Analysis of polychlorinated n-alkanes in environmental samples

Biosurfactants: Secondary Metabolites Involved in the Process of Bioremediation and Biofilm Removal

The search for environmentally friendly methods to remove persistent substances such as organic pollutants and sessile communities such as biofilms that severely affect the environment and human health resulted in biosurfactant discovery. Owing to their low level of toxicity and high biodegradability, biosurfactants are increasingly preferred to be used for removal of pollutants from nature. These amphipathic molecules can be synthesized inexpensively, employing cheap substrates such as agricultural and industrial wastes. Recent progress has been made in identifying various biosurfactants that can be used to remove organic pollutants and harmful microbial aggregates, as well as novel microbial strains that produce these surface-active molecules to survive in a hydrocarbon-rich environment. This review focuses on the identification and understanding the role of biosurfactants and the microorganisms involved in the removal of biofilms and remediation of xenobiotics and various types of hydrocarbons such as crude oil, aromatic hydrocarbons, n-alkanes, aliphatic hydrocarbons, asphaltenes, naphthenes, and other petroleum products. This property of biosurfactant is very important as biofilms are of great concern due to their impact on the environment, public health, and industries worldwide. This work also includes several advanced molecular methods that can be used to enhance the production of biosurfactants by the microorganisms studied.

Medium- and long-chain chlorinated paraffins in air: A review of levels, physicochemical properties, and analytical considerations

Chlorinated paraffins (CPs) are synthetic chemicals that are produced at high volumes and have a global presence. CPs are generally divided into three groups based on their carbon chain lengths: short-chain CPs (SCCPs, C_10-13), medium-chain CPs (MCCPs, C_14-17), and long-chain CPs (LCCPs, C_≥18). SCCPs have been formally recognized as persistent organic pollutants (POPs) and have been listed under the Stockholm Convention on POPs. Concerns about increases in MCCP and LCCP production as replacements for SCCP products are rising, given their similar properties to SCCPs and the fact that they remain relatively understudied with only a few reported measurements in air. Passive air samplers with polyurethane foam disks (PUF-PAS), which have been successfully applied to SCCPs, provide an opportunity to expand the existing body of data on MCCP and LCCP air concentrations, as they are inexpensive and require little maintenance. The uptake of MCCPs and LCCPs by PUF disk samplers is characterized in this paper based on newly derived PUF-air partitioning coefficients using COSMOtherm. The ability of PUF disk samplers to capture both gas-phase and particle fractions is important because MCCPs and LCCPs have reduced volatility compared to SCCPs and therefore are mainly associated with particulate matter in air. In addition, due to their use as additives in plastics and rubber products, they are associated with micro- and nanoplastics, which are considered to be potential vectors for the long-range atmospheric transport (LRAT) of these chemicals. The review has highlighted other limitations to reporting of MCCPs and LCCPs in air, including the lack of suitable analytical standards and the requirement for advanced analytical methods to detect and resolve these complex mixtures. Overall, this review indicates that further research is needed in many areas for medium- and long-chain chlorinated paraffins in order to better understand their occurrence, transport and fate in air.

Disentangling the contributions of urban and production sources in short- and medium-chain chlorinated paraffin concentrations in a complex source region

Short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were measured in tree bark samples. These samples were collected around a chemical industrial park containing several chlorinated paraffin (CP) production plants, in a nearby city (Zhengzhou), and along a transect between the industrial park and city. Theoretical air concentrations were back-calculated from concentrations in bark using a predictive equation for estimating equilibrium bark-air partition coefficients. We developed this equation from a series of previously published K_bark-air measurements. Comparison of the normalized concentration profiles along south to north transects showed that wind played only a minor role in CP concentrations and profiles in the region. Three distinct source profiles were found in the complex source region. A fingerprint analysis technique was used to quantify the contribution of each source to the CP burden at various locations along the transect. We found that CP profiles at sites up to 6 km from the industrial park were strongly influenced by CP plant emissions, whereas the sites located in the rural zone and rural-urban interface were influenced by a mixture of CP plant emissions and the neighboring city.

Identification and evaluation of chlorinated nonane paraffins in the environment: A persistent organic pollutant candidate for the Stockholm Convention?

