Industrial Organic Contaminants Research Articles

Study on the adsorption characteristics of organic contaminants on alumina surface coated with clean graphene and the influence of amorphous carbon on wetting behavior

This paper investigates the adsorption performance of clean graphene coated on an alumina (Al2O3) substrate towards two common industrial organic contaminants, dibutyl phthalate (DBP), and n-dodecane. The adsorption effects were examined through contact angle measurements. We have observed that the alumina exhibits enhanced adsorption capacity for both organic contaminants, DBP and n-dodecane, after being coated with clean graphene. The presence of graphene significantly enhances the polar component of the surface free energy of alumina, resulting in the extraordinary attraction of the substrate towards the liquids with highly polar components in surface tension. In our experiments, we observed that although graphene was not contaminated by hydrocarbons in the air, the presence of amorphous carbon on its surface still had an impact on the wettability of the substrate. Molecular dynamics simulations are utilized to explore the adsorption behavior of the two organic contaminants on graphene with varying degrees of amorphous carbon present on its surface. The presence of amorphous carbon also reduces the adhesion energy and desorption free energy between organic contaminants and the substrate, weakening the interaction between the liquid and the substrate and increasing the risk of spontaneous desorption. These findings lay the foundation for graphene-based alumina materials in the field of adsorption of organic contaminants.

Yesterday's contamination–A problem of today? The case study of discontinued historical contamination of the Mrežnica River (Croatia)

The remnants of historical industrial contamination can be detected in many aquatic ecosystems worldwide even at present time. Mrežnica is a river in Croatia that has been, for more than a hundred years, continually exposed to effluents of various industries, which have, in modern time, mostly ceased to operate. Our aim was to establish the level of current contamination and pollution of the Mrežnica river-water and sediments. The study of river contamination at three sites (reference site; site nearby former cotton industry facility in Duga Resa – DRF; industrial zone of Karlovac town - KIZ) in three sampling campaigns (May 2020, April and September 2021) encompassed analyses of physico-chemical water parameters, screening of 369 pesticides, measurement of metal (loid) concentrations in the sediments, and in the dissolved and particulate phases of the river-water. The sediment pollution was assessed through the analyses of total bacteria abundance (by targeting 16S rRNA genes), and their associated metal resistance genes (cnrA, pbrT and czcD) and class 1 integrons (intl1). At the DRF site, industrial organic contaminants that can be traced to textile production were detected (dye and nylon components), as well as increased levels of some metals bound to suspended particulate matter and sediments. At the most downstream KIZ site, occasional high level of industrial herbicide neburon was measured in the river-water, and metal contamination of suspended particulate matter and sediments was evident. Although, based on the comparison with legislation and literature data, the level of contamination was rather mild, the effects on microbial communities were unquestionable, confirmed by increased abundance of the czcD gene at DRF site and the intI1 gene at both industrially impacted sites. Obtained results indicated long-term sediment retention of some industrial contaminants at the places of historical freshwater contamination, and, thus, the necessity for their monitoring even after the termination of contamination sources.

Increasing Trends of Legacy and Emerging Organic Contaminants in a Dated Sediment Core From East-Africa

Temporal trends of industrial organic contaminants can show how environmental burdens respond to changes in production, regulation, and other anthropogenic and environmental factors. Numerous studies have documented such trends from the Northern Hemisphere, while there is very limited data in the literature from sub-Saharan Africa. We hypothesized that the temporal trends of legacy and contemporary industrial contaminants in sub-Saharan Africa could greatly differ from the regions in which many of these chemicals were initially produced and more extensively used. For this purpose, a dated sediment core covering six decades from a floodplain system in urban Dar es Salaam, Tanzania, was analysed. The samples were analysed for selected legacy persistent organic pollutants (POPs) [polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs)] and chemicals of emerging concern (CECs) [alternative brominated flame retardants (aBFRs), chlorinated paraffins (CPs), and dechloranes]. All groups of chemicals showed a steep increase in concentrations towards the uppermost sediment layers reflecting the more recent years. Concentrations of the individual compound groups in surface sediment were found in the order CPs >> aBFRs ∼ ∑25PBDEs > dechloranes ∼ ∑32PCBs. Time trends for the individual compounds and compound groups differed, with ∑32PCBs showing presence in sediments since at least the early 1960s, while some CECs first occurred in sediments corresponding to the last decade. Investigations into potential drivers for the observed trends showed that socioeconomic factors related to growth in population, economy, and waste generation have contributed to increasing concentrations of PBDEs, aBFRs, CPs, and Dechlorane Plus. Further monitoring of temporal trends of industrial organic contaminants in urban areas in the Global South is recommended.

