Organochlorine pesticides in soil, moss and tree-bark from North-Eastern Romania

What potential do mosses have as biomonitors of POPs? A comparative study of hexachlorocyclohexane sorption

Persistent organic pollutants (POPs) pose a significant global threat to human health and the environment, and require continuous monitoring due to their ability to migrate long distances. Active biomonitoring using cloned mosses is an inexpensive but underexplored method to assess POPs, mainly due to the poor understanding of the loading mechanisms of these pollutants in mosses. In this work, Fontinalis antipyretica (aquatic moss) and Sphagnum palustre (terrestrial moss) were evaluated as potential biomonitors of hexachlorocyclohexanes (HCHs: α-, β-, γ-, δ-HCH), crucial POPs. Moss clones, grown in photobioreactors and subsequently oven-dried, were used. Their lipid composition and distribution were characterized through molecular and histochemical studies. Adsorption experiments were carried out in the aqueous phase using the repeated additions method and in the gas phase using an active air sampling technique based on solid-phase extraction, a pioneering approach in moss research. F. antipyretica exhibited greater lipid content in the walls of most cells and higher adsorption capacity for all HCH isomers in both gaseous and liquid environments. These findings highlight the need for further investigation of POP loading mechanisms in mosses and open the door to explore other species based on their lipid content.

Uptake and Transformation of Hexachlorocyclohexane Isomers (HCHs) in Tree Growth Rings at a Contaminated Field Site

The potential transformation of hexachlorocyclohexane isomers (HCHs) within tree trunks could have a significant impact on the use of phytoscreening. However, the transformation mechanisms of HCH in trunks particularly in growth rings are not yet well understood. Therefore, a field study on an HCH-contaminated field site was conducted to investigate the fate of HCH, particularly α-HCH in tree trunks using multielement compound-specific isotope analysis (ME-CSIA) and enantiomer fractionation. The results indicate that α-HCH was transformed, as evidenced by higher δ¹³C and δ³⁷Cl values detected across different growth ring sections and in the bark compared to those in muck and soil. Remarkably, in the middle growth ring section, δ¹³C values of HCH were only marginally higher or comparable to those in muck, whereas δ³⁷Cl values were higher than those of the muck, indicating a different transformation mechanism. Moreover, the δ³⁷Cl values of β-HCH also increased in the tree trunks compared to those in soil and muck, implying a transformation of β-HCH. Additionally, dual-element isotope analysis revealed that there are different transformation mechanisms between the middle growth rings and other sections. Our findings suggest that the transformation of HCHs in trunks could bias quantitative phytoscreening approaches; however, ME-CISA offers an option to estimate the degradation extent.

Evaluation of the spatiotemporal variations of organochlorine pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the forests of the Himalaya and Hengduan mountains using tree bark and tree core samples

There have been few reports of the large-scale spatial distribution and long-term historical variations of pollutants in high-altitude forests. Tree bark and tree core samples were collected from forests in the Himalaya and Hengduan mountains to determine the spatiotemporal variations of persistent organic pollutants. The average concentrations of dichlorodiphenyl trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in tree bark samples were 9.09, 0.10, 0.13, 0.11and 26 ng/g dry weight, respectively, and 1.30, 0.02, 0.17, 0.07 and 186 ng/g dry weight, respectively, in tree core samples. Higher levels of these pollutants were observed in the forests on the southern slopes of the Himalaya (Nepal) and the southern part of the Hengduan mountains (Yunnan, China). Lower concentrations of these pollutants were found in the interior of the Tibetan Plateau on the northern slopes of the Himalaya as a result of the blocking effect of these mountain ranges. The concentrations of DDTs and HCHs in Himalayan tree cores showed increasing trends from 1956 to 1975 when they were used as pesticide extensively worldwide, especially in India. Peak concentrations of DDTs, HCHs and PAHs in tree cores of Qamdo located in Hengduan Mountains were observed in 2013, which were consistent with the history of industrial and agricultural development in Sichuan. This study provides new insights into the impact of atmospheric pollutants in South and Southeast Asia.

Occurrence, correlation, and partitioning of organophosphate esters in soil and tree bark from a megacity, Western China

Concern over the influences of constant addition of emerging anthropogenic chemicals to the environment has become a public issue during the rapid urbanization. Here, we investigated the occurrence of organophosphate esters (OPEs) in soil and corresponding tree bark in a megacity, Western China. Our results showed levels of OPEs in tree bark (1250 ± 573 ng/g dry weight (dw)) were 1-2 orders of magnitude higher than those in soil (40.4 ± 30.8 ng/g dw). Rooster Mountain is a background mountain area, exhibiting significantly lower concentrations of OPEs in soil and tree bark than those in other sites with relatively high population density. This result highlights the effect of human activities on the distribution of OPEs in environmental matrices. Alkyl-OPEs were predominant compounds in soil, whereas halogenated- (Cl-) OPEs were characterized in tree bark. Furthermore, tris(2-chloroethyl) phosphate (TCEP) positively correlated with tris(2-chloroisopropyl) phosphate (TCIPP) in soil (r² = 0.43, P < 0.05) while negatively correlated with TCIPP in tree bark (r² = 0.31, P < 0.05). The ratios of logarithm concentrations of OPEs in tree bark to those in soil correlated well with logK_OA values of OPEs from 6 to 10, indicating the equilibrium status was achieved between OPE partitioning in soil and in tree bark. Nevertheless, tris (2-butoxyethyl) phosphate (TBEP) and tris(2-ethylhexyl) phosphate (TEHP) with high values of logK_OA deviated from this linear tendency, which was possibly due to the fact that they were subjected to the particle-bound deposition process, leading to partition into the soil.