Short-chain chlorinated paraffins (SCCPs), with 10-13 carbon atoms, are persistent organic pollutants under the Stockholm Convention because they are persistent, toxic, and bioaccumulative. However, little information is available on CPs with <10 carbon atoms. C₉-CPs were identified and quantified in environmental matrices in this study. The occurrences and sources of C₉-CPs in environmental samples were investigated by determining C₉-CPs in technical CP products and environmental matrices, including indoor air and sediment, by GC×GC‒ECNI‒TOFMS. Quantitative structure-property relationship modeling revealed C₉-CPs have high octanol-water partition coefficients (log Kow 5.99), octanol-air partition coefficients (log Koa 7.24), and bioaccumulation factors (log BAF 4.07), indicating C₉-CPs are semivolatile and could bioaccumulate. C₉-CPs were detected in different fish (at 3.4-153 ng/g dw), confirming they can bioaccumulate. C₉-CPs were found in soil (at 3.0-25.6 ng/g dw) and biota (at 7.5-57.8 ng/g dw) from the Antarctic, demonstrating they can undergo long-range transport and are global pollutants. This is the first comprehensive study reporting the sources, occurrences, and fates of C₉-CPs in the environment, laying foundations for further evaluation of C₉-CPs and their inclusion as candidate persistent organic pollutants under the Stockholm Convention.

Fate and transport of estrogenic compounds in an integrated swine manure treatment systems combining algal-bacterial bioreactor and hydrothermal processes for improved water quality

An integrated manure treatment system, including a mixed algal-bacterial bioreactor (MABB) and hydrothermal processing of biomass solids, was found to remove 76.4-97.0% of the total estrogenic hormones (estrone (E1), 17β-estradiol (E2), and estriol (E3)) from the liquid portion of animal manure (LPAM). The mixed biomass was converted into either biocrude oil with a yield up to 40% via hydrothermal liquefaction (HTL) or syngas with a yield up to 54% yield via catalytic hydrothermal gasification (CHG). Adding granular activated carbon (GAC) in the MABB enhanced the removal of estrogenic hormones (+ 7.2%), cytotoxicity (+ 58%), and heavy metals (+ 10.5%). After the integrated system with the MABB, HTL, and CHG processes, the overall percent removal of heavy metals from the LPAM ranged from 27.1 to 40.3%. The concentrations of potentially toxic heavy metals (lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), chromium (Cr)) in the aqueous phase after HTL and CHG tests ranged from 0.01 to 25.3 mg/L.

The atmospheric transport and pattern of Medium chain chlorinated paraffins at Shergyla Mountain on the Tibetan Plateau of China

Large amounts of short chain and medium chain chlorinated paraffins (SCCPs and MCCPs) are released into the environment during production and usage. However, compared to SCCPs, there is a significant lack of attention for MCCPs. In this work, 83 air samples, collected between 2012 and 2015 from the Tibetan Plateau, were analyzed to investigate the airborne levels and distributions of MCCPs, further to evaluate their potential long-range transport behavior on the alpine area. The total air MCCP concentrations at Shergyla Mountain and Lhasa were between 50 and 690 pg/m³ and 800-6700 pg/m³, respectively. At Shergyla Mountain, MCCP concentrations in the air appeared an increasing trend with altitude, which indicated that MCCPs could potentially possess the ability of "mountain cold trapping". C₁₄ and C₁₅ congener groups were the dominant homologue groups. The mountain contamination potential (MCP) of different congener groups is closely related to their equilibrium partitioning coefficients between octanol and air (K_OA), and water and air (K_WA). Increasing MCCPs levels might be a potential threat to the environment and human exposure.

Spatiotemporal Distribution and Alpine Behavior of Short Chain Chlorinated Paraffins in Air at Shergyla Mountain and Lhasa on the Tibetan Plateau of China

Pristine high-altitude mountains are ideal areas for studying the potential mechanism behind the long-range transport and environmental behavior of persistent organic pollutants in remote areas. Short chain chlorinated paraffins (SCCPs) are the most complex halogenated contaminants in the environment, and have attracted extensive worldwide interest in recent years. In this study, the spatiotemporal concentrations and distributions of SCCPs in air collected from Shergyla Mountain (located in the southeast of the Tibetan Plateau) and Lhasa were investigated during 2012-2015. Generally, the total SCCP levels at Shergyla Mountain and Lhasa were between 130 and 1300 pg/m³ and 1100-14440 pg/m³, respectively. C₁₀ and C₁₁ components were the most abundant homologue groups, indicating that lighter SCCP homologue groups are capable of relatively long-range atmospheric transport. Relatively high but insignificant atmospheric SCCP concentrations at Shergyla Mountain area and Lhasa were observed from 2013 to 2015 compared with 2012. At Shergyla Mountain, SCCP concentrations on the eastern and western slopes increased with altitude, implying that "mountain cold-trapping" might occur for SCCPs. A back-trajectory model showed that SCCP sources at Shergyla Mountain and Lhasa were primarily influenced by the tropical monsoon from Southwest and South Asia.

