposure effects of these materials. This is because long term risk assessments studies are either underway or absent. While there is an existing regulatory framework and legislation in various countries now, there is still a need of stricter, more explicit guidelines for handling these materials. Elaborate risk assessment framework and stronger government regulations are necessary to fully comprehend the behavior of nanoparticles and their interaction with biological system and environmental matrices. This review article brings together an overview of production strategies, sources of nanowaste generation, disposal strategies and regulatory framework in place to handle ENMs.

Innovation in agriculture chemicals and delivery systems is essential for the production of food for sustainable development. Herein, natural polymers and agar-gelatin-derived controlled delivery devices for linuron herbicide to prevent environmental and health hazards. These hydrogels were designed by the graft-copolymerization reaction of poly(methacrylamide) [poly(MAAm)] on agar-gelatin for use as controlled-release formulations (CRF). Copolymers were characterized by Copolymers were characterized scanning electron micrographs (SEM), Atomic force microscopy (AFM), X-ray diffraction (XRD) Fourier transform infrared spectroscopy (FTIR), ¹³C-nuclear magnetic resonance (NMR), and thermogravimetric analysis -differential thermogravimetry (TGA-DTG) techniques. SEM shows the uneven surface morphology, and AFM showed a rough surface with an average roughness value of 137.50 nm in the polymeric matrix. The amorphous nature of the polymer was confirmed with XRD techniques. Grafting of the poly(MAAm) on the agar and gelatin was confirmed by FTIR and ¹³C NMR spectra. Agar-gelatin-cl-poly(MAAm) hydrogels absorbed water at 4.05 ± 0.32 g per gram, which is useful for soil water retention. Release of the linuron herbicide occurred in a controlled manner during 72 h of observations and followed non-Fickian diffusion mechanism. The slow release of the linuron from the hydrogel is a useful observation for preventing leaching and evaporation loss of herbicide. In the soil column, the release of linuron occurred in a slow and sustained manner for 240 h. A soil adsorption study showed a decrease in ground water ubiquity score (GUS) for linuron-encapsulated hydrogel as compared to commercial formulations. It can reduce groundwater contamination risk due to the leaching of the linuron herbicide. Degradation of CRF may improve micronutrient and soil quality.

Brominated flame retardants (BFRs), categorized as persistent organic pollutants (POPs) are difficult to degrade, exhibiting reproductive toxicity and carcinogenicity. Exposure to dust and soil particles containing BFRs may cause various health problems. The research aimed to assess the concentrations, potential origins, and health risks associated with polybrominated diphenyl ethers (PBDEs) and novel BFRs (NBFRs) in road dust and green belt soil in Harbin. The study revealed that ΣPBDE concentrations ranging from 0.15 to 193.75 ng/g (median: 48.01 ng/g) in road dust and 8.07 to 195.33 ng/g (median: 38.19 ng/g) in green belt soil. Notably, TBBPA contributed the most to the ΣPBDEs concentrations. And the concentrations of ΣNBFRs ranged from 2.34 to 130.53 ng/g (median: 18.48 ng/g) in road dust and 2.50 to 46.70 ng/g (median: 7.85 ng/g) in green belt soil. And tetrabromobisphenol A (TBBPA) was the most dominant compound in both samples. Highways exhibited lower ΣPBDE concentrations in dust samples but higher ΣNBFR concentrations in soil samples compared to other roads. Moreover, most of the BFRs had a positive correlation with each other, suggesting that they may have similar sources. Principal component analysis (PCA) suggested BFRs sources in road dust may come from wire, paint, building materials or commercial products, likewise, BFRs in green belt soil may come from household or industrial products. Health risk assessment indicated that BFRs in both types of samples in Harbin had no non-carcinogenic risk to residents. These findings provide valuable insights into understanding BFR pollution characteristics, identifying specific sources, and recognizing health hazards in dust and soil samples on roads from Harbin.