Influence of industrial contamination in municipal secondary effluent disinfection by UV/H2O2.

Advanced oxidation processes, including UV/H2O2, are methods able to remove diverse classes of organic contaminants and disinfect water and wastewater. However, the variation in the matrix composition can influence the inactivation of microorganisms due to the presence of competing reactive material, which consumes the available oxidants. This problem can lead to the use of inadequate oxidant/radiation dose and disturb a correct treatment. The aim of this study was to assess the efficiency of UV/H2O2 to inactivate microbiological indicators in secondary effluents in the presence of high concentration of carbonate, nitrate, metals, and industrial organic contaminants. Metals had a positive influence on inactivation acting as catalysts. Zn, Fe, and all metals simultaneously presented toxic effects to the indicator organisms in the higher concentrations before the treatment. Even in metals presence, the negative effect of carbonate and the industrial organic contaminants on indicators inactivation was very important. Bacteria regrowth after 72h was also affected by the same inhibiting substances, but the metals acted positively inhibiting it. The disinfection indicators had different sensibilities to the spiked substances. Escherichia coli inactivation was more affected than total coliforms by the presence of the industrial contamination, which can lead to different interpretation of inhibition degree depending of the used disinfection indicator.

Photocatalytic Degradation of Azo Dyes and Organic Contaminants in Wastewater Using Magnetically Recyclable Fe3O4@UA-Cu Nano-catalyst

In this study, we delineated the structural properties and catalytic behavior of nanocrystalline Fe3O4@Urocanic acid(UA)–Cu magnetically recyclable nanocatalyst (MRCs) which was produced via hydrothermal route. Here, Urocanic acid (UA) used as a linker to attach Cu nanoparticles and stabilized the iron oxide. Structural properties were examined through Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDX). Moreover, thermal and magnetic properties of MRCs were completed using thermal gravimetry (TG) and vibrating sample magnetometry (VSM) respectively. Moreover, the catalytic studies of product were recorded by UV–Vis absorption spectrophotometer for azo dyes and aromatic nitro compounds. The synthesized MRCs was found as an efficient nanocatalyst and magnetically recyclable from the reaction medium without significantly loss in its catalytic activity. Fe3O4@UA-Cu MRCs can be considered for the treatment of industrial dyes pollutants and organic contaminants from wastewater. Proposed mechanism of photocatalysis degradation of dye by Fe3O4@UA-Cu MRCs.

Long-Term Temporal Trends of Polychlorinated Biphenyls and Their Controlling Sources in China.

Polychlorinated biphenyls (PCBs) are industrial organic contaminants identified as persistent, bioaccumulative, toxic (PBT), and subject to long-range transport (LRT) with global scale significance. This study focuses on a reconstruction and prediction for China of long-term emission trends of intentionally and unintentionally produced (UP) ∑7PCBs (UP-PCBs, from the manufacture of steel, cement and sinter iron) and their re-emissions from secondary sources (e.g., soils and vegetation) using a dynamic fate model (BETR-Global). Contemporary emission estimates combined with predictions from the multimedia fate model suggest that primary sources still dominate, although unintentional sources are predicted to become a main contributor from 2035 for PCB-28. Imported e-waste is predicted to play an increasing role until 2020-2030 on a national scale due to the decline of intentionally produced (IP) emissions. Hypothetical emission scenarios suggest that China could become a potential source to neighboring regions with a net output of ∼0.4 t year-1 by around 2050. However, future emission scenarios and hence model results will be dictated by the efficiency of control measures.

Stirring Enhances Removal of Oil by Kapok Fiber

The natural hollow fiber, namely kapok, has been studied for the removal of oil, particularly in the area of oil spill clean-up. The hydrophobic nature of the natural absorbent has been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. Kapok fiber is inexpensive, readily available, very lightweight which makes it easy for transportation and its excellent buoyancy eases retrieval. Reusability of the material up to 15 cycles has been reported and this supports its being environmental-friendly. This paper looks into the oil absorption capacity of raw kapok fiber that can be dramatically enhanced by the simple mechanism of stirring. The oil absorption capacity is greatly increased to more than 200 times the mass of kapok used, i.e., with stirring, 1 g of the kapok fiber is able to absorb at least 200 g of the oil (200 g/g) which in this case is the refined palm oil used for cooking. The paper also discusses the reasons for the improvement due to stirring. And as a natural agricultural product which is abundant, besides being environmental-friendly, its application would be a sustainable approach to control water pollution due to oil spills and industrial organic contaminants.