Bioaccumulation and biomagnification of short and medium chain polychlorinated paraffins in different species of fish from Liaodong Bay, North China

Chlorinated paraffins (CPs) are highly complex technical mixtures, and the short chain chlorinated paraffins (SCCPs) are classed as persistent and have been included in the Stockholm Convention. However, there have been few studies of SCCPs and medium chain chlorinated paraffins (MCCPs) and their bioaccumulation and biomagnification in different species of fish. The present study investigated the levels, congener group profiles, bioaccumulation, and biomagnification of SCCPs and MCCPs in different species of fish from Liaodong Bay, North China. The ranges for the ΣSCCP and ΣMCCP concentrations were 376.3-8596 ng/g lipid weight (lw) and 22.37-5097 ng/g lw, respectively. The logarithms of bioaccumulation factors of ΣSCCPs ranged from 4.69 to 6.05, implying that SCCPs bioaccumulated in the fish. The trophic magnification factor of ΣSCCPs was 2.57, indicating that SCCPs could biomagnify in fish. Carbon chain length, the numbers of chlorine atoms, and octanol/water partition coefficients of the SCCPs and MCCPs might be important factors affecting the bioaccumulation of these chemicals in fish. The risk posed to human health by consumption of fish containing SCCPs was low. New SCCPs with nine carbons (C₉) were detected in fish in this study.

Spatial and temporal trends of short- and medium-chain chlorinated paraffins in sediments off the urbanized coastal zones in China and Japan: A comparison study

To examine the impacts of urbanization and industrialization on the coastal environment, and assess the effectiveness of control measures on the contamination by chlorinated paraffins (CPs) in East Asia, surface and core sediments were sampled from the urbanized coastal zones in China and Japan (i.e., Pearl River Delta (PRD), Hong Kong waters and Tokyo Bay) and analyzed for short-chain (SCCPs) and medium-chain CPs (MCCPs). Much higher concentrations of CPs were found in the industrialized PRD than in adjacent Hong Kong waters. Significant correlation between CP concentration and population density in the coastal district of Hong Kong was observed (r² = 0.72 for SCCPs and 0.55 for MCCPs, p < 0.05), highlighting the effect of urbanization. By contrast, a relatively lower pollution level of CPs was detected in Tokyo Bay. More long-chain groups within SCCPs in the PRD than in Hong Kong waters and Tokyo Bay implied the effect of industrialization. Comparison of temporal trends between Hong Kong outer harbor with Tokyo Bay shows the striking difference in historical deposition of CPs under different regulatory situations in China and Japan. For the first time, the declining CP concentrations in Tokyo Bay, Japan, attest to the effectiveness of emissions controls.

A Novel Method for Profiling and Quantifying Short- and Medium-Chain Chlorinated Paraffins in Environmental Samples Using Comprehensive Two-Dimensional Gas Chromatography-Electron Capture Negative Ionization High-Resolution Time-of-Flight Mass Spectrometry

Chlorinated paraffins (CPs) are complex technical mixtures containing thousands of isomers. Analyzing CPs in environmental matrices is extremely challenging. CPs have broad, unresolved profiles when analyzed by one-dimensional gas chromatography (GC). Comprehensive two-dimensional GC (GC×GC) can separate CPs with a high degree of orthogonality. A novel method for simultaneously profiling and quantifying short- and medium-chain CPs, using GC×GC coupled with electron capture negative ionization high-resolution time-of-flight mass spectrometry, was developed. The method allowed 48 CP formula congener groups to be analyzed highly selectively in one injection through accurate mass measurements of the [M - Cl](-) ions in full scan mode. The correlation coefficients (R(2)) for the linear calibration curves for different chlorine contents were 0.982 for short-chain CPs and 0.945 for medium-chain CPs. The method was successfully used to determine CPs in sediment and fish samples. By using this method, with enhanced chromatographic separation and high mass resolution, interferences between CP congeners and other organohalogen compounds, such as toxaphene, are minimized. New compounds, with the formulas C9H14Cl6 and C9H13Cl7, were found in sediment and biological samples for the first time. The method was shown to be a powerful tool for the analysis of CPs in environmental samples.

