Treatment Of Persistent Organic Pollutants Research Articles

Folic acid supplementation reduces multigenerational sperm miRNA perturbation induced by in utero environmental contaminant exposure.

Persistent organic pollutants (POPs) can induce epigenetic changes in the paternal germline. Here, we report that folic acid (FA) supplementation mitigates sperm miRNA profiles transgenerationally following in utero paternal exposure to POPs in a rat model. Pregnant founder dams were exposed to an environmentally relevant POPs mixture (or corn oil) ± FA supplementation and subsequent F1–F4 male descendants were not exposed to POPs and were fed the FA control diet. Sperm miRNA profiles of intergenerational (F1, F2) and transgenerational (F3, F4) lineages were investigated using miRNA deep sequencing. Across the F1–F4 generations, sperm miRNA profiles were less perturbed with POPs+FA compared to sperm from descendants of dams treated with POPs alone. POPs exposure consistently led to alteration of three sperm miRNAs across two generations, and similarly one sperm miRNA due to POPs+FA; which was in common with one POPs intergenerationally altered sperm miRNA. The sperm miRNAs that were affected by POPs alone are known to target genes involved in mammary gland and embryonic organ development in F1, sex differentiation and reproductive system development in F2 and cognition and brain development in F3. When the POPs treatment was combined with FA supplementation, however, these same miRNA-targeted gene pathways were perturbed to a lesser extend and only in F1 sperm. These findings suggest that FA partially mitigates the effect of POPs on paternally derived miRNA in a intergenerational manner.

Persistent organic pollutants (POPs) increase rage signaling to promote downstream cardiovascular remodeling.

Exposure to environmental contaminants and consumption of a high, saturated fatty diet has been demonstrated to promote precursors for metabolic syndrome (hyperglycemia, hyperinsulinemia, and hypertriglyceridemia). The purpose of this study was to determine if exposure to the most prevalent environmental persistent organic pollutants (POPs) would act as causative agents to promote metabolic syndrome independent of dietary intake. We hypothesized that POPs will activate the advanced glycated end‐product (AGE)‐and receptor for AGE (RAGE) signaling cascade to promote downstream signaling modulators of cardiovascular remodeling and oxidative stress in the heart. At 5‐weeks of age nondiabetic (WT) and diabetic (ob/ob) mice were exposed POPs mixtures by oral gavage twice a week for 6‐weeks. At the end of 6‐weeks, animals were sacrificed and the hearts were taken for biochemical analysis. Increased activation of the AGE‐RAGE signaling cascade via POPs exposure resulted in elevated levels of fibroblast differentiation (α‐smooth muscle actin) and RAGE expression indicated maladaptive cardiac remodeling. Conversely, the observed decreased superoxide dismutase‐1 and ‐2 (SOD‐1 and SOD‐2) expression may exacerbate the adverse changes occurring as a result of POPs treatment to reduce innate cardioprotective mechanisms. In comparison, ventricular collagen levels were decreased in mice exposed to POPs. In conclusion, exposure to organic environmental pollutants may intensify oxidative and inflammatory stressors to overwhelm protective mechanisms allowing for adverse cardiac remodeling.

Pilot‐Scale Electrochemical Treatment of a 1,4‐Dioxane Source Zone

AbstractElectrochemical treatment is a promising emerging technology in which direct current is applied to drive the degradation of aqueous contaminants. Several bench‐scale studies have demonstrated the capability of electrochemical oxidation to fully mineralize refractory organics such as pesticides and perfluorinated compounds. However, insights into large‐scale design and field performance are critically lacking. Here, we designed six pilot‐scale reactors and tested their performance and efficiency for the treatment of groundwater contaminated with 1,4‐dioxane (1,4‐DX) at concentrations exceeding 1000 mg/L. Anode surface area‐normalized degradation rates increased with increasing potential applied, while the process was more energy‐efficient per mass unit removed at low potentials. While not all 1,4‐DX was completely mineralized, the detected ring‐opening intermediates are known to be readily biodegradable. Analyses of potential by‐products from chloride oxidation revealed the generation of chloromethanes and perchlorate at low mg/L concentrations. Towards the end of the 8.5‐month pilot test, decreasing currents and degradation rates indicated progressing passivation of the electrodes, likely due to cathodic carbonate precipitation and/or poisoning by the uniquely high organic carbon load of this source zone groundwater. The findings of our study demonstrate that electrochemical groundwater remediation is a capable approach for the treatment of persistent organic pollutants. Our pilot‐scale test provides practitioners with a basis for evaluating its efficiency under site‐specific conditions and collecting critical performance metrics for technology scale‐up.