Presence of pesticides in the environment, transition into organic food, and implications for quality assurance along the European organic food chain - A review

The use of synthetic pesticides is not allowed in organic production, but traces of synthetic pesticides are regularly detected in organic food. To safeguard the integrity of organic production, organic certifiers are obliged to investigate the causes for pesticide residues on organic food, entailing high costs to the organic sector. Such residues can have various origins, including both fraud and unintentional contamination from the environment. Because the knowledge about contamination from environmental sources is scattered, this review provides an overview of pathways for unintentional and technically unavoidable contamination of organic food with synthetic pesticides in Europe. It shows that synthetic pesticides are widely present in all environmental compartments. They originate from applications in the region, in distant areas or from historical use. Transition into the food chain has been demonstrated by various studies. However, large uncertainties remain regarding the true pesticide contamination of the environment, their dynamics and the contamination risks for the food chain. Organic operators can take certain measures to reduce the risks of pesticide contamination of their products, but a certain extent of pesticide contamination is technically unavoidable. The present paper indicates that (i) a potential risk for pesticide residues exists on all organic crops and thus organic operators cannot meet a 'zero-tolerance' approach regarding pesticide residues at the moment. (ii) Applying a residue concentration threshold to distinguish between cases of fraud and unavoidable contamination for all pesticides is not adequate given the variability of contamination. More reliable answers can be obtained with a case-by-case investigation, where evidence for all possible origins of pesticide residues is collected and the likelihood of unavoidable contamination and fraud are estimated. Ultimately, for organic certification bodies and control authorities it will remain a challenge to determine whether a pesticide residue is due to neglect of production rules or technically unavoidable.

Spatial distribution of legacy pesticides in river sediment from the Republic of Moldova

Historical use of organochlorine pesticides (OCPs) in the Republic of Moldova could pose a potential risk for the aquatic environment due to the persistence, bioaccumulation and toxic properties of these environmental pollutants. However, knowledge on environmental concentrations of legacy OCPs in Moldova is limited. In this study, surface sediment from the two main rivers; Dniester (8 sites, n = 15) and Prut (6 sites, n = 12), and two tributary rivers; Bîc (11 sites, n = 11) and Răut (6 sites, n = 6), were collected during 2017-2018 and analyzed for hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and their transformation products (DDDs and DDEs) using gas chromatography coupled to mass spectrometry (GC-MS/MS). Sediment concentrations of Ʃ₆DDX (1.9-140 ng g^-1 dry weight (dw)) and Ʃ₄HCHs (n.d-2.5 ng g^-1 dw) were found. In the big rivers, the average Ʃ₆DDX concentration (18 ng g^-1 dw) were 35 times higher than Ʃ₄HCHs (0.51 ng g^-1 dw). Whereas, in the small rivers the average Ʃ₆DDX concentration (32 ng g^-1 dw) was approximately 41 times higher than Ʃ₄HCHs (0.77 ng g^-1 dw). Compared to previous studies from Eastern Europe, the sediment levels were generally similar as found in Moldova's neighboring countries (Romania and Ukraine). Overall, the contamination profile indicates long-term ageing of OCPs used in the past in the agricultural sector. Less than half of the sites (45%) had levels that pose a potential risk for benthic organisms. Hence, further work is needed to determine the bioaccumulation of OCPs in the aquatic food web in this region and the associated risks to ecosystems and human health.

Organochlorines burden in moss H. cupressiforme and topsoil across Serbia

Following up-to-date initiatives of the Stockholm Convention, its global monitoring plan, and the International Cooperative Programme on Natural Vegetation and Crops (ICP Vegetation 2015) under the convention on long-range transboundary air pollution, this study examined 17 polychlorinated biphenyls (PCBs) and seven organochlorine pesticides (OCPs) in the moss Hypnum cupressiforme Hedw. and topsoil sampled across Serbia. In the topsoil, OCPs ranged from 0.0158 to 9.6804 ng g^-1 while concentrations of individual PCB congeners were in the range between 0.0185 and 0.3107 ng g^-1. The levels of OCPs and PCBs in the moss H. cupressiforme ranged from 2.7785 to 23.9501 ng g^-1, and from 0.4325 to 15.8013 ng g^-1, respectively. POP relationships between topsoil and moss investigated by fugacity model equations indicated that the moss POP enrichment was a result of atmospheric long-range transport rather than secondary reemissions from soil.

Monitoring of DDT in Agricultural Soils under Organic Farming in Poland and the Risk of Crop Contamination

The analysis of 142 agricultural soil samples collected in organic farms across Poland with the intent to evaluate the level of DDT contamination resulted in more than 80% of the soils containing DDT. The ΣDDT (sum of all metabolites and isomers) concentration ranged between 0.005 and 0.383 mg/kg ΣDDT, with an average value of 0.064 mg/kg ΣDDT. However, the majority of plant samples collected from the crops growing on the sampled soils did not contain detectable DDT residues. The high DDT pollution levels detected in samples from four voivodeships (regions) among those monitored have been hypothesised to be linked to horticultural productions occurring to the sampled fields and typical of those regions, particularly in big-sized farms, during the period of DDT application, as well as the number of pesticides landfills present in these voivodeships. The elaboration of the o,p'-DDT/p,p'-DDT and DDT/(DDE + DDD) ratios to appraise the source or the period of contamination suggested that the contamination originated from past use of DDT rather than from impurities of more recent applications of other formulated substances. Such outcome thus suggests that the risk of contamination of organic products is likely derived from general environmental pollution levels rather than from the use of unauthorised substances in organic farming productions. Data from a trial with artificial contamination of soils indicated that using the DDT/(DDE + DDD) ratio in the presence of a low level of contamination could be less reliable than in highly contaminated soils.

