Biodegradation of polyethylene films with prooxidant additives

Prooxidant additives represent a promising solution to the problem of the environment contamination with polyethylene film litter. Prooxidants accelerate photo- and thermo-oxidation and consequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. The question not fully resolved remains the biodegradation itself, its mechanism and especially the factors influencing the time-frame in which it can occur. The presented review is aimed to provide comprehensible information for both microbiologists and polymer scientists, who need participate in the research leading to an understanding of the microorganism action on the oxidized polyethylene and to design of new materials.     

A field method using microcosms to evaluate transfer of Cd,Cu, Ni,Pb and Zn from sewage sludge amended forest soils to Helix aspersa snails

Juvenile Helix aspersa snails exposed in field microcosms were used to assess the transfer of Cd, Cu, Ni, Pb and Zn from forest soils amended with liquid and composted sewage sludge. Zn concentrations and contents were significantly higher in snails exposed to liquid and composted sludge after 5 and 7 weeks of exposure, when compared with control. Trends were less clear for the other metals. Present results show that Zn, among the cocktail of metallic trace elements (MTE) coming from sewage sludge disposal, represents the principal concern for food chain transfer and secondary poisoning risks. The microcosm design used in this experiment was well suited for relatively long-term (about 2 months) active biomonitoring with H. aspersa snails. The snails quickly indicated the variations of MTE concentrations in their immediate environment. Therefore, the present study provides a simple but efficient field tool to evaluate MTE bioavailability and transfer.     

Lipophilicity and Metabolic Route Prediction of Imidazolium Ionic Liquids * (6 pp)

- Aims and Background. Ionic liquid application in industry will offer several excellent solutions, but it also means that they will enter the environment sooner or later. Responsible product design should always take into consideration not only technological demands, but also the risks arising out of possible toxicity and ecotoxicity. In our strategy we are aiming to understand the fate of these entities through their life cycle in the environment as a complimentary element of their design. This paper presents results on the lipophilicity of selected imidazolium ionic liquids, a parameter that plays a key role in environmental and biological distribution. Additionally, the prediction of the most stable metabolite of a 1-butyl-3-methylimidazolium (BMIM) cation – a congener representative of this group of compounds is presented. Materials and Methods Lipophilicity was evaluated by means of reversed phase and immobilized artificial membrane chromatography and further compared to calculated data. Theoretical prediction of lipophilicity was undertaken using fragmental methodology combined with manual calculations of the geometric bond factor for quaternary ammonium and the electronic bond factor due to the presence of a charge. Results and Discussion All the substances studied are characterized by very low partition coefficients, and lipophilicity varies linearly with elongation of the n-alkyl chain. Prediction of metabolic routes was based solely on thermodynamic data of the radical intermediates formed during the reaction with the cytochrome P450 system. The energetically most stable radical structure is generated by hydrogen abstraction from the gamma position of the BMIM cation. Conclusions and Recommendations. The experimentally measured and theoretically estimated lipophilicity coefficients obtained for all the compounds studied generally indicate a relatively low lipophilicity and thus preferable partition to the aqueous phase. By means of thermodynamic data, it was also confirmed that the energetically most stable radical structure is generated by hydrogen abstraction from the gamma position on the alkyl chain in the 1-alkyl-3-methylimidazolium cation, as a result of which the C1 atom is preferentially oxidized. - * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on 'Chemistry and Environment', 29 August to 1 September 2004, Bordeaux, France.     

Biodegradation of a nonylphenol ethoxylate by the autochthonous microflora in lake water with observations on the influence of light

Alkylphenol polyethoxylates (APE) are routinely used as additives in pesticide formulations. Biodegradation of APEs results in the accumulation of persistent short chain mono-, di- and tri-ethoxylates (AP1EO, AP2EO AP3EO) that are more toxic than the parent compounds and potentially oestrogenic. Accumulation of persistent APE metabolites in shallow or ephemeral waters may pose a hazard to aquatic fauna. This study has followed the degradation and formation of individual oligomers in freshwater in static die-away tests with and without illumination. Over 33 days in darkness there was a progressive and complete loss of long chain oligomers (NP8-17EO), transient increases and subsequent loss of short to medium chain oligomers (NP4-7EO), and large persistent increases (approximately 1000%) in short chain oligomers (NP1-3EO). In the presence of illumination, biodegradation was retarded and heterotrophic bacterial proliferation was inhibited. After 33 days there was complete loss of long chain oligomers (NP9-17EO), incomplete loss of medium chain oligomers (NP6-8EO) and increases in short chain oligomers (NP1-5EO).     

