Organochlorine Pollutants Research Articles

Advances in the electrochemical degradation of environmental persistent organochlorine pollutants: materials, mechanisms, and applications

Advances in the electrochemical degradation of environmental persistent organochlorine pollutants: materials, mechanisms, and applications

Assessment of organochlorine pesticide pollution in Donax trunculus from Agadir Bay (Center of Morocco): Utilization of integrated biomarkers

This study investigated the impact of seasonal organochlorine pesticide pollution on the physiological responses of Donax trunculus at Aghroud Beach during 2009 and 2010. Significant findings include the detection of six pesticides, with Endosulfan S being the most prevalent, reaching concentrations up to 62.63 ng/g dry weight. Biomarker analysis revealed notable seasonal variations, with the highest Acetylcholinesterase (AChE) activity in winter 2009 and the lowest in spring 2010. Glutathione S-transferase (GST) activity peaked in autumn 2009, while Catalase (Cat) showed maximum activity in autumns of 2009 and 2010. Malondialdehyde (MDA) levels were highest in summer 2010, indicating increased oxidative stress and lipid peroxidation during this period. Integrated Biomarker Response (IBR) values were highest in autumns, suggesting significant pollution stress. Principal Component Analysis (PCA) revealed strong correlations: a synergy between GST and Cat, and positive links between MDA and lipids, as well as AChE and Endosulfan B. This study highlights the efficacy of using integrated biomarker responses to assess environmental health and stresses the importance of autumn and summer monitoring due to higher pollution impacts.

Persistent Organochlorine Pollutants in High-Moor Peats of the Arkhangelsk Region

The results of a study of the contamination of a peat deposit of a representative oligotrophic bog complex (Primorsky district of the Arkhangelsk region) with persistent organic pollutants of polychlorobenzenes and pentachlorophenol are presented. Data on the quantitative content, composition and depth distribution of organochlorine pollutants have been obtained. The maximum amounts of polychlorobenzenes, pentachlorophenol and other chlorinated phenols in the upper 40-centimeter aerated layer of the peat deposit, the formation of which coincides with the period of “chlorine chemistry”, have been established. In addition, the presence of polychlorobenzenes and pentachlorophenol was revealed in all horizons of the upper meter layer of the peat deposit, which indicates their vertical migration in the peat body.

Organochlorine Exposure Influences the Cellular Morphology of Red Algae Eucheuma denticulatum (N.L. Burman) Collins & Hervey, 1917

Higlight Research The research demonstrates the negative impact of organochlorine content on the morphological structure and biomineral composition of E. denticulatum, highlighting the need for effective measures to prevent and reduce organochlorine pollution in marine environments. Further research could focus on specific mechanisms of organochlorine toxicity and potential remediation strategies. Abstract Organochlorine compounds not only pollute marine waters but also interfere with the survival of marine biota. Organochlorine compounds absorbed by organisms disrupt metabolism and inhibit cellular functions. The implication of this research is to prevent and reduce the disposal of organochlorines into the environment because they can accumulate in soil, water, and air, remaining for years in the environment. This accumulation can affect food chains and negatively affect ecosystems and marine animals.This research aimed to investigate the impact of organochlorine content on the surface morphology and biomineral characteristics of the red alga E. denticulatum cells. Electron Microscope (SEM) analysis was used to observe particle morphology surfaces down to 1 nm, while Energy Dispersive Spectroscopy (EDS) was used to analyze the specimens' element composition and chemical characteristics. Energy Dispersive Spectroscopy (EDS) analysis revealed that red algae had the highest content of Chlorine (Cl) at 57.20%, followed by Sodium (Na) at 34.84%, Oxygen (O) at 5.21%, Calcium (Ca) at 1.64%, and the lowest element being Sulfur (S) at 1.11%. Overall, this research demonstrates the negative impact of organochlorine content on the morphological structure and biomineral composition of E. denticulatum, highlighting the need for effective measures to prevent and reduce organochlorine pollution in marine environments. Further research could focus on specific mechanisms of organochlorine toxicity and potential remediation strategies.