Concentration and distribution of pesticide residues in soil: Non-dietary human health risk assessment

Soil contamination by pesticide residues is a primary concern because of the high soil persistence of pesticides and their toxicity to humans. We investigated pesticide concentration and distribution at 3 soil depths in 147 soil samples from agricultural land and assessed potential health risks due to non-dietary human exposure to pesticides in Nepal. About sixty percent of the soil samples had pesticides (25% of the soil samples had single residue, 35% of the soil samples had mixtures of 2 or more residues) in 39 different pesticide combinations. Pesticide residues were found more frequently in topsoil. Overall, the concentration of pesticides ranged from 1.0 μg kg^-1 to 251 μg kg^-1, with a mean of 16 μg kg^-1. The concentration of the primary group, organophosphates (OPs), ranged from 1.23 μg kg^-1 to 239 μg kg^-1, with a mean of 23 μg kg^-1. Chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) were the predominant contaminants in soils. The ionic ratio of DDT and its degradation products suggested a continuing use of DDT in the area. Human health risk assessment of the observed pesticides in soil suggested negligible cancer risks and negligible non-cancer risks based on ingestion as the primary route of exposure. The predicted environmental concentrations (PECs) of pesticides were higher than the values found in the guidance for soil contamination used internationally. Low concentrations of residues in the soils from agricultural farms practicing integrated pest management (IPM) suggest that this farming system could reduce soil pollution in Nepal.

Short- and medium-chain chlorinated paraffins in multi-environmental matrices in the Tibetan Plateau environment of China: A regional scale study

Research on the environmental fate and behavior of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively), especially in high-altitude remote mountain areas, has rarely been conducted. In this study, the distribution and profiles of SCCPs and MCCPs in soils, barks, needles, lichens, and mosses in the Tibetan Plateau area were investigated during the period from 2010 to 2016. The total CP concentrations in soils, barks, needles, lichens, and mosses increased with increasing altitude from 1983 to 5147 m a.s.l. (above sea level), covering a range of 1843.5 km × 370.6 km. Generally, the mean SCCP levels were higher than mean MCCP levels in different environmental matrices. Moreover, as-obtained linear relationships between CP concentrations in different environmental matrices and altitudes (p < 0.05) indicated that the mountain cold-trapping could affect the presence and congener patterns of both SCCPs and MCCPs in the Tibetan Plateau environment. C_10-11 and C₁₄ congener groups were found to be the dominant groups in SCCPs and MCCPs in the environmental samples, respectively. Finally, the back-trajectory model was employed to reveal the differences of the potential sources in different regions of the Tibetan Plateau.

Spatial distribution patterns and human exposure risks of polycyclic aromatic hydrocarbons, organochlorine pesticides and polychlorinated biphenyls in Nepal using tree bark as a passive air sampler

Nepal is abutted between the populated Indo-Gangetic Plain (IGP) and Himalayan mountains. Currently, knowledge on the country-wide distribution and cancer risks of atmospheric organic toxicants in Nepal remains limited. In this study, the concentrations, sources, and distributions of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs), along with their cancer risks, were investigated in Nepal by using tree bark as a passive air sampler. After transferring by a bark/air partitioning model, the averaged concentrations of ∑PAHs, ∑DDTs, ∑HCHs, HCB, ∑Endo and ∑PCBs in the atmosphere of Nepal were 3.71 × 10⁴ pg/m³, 1.10 × 10³ pg/m³, 2.92 × 10² pg/m³, 4.38 × 10² pg/m³, 4.66 pg/m³ and 65.8 pg/m³, respectively. Source diagnosis suggested that biomass burning is the major source for PAHs, while local application and long-range transport jointly contribute to the high levels of DDT and HCH in the air. The ILCR (incremental lifetime cancer risk) value was used to assess the risks of various chemicals. Adults have a higher risk than other age groups; the major exposure pathway for risk is by inhalation; and PAHs and HCHs are the dominant chemical classes that lead to risk. It was also found that, in certain hotspots in south Nepal, the carcinogenic risks caused by DDT and HCH were particularly high (>1 × 10^-4). Given that illegal and disordered use of legacy POPs in south Nepal and the IGP region is common, our results highlight an urgent need for voluntary regulation of the ongoing use of pesticides.

Concentrations and distributions of polybrominated diphenyl ethers (PBDEs) in surface soils and tree bark in Inner Mongolia, northern China, and the risks posed to humans

Three functional zones, namely the industrial (IND), the agricultural (AGR), and the grassland (GRA) areas from Inner Mongolia (a remote province in northern China), were selected to evaluate the levels and distributions of PBDEs and the risks posed to local humans. PBDEs concentrations in surface soils and tree bark were detected and the air levels were estimated based on bark measurements. The total concentrations (∑₈PBDEs) of BDE-28, -47, -100, -99, -154, -153, -183, and -209 in soils were 1.71-64.9 ng/g dry weight (d.w.), 0.720-4.08 ng/g d.w., and 0.604-3.76 ng/g d.w. in the IND, AGR and GRA areas respectively. The average total concentrations in bark and air were 0.792 ng/g d.w. and 0.125 ng/m³ in the AGR areas respectively, which were lower than those (1.69 ng/g d.w. in the bark and 0.476 ng/m³ in the air) in the IND areas. BDE-209 was the dominant congener, consistent with DeBDE being the dominant commercial products used in China. However, except for BDE-209, BDE-28 and BDE-47 in the AGR and GRA areas averagely contributed about half of the total PBDEs concentrations in soils. BDE-28 concentrations in the bark samples of the AGR areas were significantly higher (p < 0.05) than in the IND areas, and the average total hazard quotients (∑₈PBDEs) were higher for humans in the AGR areas (0.12) than in the IND areas (0.08). Degradation of higher-brominated congeners (e.g., BDE-209) and migration of lower-brominated congeners (mainly BDE-28 and BDE-47) may increase the risks to humans in pristine areas.