Influence of creating an oligopoly through government intervention to improve partner collaboration intentions in the context of green supply chains

Pollution from supply chains can be controlled through the high level of efficiency realized by green supply chains. However, realizing a green supply chain depends on partners’ collaboration intentions. The purposes of this study are to explore the influence of oligopolies created through government intervention and how they can promote supply chain partners’ collaboration intentions in the context of green supply chains. Spearman’s correlation analysis, partial least squares, and the Sobel test are the main approaches adopted to evaluate the theoretical framework and hypotheses of this study. Our findings indicate that, in addition to a few leaders of the supply chain obtaining market order distribution authority, oligopolies created through government intervention guide consumers to more fully scrutinize these supply chain leaders and their partners. When their partners exhibit a lower collaboration intention in green supply chain improvement and increase the pollution emission risk, it is easy to induce and increase social pressure from consumers and thus pressure these leaders to reduce or even cancel the order distribution of these partners. To avoid order profit loss, these partners will continue to actively maintain their collaboration intentions in the green supply chain. In addition, environmental risk audits by supply chain leaders’ interventions are a common approach to improve green supply chains. However, partners are usually unwilling to cooperate with leaders’ audit interventions and show lower collaboration intentions. However, social pressure can threaten partners’ order profits and thus drive partners to show positive collaboration intentions and further accept leaders’ reasonable interventions in environmental risk audits and will have a positive effect on green supply chain improvement. Based on the above, to expedite the improvement of the green supply chain, oligopolies created through government intervention are not only an important external force but also an important national strategy in green environmental improvement.

     

Risk assessment of metals and organic pollutants for herbivorous and carnivorous small mammal food chains in a polluted floodplain (Biesbosch, The Netherlands)

A risk assessment was made for a carnivorous and a herbivorous food chain in a heavily polluted natural estuary (Biesbosch), by determining the most critical pollutants and the food chain most at risk. Exposure of food chains to metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) was assessed by analyzing dietary concentrations, internal concentrations, and biomarkers of exposure. Common shrew (Sorex araneus) and bank vole (Clethrionomys glareolus) were selected as representative small mammal species for the carnivorous and herbivorous food chain, respectively, and earthworms (Lumbricus rubellus) and snails (Cepaea nemoralis) as representative prey species for the carnivorous food chain. Metals contributed most to the total risk for small mammals and earthworms. PCBs, but not PAHs, contributed to the overall risk for S. araneus at regularly flooded locations. The carnivorous food chain appeared most at risk given the higher exposure levels and bioaccumulating potency found for contaminants in S. araneus.     

Rigorous uncertainty assessment in contaminant transport inverse modelling: a case study of fluoride diffusion through clay liners

Inverse methods used in assessing landfill liner design have not yet taken advantage of current developments in inverse procedures. Here, a method for inverting contaminant transport models is presented including a general error model and procedures for differentially weighted multiple response regression. General error models are employed in cases where the residuals are heteroscedastic and correlated, and lead to valid inference on model parameter and predictive uncertainty. The Shuffled Complex Evolution algorithm is used to optimise model parameters. Model parameter uncertainty is assessed by exploring the posterior probability distribution with the Metropolis algorithm, a Markov chain Monte Carlo sampling method. The inverse method is applied to simultaneously determine the sorption and diffusion parameters from laboratory diffusion cell experiments. In these experiments, fluoride migration through kaolin clays was measured by sampling the source and collector cells over time. To uniquely determine the transport model parameters, it was necessary to simultaneously fit the observed data from two independent diffusion cell experiments with different initial concentrations. The jointly fitted transport model parameters compared well with those fitted to independent batch experiments.     

Distribution and desorption of perfluorinated compounds in fractionated sediments

This study provides particle-scale understanding of perfluorinated compounds (PFCs) distribution in sediments collected from two locations in Tianjin, China. The sediments were fractionated according to particle size and density. Even though lower density carbonaceous fractions contributed only 17.8-22.3% of the total sediment mass, they displayed stronger affinity to PFCs with much higher PFC concentrations than in the heavy fractions. Hydrophobic interaction predominated the partition of longer chain PFCs while electrostatic interaction could affect the sorption of short chain PFCs in sediment fractions. The individual PFC concentrations increased with increasing perfluorocarbon chain length, and the concentrations of perfluoroalkanesulfonates (PFSAs) in the same sediment fraction were higher than perfluorocarboxylates (PFCAs) with the same chain length. Log K(oc) was in the range of 1.70-3.80 for C5-C12 PFCAs and 1.75-2.97 for C4-C8 PFSAs. Desorption experiments indicated desorption became difficult as the chain length increased, and PFSAs were harder to be desorbed than the corresponding PFCAs.     