An overview on persistent organic pollutants levels in the White Drin River, Kosovo

The purpose of this study was to assess the concentrations of persistent organic pollutants in the White Drin River, Kosovo region. The study focused on organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes. The White Drin River originates from Peja, Kosovo, and extends to the Albanian border near Kukesi, making it a significant water body. It is potentially affected by anthropogenic pollution due to its passage through Kosovo’s urban areas, villages, farms, and industries. Sampling was conducted at 15 stations along the river, from the river waterfall to the Albanian border, during two distinct periods in 2023 (January – February and August – September). Organochlorine pollutants were concurrently extracted using liquid-liquid extraction followed by analysis using capillary gas chromatography equipped with an electron capture detector. Polycyclic aromatic hydrocarbons were isolated through a two-step liquid-liquid extraction, with dichloromethane and hexane. Benzene, toluene, ethylbenzene, and xylenes were isolated using headspace solid – phase microextraction assisted by polydimethylsiloxane fibre. Qualitative and quantitative analyses of polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes, were conducted via gas chromatography with a flame ionization detector. The analyses showed the presence of persistent organic pollutants in the river water samples during both sampling periods. Elevated concentrations of volatile polychlorinated biphenyls, benzene, toluene, ethylbenzene, and xylenes, and polycyclic aromatic hydrocarbons, were observed in the water samples during both periods. This study underscores the significance of investigating organic pollutants in Kosovo’s water systems, considering both local geographic concerns and the broader global issue of environmental pollution

Presence of polycyclic aromatic hydrocarbons and persistent organochlorine pollutants in human Milk: Evaluating their levels, association with Total antioxidant capacity, and risk assessment

Breastfeeding provides numerous health benefits for both infants and mothers, promoting optimal growth and development while offering protection against various illnesses and diseases. This study investigated the levels of polychlorinated biphenyls (PCB), organochlorine pesticides (OCP) and polycyclic aromatic hydrocarbons (PAH) in human milk sampled in Zadar (Croatia). The primary objectives were twofold: firstly, to evaluate the individual impact of each compound on the total antioxidant capacity (TAC) value, and secondly, to assess associated health risks. Notably, this study presents pioneering and preliminary insights into PAH levels in Croatian human milk, contributing to the limited research on PAH in breast milk worldwide. PCB and OCP levels in Croatian human milk were found to be relatively lower compared to worldwide data. Conversely, PAH levels were comparatively higher, albeit with lower detection frequencies. A negative correlation was established between organic contaminant levels and antioxidative capacity, suggesting a potential link between higher antioxidative potential and lower organic contaminant levels. Diagnostic ratio pointed towards traffic emissions as the primary source of the detected PAH. The presence of PAH suggests potential health risk, underscoring the need for further in-depth investigation.

Efficiency of clustering methods and self-organizing maps of Adriatic sardines and anchovies regarding organochlorine and fatty acid burden.

The Adriatic Sea plays a crucial role as both a significant fishing ground and a thriving trading market for small pelagic edible fish. Recognized for their nutritional value, these fish are esteemed for their high protein content and abundance of polyunsaturated omega-3 and omega-6 fatty acids, making them a sought-after and healthful food choice. Nevertheless, pelagic species can also serve as a reservoir for lipophilic organochlorine pollutants, posing potential risks to human health. In this study, we compared traditional classification methods traditional principal component analysis (PCA) and Ward's clustering with an advanced self-organizing map (SOM) algorithm in determining distribution patterns of 24 organochlorines and 19 fatty acids in sardine and anchovy samples taken from the eastern Adriatic. The outcomes reveal the strengths and weaknesses of the three approaches (PCA, Ward's clustering, and SOM). However, it is evident that SOM has proven to be the most effective in offering detailed information and data visualization. Although sardines and anchovies exhibit similar distribution patterns for p,p'-DDE, PCB-28, PCB-138, PCB-153, PCB-118, and PCB-170, they differ in the concentrations of fatty acids such as stearic, palmitic, myristic, oleic, docosapentaenoic, and docosahexaenoic acid. Our findings supply valuable insights for environmental authorities and fish consumers concerning the potential risks associated with organochlorines in these two types of fish.