A traceless clean-up method coupled with gas chromatography and mass spectrometry for analyzing polycyclic aromatic hydrocarbons in complex plant leaf matrices

This study developed a traceless clean-up method by combining solid phase extraction (SPE) with gas purge–microsyringe extraction (GP–MSE) to purify sample extracts for the determination of polycyclic aromatic hydrocarbons (PAHs) in plant leaves.

Study of organochlorine pesticides and heavy metals in soils of the Juarez valley: an important agricultural region between Mexico and the USA

The Juarez Valley is an important agricultural region in northern Mexico, conveniently organized into three modules (I to III). For decades, their soils have been exposed to organochlorine pesticides (OCPs) and also have been irrigated with wastewaters, which may contain heavy metals. Nowadays, there is very limited information regarding the presence of OCPs and heavy metals in these soils. Thus, the aim of this study was to diagnose these soils for OCPs and heavy metal content by using gas chromatography coupled with electron micro-capture detector and atomic absorption spectrometry, respectively. The results indicated that 4,4'-dichlorodiphenyldichloroethylene and 4,4'-dichlorodiphenyltrichloroethane were primarily disseminated across the three modules since they were found in 100% and 97% of the analyzed soils, respectively. According to international regulations, none of the determined OCP concentrations are out of the limits. Additionally, the Cu, Zn, Fe, Pb, and Mn were found in all sampled soils from the three modules. The highest concentration of Fe was found in module II (1902.7 ± 332.2 mg kg^-1), followed by Mn in module III (392.43 ± 74.43 mg kg^-1), Zn in module I (38.36 ± 26.57 mg kg^-1), Pb in module II (23.48 ± 6.48 mg kg^-1), and Cu in module I (11.04 ± 3.83 mg kg^-1) (p ≤ 0.05). These values did not exceed the limits proposed by international standards. The Cd was detected in most of the analyzed soils and all their values, with an average of 2 mg kg^-1, surpassed the Mexican standards (0.35 mg kg^-1). This study has mapped the main OCPs and heavy metals in the Juarez Valley and can serve as a starting point to further monitor the behave of xenobiotics. Since these recalcitrant compounds might be bio-accumulated in biological systems, further analytical methods, as well as remediation techniques, should be developed.

Lessons from the genomes of lindane-degrading sphingomonads

Bacterial strains capable of degrading man-made xenobiotic compounds are good materials to study bacterial evolution towards new metabolic functions. Lindane (γ-hexachlorocyclohexane, γ-HCH, or γ-BHC) is an especially good target compound for the purpose, because it is relatively recalcitrant but can be degraded by a limited range of bacterial strains. A comparison of the complete genome sequences of lindane-degrading sphingomonad strains clearly demonstrated that (i) lindane-degrading strains emerged from a number of different ancestral hosts that have recruited lin genes encoding enzymes that are able to channel lindane to central metabolites, (ii) in sphingomonads lin genes have been acquired by horizontal gene transfer mediated by different plasmids and in which IS6100 plays a role in recruitment and distribution of genes, and (iii) IS6100 plays a role in dynamic genome rearrangements providing genetic diversity to different strains and ability to evolve to other states. Lindane-degrading bacteria whose genomes change so easily and quickly are also fascinating starting materials for tracing the bacterial evolution process experimentally in a relatively short time period. As the origin of the specific lin genes remains a mystery, such genes will be useful probes for exploring the cryptic 'gene pool' available to bacteria.

Pesticide residues in European agricultural soils - A hidden reality unfolded

Pesticide use is a major foundation of the agricultural intensification observed over the last few decades. As a result, soil contamination by pesticide residues has become an issue of increasing concern due to some pesticides' high soil persistence and toxicity to non-target species. In this study, the distribution of 76 pesticide residues was evaluated in 317 agricultural topsoil samples from across the European Union. The soils were collected in 2015 and originated from 11 EU Member States and 6 main cropping systems. Over 80% of the tested soils contained pesticide residues (25% of samples had 1 residue, 58% of samples had mixtures of two or more residues), in a total of 166 different pesticide combinations. Glyphosate and its metabolite AMPA, DDTs (DDT and its metabolites) and the broad-spectrum fungicides boscalid, epoxiconazole and tebuconazole were the compounds most frequently found in soil samples and the compounds found at the highest concentrations. These compounds occasionally exceeded their predicted environmental concentrations in soil but were below the respective toxic endpoints for standard in-soil organisms. Maximum individual pesticide content assessed in a soil sample was 2.05 mg kg^-1 while maximum total pesticide content was 2.87 mg kg^-1. This study reveals that the presence of mixtures of pesticide residues in soils are the rule rather than the exception, indicating that environmental risk assessment procedures should be adapted accordingly to minimize related risks to soil life and beyond. This information can be used to implement monitoring programs for pesticide residues in soil and to trigger toxicity assessments of mixtures of pesticide residues on a wider range of soil species in order to perform more comprehensive and accurate risk assessments.