ESF Workshop

Dioxin and PCB monitoring programs for food and feeding stuff in most countries of the world, including many European Countries are currently inadequate. Better control of food production lines and food processing procedures is needed to minimize entry of dioxin to the food chain and will help to avoid dioxin contamination accidents. This would also improve the ability to trace back a possible contamination to its source. European guidelines for monitoring programs should be established to ensure comparable and meaningful results. These guidelines should define the minimum requirements for the design of monitoring programs, analytical methods, and quality assurance. Though data from Northern Europe shows that the general population exposure to dioxin and PCB has decreased during the last ten years these compounds continue to be a risk of accidental contamination of the food chain. The most prominent recent example is the Belgian dioxin contamination of feeding stuff in 1999. The Belgian dioxin contamination was not detected due to dioxin monitoring programs but by their direct biological effects seen in animals. Four other cases of dioxin contamination have been detected in Europe since 1997 due to local monitoring programs. One of them (citrus pulp pellets 1998) was in a much larger scale than the Belgian dioxin contamination. The general population's exposure to dioxins and PCBs is still in the same range (1-4 pg WHO-TEQ/kg body weight and day) as the recently revised WHO tolerable daily intake (TDI). There is concern that short-term high level exposure to dioxins, furans, and PCB may cause biological effects on the human fetal development and further research is required. Further actions to control sources building on considerable advances already made in many countries may need to be supplemented by measures to prevent direct contamination of feeding stuff or food to reduce general population exposure further.     

Structure-activity relationships for association of linear alkylbenzene sulfonates with activated sludge

Sorption of linear alkylbenzene sulfonates (LAS) on sludge particles from wastewater treatment plants was studied. The effect of alkyl chain length and the water hardness were investigated. Sorption on sludge increases with increasing alkyl chain length in the LAS molecules. The results are interpreted in terms of a hydrophobic bonding mechanism being the critical micelle concentration a good index of the surfactant hydrophobicity. The increase in free energy of adsorption for the addition of successive methylene groups to the alkyl chain was estimated as 2.4 kJ/mol. Water hardness clearly enhances the sorption of LAS homologues on sludge and seems to promote cooperative sorption at high surfactant and calcium ion concentrations. An empirical equation was provided that allow to estimate the partition coefficient between aqueous and solid phases for LAS homologues as a function of the alkyl chain length and the water hardness.     

Intellectual capital,financial resources,and green supply chain management as predictors of financial and environmental performance

This research examines the influence of intellectual capital on financial and environmental performance with a mediating role of green supply chain management and a moderating role of financial resources. Structural model estimation was conducted on the data set of 324 Pakistani manufacturing SMEs and showed that intellectual capital significantly encourages green supply chain management as well as significantly contributes to financial and environmental performance. Green supply chain management partially mediates the relationship between intellectual capital and performance both the financial and environmental. Financial resources significantly strengthen the relationship between intellectual capital and green supply chain management. In light of the results, we suggest that firms should encourage intellectuality among their managers and employees to adopt green practices that can improve their financial and environmental performance. In addition, it is also suggested for managers and CEOs to effectively manage financial resources that are necessary for green practices.

     

Analysis of chlorinated paraffins in cutting fluids and sealing materials by carbon skeleton reaction gas chromatography

Chlorinated paraffins (CPs) pose a major risk in the environment, due to their wide application, to their persistence, to their carcinogenic potential, and in view of the fact, that they cannot be easily identified. Various commercial cutting fluids and sealing materials were analysed for CPs with carbon skeleton reaction gas chromatography (GC) and flame ionization detection. CPs are simultaneously dechlorinated and hydrogenated to the corresponding alkanes with Pd catalyst material in the GC injector. With this method, the carbon chain length of commercial technical CPs was determined. In six of sixteen sealing materials we found five short and one medium chain length polychlorinated paraffins in percentages of 9-16% (w/w). In five cutting fluids we found predominantly medium to long chain length chloroparaffins with percentages of 2.5-31% (w/w), only one fluid contained short chain CPs.     