Biosynthesized Metallic Nanoarchitecture for Photocatalytic Degradation of Emerging Organochlorine and Organophosphate Pollutants: A Review

AbstractThe use of efficacious and cost‐effective pesticides (OP and OC) has undoubtedly proven to be a blessing and a baron because these pesticides are safeguarding the world from food insecurity. Unfortunately, their presence in aquatic bodies brings about an upsurge in water pollution. Amazingly, the photocatalytic degradation approach utilizing biogenic nanoparticles (BNPs) is a trendy state‐of‐the‐art approach and has been established to be a sustainable methodology for the complete mineralization of contaminants into harmless molecules. Thus, this work holistically explores the use of BNPs for photocatalytic degradation of OP and OC. Based on the review, it was found that the least amount of time needed for degradation was less than 5 minutes, while the maximum degradation efficiency was >80 %. The dominant radicals participating in the degradation are ⋅OH and O2⋅ and this radical dominance was enhanced by the oxygenated functional groups present in the biogenic entities employed for the biosynthesis of BNPs. The photocatalytic degradation data fits the pseudo‐first‐order and Langmuir isotherm models (R2 > 0.9), which indicates that the main adsorption mechanisms involved during electron‐hole pair formation and photocatalytic degradation are physisorption and monolayer at the surface of the BNPs. BNPs can sustain a >80 % degradation efficiency for approximately 5 cycles and are reusable for up to 8 cycles. It was also revealed that plants constitute 80 % of the engaged biogenic entities for BNP synthesis. Ultimately, this work offers novel avenues and future research hotspots that might accelerate the use of BNPs for sustainable agricultural and wastewater management practices.

Removal of organochlorine pollutants from DNAPL-saturated groundwater using electrolysis with MMO anodes

This work evaluates the electrolysis of groundwater saturated with dense non-aqueous phase liquid (DNAPL) from lindane production wastes using mixed metal oxide (MMO) anodes to remove 26 Chlorinated Organic Compounds (COCs). Synthetic groundwater saturated with DNAPL from an industrial landfill was employed, and the influence of the current density (5–50 mA cm−2) was studied. Results show that removing COCs from DNAPL-saturated groundwater in 300 min is possible, reaching a final conversion of 0.99 when current densities of 50 mA cm−2 are applied. Under these operating conditions, the mineralisation conversion achieved is above 0.80. Low molecular weight COCs are rapidly oxidised because the evaporation also contributes to decrease their concentration in groundwater. Chlorine-based electrogenerated oxidants are the main species responsible for the removal of COCs. Toxicity and biodegradability tests performed on treated groundwater reveal that EC50 increases above 65 %, and 100 % biodegradability is obtained. The highest energy efficiencies are obtained during the treatment at 5 mA cm−2 (over 0.03 m3 kW-1h−1 for all COCs) due to the minimisation of parallel oxidation reactions promoted at higher current densities.

Review on Organochlorine Pollution in Malaysia

Organochlorine is a type of persistent organic pollutants which can last long in environment due to the resistance towards the microbial degradation. Previously, the organochlorine pesticides are widely used to reduce the pests in the farm so, the crop yield could be increased, and the losses can be decreased. The organochlorine pesticides previously are used without having a proper study on the effect of organochlorine to the environment. Although the use of organochlorine pesticides has been banned, the residues of organochlorine from previous usage, still exist in the environment, causing negative impacts to the environment and human health. The distribution of the organochlorine pollution in Malaysia is required to be studied more to ensure that the organochlorine concentration will not be increasing according to time. Due to the ban of organochlorine pesticides, other pests control methods such as organophosphate pesticides, and integrated pest management are being used by the farmers. However, there are challenges raised such as financial problem of the farmers to afford the new chemicals or methods and the negative effect from the use of new chemicals, and these challenges should be solved to improve the pest control in Malaysia. Impacts of organochlorines on human health and environment are discussed in this review to show the hazard of organochlorines.