Recent developments in capabilities for analysing chlorinated paraffins in environmental matrices: A review

Concerns about the high production volumes, persistency, bioaccumulation potential and toxicity of chlorinated paraffin (CP) mixtures, especially short-chain CPs (SCCPs), are rising. However, information on their levels and fate in the environment is still insufficient, impeding international classifications and regulations. This knowledge gap is mainly due to the difficulties that arise with CP analysis, in particular the chromatographic separation within CPs and between CPs and other compounds. No fully validated routine analytical method is available yet and only semi-quantitative analysis is possible, although the number of studies reporting new and improved methods have rapidly increased since 2010. Better cleanup procedures that remove interfering compounds, and new instrumental techniques, which distinguish between medium-chain CPs (MCCPs) and SCCPs, have been developed. While gas chromatography coupled to an electron capture negative ionisation mass spectrometry (GC/ECNI-MS) remains the most commonly applied technique, novel and promising use of high resolution time of flight MS (TOF-MS) has also been reported. We expect that recent developments in high resolution TOF-MS and Orbitrap technologies will further improve the detection of CPs, including long-chain CPs (LCCPs), and the group separation and quantification of CP homologues. Also, new CP quantification methods have emerged, including the use of mathematical algorithms, multiple linear regression and principal component analysis. These quantification advancements are also reflected in considerably improved interlaboratory agreements since 2010. Analysis of lower chlorinated paraffins (<Cl5) remains, however, challenging and better approaches to analysing these homologues are needed. Furthermore, suitable quantification standards would facilitate improving the quality of CP analysis.

Parameters optimization using experimental design for headspace solid phase micro-extraction analysis of short-chain chlorinated paraffins in waters under the European water framework directive

The water framework directives (WFD 2000/60/EC and 2013/39/EU) force European countries to monitor the quality of their aquatic environment. Among the priority hazardous substances targeted by the WFD, short chain chlorinated paraffins C10-C13 (SCCPs), still represent an analytical challenge, because few laboratories are nowadays able to analyze them. Moreover, an annual average quality standards as low as 0.4μgL(-1) was set for SCCPs in surface water. Therefore, to test for compliance, the implementation of sensitive and reliable analysis method of SCCPs in water are required. The aim of this work was to address this issue by evaluating automated solid phase micro-extraction (SPME) combined on line with gas chromatography-electron capture negative ionization mass spectrometry (GC/ECNI-MS). Fiber polymer, extraction mode, ionic strength, extraction temperature and time were the most significant thermodynamic and kinetic parameters studied. To determine the suitable factors working ranges, the study of the extraction conditions was first carried out by using a classical one factor-at-a-time approach. Then a mixed level factorial 3×2(3) design was performed, in order to give rise to the most influent parameters and to estimate potential interactions effects between them. The most influent factors, i.e. extraction temperature and duration, were optimized by using a second experimental design, in order to maximize the chromatographic response. At the close of the study, a method involving headspace SPME (HS-SPME) coupled to GC/ECNI-MS is proposed. The optimum extraction conditions were sample temperature 90°C, extraction time 80min, with the PDMS 100μm fiber and desorption at 250°C during 2min. Linear response from 0.2ngmL(-1) to 10ngmL(-1) with r(2)=0.99 and limits of detection and quantification, respectively of 4pgmL(-1) and 120pgmL(-1) in MilliQ water, were achieved. The method proved to be applicable in different types of waters and show key advantages, such as simplicity, automation and sensitivity, required for the monitoring programs linked to the WFD.

The OH-initiated chemical transformation of 1,2,4,6,8,10,11-heptachloroundecane in the atmosphere

1,2,4,6,8,10,11-Heptachloroundecane (HCU) is selected to investigate the chemical transformation of SCCPs using the density functional theory method.

Screening of atmospheric short- and medium-chain chlorinated paraffins in India and Pakistan using polyurethane foam based passive air sampler

Production and use of chlorinated paraffins (CPs) have been increasing in India. Distribution of CPs in the area and vicinity have become a great concern due to their persistency and toxicity. Polyurethane foam based passive air samplers (PUF-PAS) was deployed in order to screen the presence of short- and medium- chain chlorinated paraffins (SCCPs and MCCPs) in the outdoor atmosphere at many sites in India (in winter 2006) and Pakistan (in winter 2011). Concentrations of SCCPs and MCCPs ranged from not detected (ND) to 47.4 and 0 to 38.2 ng m(-3) with means of 8.11 and 4.83 ng m(-3), respectively. Indian concentrations showed higher average levels of both SCCPs and MCCPs India (10.2 ng m(-3) and 3.62 ng m(-3)than the samples from Pakistan (5.13 ng m(-3) and 4.21 ng m(-3)). Relative abundance patterns of carbon number are C10 > C11 > C12 ∼ C13 for SCCPs and C14 > C15 > C16 C17 for MCCP with similarity to the profiles of samples from China, the biggest CPs producer in the world. Principal Component Analysis suggested that detected SCCPs and MCCPs in this study originated from the same emission source.