Concentration, uptake and human dietary intake of novel brominated flame retardants in greenhouse and conventional vegetables

The possible adverse effects of organic pollutants entering vegetables have attracted increasing attention in recent years. However, research on the behavior of novel brominated flame retardants (NBFRs) in soil-vegetable systems is still limited. This work was initiated to investigate the uptake of seven representative NBFRs by vegetables from bulk soil and suspended soil particles under greenhouse and conventional conditions. The mean concentrations of the sum of seven NBFRs (Σ₇ NBFRs) were 2.8 and 3.8 ng g^-1 dw in greenhouse tomatoes and cucumbers, respectively, and 1.1 and 1.7 ng g^-1 dw in conventional tomatoes and cucumbers, respectively. Greenhouse vegetables had higher concentrations of Σ₇ NBFRs than conventional vegetables. The root bioaccumulation factors (RBCFs) of tomatoes and cucumbers in response to NBFRs ranged from 0.6 to 6.3. The range of fruit bioaccumulation factors (FBCFs) was 0.3-7.0. The bioaccumulation factors (BCFs) in greenhouse vegetables were significantly higher than those in conventional vegetables, indicating that greenhouses increased the uptake of NBFRs by vegetables. To address human dietary exposure to NBFRs, the estimated dietary intake (EDI) and the amounts available for human absorption (EDI_ba) were calculated using vegetable consumption and gastrointestinal absorption, respectively. The mean EDI values of NBFRs from greenhouse and conventional tomato consumption were 344 ng d^-1 and 109 ng d^-1, respectively. The mean EDI values of NBFRs from greenhouse and conventional cucumber consumption were 445 ng d^-1 and 217 ng d^-1, respectively. The higher EDI values of NBFRs implied that consuming greenhouse vegetables was associated with higher health risks than consuming conventional vegetables. The mean EDI_ba values of the DBDPEs were 68 ng d^-1 and 46 ng d^-1 for tomatoes and cucumbers, respectively, and were significantly different from the EDI values due to lower bioaccessibility. Gastrointestinal absorption should not be neglected during risk assessments of human exposure to pollutants.

Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 2 - Persistent Organic Pollutants

Despite typically not being taken into account (usually in favour of the 'global distillation' process), the input of persistent organic pollutants (POPs) through biological activities can be indeed relevant at the local scale in terrestrial polar environments when seabird colonies are considered. Seabirds can bioaccumulate and biomagnify POPs, gather in large numbers and excrete on land during their reproductive season, thus making them locally as relevant secondary sources of POPs. The first part of this study indicated that these colonies act as so for several essential and non-essential trace elements, and this second part tests the same hypothesis concerning POPs using the very same samples. Lichens (n = 55), mosses (n = 58) and soil (n = 37) were collected from 13 locations in the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in colony (within the colony itself for soil and within and surrounding the colony for vegetation) and control (at least 150 m away from any colony interference) and analysed for POPs such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers and stable isotopes (C and N). Results showed that colonies act clearly as a secondary source for PCBs and likely for hexachlorobenzene. As in the first part, probable local sources other than the colonies themselves are hypothesised because of high concentrations found in control sites. Again, soil seemed the most adequate matrix for the intended purposes especially because of some particularities in the absorption of animal-derived organic matter by vegetation, pointed out by stable isotope analyses.

Presence and distributions of POPS in soil, atmospheric deposition, and bioindicator samples in an industrial-agricultural area in Turkey

In this study, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were detected in the soil, lichen pine needle, and total deposition samples in the Meriç-Ergene Basin, which is one of the most important regions in terms of industrial and agricultural activities in Turkey. POP concentrations were measured in 192 samples selected to represent four seasons over a 1-year period across four different regions: an intensive industrial area, an industrial + residential area, an agricultural area, and a background area. Total PAH concentrations are found in the range of 69.6-887.6 ng/g, 74.6-1277.7 ng/g, 113.4-588.9 ng/g, and 0.00-937.8 ng/m²-day; total PCB concentrations are 9.98-62.9 ng/g, 6.8-68.1 ng/g, 11.3-32.7 ng/g, and 0.00-144.4 ng/m²-day; total OCPs concentrations are 5.9-83.2 ng/g, 7.3-85.6 ng/g, 9.9-97.1 ng/g, and 0.00-137.6 ng/m²-day respectively for soil, lichen, pine needles, and bulk samples. The data were evaluated according to pollutant groups and spatial and temporal changes. The highest PAH and PCB values were detected in lichen samples from industrial areas. The highest OCP values were detected for total deposition and soil samples and in the agricultural area. The results showed that two- to three-ring PAHs, hepta-PCBs, and cyclodienes were the most widespread pollutant groups. Statistical analyses were performed to evaluate the accumulation and indication properties of the matrices in the study for 0.05 significance level. The pollutant group in which matrices are most similar is PAHs. Total deposition samples showed the most different pattern in terms of indications, especially for PCBs. For OCP results, the concentration values obtained in soil samples were different from all other matrices. It was determined that the indication properties of the matrices identified as pollutant indicators differ markedly from the pollutant type, and this difference is at the lowest level for PAH pollutants. Graphical abstract ᅟ.

Spatial distribution of and seasonal variations in endosulfan concentrations in soil, air, and biota around a contaminated site

Soil, air, tree bark, rice, wheat, invertebrates, and chicken tissues around a typical endosulfan-contaminated site were analyzed in each season in each of two years. The total endosulfan (the sum of α-, β-endosulfan and endosulfan sulfate) were significantly different in soil and air samples collected in the four seasons (P < 0.01) and the mean concentrations were 6.53 ng/g dry weight (d.w.) and 2.40 ng/m³, respectively, in autumn, 3.32 ng/g d.w. and 2.48 ng/m³, respectively, in winter, 2.10 ng/g d.w. and 0.93 ng/m³, respectively, in spring, and 1.03 ng/g d.w. and 0.83 ng/m³, respectively, in summer. The total endosulfan concentrations in tree bark, rice, wheat, and invertebrates were 23.0-278 (mean 95.5) ng/g d.w., 7.36-35.5 (mean 17.4) ng/g d.w., 34.3-158 (mean 83.1) ng/g d.w., and 401-4354 (mean 2125) ng/g lipid weight, respectively. The total endosulfan concentrations in the chicken gizzard, heart, liver, and meat samples were 552, 212, 699, and 221 ng/g lipid weight, respectively. The endosulfan concentrations in soil, air, and biota around the site were strongly influenced by endosulfan emissions from the site, and the concentrations had decreased to half the initial concentrations six months after endosulfan production stopped. The invertebrate and chicken bioconcentration and biomagnification factors indicated that endosulfan accumulated in the invertebrates and chicken tissues was slightly biomagnified by chickens.

Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 1 - Trace elements

Global distillation is classically pointed as the biggest responsible for contaminant inputs in Polar ecosystems. Mercury (Hg) and other trace elements (TEs) also present natural sources, whereas the biologically mediated input is typically ignored. However, bioaccumulation and biomagnification combined with the fact that seabirds gather in large numbers into large colonies and excrete on land might represent an important local TEs input. A previous work suggested these colonies as sources of not only nutrients, but also organic contaminants. To evaluate a similar hypothesis for TEs, samples of lichen (n = 55), mosses (n = 58) and soil (n = 37) were collected in 13 locations within the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in: "colony" (within the colony itself for soil and bordering it for vegetation) and "control" (at least 50 m away from colony interference), analysed for TEs (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) and stable isotopes (C and N). In most cases, soil seems the best matrix to assess colonies as TEs sources, as it presented more differences between control/colony sites than vegetation. Colonies are clearly local sources of organic matter, Cd, Hg and likely of As, Se and Zn. Conversely, Co, Cr, Ni and Pb come presumably from other sources, natural or anthropogenic. In general, isotopes were more useful for interpreting vegetation data due to fractionation of absorbed animal-derived organic matter. Other local Hg sources could be inferred from high levels in control sites, location and wind patterns.

Spatial and seasonal variations in air-soil exchange, enantiomeric signatures and associated health risks of hexachlorocyclohexanes (HCHs) in a megacity Hangzhou in the Yangtze River Delta region, China

Large amounts of hexachlorocyclohexanes (HCHs) have been historically applied in the Yangtze River Delta (YRD) region, China. Estimating the air-soil exchange of HCHs after >30years of restricted use is important for understanding their cycling in the environment. In this study, air and soil samples were concurrently collected in two seasons at agricultural and industrial sites from a megacity in the YRD region. The concentrations of HCH isomers and the enantiomeric fractions of chiral α-HCH were determined. The mean concentrations of ∑HCHs in soils from an agricultural area (AA) and an eco-industrial park (EIP) were 1.74ng/g and 0.652ng/g, respectively, in winter, and 0.723ng/g and 0.350ng/g, respectively, in summer. The mean concentrations of ∑HCHs in the air from the AA and the EIP were 31.2pg/m³ and 47.7pg/m³, respectively, in winter, and 45.0pg/m³ and 50.0pg/m³, respectively, in summer. The variations in spatial and seasonal distributions might be related to diverse geographical factors, soil properties and meteorological conditions. Source identification demonstrated that HCHs in most samples were residues from past use, which was further evidenced by the enantiomeric signatures of chiral α-HCH. A preferential degradation of (-)-α-HCH was showed in soils and summer air, while a preferential depletion of (+)-α-HCH was displayed in winter air. The values of the fugacity fraction (ff) of HCHs suggest a net volatilization from soils to air, but long-range transport may also partly contribute to the atmospheric HCHs according to the results from enantiomeric analysis. The human health risk assessments indicated an absence of noncarcinogenic risks and very low carcinogenic risks for HCHs in both soils and air to human health. Results from this study provide valuable data for assessing the fate and health risks of HCHs in the YRD region.

Spatial distributions and enantiomeric signatures of DDT and its metabolites in tree bark from agricultural regions across China

Tree bark is considered as an effective passive sampler for estimating the atmospheric status of pollutants. In this study, we conducted a national scale tree bark sampling campaign across China. Concentration profiles revealed that Eastern China, especially the Jing-Jin-Ji region (including Hebei Province, Beijing and Tianjin) was a hot spot of bark DDT pollution. The enantioselective accumulation of o,p'-DDT was observed in most of the samples and 68% of them showed a preferential depletion of (+)-o,p'-DDT. These results suggest that DDTs in rural bark are likely from combined sources including historical technical DDTs and fresh dicofol usage. The tree bulk DDT levels were found to correlate with soil DDT concentrations, socioeconomy and PM_2.5 of the sampling sites. It thus becomes evident that the reemission from soils and subsequent atmospheric deposition were the major pathways leading to the accumulation of DDTs in bark. Based on a previously established bark-air partitioning model, the concentrations of DDTs in the air were estimated from measured concentrations in tree bark, and the results were comparable to those obtained by the use of passive sampling with polyurethane foam (PUF) disks. Our results demonstrate the feasibility of delineating the spatial variations in atmospheric concentration and tracing sources of DDTs by integrating the use of tree bark with enantiomeric analysis.

Towards improved comparability of studies addressing atmospheric concentrations of semivolatile organic compounds based on their sequestration in pine needles

Coniferous needles can be used as a passive air sampler of semivolatile organic compounds (SVOC) and an indicator of atmospheric pollution patterns and trends. There is limited information on whether different parts of the plant (e.g., foliage leaves, dwarf shoots, twig, etc.) contain different levels of SVOC. Only few studies have compared levels of SVOC surface layer of wax and to their total content in all needle tissues and what affects an uptake and distribution of SVOC. It is important to have better understanding of the extent to which sampling and sample preparation procedures affect measured levels of SVOC in pine needles and reduce comparability of data from samples processed in different ways. In the present study, we assessed an impact of various sampling and sample preparation techniques on the levels of SVOC in Pinus sylvestris needles. While the impact of various storing, washing and drying methods was not significant, presence of dwarf shoots in the sample or structural damage of needles affected the results significantly. Results show that levels of SVOC in dwarf shoots are 2-8 times higher than those in foliage leaves. Therefore, dwarf shoots must be carefully removed before foliage leaves extraction to improve comparability of results. There were different patterns in SVOC on the surface of the foliage leaves compared to the whole leaves. An uptake of these substances by the surface wax as well as their occurrence in the internal structure was of function of the physico-chemical properties of the substances (log K_ow, molar weight).