A novel soluble di-iron monooxygenase from the soil bacterium Solimonas soli.

Soluble di-iron monooxygenase (SDIMO) enzymes enable insertion of oxygen into diverse substrates and play significant roles in biogeochemistry, bioremediation and biocatalysis. An unusual SDIMO was detected in an earlier study in the genome of the soil organism Solimonas soli, but was not characterized. Here, we show that the S. soli SDIMO is part of a new clade, which we define as 'Group 7'; these share a conserved gene organization with alkene monooxygenases but have only low amino acid identity. The S. soli genes (named zmoABCD) could be functionally expressed in Pseudomonas putida KT2440 but not in Escherichia coli TOP10. The recombinants made epoxides from C2 C8 alkenes, preferring small linear alkenes (e.g. propene), but also epoxidating branched, carboxylated and chlorinated substrates. Enzymatic epoxidation of acrylic acid was observed for the first time. ZmoABCD oxidised the organochlorine pollutants vinyl chloride (VC) and cis-1,2-dichloroethene (cDCE), with the release of inorganic chloride from VC but not cDCE. The original host bacterium S. soli could not grow on any alkenes tested but grew well on phenol and n-octane. Further work is needed to link ZmoABCD and the other Group 7 SDIMOs to specific physiological and ecological roles.

Organochlorine compounds in the bottom sediments of the meromictic Mogilnoe Lake (Kildin Island, Russia)

The paper presents the results of a study of the behavior of organochlorine compounds (chlorinated benzenes and phenols) in the bottom sediments of Mogilnoe Lake (Kildin Island, Barents Sea). Mogilnoe Lake is a meromictic water reservoir located in the high latitudes of the Russian Arctic. A unique feature of the lake is its underground connection with the sea, which makes it similar to tropical anchialine lakes. Lake sediment samples were taken at three deep-water stations during complex expedition work in June 2019 by employees of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences (Arkhangelsk). Organochlorine compounds were extracted from air-dried samples of bottom sediments using accelerated flow-through solvent extraction with a hot mixture of organic solvents. Determination of the concentrations of chlorinated benzenes was carried out according to RD 52.24.417-2011 (RF), and the concentrations of chlorinated phenols and their derivatives – in accordance with the ISO 14154:2005. Quantification and identification of individual organochlorine compounds were carried out by capillary gas chromatography with electron capture detection. The presence of organochlorine compounds in sediments of the meromictic Mogilnoe Lake has been established. Concentrations of persistent organochlorine pollutants were assessed as high. Most likely, the component composition of organochlorine compounds and their detected levels (primarily pollutants) in the bottom sediments of the lake are due to the influence of various local anthropogenic sources, as well as atmospheric long-range transport from low/moderate latitudes and nearby regions.

Research progress on remediation of organochlorine pesticide contamination in soil.

Deteriorated soil pollution has grown into a worldwide environmental concern over the years. Organochlorine pesticide (OCP) residues, featured with ubiquity, persistence and refractoriness, are one of the main pollution sources, causing soil degradation, fertility decline and nutritional imbalance, and severely impacting soil ecology. Furthermore, residual OCPs in soil may enter the human body along with food chain accumulation and pose a serious health threat. To date, many remediation technologies including physicochemical and biological ways for organochlorine pollution have been developed at home and abroad, but none of them is a panacea suitable for all occasions. Rational selection and scientific decision-making are grounded in in-depth knowledge of various restoration techniques. However, soil pollution treatment often encounters the interference of multiple factors (climate, soil properties, cost, restoration efficiency, etc.) in complex environments, and there is still a lack of systematic summary and comparative analysis of different soil OCP removal methods. Thus, to better guide the remediation of contaminated soil, this review summarized the most commonly used strategies for OCP removal, evaluated their merits and limitations and discussed the application scenarios of different methods. It will facilitate the development of efficient, inexpensive and environmentally friendly soil remediation strategies for sustainable agricultural and ecological development.