The environmental photolysis of perfluorooctanesulfonate,perfluorooctanoate, and related fluorochemicals

A field study on the photolysis of perfluoroalkyl substances (PFASs) was conducted at high altitudes in Mt. Mauna Kea (Hawaii, USA; 4200 m) and Mt. Tateyama (Toyama, Japan; 2500 m). Results of photolysis of PFASs in the field were further confirmed in laboratory studies. Perfluorooctanesulfonate (PFOS), which is perceived as a non-degradable chemical in the environment, can undergo photolysis. Long chain PFASs can be successively dealkylated to short chain compounds such as perfluorobutyric acid (PFBA) and perfluorobutane sulfonate (PFBS), but the short chain compounds were relatively more resistant to photodegradation. These results suggest that environmental levels of short chain PFASs would increase both due to their formation from photolysis of long chain PFASs and from direct releases. Earlier studies on photolysis of PFASs were focused on the formation of perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs) from precursor compounds (such as fluorotelomer alcohols) under laboratory conditions. Our study suggests that PFSAs and PFCAs themselves can undergo photodegradation in the environment.     

Industrial metabolism of chlorine: a case study of a chlor-alkali industrial chain

Substance flow analysis (SFA) is applied to a case study of chlorine metabolism in a chlor-alkali industrial chain. A chain-level SFA model is constructed, and eight indices are proposed to analyze and evaluate the metabolic status of elemental chlorine. The primary objectives of this study are to identify low-efficiency links in production processes and to find ways to improve the operational performance of the industrial chain. Five-year in-depth data collection and analysis revealed that system production efficiency and source efficiency continued increasing since 2008, i.e., when the chain was first formed, at average annual growth rates of 21.01 % and 1.01 %, respectively. In 2011, 64.15 % of the total chlorine input was transformed into final products. That is, as high as 98.50 % of the chlorine inputs were utilized when other by-products were counted. Chlorine loss occurred mostly in the form of chloride ions in wastewater, and the system loss rate was 0.54 %. The metabolic efficiency of chlorine in this case was high, and the chain system had minimal impact on the environment. However, from the perspectives of processing depth and economic output, the case study of a chlor-alkali industrial chain still requires expansion.     

C3-C14-alkyl nitrates in remote South Atlantic air

Alkyl nitrates with chain lengths up to fourteen carbons have been detected in the remote troposphere of the South Atlantic Ocean. The concentrations of numerous iso- and n-alkyl nitrates in the range of C3-C12 have been measured. Tenax-GC analysis was applied to determine short chain alkyl nitrates (< C6), while the novel detection of long chain iso- and n-alkyl nitrates was achieved with a high volume sampling technique using silica gel. C3-C12-alkyl nitrates show the lowest concentrations in the trade wind region (3.5 pptv). Higher concentrations in the west wind belt (11.1 pptv) reveal the influence of the South American continent as the source for the alkyl nitrates after long range transport. The concentrations of alkyl nitrates increase in proximity to South America. Measurements of long chain alkyl nitrates in rural air near the city of Ulm (Germany) are given for comparison. In addition, pattern analysis of long chain alkyl nitrates reveal this complex mixture of new compounds to be useful as trace indicators to distinguish continental and marine air masses. Despite the lower photochemical formation yields of primary n-alkyl nitrates compared to secondary n-alkyl nitrates, the primary n-alkyl nitrates are relatively increased in marine air. The reason for this finding cannot be explained so far, but the correlation of secondary/primary n-alkyl nitrates shows a significant differentiation of air samples with continental or marine character.     

Congener group patterns of chloroparaffins in marine sediments obtained by chloride attachment chemical ionization and electron capture negative ionization

Congener group patterns of technical short chain and medium chain chloroparaffins (SCCP and MCCP) were determined by electron capture negative ionization (ECNI) and chloride attachment chemical ionization (CACI) mass spectrometry (MS). In contrast to CACI-MS, congener patterns obtained by ECNI showed always a shift to the next higher chlorinated congener and carbon chain length group. Consequently, the calculated molecular masses and chlorine contents were higher for ECNI (factor 1.10+/-0.03 and 1.09+/-0.03, respectively). ECNI/CACI ratios in sediment samples from the North and Baltic Sea were also slightly higher. However, a more pronounced shift of the congener pattern for a given carbon chain length to congeners with 2-3 more chlorine atoms was observed. SCCP and MCCP concentrations obtained by ECNI-MS were in the range of 8-63ngg(-1) (North Sea) and 22-149ngg(-1) dry weight (Baltic Sea). MCCP levels were highest in all samples (MCCP/SCCP factor 1.1-3.2).     