Pesticide residues in nut-planted soils of China and their relationship between nut/soil

Twenty-nine pesticide residues in nut-planted soils from China were investigated. One organophosphate (chlorpyrifos) was detected in 5.3% soils, and the residue levels of 7.2 μg/kg to 77.2 μg/kg. The concentrations of six organochlorines (DDT, HCH, endosulfan, quintozene, aldrin and dieldrin) detected in 78.9% soils were 0.6 μg/kg to 90.1 μg/kg. The residue levels of six pyrethroids (bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) detected in 65.8% soils were 1.5 μg/kg to 884.3 μg/kg. Triadimefon and buprofezin were found in 71.1% and 52.6% samples, respectively, with the corresponding concentrations of 9.8 μg/kg to 193.7 μg/kg and 87.9 μg/kg to 807.4 μg/kg. The multiple residues were found in 76.3% soils. A significant correlation between pesticide residues in nuts and soils was observed, with the correlation coefficient (r) 0.83 (P < 0.001). In addition, the bioconcentration factor (BCF) values for the explanation of pesticides from soils into nuts were ranged from 0.8 to 16.5. The results showed that some pesticides could accumulate in nut by the uptake effect from soil.

Seasonal variation and health risk assessment of organochlorine compounds in urban soils of Novi Sad, Serbia

The aim of this paper was to determine spatial and seasonal variation of 6 indicator polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides (OCPs) in urban soils of Novi Sad, Serbia. Sixty surface soil samples were collected during both winter and summer season, from different types of locations: schools, recreational areas, residential and industrial zones. Samples were treated using the method of accelerated solvent extraction, which allows simultaneous extraction and clean up of PCBs and OCPs. Targeted compounds were analyzed by GC-μECD and confirmed by GC-MS. The total concentrations of studied PCBs varied from <LOD to 18.9 ng g^-1 (mean 2.84 ng g^-1 and median value of 1.21 ng g^-1) in winter and from <LOD to 24.6 ng g^-1 (mean 3.27 ng g^-1 and median value of 1.60 ng g^-1) in summer. Regarding the OCPs analyzed, dichlorodiphenyltrichloroethanes (DDTs) were only detected in both seasons. The total concentration of DDTs ranging from <LOD to 86.3 ng g^-1 (mean 7.57 ng g^-1 and median value of 1.87 ng g^-1) in summer and from <LOD to 182 ng g^-1 (mean 15.6 ng g^-1 and median value of 3.15 ng g^-1) in winter. There were no significant difference between seasons for studied PCBs and DDTs. Spatial distribution of PCBs and DDTs were also evaluated using Arc GIS. Additional, principle component analysis was performed to evaluate relationships between PCBs, DDTs and soil characteristics. Positive correlation was observed among p,p'-DDE, p,p'-DDD and organic matter. The total lifetime carcinogenic risk indicated that the lifetime cancer risk was acceptable.

Assessment of DDT and Metabolites in Soil and Sediment of Potentially Contaminated Areas of Belém, Amazon Region, Brazil

The aim of this study was to evaluate the distribution of DDT and metabolites in surface soils and soil profiles from two areas containing deposits of obsolete pesticides in Belém, Amazon Region, Brazil. DDT and metabolites were extracted by microwave assisted extraction and analyzed by gas chromatography with electron capture detection. Concentrations of total DDT in surface soil samples ranged from 64.22 mg kg^-1 in area 1 (A1) to 447.84 mg kg^-1 in area 2 (A2). Lower levels were found in soil profiles than at the surface (6.21-21.17 mg kg^-1 in A1 and 36.13-113.66 mg kg^-1 in A2). pp'-DDT, pp'-DDE and pp'-DDD were detected in sediments at levels of 2.01, 0.96 and 0.35 mg kg^-1, respectively. The ratio (DDE + DDD)/ΣDDT was low indicating the recent introduction of DDT to the environment in the two study areas, through the volatilization and atmospheric deposition of the obsolete pesticides.

Organochlorine pesticides in tree bark and human hair in Yunnan Province, China: Concentrations, distributions and exposure pathway

The concentrations and distributions of organochlorine pesticides (OCPs) in West China were investigated and internal and external exposure of humans to OCPs were assessed by analyzing samples of human hair and tree bark collected in Kaiyuan, in Yunnan Province, China. Dichlorodiphenyltrichloroethane and its metabolites (collectively called DDTs), hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB) were the dominant OCPs in the human hair and tree bark samples. The mean total DDT, total HCH, and HCB concentrations in the tree bark samples were 298pg/g dry weight (dw), 100pg/g dw, and 183pg/g dw, respectively, and the mean total DDT, total HCH, and HCB concentrations in the hair samples were 2850pg/g dw, 348pg/g dw, and 1026pg/g dw, respectively. The results indicated that relatively new DDT and lindane inputs have occurred in the study area. DDT and lindane may have been released in products that are used locally. The HCB in the environment in the study area is mainly supplied by long-range atmospheric transport. External exposure was found to be the main factor controlling the p,p'-DDT, γ-HCH, and HCB concentrations in human hair, whereas p,p'-DDE and β-HCH were found to be mainly controlled by internal exposure.