Determination of persistent organochlorine pollutants in human serum by combining liquid-liquid extraction and solid-phase extraction with gas chromatography-tandem mass spectrometry

Persistent organochlorine pollutants (POCPs) are a group of “forever chemicals” that are ubiquitous in the environment and pose adverse health effects to humans. However, the lack of sensitive and widely applicable analytical method for internal POCPs exposure assessment puts limits on the researches of health risk evaluations. Therefore, we developed a method for the measurement of 43 POCPs in human serum using gas chromatography-tandem mass spectrometry (GC-MS/MS). Serum samples were treated with methanol and acid to precipitate protein and remove lipids, respectively. 13C-labeled analogue was spiked and liquid-liquid extraction (LLE) was performed to extract target analytes by hexane and methyl tert-butyl ether. The extract was purified by solid-phase extraction (SPE) and eluted with dichloromethane. The eluate was concentrated under nitrogen stream and reconstituted with toluene. Samples were analyzed by GC-MS/MS operated in electron impact (EI) and multiple reaction monitoring (MRM) mode. Calibration curves of all target analytes showed favorable linearity within the concentration range of 0.008 to 10 μg/L for different POCPs, with regression coefficients above 0.991. The method detection limits and limits of quantification ranged from 0.005 to 0.10 μg/L and 0.017 to 0.34 μg/L, respectively. The recoveries and precision of all analytes at 3 different spike levels were in the range of 65.3 % to 121.8 % and 1.8 % to 13.9 %, respectively. The matrix effects (ME) ranged from 74.9 % to 125.6 %. The results of measuring quality control samples from the National Institute of Standards and Technology (NIST) were with relative deviations of less than 30 %. With an optimized sample preparation procedure, the proposed method has successfully achieved in improving extraction efficiency and reducing ME. It was applied in the simultaneous determination of POCPs in a small volume of human serum in China National Human Biomonitoring.

Assessment of Water Quality and Parasitofauna, and a Biometric Analysis of the Prussian Carp of the Romanian Lentic Ecosystem in Moara Domnească, Ilfov County

The aim of this study was to perform a morphometric analysis of Prussian carp individuals collected from the Moara Domnească pond in Ilfov County, Romania. This was accompanied by a physico-chemical characterization of the water, which was sampled from the same location. Consequently, we analyzed a total of 60 Prussian carp individuals that were caught in April (N = 32) and May 2023 (N = 28). For the Carassius gibelio in the study site, we provided, for the first time, data on the weight–length relationships (WLRs), the Fulton K condition factor and the biometric features, including the total length (TL), standard length (SL), head length (HL), snout length (SNL), body depth (BD), girth and ratios for the TL/HL, as well for the TL/BD and TL/SL. A negative growth type was estimated for both the samples of C. gibelio. Based on other studies and fishing reports, besides C. gibelio, there are another 11 species that belong to the Cypriniformes order, and there are two teleost members of the Perciformes order (Lepomis gibbosus and Perca fluviatilis)—these were also associated with this habitat. Water samples were collected from 12 sampling points (SP), which were subjected to physico-chemical characterizations that consisted of an assessment of the turbidity (T), pH, electrical conductivity (EC), chloride (Cl−), total hardness (TH), oxygen regime parameters, phosphate phosphorus (P-PO43−), nitrate nitrogen (N-NO3−), nitrite nitrogen (N-NO2−) and ammonium nitrogen (N-NH4+) levels. In addition, considering their characteristics (high toxicity, non-biodegradability, long-range atmospheric transport and bioaccumulation potential), a number of organochlorine pollutants (OCPs) were identified. The total hardness values presented a very significant correlation with conductivity (r = 0.5974 ***) and with pH (r = 0.5854 ***). The results allowed for the water samples to be placed into the quality classes established by legislation, and they were also discussed in relation to the fishes’ requirements.