Effective removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- from landfill leachate using locust bean gum.

The widespread distribution of persistent organic pollutants (POPs) in landfill leachate is problematic due to their acute toxicity, carcinogenicity and genotoxicity effects, which could be detrimental to public health and ecological systems. The objective of this study was to evaluate the effective removal of POPs - namely, p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- - from landfill leachate using locust bean gum (LBG), and in comparison with commonly used alum. The response surface methodology coupled with a Box-Behnken design was employed to optimize the operating factors for optimal POPs removal. A quadratic polynomial model was fitted into the data with the R2 values of 0.97 and 0.96 for the removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl), (S)-, respectively. The physicochemical characteristics of the flocs produced by LBG and alum were evaluated with Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The infrared spectra of LBG-treated floc were identical with LBG powder, but there was some variation in the peaks of the functional groups, signifying the chemical interactions between flocculants and pollutant particles resulting from POPs removal. The results showed that p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- obtained 96% and 100% removal using 500 mg/L of LBG at pH 4. pH have a significant effect on POPs removal in leachate. It is estimated that treating one million gallons of leachate using alum (at 1 g/L dosage) would cost US$39, and using LBG (at 500 mg/L dosage) would cost US$2. LBG is eco-friendly, biodegradable and non-toxic and, hence, strongly recommended as an alternative to inorganic coagulants for the treatment of POPs in landfill leachate.

Evaluation of the effect of cold atmospheric plasma on oxygenases’ activities for application in water treatment technologies

ABSTRACT Plasma-based technologies take an increasing place in the new conceptions of wastewater management as a promising tool for the treatment of persistent organic pollutants with low biodegradability. Plasma major advantage is the synergy of diverse active components with high oxidative action and additional benefits as disinfection of treated water. But the bactericidal effect of plasma can influence the treatment effectiveness when this technology is used in combination with biological methods for the removal of pollutants. The aim of this paper is to study the effect of non-thermal atmospheric plasma torch on key enzymes from phenol biodegradation pathways in Pseudomonas aureofaciens (chlororaphis) AP-9. The strain was isolated from contaminated soils and had a high potential for biodegradation of aromatic compounds. The used plasma source is surface-wave-sustained discharge operating at 2.45 GHz in argon produced by an electromagnetic wave launcher surfatron type. The enzyme activities of phenol 2-monooxygenase (P2MO), catechol 1,2-dioxygenase (C12DO), catechol 2,3-dioxygenase (C23DO), protocatechuate 3,4-dioxygenase (P34DO) and succinate dehydrogenase (SDH) were measured in control and after plasma treatment of 10, 30 and 60 s. At short-time treatment, the activities of intradiol dioxygenases increased with 26% and 59% for C12DO and P34DO, respectively. Other oxygenases and SDH were inhibited with 35% even at 10 s treatment. Longer treatment times had a clear negative effect but SDH kept the higher activity at 60 s treatment compared to the oxygenases. Our data suggest that plasma-based technologies are a useful approach for post-treatment of aryl-containing wastewater in order to increase the effectiveness of biological removal.

Graphitic Carbon Nitride-Based Heterojunction Photoactive Nanocomposites: Applications and Mechanism Insight.