Eco-friendly PEG-based controlled release nano-formulations of Mancozeb: Synthesis and bioefficacy evaluation against phytopathogenic fungi Alternaria solani and Sclerotium rolfsii

Controlled release (CR) nano-formulations of Mancozeb (manganese-zinc double salt of N,N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory-synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers without using any surfactants or external additives. The release kinetics of the developed Mancozeb CR formulations were studied and compared with that of commercially available 42% suspension concentrate and 75% wettable powder. Maximum amount of Mancozeb was released on 42nd day for PEG-600 and octyl chain, PEG-1000 and octyl chain, and PEG-600 and hexadecyl chain, on 35th day for PEG-1000 and hexadecyl chain, on 28th day for PEG-1500 and octyl chain, PEG-2000 and octyl chain, PEG-1500 and hexadecyl chain, and PEG-2000 and hexadecyl chain in comparison to both commercial formulations (15th day). The diffusion exponent (n value) of Mancozeb in water ranged from 0.42 to 0.62 in tested formulations. The half-release (t_1/2) values ranged from 17.35 to 35.14 days, and the period of optimum availability of Mancozeb ranged from 18.54 to 35.42 days. Further, the in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Alternaria solani and Sclerotium rolfsii by poison food technique. Effective dose for 50% inhibition in mgL^?1 (ED₅₀) values of developed formulations varied from 1.31 to 2.79 mg L^?1 for A. solani, and 1.60 to 3.14 mg L^?1 for S. rolfsii. The present methodology is simple, economical, and eco-friendly for the development of environment-friendly CR formulations of Mancozeb. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, the maximum amount of active ingredient remains available for a reasonable period after application. In addition, the developed CR formulations were found to be suitable for fungicidal applications, allowing use of Mancozeb in lower doses.     

Behavior of perfluorinated compounds in soils during leaching experiments

Perfluorinated compounds (PFCs) can be detected worldwide in both, soil and water. In order to study the leaching behavior of this heterogeneous group of compounds in soil, flow-through column experiments have been conducted. Ten perfluoro carboxylates and four perfluoro sulfonates ranging from C4 to C14 in chain length, and contaminated sewage sludge, have been used to spike a standard soil. The aqueous column effluent was analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) with direct injection. The observed percolation velocity seems to be strongly correlated with the length of the perfluorinated chain. Other factors that additionally contribute to the leaching behavior are the functional group of the PFC, the organic carbon content of the soil and the presence of other adsorbates. A mass balance calculation showed that perfluorobutanoic acid can adsorb strongly to the soil, when no PFC with longer carbon chain are present. Only about 60% of the added perfluorobutanoic acid could be detected in the percolate water. The missing amount started to elute again when longer chain PFC or stearate were added to the soil. Thus it would appear that larger and more lipophilic molecules can displace shorter PFC from their binding sites in the soil.The results of a monitoring study using 32 surface water samples and 150 groundwater samples confirm that the PFC with the highest concentrations in groundwater are the short chain PFC with less than 7 (fluorinated) carbon atoms. The dominating PFC in surface waters are perfluorooctanoic acid and perfluorooctane sulfonic acid.     

Changing pollutants to green biogases for the crop food cycle chain

Purpose

When fossil fuels on the Earth are used up, which kind of green energy can be used to replace them? Do every bioenergy generation or crop food chain results in environmental pollution? These questions are major concerns in a world facing restricted supplies of energy and food as well as environmental pollutions. To alleviate these issues, option biogases are explored in this paper.

Materials and methods

Two types of biogas generators were used for modifying the traditional crop food chain [viz. from atmospheric CO₂ photosynthesis to crops, crop stem/husk biowastes (burnt in cropland or as home fuels), to livestock droppings (dumping away), pork and people foods, then to CO₂], via turning the biowaste pollutants into green bioenergies. By analyzing the traditional food chain via observation method, the drawbacks of by-product biowastes were revealed. Also, the whole cycle chain was further analyzed to assess its ??greenness,?? using experimental data and other information, such as the material balance (e.g., the absorbed CO₂, investment versus generated food, energy, and wastes).

Results and discussion

The data show that by using the two types of biogas generators, clean renewable bioenergy, crop food, and livestock meat could be continuously produced without creating any waste to the world. The modification chain largely reduced CO₂ greenhouse gas and had a low-cost investment. The raw materials for the gas generators were only the wastes of crop stems and livestock droppings. Thus, the recommended CO₂ bioenergy cycle chain via the modification also greatly solved the environmental biowaste pollutions in the world.

Conclusions

The described two type biogases effectively addressed the issues on energy, food, and environmental pollution. The green renewable bioenergy from the food cycle chain may be one of suitable alternatives to fossil and tree fuels for agricultural countries.