Soil properties and organochlorine compounds co-shape the microbial community structure: A case study of an obsolete site

Organochlorine compounds (OCs) such as chlorobenzenes (CB) are persistent organic pollutants that are ubiquitous in soils at organochlorine pesticides (OCP) production sites. Long-term contamination with OCs might alter the soil microbial structure and further affect soil functions. However, the effects of OCs regarding the shaping of microbial community structures in the soils of OCs-contaminated sites remain obscure, especially in the vertical soil profile where pollutants are highly concealed. Hence this paper explored the status and causes of OCs pollution (CB, hexachlorocyclohexane (HCH), and dichlorodiphenyltrichloroethane (DDT)) in an obsolete site, and its combined effects with soil properties (pH, available phosphorus (AP), dissolved organic carbon (DOC), etc) on microbial community structure. The mean total concentration of OCs in the subsoils was up to 996 times higher than that in the topsoils, with CB constituting over 90% of OCs in the subsoil. Historical causes, anthropogenic effects, soil texture, and the nature of OCs contributed to the differences in the spatial distribution of OCs. Redundancy analysis revealed that both the soil properties and OCs were important factors in shaping microbial composition and diversity. Variation partitioning analysis further indicated that soil properties had a greater impact on microbial community structure than OCs. Significant differences in microbial composition between topsoils and subsoils were observed through linear discriminant analysis effect size (LEfSe) analysis, primarily driven by different pollutant conditions. Additionally, co-occurrence network analysis indicated that heavily contaminated subsoils exhibited closer and more intricate bacterial community interactions compared to lightly contaminated topsoils. This work reveals the impact of environmental factors in co-shaping the structure of soil microbial communities. These findings advance our understanding of the intricate interplay among organochlorine pollutants, soil properties, and microbial communities, and provides valuable insights into devising effective management strategies in OCs-contaminated soils.

ORGANOCHLORINE PESTICIDES POLLUTION OF THE BOTTOM SEDIMENTS OF NAKHODKA BAY AND PARTIZANSKAYA RIVER

Link for citation: Mazlova E.A., Blinovskaya Ya.Yu., Sokolova L.I., Tursunova G.Sh. Organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 25-35. In Rus. Relevance. The new data on the organochlorine pesticides pollution of the bottom sediments of Nakhodka bay and Partizanskaya river were obtained in 2020–2021. The objective of the article is to report the organochlorine pesticides pollution level of the bottom sediments and to define the possible sources of organochlorine pesticides in the marine environment. Techniques: sample collection of bottom sediments, Gas Chromatography Mass Spectrometry analysis of samples, Gas-liquid Chromatography method with electronic capture detector, statistical processing, assessment of the organochlorine pesticides contamination of sediments. Results. The new data were obtained on the organochlorine pesticides concentrations in Nakhodka bay in 2020–2021. The previous data on the studied area are described. The concentration of HCH pesticides (α- , β- and γ-HCH), DDT and its metabolites was analyzed. It was found that the concentration of α- , β- HCCH and DDT in bottom sediments increased in 2021.To determine the quality of bottom sediments, the average annual values of organochlorine pesticides concentrations in the bottom sediments gathered during the field works were compared with the quality guidelines. There are no approved quality guidelines for maximum permissible concentrations of pollutants in bottom sediments in the Russian Federation. For this reason, we used the quality guidelines applied in foreign countries («Dutch sheets» (Neue Niederlandische Liste. NNL) and Canadian quality standards for marine and estuarine bottom sediments (Canadian Sediment Quality Guidelines, CSQGs). Possible sources of organochlorine pesticides in the marine environment were analyzed. The results of this work showed that despite the ban on the use of these substances, these pesticides are included in the multiple compounds used in different industries and continue to enter and accumulate in the marine environment.