Industrial organic contaminants: identification, toxicity and fate in the environment

Industrialization and urbanization in the more economically developed countries and also in emerging and developing nations have led to an intensive and still increasing use of water resources. The involved chemical contamination led to a deterioration of aquatic systems in many areas. Industries are important pollution sources and the discharged wastewaters may contain very diverse and potentially harmful organic compound groups. We therefore present here a comprehensive review of the current state of knowledge of organic contaminants from industrial wastewaters. The available studies proved the heterogenic chemical composition of industrial wastewaters, even from the same industry branches, and the presence of heterogenic organic contaminant mixtures from industrial sources in aquatic systems. We conclude that our knowledge of the chemical composition of industrial wastewaters and the occurrence of industrial organic contaminants in the environment is as yet very limited. A combination of chemical and toxicological methods enabled the identification of toxic organic constituents in industrial wastewaters. Chemical evaluations of industrial contamination linked to surveys of environmental impacts could relate toxic effects of field samples to the presence of specific contaminants. Exposure experiments in the field proved the bioaccumulation and toxicity of several industrial compounds. Ecological surveys in industrial areas combined with a comprehensive chemical characterization and toxicity evaluation are so far missing. Some of the identified organic contaminants are related to characteristic industrial production processes, and their presence in water, sediment or biota indicates the input of specific industrial wastewaters. Accordingly, these compounds can be used as industrial markers. We suggest the proceeding application of the marker concept, as markers are useful to verify the input of specific industrial wastewaters to aquatic systems and to investigate the spatial distribution of the emission. Such information helps to disentangle different emission sources for the subsequent investigation of potential impacts in the environment.

Identification of specific organic contaminants in different units of a chemical production site.

Due to the very limited number of studies dealing with the chemical composition of industrial wastewaters, many industrial organic contaminants still escape our view and consequently also our control. We present here the chemical characterization of wastewaters from different units of a chemical complex, thereby contributing to the characterization of industrial pollution sources. The chemicals produced in the investigated complex are widely and intensively used and the synthesis processes are common and applied worldwide. The chemical composition of untreated and treated wastewaters from the chemical complex was investigated by applying a non-target screening which allowed for the identification of 39 organic contaminants. According to their application most of them belonged to four groups: (i) unspecific educts or intermediates of industrial syntheses, (ii) chemicals for the manufacturing of pharmaceuticals, (iii) educts for the synthesis of polymers and resins, and (iv) compounds known as typical constituents of municipal sewage. A number of halogenated compounds with unknown toxicity and with very high molecular diversity belonged to the second group. Although these compounds were completely removed or degraded during wastewater treatment, they could be useful as "alarm indicators" for industrial accidents in pharmaceutical manufacturing units or for malfunctions of wastewater treatment plants. Three potential branch-specific indicators for polymer manufacturing were found in the outflow of the complex. Among all compounds, bisphenol A, which was present in the leachate water of the on-site waste deposit, occurred in the highest concentrations of up to 20 000 μg L(-1). The comparison of contaminant loads in the inflow and outflow of the on-site wastewater treatment facility showed that most contaminants were completely or at least significantly removed or degraded during the treatment, except two alkylthiols, which were enriched during the treatment process. The chemical composition of the inflow samples showed a very heterogenic composition and strongly varied, reflecting that large scale industrial synthesis is carried out in batches. The outflow contained mainly unspecific chlorinated educts or intermediates of industrial syntheses as well as compounds which are known as typical constituents of municipal wastewaters.

Using the kingfisher (Alcedo atthis) as a bioindicator of PCBs and PBDEs in the dinghushan biosphere reserve, China