Evaluating the environmental fate of short-chain chlorinated paraffins (SCCPs) in the Nordic environment using a dynamic multimedia model

Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SCCPs in the Nordic environment. Realistic SCCP emission scenarios, resolved by formula group, were estimated and used to predict the composition and concentrations of SCCPs in the environment and the human food chain. Emissions at the upper end of the estimated range resulted in predicted total concentrations that were often within a factor of 6 of observations. Similar model performance for a complex group of organic contaminants as for the well-known polychlorinated biphenyls strengthens the confidence in the CoZMoMAN model and implies a relatively good mechanistic understanding of the environmental fate of SCCPs. However, the degree of chlorination predicted for SCCPs in sediments, fish, and humans was higher than observed and poorly established environmental half-lives and biotransformation rate constants contributed to the uncertainties in the predicted composition and ∑SCCP concentrations. Improving prediction of the SCCP composition will also require better constrained estimates of the composition of SCCP emissions. There is, however, also large uncertainty and lack of coherence in the existing observations, and better model-measurement agreement will require improved analytical methods and more strategic sampling. More measurements of SCCP levels and compositions in samples from background regions are particularly important.

Spatial distributions and deposition chronology of short chain chlorinated paraffins in marine sediments across the Chinese Bohai and Yellow Seas

As the most complex halogenated contaminants, short chain chlorinated paraffins (SCCPs) are scarcely reported in marine environments. In this work, a total of 117 surficial sediment (0-3 cm) samples and two sediment cores were collected from the Chinese Bohai and Yellow Seas to systematically study the spatial and temporal trends of SCCPs at a large scale in the Chinese marine environment. Total SCCP concentrations in the surficial sediments were in the range of 14.5-85.2 ng g(-1) (dry weight, d.w.) with an average level of 38.4 ng g(-1) d.w. Spatial distribution showed a decreasing trend with the distance from the coast to the open waters. Compositional pattern analysis suggested that C10 was the most predominant homologue group, followed by C11, C12, and C13 homologue groups. The concentrations of total SCCPs in sediment cores ranged from 11.6 to 94.7 ng g(-1) d.w. for YS1 and from 14.7 to 195.6 ng g(-1) d.w. for YS2, with sharp rise from the early 1950s to present based on (210)Pb dating technique. The historical records in cores correspond well to the production and usage changes of CPs in China. Multivariate regression statistics indicate TOC, latitude and longitude are the major factors influencing surficial SCCP levels in the Chinese East Seas by combining analysis with the data from the East China Sea (R(2) = 0.332, p < 0.01). These findings indicated that the sources of SCCPs were mainly from river outflows via ocean current and partly from atmospheric depositions by East Asian monsoon in the sampling areas.

Using quantitative structural property relationships, chemical fate models, and the chemical partitioning space to investigate the potential for long range transport and bioaccumulation of complex halogenated chemical mixtures

Some substances are mixtures of very large number of constituents which vary widely in their properties, and thus also in terms of their environmental fate and the hazard that they may pose to humans and the environment. Examples of such substances include industrial chemicals such as the chlorinated paraffins, technical pesticides such as toxaphene, and unintended combustion side products, such as mixed halogenated dibenzo-p-dioxins and dibenzofurans. Here we describe a simple graphical superposition method that could precede a more detailed hazard assessment for such substances. First, partitioning and degradation properties for each individual constituent of a mixture are estimated with high-throughput quantitative structure-property relationships. Placed in a chemical partitioning space, i.e. a coordinate system defined by two partitioning coefficients, the mixtures appear as 'clouds'. When model-derived hazard assessment metrics, such as the potential for bioaccumulation and long range transport, are superimposed on these clouds, the resulting maps identify the constituents with the highest value for a particular parameter and thus potentially the greatest hazard. The maps also indicate transparently how the potential for long range transport and bioaccumulation is dependent on structural attributes, such as chain length, and the degree and type of halogenation. In contrast to previous approaches, in which the mixture is represented by a single set of properties or those of a few selected constituents, the whole range of environmental fate behaviors displayed by the constituents of a mixture are being considered. The approach is illustrated with three sets of chemical substances.