Pharmaceuticals and personal care products (PPCPs) are ubiquitously found pseudo-persistent group of emerging contaminants that causes ecotoxicity even at nano-concentrations. Due to their persistence and bio-accumulative behavior, long-term exposure to these pollutants increases the risk of severe health disorders in humans and poses ecological risks to aquatic life. Sedimentation, membrane filtration, advanced oxidation, activated sludge, and membrane bioreactors are a few of the treatment processes with treatment efficiency ranging from 50 to 95%, but they have limitations such as high investment, towering operating costs, use of chemicals, membrane fouling issues etc. Constructed wetlands (CW) are promising low cost, nature-based solutions having potential of PPCPs removal by simultaneous action of physical, chemical and biological processes. Herein, substrate material, plants and microbes play crucial roles in eliminating PPCPs. Phytoremediation of PPCPs occurs via plant uptake, translocation and degradation. Plants like Canna indica and Phragmites australis have shown ∼70–90% antibiotics removal efficiency. Biofilm formation and colonization of microbes lead to the microbial degradation of micro-pollutants apart from the synergistic effect of the plant-endophytic relationship. This bacterial property could be used in CWs for bioremediation of water and wastewaters, as substrates provide substratum for microbial adherence and biofilm formation. Quorum sensing (QS) is a density-based cell-communication system where bacterial cells send signals among themselves during biofilm formation. In this respect, QS-assisted biodegradation via augmentation of engineered bacteria with genes to enhance QS can be a novel approach for the degradation of organic pollutants in CWs with microbial richness.

This is the first inclusive research concerning PM₁₀ samples collected from 3 cities of Maharashtra State of India which categorized into 9 microenvironments. This study presents insights to chemical and morphological analysis, health risks, source apportionment, with sustainable solutions to improve air quality. These samples were analyzed for elemental composition as well as morphological features. Average PM₁₀ concentration at industrial area of Jalgaon city was found to be maximum (70.9 ± 2.7 μg/m³) while minimum at residential area of Pachora city (43.1 ± 5.2 μg/m³). The mean concentration of 8 elements followed the order of (Co < Cd < Ni < Cr < Pb < Mn < Zn < Fe). These particles showed varying morphologies such as spherical, rectangular, cluster, porous shape. Principal Component Analysis (PCA) revealed that elements mainly originate from vehicular exhaust, construction activities, coal combustion and re-suspension of crustal elements due to anthropogenic activities. Health risk assessment showed that the incremental excess lifetime cancer risk (IELCR) for Pb was below threshold limit. Nonetheless, the exposed population is highly susceptible to Cr, Ni, and Co causing high risk of cancer at all sites.

Background

Crude oil related activities in the Niger Delta region has exposed the environment to various degrees of pollutants, including heavy metals (HMs) and BTEX (Benzene, Toluene, Ethylbenzene, m, p-xylene, and o-xylene). The study assessed the human health risk exposure to BTEX and HMs (Lead, (Pb), chromium (Cr), cadmium (Cd), Nickel (Ni), copper (Cu) and iron (Fe) from remediated oil spilled field. Soil and Cassava tubers were collected around the field and analysed through laboratory procedures using Atomic Absorption Spectrophotometry and Gas Chromatography Flame under ASTMD 4691 and USEPA 8260B for HMs and BTEX, respectively.

Result

The mean concentration of Pb, Cd, Cr, Ni, Fe and Cu in the soil was 0.234 mg/kg, 0.004 mg/kg, 0.299 mg/kg, 0.307 mg/kg, 1.552 mg/kg and 0.527 mg/kg respectively and the concentration exceeded the allowable limit of WHO. The mean concentration of BTEX in the soil and Cassava was 0.0419 mg/kg and 0.1603 mg/kg, respectively and trended as Toluene (0.016 mg/kg) > Xylene (0.011 mg/kg) > Benzene (0.007 mg/kg) > Ethylbenzene (0.007 mg/kg) in soil and Ethylbenzene (0.057 mg/kg) > Xylene (0.051 mg/kg) > Benzene (0.034 mg/kg) > Toluene (0.02 mg/kg). The human health risk based on the target hazard quotient (THQ) for non-carcinogenic parameters in soil and Cassava ranged from “No Significant Risk of Non-Carcinogenic-NSRNc (THQ x 10^-6) to Moderate Significant Risk of Non-Carcinogenic- MSRNc (THQ × 10^-3)” for adults and children. The total carcinogenic risk (TCR) of the HMs and BTEX in soil and Cassava for adults and children was within the “Negligible Carcinogenic Risk for Human-ACRH (TCR × 10^-6 to TCR × 10^-9)”.

Conclusion

Continuous consumption and bioaccumulation of Cassava means the population are not entirely free from the risk of health exposure to BTEX and heavy metals; therefore, effective environmental sustainability practices must be encouraged.