The design of heterojunction with superior performance of light absorption and appropriate conduction band and valence band potentials is a promising approach for the applications in efficient environmental remediation and the solar energy storage. In recent years, many studies have been devoted to the applications of graphitic carbon nitride (g-C3N4)-based heterojunction photoactive nanomaterials under visible light irradiation due to its excellent physical, optical, and electrical properties, which inspired us to compile this review. Although many reviews demonstrated about the syntheses and applications of g-C3N4 composites, a targeted review on the systematic application and photocatalytic mechanisms of g-C3N4-based heterojunction, in which components are in intimate linkage with each other rather than a physical mixture, is still absent. In this review, the applications of g-C3N4-based heterojunction photoactive nanomaterials in environmental remediation and solar energy storage, such as photocatalytic treatment of persistent organic pollutants, heavy-metal-ion redox, oxidative decomposition of pathogens, water splitting for H2 evolution, and CO2 reduction, are systematically discussed. In addition, some emerging applications, such as solar cells and biosensors, are also introduced. Meanwhile, a comprehensive assessment on the basis of first-principles calculations and the thermodynamics and kinetics of surface catalytic reaction for the electronic structure and photocatalytic properties of g-C3N4-based heterojunction are valued by this review. In the end, a brief summary and perspectives in designing practical heterojunction photoactive nanomaterials also showed the bright future of g-C3N4-based heterojunction. Altogether, this review systematically complements the information that previous reviews have frequently ignored and points out the future development trends of g-C3N4-based heterojunction, which expected to provide important references and right directions for the development and practical applications of g-C3N4-based heterojunction photoactive nanomaterials.

Treatment of persistent organic pollutants in wastewater using hydrodynamic cavitation in synergy with advanced oxidation process.

Persistent organic pollutants (POPs) are very tenacious wastewater contaminants. The consequences of their existence have been acknowledged for negatively affecting the ecosystem with specific impact upon endocrine disruption and hormonal diseases in humans. Their recalcitrance and circumvention of nearly all the known wastewater treatment procedures are also well documented. The reported successes of POPs treatment using various advanced technologies are not without setbacks such as low degradation efficiency, generation of toxic intermediates, massive sludge production, and high energy expenditure and operational cost. However, advanced oxidation processes (AOPs) have recently recorded successes in the treatment of POPs in wastewater. AOPs are technologies which involve the generation of OH radicals for the purpose of oxidising recalcitrant organic contaminants to their inert end products. This review provides information on the existence of POPs and their effects on humans. Besides, the merits and demerits of various advanced treatment technologies as well as the synergistic efficiency of combined AOPs in the treatment of wastewater containing POPs was reported. A concise review of recently published studies on successful treatment of POPs in wastewater using hydrodynamic cavitation technology in combination with other advanced oxidation processes is presented with the highlight of direction for future research focus.

Evaluation of advanced oxidation processes (AOP) using O3, UV, and TiO2 for the degradation of phenol in water

The treatment of persistent organic pollutants in wastewater from chemical factories by decomposition using advanced oxidation processes (AOPs) has recently been studied. However, the AOPs studied to date suffer from problems such as high running costs for ozone generation and difficulties with operational parameters in the addition of hydrogen peroxide. In this study, a compact AOP reactor that generates ozone by UV irradiation was developed. Ozone was generated using the Chapman method, i.e., by irradiating oxygen with UV light; the use of this method saves energy. The decomposition activity of the designed reactor and the effects of a combination of ozone, UV, and TiO2 were examined. The results showed that 100% decomposition of 50mg/dm3 phenol was reached within 120min using an O3–UV–TiO2 process, and COD removal reached 100% within 240min. COD analysis confirmed that a synergistic effect was obtained using ozone, UV, and TiO2 simultaneously.