The Dinghushan Biosphere Reserve is a nature reserve and a site for the study of tropical and subtropical forest ecosystems. Rapid industrialization and intensive electronic waste-recycling activities around the biosphere reserve have resulted in elevated levels of industrial organic contaminants in the local environment that may cause adverse effects on wildlife that inhabits this area. In the present study, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and 2 alternative brominated flame retardants (BFRs)-decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE)-were investigated in the biosphere reserve and a reference site by using the kingfisher (Alcedo atthis) as a bioindicator. Residue concentrations in kingfishers from the Dinghushan Biosphere Reserve ranged from 490 ng/g to 3000 ng/g, 51 ng/g to 420 ng/g, 0.44 ng/g to 90 ng/g, and 0.04 ng/g to 0.87 ng/g lipid weight for ∑PCBs, ∑PBDEs, DBDPE, and BTBPE, respectively. With the exception of the BTBPE, these levels were 2 to 5 times higher than those detected in kingfishers from the reference site. The contaminant patterns from the biosphere reserve were also different, with larger PCB contributions in comparison with the reference site. The estimated predator-prey biomagnification factors (BMFs) showed that most of the PCB and PBDE congeners and BTBPE were biomagnified in kingfishers from the biosphere reserve. The calculated toxic equivalent quantity (TEQ) concentrations of major coplanar PCB congeners in kingfishers from the biosphere reserve ranged from 18 pg/g to 66 pg/g wet weight, with some of these TEQ concentrations reaching or exceeding the levels known to impair bird reproduction and survival.

Are Reductions in Industrial Organic Contaminants Emissions in Rich Countries Achieved Partly by Export of Toxic Wastes?

Recent studies show that PCB (polychlorinated biphenyl) air concentrations remain surprisingly high in parts of Africa and Asia. These are regions where PCBs were never extensively used, but which are implicated as recipients of obsolete products and wastes containing PCBs and other industrial organic contaminants, such as halogenated flame retardants (HFRs). We hypothesize that there may be different trends in emissions across the globe, whereby emissions of some industrial organic contaminants may be decreasing faster in former use regions (due to emission reductions combined with uncontrolled export), at the expense of regions receiving these substances as obsolete products and wastes. We conclude that the potential for detrimental effects on the environment and human health due to long-range transport by air, water, or wastes should be of equal concern when managing and regulating industrial organic contaminants. This calls for a better integration of life-cycle approaches in the management and regulation of industrial organic contaminants in order to protect environmental and human health on a global scale. Yet, little remains known about the amounts of industrial organic contaminants exported outside former use regions as different types of wastes because of the often illicit nature of these operations.

Impact of metals bioleaching on the nutrient value of biological nutrient removal biosolids

The biosolids industry in Australia is evolving around the beneficial use of biosolids as a resource. Phosphorus rich biosolids from biological nutrient removal (BNR) facilities are highly desirable for land application. However, the accumulation of toxic heavy metals and industrial organic contaminants may render the biosolids unsuitable for land application. The presence of toxic heavy metals has been identified by Local Authorities in Australia as a major constraint limiting the beneficial use of biosolids. The potential of off-site contamination due to the migration of nutrients is also a major concern especially when applying biosolids to acidic agricultural land. Accordingly, the relevant environment protection and conservation agencies are involved in either developing or finalising guidelines to control the beneficial use of biosolids products. Metals bioleaching is a process achieved through bio-acidification. Bio-acidification of biosolids prior to land application can be used to dissolve and remove a significant fraction of the heavy metals content of the product. However, the process also reduces the nutrients content of the resource. Bio-acidification of Loganholme (Queensland) BNR biosolids dissolved 76% of the total phosphorus and 38% of the TKN. The heavy metals solubilisation results reached 50% for Cr, 79% for Ni, 45% for Zn, 24% for Cu, 30% for Cd, and 82% for Pb.

Impact of metals bioleaching on the nutrient value of biological nutrient removal biosolids

The biosolids industry in Australia is evolving around the beneficial use of biosolids as a resource. Phosphorus rich biosolids from biological nutrient removal (BNR) facilities are highly desirable for land application. However, the accumulation of toxic heavy metals and industrial organic contaminants may render the biosolids unsuitable for land application. The presence of toxic heavy metals has been identified by Local Authorities in Australia as a major constraint limiting the beneficial use of biosolids. The potential of off-site contamination due to the migration of nutrients is also a major concern especially when applying biosolids to acidic agricultural land. Accordingly, the relevant environment protection and conservation agencies are involved in either developing or finalising guidelines to control the beneficial use of biosolids products. Metals bioleaching is a process achieved through bio-acidification. Bio-acidification of biosolids prior to land application can be used to dissolve and remove a significant fraction of the heavy metals content of the product. However, the process also reduces the nutrients content of the resource. Bio-acidification of Loganholme (Queensland) BNR biosolids dissolved 76% of the total phosphorus and 38% of the TKN. The heavy metals solubilisation results reached 50% for Cr, 79% for Ni, 45% for Zn, 24% for Cu, 30% for Cd, and 82% for Pb.