Short- and medium-chain chlorinated paraffins in air and soil of subtropical terrestrial environment in the pearl river delta, South China: distribution, composition, atmospheric deposition fluxes, and environmental fate

Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m(3)) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C(10-11) C(l6-7) and C(14) C(l6-7), C(10-12) C(l6-7) and C(14) C(l6-8), and C(11-12) C(l6-8) and C(14) C(l7-8) dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.

Behavior, fate, and mass loading of short chain chlorinated paraffins in an advanced municipal sewage treatment plant

Sewage treatment plants (STP) are an important source of short chain chlorinated paraffins (SCCPs) to the ambient environment through discharge of effluent and application of sludge. In this work, a field study was conducted to determine the behavior and possible removal of SCCPs during the sewage treatment process in an advanced municipal STP in Beijing, China. SCCPs were detected in all sewage water and sludge samples, and 97% of the initial mass loading in raw sewage was found to be associated with suspended matter. The total concentrations in raw influent, tertiary effluent, and dewatered sludge were 184 ± 19 ng/L, 27 ± 6 ng/L, and 15.6 ± 1.4 μg/g dry weight (d.w.), respectively. The dissolved concentrations of total SCCPs (∑SCCPs) significantly decreased during mechanical, biological, and chemical treatments. SCCP homologue profiles in aqueous phase were distinctly different from those in solid phase. Along the treatment process, the relative abundance of shorter chain and lower chlorinated congeners gradually increased in sewage water, but no obvious variations of homologue profiles were found in sludge. Mass flow analysis indicated, the removal efficiency in aqueous phase for ∑SCCPs was 82.2%, and the congener-specific removal efficiencies were positively related to their solid-water partition coefficients (K(d)). Mass balance results indicated that 0.8% and 72.6% of the initial SCCP mass loading were ultimately found in the effluents and dewatered sludge, respectively, while the remaining 26.6% was lost mainly due to biodegradation/biotransformation. It was suggested that the activated sludge system including basic anaerobic-anoxic-aerobic processes played an effective role in removing SCCPs from the wastewater, while the sorption to sludge by hydrophobic interactions was an important fate of SCCPs during the sewage treatment.

Dechlorination of short chain chlorinated paraffins by nanoscale zero-valent iron

In this study, nanoscale zero-valent iron (NZVI) particles were synthesized and used for the reductive dehalogenation of short chain chlorinated paraffins (SCCPs) in the laboratory. The results show that the dechlorination rate of chlorinated n-decane (CP(10)) by NZVI increased with decreased solution pH. Increasing the loading of NZVI enhanced the dechlorination rate of CP(10). With an increase in temperature, the degradation rate increased. The reduction of CP(10) by NZVI was accelerated with increasing the concentration of humic acid up to 15 mg/L but then was inhibited. The dechlorination of CP(10) within the initial 18 h followed pseudo-first order rate model. The formation of intermediate products indicates a stepwise dechlorination pathway of SCCPs by NZVI. The carbon chain length and chlorination degree of SCCPs have a polynominal impact on dechlorination reactions.

Distribution of short chain chlorinated paraffins in marine sediments of the East China Sea: influencing factors, transport and implications

Short chain chlorinated paraffins (SCCPs) are high production volume chemicals in China and found to be widely present in the environment. In this study, fifty-one surface sediments and two sediment cores were collected from the East China Sea to study their occurrence, distribution patterns and potential transport in the marginal sea. SCCPs were found in all surface sediments and ranged from 5.8 to 64.8 ng/g (dry weight, d.w.) with an average value of 25.9 ng/g d.w. A general decreasing trend with distance from the coast was observed, but the highest value was found in a distal mud area far away from the land. The C10 homologue was the most predominant carbon chain group, followed by C11, C12, and C13 homologue groups. Significant linear relationship was found between total organic carbon (TOC) and total SCCP concentrations (R(2) = 0.51, p < 0.05). Spatial distributions and correlation analysis indicated that TOC, riverine input, ocean current, and atmospheric deposition played an important role in controlling SCCP accumulation in marine sediments. Vertical profiles of sediment cores showed that SCCP concentrations decreased from surface to the depth of 36 cm, and then slightly increased again with depth, which showed a significant positive correlation with TOC and chlorine contents (Cl%). The results suggest that SCCPs are being regionally or globally distributed by long-range atmospheric or ocean current transport.