Silver Oxide as Superb and Stable Photocatalyst under Visible and Near-Infrared Light Irradiation and Its Photocatalytic Mechanism

Photocatalytic processes are an environmentally friendly technology for treatment of persistent organic pollutants. However, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize fast decomposition of organic pollutants. In this research, a silver oxide nanoparticle aggregation with superb photocatalytic performance under artificial light source and sunlight was prepared and characterized. The results showed that methyl orange (MO) was decomposed completely in 120 s under irradiation of artificial visible light, artificial ultraviolet light, and sunlight, and in 40 min under near-infrared (NIR) light. The superb photocatalytic performance of as-prepared silver oxide remained almost constant after reuse or exposure under sunlight. It was confirmed that the co-working effect of photogenerated hole and ozone anion radicals did play an important role in the process of MO photodegradation with the existence of Ag2O. The narrow band gap of Ag2O, less than 1.3 eV, resulted in the...

Persistent organic pollutant waste in China: a review of past experiences and future challenges

As one of the world’s fastest developing countries, China is inevitably facing the problem of persistent organic pollutants (POPs). Owing in part to an inadequate management framework, insufficient and improper disposal of POP waste has caused serious pollution problems. In this study, we discuss: (1) the generation, amount, and distribution of POP waste in China; (2) past experience with respect to POP treatment and existing problems in management of POP waste. Additionally, we put forward suggestions regarding POP management. The results showed that the total amount of pesticide POP waste was about 4,059–6,093 tons, and more than 2,750 tons pesticide waste have been disposed in recent years. The total amount of polychlorinated biphenyl waste with high concentrations was approximately 50,000 tons; some of them have been disposed by incineration. Dioxin released to the environment through waste was 4,979 g I-TEQ in 2004. To eliminate environmental risk of POP waste, a series of disposal activities have been conducted or planned, but the disposal technique was still single on the whole. Furthermore, we suggest the POP waste inventory should be elevated, and then taking measures to promote disposal and treatment of wastes and strengthening POP waste environmental regulatory capacity building. This work may contribute to understanding the current situation of POP waste, and to developing an inventory of POP waste in the country. Moreover, as there may be many similar situations worldwide, especially in developing countries, the Chinese POP management experience can also provide valuable information to control and manage POP waste.

Remediation of DDTs‐Contaminated Sediments through Retrievable Activated Carbon Fiber Felt

AbstractAddition of adsorbent to the sediments has become an effective way for in situ treatment of persistent organic pollutants (POPs) contaminated sediments in recent years. However, once the adsorbents are added to the sediments, they are difficult to be retrieved, and potential risks of POPs are still existed. In this study, we proposed a new method that used activated carbon fiber felt (ACFF) to remediate POPs‐contaminated sediments with the advantage of retrievability. As an example of POPs remediation, three sediments were spiked with p,p′‐dichlordiphenyltrichloroethanes (DDT), o,p′‐DDT, p,p′‐dichlorodiphenyldichloroethylene, and p,p′‐dichlorodiphenyldichloroethane, and were allowed to age for 7, 28, or 100 days before viscose‐based ACFF was added to the spiked aqueous slurry in batch experiments. The effects of ACFF on DDTs removal efficiency in these sediments were examined. It was found that ACFF could efficiently remove DDTs released from the sediments. The DDTs removal efficiency of ACFF was influenced by the initial spiking concentrations, hydrophobicity of DDTs, aging times of the contaminated sediments, and organic carbon contents of the sediments. Moreover, the removal efficiency of ACFF was enhanced by increasing the amount of ACFF, as well as by sequential replacement of ACFF. The use of retrievable ACFF could potentially be an effective method for in situ remediation of sediments contaminated with POPs.

Noncombustion technologies for remediation of persistent organic pollutants in stockpiles and soil

Persistent organic pollutants (POPs) are a set of chemicals that are toxic, persist in the environment for long periods of time, and biomagnify as they move up through the food chain. Combustion technologies have been the principal technology used to destroy POPs. However, combustion technologies can create polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans, which are human carcinogens. Two organizations, the United Nations Environment Programme (UNEP) and the International HCH and Pesticides Association (IHPA) have developed detailed reports and fact sheets about noncombustion technologies for POP treatment. This article is intended to update and summarize these reports in a concise reader's guide, with links to sources of further information. The updated information was obtained by reviewing various Web sites and documents, and by contacting technology vendors and experts in the field. © 2006 Wiley Periodicals, Inc.