Precision laser-based decontamination of microcavities

The removal of oil-based contaminants from microcavities with narrow apertures and comparatively long axial dimensions presents a number of challenges in an industrial production line environment. Traditional solvent-based approaches are costly to implement, inefficient in cleaning such microcavity geometries, and increasingly unacceptable from an environmental standpoint. An attractive alternative is to employ high-energy laser pulses to selectively remove the contaminants without introducing damage to the component undergoing the cleaning procedure. This paper will present results of initial ablation trials on example industrial oil-based organic contaminants whose residues within microcavities in steel-based components are to be removed. At present, higher order lines from a frequency tripled/quadrupled Nd:YAG laser are used to study the optimum fluence for removal of the oil-based contaminant without inflicting damage to the steel. Absorption spectroscopy of the contaminant fluid indicates that photon wavelengths shorter than ∼370 nm will interact with the material. Initial results show that the required intensity at 355 nm (>25 J/cm 2) also damages the type of steel under investigation, but that exposure to even single pulses at 266 nm (∼100 mJ/cm 2) shows adequate removal of the contaminant without significant damage to the steel. Monitoring of the removal process is achieved through exploitation of the blue fluorescence of the oil-based contaminant that occurs as a result of ultraviolet pumping.

Monitoring and prioritisation of organic contaminants in sewage sludges using specific chemical analysis and predictive, non-analytical methods

Municipal sludge application on agricultural land (land utilization) is practised widely and accounts for between 30–40% of production in Canada and the UK. Land utilization is subject to public concerns over the potential for deleterious effects of organic contaminants on agricultural productivity and uptake into the foodchain. Consequently, reliable data on the concentrations of organic contaminants in sludge are required to assess risks associated with land use. A detailed monitoring survey has been carried out by WTC to determine the concentrations of a range of industrial organic contaminants in 11 Canadian sewage sludges and one sludge compost. Volatile, base-neutral and acid extractable contaminants seldom exceeded 5 mg kg−1 dry wt., organochlorine pesticides and polychlorinated biphenyls did not exceed 1 mg kg−1 dry wt. and toxaphene and N-nitrosodimethylamine were not detected in the materials analyzed. Mean total PCDD and PCDF concentrations were ≤ 36 μg kg−1 dry wt. (median 6.7 μg kg−1 dry wt.) and mean toxic equivalents were ≤ 0.12 μg kg−1 dry wt. (median 0.02 μg kg−1 dry wt.). It was concluded that in many Canadian sludges the aforementioned organic contaminants represent no significant risk to agriculture and the environment. However, other organic contaminants potentially present in sewage sludge may not be amenable to analysis by the target compound techniques widely used. Consequently, WRc have applied a non-analytical approach to assess which contaminants may occur in sewage sludges and persist in treated soils. Predictions of physicochemical properties using quantitive structure activity relationships (QSARs) have been used to aid the screening and prioritisation of a range of high production volume chemicals (HPVCs) that may enter sewage treatment works. Analytical surveys for organic residues are expensive and this type of approach may assist in identifying further contaminants which should be analyzed in sewage sludges and treated soils.

Rates and Routes of Transport of PCBs in the Environment

Polychlorinated biphenyls (PCBs) are one member of a class of chlorinated organic compounds which give rise to concern, because of their wide dispersal and persistence in the environment and tendency to accumulate in food chains, with possible adverse effects on animals at the top of the food webs, including man. In the past, attention has been concentrated on chlorinated hydrocarbon pesticides, such as DDT, dieldrin, heptachlor and HCH (hexachlorocyclohexane). More recently attention has been focused on PCBs and on chlorinated dibenzodioxins. Likely candidates for future attention are hexachlorobenzene, chlorinated dibenzofurans, and chlorinated phenols. In the past, such compounds have generally been studied individually. As the number of compounds giving rise to concern increases, there is an urgent need to establish uniform monitoring schemes and generalized models describing environmental transport and bioaccumulation which will be applicable to all compounds with these properties. Models such as the global monitoring scheme outlined by the SCEP study (1), and the global transport model outlined recently by Woodwell et al. (2), are needed in order to help identify sources of environmental contamination, to establish acceptable levels of discharge, and to estimate the effectiveness of different control strategies. This paper summarizes the fragmentary knowledge available about production, uses, and losses of PCBs, and attempts to define the major routes of transport and reservoirs of PCBs in the environ-

Rates and Routes of Transport of PCBs in the Environment

Rates and Routes of Transport of PCBs in the Environment