Persistent Organic Pollutants in gull eggs of two species (Larus michahellis and Larus audouinii) from the Ebro delta Natural Park

The aim of this study was to determine the impact of priority and emerging Persistent Organic Pollutants (POPs) in gull eggs from two species, the scavenger Larus michahellis and the protected species, Larus audouinii. These two species share habitat in the Natural Park of the Ebro delta (Catalonia, Spain). Compounds studied are included or under consideration in the Stockholm Convention and comprise polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorinated compounds (OCs), perfluorinated compounds (PFCs) and short chain chlorinated paraffins (SCCPs). Four methods based in selective extraction and gas or liquid chromatography coupled to mass spectrometry were used and quality parameters are provided. OC pesticides and marker PCBs were the most abundant chemical families detected in eggs from the two species, followed by PFCs, PBDEs (especially BDE 209) and SCCPs. Dioxin-like PCBs and PCDD/Fs were also detected in all samples. The overall widespread presence of POPs is discussed in terms of feeding habits, bird ecology and anthropogenic pressures in the protected Ebro delta breeding area.

Environmental occurrence and distribution of short chain chlorinated paraffins in sediments and soils from the Liaohe River Basin, P. R. China

Chlorinated paraffins (CPs) are industrially produced in large quantities in the Liaohe River Basin. Their discharge inevitably causes environmental contamination. However, very limited information is available on their environmental levels and distributions in this typical industrial region. In this study, short chain CPs (SCCPs) were analyzed in sediments, paddy soils, and upland soils from the Liaohe River Basin, with concentrations ranging from 39.8 to 480.3 ng/g dry weight. A decreasing trend in SCCP concentrations was found with increasing distance from the cities, suggesting that local industrial activity was the major source of SCCP contamination. A preliminary sediment inventory of SCCPs indicated approximately 30.82 tonnes of SCCPs residual in the sediments from the Liaohe River. The average discharge of SCCPs was estimated to be about 74.4 mg/tonne industrial wastewater. The congener group profiles showed that the relative abundances of shorter chain and lower chlorinated CP congeners (C(10)-CPs with 5 or 6 chlorine atoms) in soils in rural areas were higher than in sites near cities, which demonstrated that long-range atmospheric transportation could be the major transport pathway. Environmental degradation of SCCPs might occur, where higher chlorinated congeners could dechlorinate to form the lower chlorinated congeners.

Identification and determination of chlorinated paraffins using multivariate evaluation of gas chromatographic data

Chlorinated paraffins (CPs) were found in the biodegradable fraction of source separated waste from Uppsala, Sweden. We identified and quantified the CPs by multivariate evaluation of gas chromatography-electron capture detection chromatograms. Using principal component analyses (PCA) we identified different types of CP-formulations and also obtain quantitative data. PCA yielded better identifications of individual CP-formulations than visual comparison of chromatograms. Partial least squares regression gave good calibration curves of the standards, but did not work for the waste samples. No source of CPs could be identified in the waste collection chain, and as the waste samples seemed to contain at least two different CP-formulations the source was probably to be found in the waste material itself. The method was used to determine CPs in additional environmental samples, demonstrating that multivariate methods may be developed into a powerful tool for identification and quantification of complex mixture.

On-line dechlorination-hydrogenation of chlorinated paraffin mixtures using GC and GC/MS

Chlorinated paraffins (CPs) are straight chain hydrocarbons that are produced as complex mixtures and are used as flame retardants and paint additives. These mixtures are extremely difficult to characterize using conventional chromatographic methods, as conventional gas chromatography results in unresolved complex chromatograms that preclude the identification and quantification of individual congeners or any reasonable assessment of the average carbon chain length. Carbon chain length is an important parameter for assessing physical properties and the toxicity of these materials. We have modified and improved a previously published gas chromatography-flame ionization detector method that uses Pd catalyst held in the gas chromatograph injector to simultaneously dechlorinate the CPs and separate the resulting alkanes. In addition, we have adapted this method to gas chromatography-mass spectrometry. Dehalogenation of other compounds was also studied with this system to investigate potential application to other complex halogenated mixtures.

Levels and distribution patterns of short chain chlorinated paraffins in sewage sludge of wastewater treatment plants in China

Short chain chlorinated paraffins (SCCPs) are listed as persistent organic pollutant candidates in the Stockholm Convention and are receiving more and more attentions worldwide. In general, concentrations of contaminants in sewage sludge can give an important indication on their pollution levels at a local/regional basis. In this study, SCCPs were investigated in sewage sludge samples collected from 52 wastewater treatment plants in China. Concentrations of total SCCPs (ΣSCCPs) in sludge were in the range of 0.80-52.7 μg/g dry weight (dw), with a mean value of 10.7 μg/g dw. Most of SCCPs in the sludge samples showed a similar congener distribution patterns, and C(11) and Cl(7,8) were identified as the dominant carbon and chlorine congener groups. Significant linear relationships were found among different SCCP congener groups (r(2) ≥ 0.9). High concentrations of SCCPs in sewage sludge imply that SCCPs are widely present in China.