OXIDATION METHODS FOR PHENOLE-CONTAINING WASTEWATER TREATMENT

One of the most complex environmental problems generated by the development of human economic activity is the problem of the negative impact of chemically polluted territories on the objects of the hydrosphere. A lot of toxic compounds, getting into water reservoirs, cause the water area deterioration, the death of their flora and fauna, make the water unusable either for drinking nor for cultural and household needs. Recently, the attention of specialists has been attracted by a group of persistent organic pollutants. All these substances belong to the class of organochlorine pollutants, as well as by-products of hydrocarbon production (for example: dioxins, furans, formaldehydes, phenols). These substances are resistant to decomposition and toxic. Among the most dangerous water pollutants, along with heavy metal ions, petroleum products, surfactants and polyaromatic compounds, are phenol and its derivatives. Phenol-containing wastewater is generated at enterprises of the pulp and paper, woodworking, food industries, leather, chemical, coke, petrochemical industries, etc. When even a small amount of phenolic compounds gets into a water body, the reservoir self-cleaning capacity decreases. In this regard, the problem of an objective assessment of hydrosphere pollution by phenols and its derivatives and the search for new effective methods of wastewater treatment are urgent tasks. The paper describes oxidation methods for wastewater treatment from phenol.

Do Organochlorine Contaminants Modulate the Parasitic Infection Degree in Mediterranean Trout (Salmo trutta)?

We investigated the occurrence of organochlorine pollutants (OCs) in the muscle of brown trout and evaluated their potential modulation of parasite infection. The toxicological risk for consumer health was assessed, too. Trout were collected from the Sila National Park (Calabria region, South of Italy). The highest concentrations emerged for the sum of the 6 non-dioxin-like (ndl) indicator polychlorinated biphenyls (Σ6ndl-PCBs), followed by the 1,1,1-trichloro-2,2-di(4-chlorophenyl)-ethane (DDT), dioxin-like PCBs, hexachlorobenzene (HCB), and dieldrin. Measured on lipid weight (LW), the mean value of Σ6ndl-PCBs amounted to 201.9 ng g-1, that of ΣDDTs (the sum of DDT-related compounds) to 100.2 ng g-1, with the major contribution of the DDT-metabolite p,p'-DDE which was detected in all sample units (97.6 ng g-1 on average). Among dioxin-like congeners, PCB 118 showed the highest mean concentration (21.96 ng g-1 LW) and was detected in all sample units. Regression analysis of intestinal parasites on OC concentration was performed, controlling for two potential confounding factors, namely sex and sexual stage. The results evidenced the existence of interactions between the dual stressors in the host-parasite system in the wild. A negative and statistically significant correlation was estimated, suggesting that OCs may decrease parasite infection degree. Regarding the toxicological risk evaluation, OC concentrations were consistently below the current European Maximum Residue Limits.

Degradation and Extraction of Organochlorine Pollutants from Environmental Solids under Subcritical Water Conditions.

A subcritical water degradation and extraction method was developed to remediate environmental soils contaminated by highly recalcitrant organochlorine pollutants. Hydrogen peroxide was used to effectively decompose organochlorine pollutants under subcritical water conditions. As a method optimization study, the static wet oxidation of chlorophenols was first performed in subcritical water with and without added hydrogen peroxide. Complete oxidation was achieved using an added oxidant, and thus, the oxidation and extraction of chlorophenols from a sand matrix was then attempted. Complete oxidation and extraction with added oxidant were achieved within 30 min at 100 °C. We then investigated the subcritical water degradation and extraction of dieldrin, mirex, and p,p'-DDD. These organochlorine pesticides were not as easily oxidized as the chlorophenols, and the benefit of adding hydrogen peroxide was only clearly observed at 200 °C. Approximately a 20% increase in degradation was noted for each pesticide and insecticide at this temperature. Unfortunately, this difference was not observed with an increase in temperature to 250 °C, except in some cases, where the amount of degradation byproducts was reduced. Dieldrin and p,p'-DDD were essentially destroyed at 250 °C, while all the pesticides and the insecticides were completely removed from the sand at this temperature. The proposed method was then used to remediate a soil sample highly contaminated with DDT. The soil was obtained from the grounds of an old DDT mixing facility in Virginia and has been aging for several decades. Not only was 100% removal of DDT from this soil achieved using the proposed method at 250 °C, but also, the extracted DDT was completely destroyed during the process. The proposed remediation method, therefore, demonstrates a high potential as an efficient and environmentally sound technique for the detoxification of soils.