Evidence of the joint association between exposure to multiple environmental chemicals and non-alcoholic fatty liver disease (NAFLD) is scarce. In this study, 281 participants from Zhuhai, China (138 patients with NAFLD vs. 143 healthy participants) were recruited to explore the associations of 40 per- and polyfluoroalkyl substances (PFAS), 11 neonicotinoid insecticides (NEOs), and 8 benzotriazoles (BTRs) and benzothiazoles (BTHs) with the risk of NAFLD. Perfluorooctane sulfonate (PFOS) and its emerging alternatives (6:2 chlorinated polyfluorinated ether sulfonate [6:2 Cl-PFESA] and 8:2 fluorotelomer sulfonic acid [8:2 FTSA]), NEO metabolites (m-NEOs), BTR, and BTH were the predominant PFAS, NEOs, BTRs and BTHs, respectively. The total median concentrations of PFAS (20.4 ng/mL vs. 7.16 ng/mL) and NEOs (7.24 ng/mL vs. 6.23 ng/mL) in NAFLD group were significantly higher than those in healthy group. Sex differences in PFAS exposure have been observed among patients with NAFLD. 8:2 FTSA and short-chain PFAS were more predominant in female patients with NAFLD, whereas other emerging (i.e., 6:2 and 8:2 Cl-PFESA) and legacy PFAS (i.e., PFOS and long-chain perfluoroalkyl carboxylic acids) easily accumulated in male patients with NAFLD. The results of the multiple linear regression analysis indicated a significant positive association between PFOS and alanine transaminase (ALT) in serum samples from patients with NAFLD (β = 23.2, 95% confidence intervals (CI): 7.82, 38.5). Conversely, negative correlations were observed between 5-hydroxy-imidacloprid (5-OH-IMI) and γ-glutamyl transpeptidase (GGT) (β = −2.73, 95% CI: −5.29, −0.18), as well as between tolyltriazole (TTR) and total bilirubin (TBIL) (β = −0.70, 95% CI: −1.33, −0.08) and direct bilirubin (DBIL) (β = −0.59, 95% CI: −0.98, −0.20). The Bayesian kernel machine regression model revealed a positive joint effect of exposure to PFAS and NEO on elevated NAFLD outcomes, suggesting that exposure to PFAS and NEO might exacerbate the severity of NAFLD. This study fills the knowledge gap between multi-pollutant exposure and NAFLD risk.

Research work on surface water bodies in Morocco has been in majority restricted to physicochemical and biological concentration. Hence, this study was conducted to address the existing research gap by evaluating heavy metal contamination and its associated risk assessment in surface water bodies, in Mohammedia prefecture, Morocco. A total of 22 water samples were evaluated regarding physicochemical factors and heavy metals. The parameters analyzed are pH, temperature (T), electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca²⁺), Sodium (Na⁺), Potassium (K⁺), Ammonia (NH⁺), dissolved oxygen (DO), Sulphate (SO₄²⁻), nitrite (NO²⁻), nitrate (NO³⁻), phosphate (PO₄³⁻), total phosphate (TP), total kjeldahl nitrogen (TKN), cadmium (Cd), copper (Cu), Iron (Fe), lead (Pb), and zinc (Zn). Overall water quality (Ow) and status of contamination presented the water quality and pollution quantitatively. Carcinogenic and noncarcinogenic risks were estimated for health risk assessment. Ca²⁺ was the most abundant cation, and SO₄³⁻ was the most abundant anion. Heavy metal concentrations were within permissible limits. Ow was good in terms of being suitable for parameters, i.e., <1 except for NH+. Which indicated water quality in the category of “highly polluted” >2.5. Pollution index (PI) indicated high pollution (14–74) at S3, S4, S5, and S6 sample points. In addition, Pb was a significant contributor to deteriorating water quality, with individual contributions ranging from 1 to 12 at sites S1, S2, and S3. For heavy metal hazards, i.e., adverse health effects, Hazard Quotient (HQ) (0.0002–0.01) was <1 for sample points, and Hazard Index (HI) (0.007–0.01) had a similar trend. They were inferring no significant non-carcinogenic health impact on its consumers. Carcinogenic risk (CR) was found to be within acceptable limits for CD, Cu, Pb, and Zn, i.e., 10⁻⁴ to 10⁻⁶. At points S2, S3, and S4, the carcinogenic index (CI) was above the acceptable limit, with values ranging from 1 × 10⁻³ to 7.9 × 10⁻³ attributed to Fe. Therefore, according to the findings of this research, the water quality is not suitable for direct consumption in its current state. Hence the study recommends treatment of surface water bodies prior to consumption.