Spatial and vertical distribution of short chain chlorinated paraffins in soils from wastewater irrigated farmlands

Chlorinated paraffins (CPs) are one of the most complex groups of halogenated contaminants in the environment. However, studies of short chain CPs (SCCPs) in China are very scarce. In this study, the concentrations and distribution of SCCPs in farm soils from a wastewater irrigated area in China were investigated. SCCPs were detected in all topsoil samples, with the sum of the concentrations (ΣSCCPs) in the range of 159.9-1450 ng/g (dry weight, dw). A noticeable spatial trend and specific congener distribution were observed in the wastewater irrigated farmland. Soil vertical profiles showed that ΣSCCP concentrations below the plowed layer decreased exponentially and had a significant positive relationship (R(2) > 0.83) with total organic carbon in soil cores. Furthermore, soil vertical distributions indicated that lower chlorinated (Cl(5-6)) and shorter chain (C(10-12)) congeners are more prone to migrate to deeper soil layers compared to highly chlorinated and longer chain congeners. This work demonstrated that effluents from sewage treatment plants (STPs) could be a significant source of SCCPs to the ambient environment and wastewater irrigation can lead to higher accumulation of SCCPs in farm soils.

The European Water Framework Directive – Chemical Monitoring Programmes, Analytical Challenges and Results from an Irish Case Study

The European Water Framework Directive (WFD) is one of the most important legislative instruments in the water field. The overarching objective of the policy is the achievement of a “good status” in all waters of European Member States by the end of 2015. Important milestones include the analysis of pressures and impacts, a characterisation of water bodies and monitoring programmes.

The effectiveness of these monitoring programmes and hence of the overall WFD implementation will depend highly on the ability of Member States’ laboratories to measure the status of water bodies. The chemical status of water bodies is linked to compliance with EU Environmental Quality Standards defined in a daughter directive. In order to assess the chemical status, a number of priority substances and priority hazardous substances have to be monitored. Requirements on the analytical methods to be used for chemical monitoring are laid down in terms of technical specifications by another daughter directive.

In some cases, the requirements on analytical methods (e.g. limit of quantification and measurement uncertainty) for chemical monitoring under WFD pose a real challenge, even for state-of-the-art analytical techniques. This has initiated a number of European activities in the development of guidance documents, harmonisation efforts and demand-driven research.

The main tasks, challenges and research needs related to chemical monitoring of water bodies under the WFD are presented, including an outlook on how these issues are tackled. This is completed by the presentation of actual chemical monitoring results from surface waters from the Republic of Ireland.

Needs for reliable analytical methods for monitoring chemical pollutants in surface water under the European Water Framework Directive

The state of the art in monitoring chemical pollutants to assess water quality status according to Water Framework Directive (WFD) and the challenges associated with it have been reviewed. The article includes information on environmental quality standards (EQSs) proposed to protect the aquatic environment and humans against hazardous substances and the resulting monitoring requirements. Furthermore, minimum performance criteria for analytical methods and quality assurance issues have been discussed. The result of a survey of existing standard methods with a focus on European (EN) and international standards (ISO) for the analysis of chemical pollutants in water is reported and the applicability of those methods for the purpose of compliance checking with EQSs is examined. Approximately 75% of the 41 hazardous substances for which Europe-wide EQSs have been proposed can be reliably monitored in water with acceptable uncertainty when applying existing standardised methods. Monitoring in water encounters difficulties for some substances, e.g., short-chain chlorinated paraffins (SCCPs), polybrominated diphenyl ethers (PBDEs), tributyltin compounds, certain organochlorine pesticides and six-ring PAHs, mainly due to a lack of validated, sufficiently sensitive methods that are applicable in routine laboratory conditions. As WFD requires monitoring of unfiltered samples for organic contaminants more attention needs to be paid to the distribution of chemical pollutants between suspended particulate matter and the liquid phase. Methods allowing complete extraction of organic contaminants from whole water samples are required. From a quality assurance point of view, there is a need to organise interlaboratory comparisons specifically designed to the requirements of WFD (concentrations around EQSs, representative water samples) as well as field trials to compare sampling methodologies. Additional analytical challenges may arise when Member States have identified their river basin specific pollutants and after revision of the list of priority substances.

Analysis of short-chain chlorinated paraffins: a discussion paper

Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.