Occurrence, profile and spatial distribution of organochlorines pesticides in soil of Nepal: Implication for source apportionment and health risk assessment

Nepal is a landlocked country located between world's two most populous countries-India and China where high level of organochlorines pesticides has been reported from multi-environmental matrices. In this study, we investigated the occurrence, distributions and profile of selected OCP chemicals in surface soil samples (N=72) from four major cities of Nepal. Overall, the sum of total OCPs in soil ranged from 20 to 250ng/g with Biratnagar being the most polluted site in Nepal. DDTs and endosulfans were the most abundant OCP chemicals in soil samples. The concentration of DDTs ranged from 8 to 230ng/g, 8-56ng/g, 8-63ng/g, and 8-27ng/g in surface soil, while endosulfans were in the range of 2.9-3.3ng/g, 2.8-8.7ng/g, 2.8-3.4ng/g, 2.8-3.2ng/g in Biratnagar, Kathmandu, Pokhara and Birgunj, respectively. The isomeric ratio of DDT and their metabolites suggested the ongoing usages of technical DDT as well as dicofol in this region. Lower ratio of α/β-endosulfan indicated past application of endosulfans in Nepal. HCHs were less detected OCPs in soil sample accounting only 4-9% of ∑OCPs. The isomeric ratio of α-/γ-HCH indicated that the HCHs may be originated from mixed source of technical HCH as well as lindane use. Scattered plot of TOC and BC showed they were weakly and positively related with concentration of OCPs in soil. Health risk assessment modeling study of OCPs in soil suggested moderate cancer risk with ingestion being the most potential pathway of OCPs exposure.

Local organochlorine pesticide concentrations in soil put into a global perspective

In this work, agricultural and background soil concentrations of p,p'-DDT, p,p'-DDE, HCB, α-, β- and γ-HCH from 1993 to 2012 were collected from 73 peer-reviewed publications, and analysed statistically. For the period 2003-2012 and for all chemicals, the mean concentration in agricultural soil is significantly higher than the concentration in background soil. In addition to the statistical analysis, concentrations of p,p'-DDT and α-HCH in soils were calculated with a global environmental fate and transport model. A decrease in the mean soil concentration from the first decade to the second was observed with the model, but this decrease is not visible in the measured concentrations, which could result from ongoing use of p,p'-DDT and α-HCH Furthermore, modelled background soil concentrations are generally lower than measurements. This implies that background soil may have received p,p'-DDT and α-HCH through additional routes not described by the model such as spray drift.

Comparison of the complete genome sequences of four γ-hexachlorocyclohexane-degrading bacterial strains: insights into the evolution of bacteria able to degrade a recalcitrant man-made pesticide

γ-Hexachlorocyclohexane (γ-HCH) is a recalcitrant man-made chlorinated pesticide. Here, the complete genome sequences of four γ-HCH-degrading sphingomonad strains, which are most unlikely to have been derived from one ancestral γ-HCH degrader, were compared. Together with several experimental data, we showed that (i) all the four strains carry almost identical linA to linE genes for the conversion of γ-HCH to maleylacetate (designated “specific” lin genes), (ii) considerably different genes are used for the metabolism of maleylacetate in one of the four strains, and (iii) the linKLMN genes for the putative ABC transporter necessary for γ-HCH utilization exhibit structural divergence, which reflects the phylogenetic relationship of their hosts. Replicon organization and location of the lin genes in the four genomes are significantly different with one another, and that most of the specific lin genes are located on multiple sphingomonad-unique plasmids. Copies of IS6100, the most abundant insertion sequence in the four strains, are often located in close proximity to the specific lin genes. Analysis of the footprints of target duplication upon IS6100 transposition and the experimental detection of IS6100 transposition strongly suggested that the IS6100 transposition has caused dynamic genome rearrangements and the diversification of lin-flanking regions in the four strains.

Concentrations and distributions of polybrominated diphenyl ethers and novel brominated flame retardants in tree bark and human hair from Yunnan Province, China

The concentrations and distributions of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in tree bark and hair samples from the same area in Yunnan Province, China, were determined. The total PBDE and NBFR concentrations in the tree bark samples were 3.8 ng/g lipid weight to 91 ng/g lipid weight and 0.23 ng/g lipid weight to 5.0 ng/g lipid weight, respectively. The total PBDE and NBFR concentrations in the hair samples were 2.1 ng/g dry weight to 14 ng/g dry weight and 0.083 ng/g dry weight to 0.29 ng/g dry weight, respectively. Decabromodiphenyl ether had similar distributions in the tree bark and hair samples, but other PBDE congeners and NBFRs had different distributions in the tree bark and hair samples. External exposure was found to be mainly responsible for the total PBDE and pentabromotoluene concentrations in hair, but both external and internal exposure were responsible for the pentabromophenyl and hexabromobenzene concentrations in hair.

Distribution and risk assessment of selected organochlorine pesticides in Kyzyl Kairat village from Kazakhstan

Concentrations of selected organochlorine pesticides (OCPs), i.e., 4,4'-dichlorodiphenyltrichloroethane (p,p'-DDT), its metabolites (p,p'-DDE, p,p'-DDD), and hexachlorocyclohexanes (HCHs), have been determined in 100 soil samples collected from a contaminated site centered around a former storehouse in the Kyzyl Kairat village, Almaty region, Kazakhstan, which constitutes an exemplary case example. The OCPs were observed in all analyzed soil samples, with predominance of α-HCH, p,p'-DDD, p,p'-DDE, and p,p'-DDT. Total concentrations ranged from 1.38 to 11,100 μg kg(-1) with an average value of 1040 μg kg(-1) for DDT and its metabolites and 0.1 to 438 μg kg(-1) with an average value of 24 μg kg(-1) for HCHs. The observed concentrations of the OCPs were found to be in agreement with previous studies and are rationalized in terms of the possible degradation pathways of DDTs and HCHs. Spatial distribution patterns of OCPs are elucidated by contour maps. Observed concentrations of the OCPs were used to evaluate the cancer risk to humans via ingestion, dermal contact, and inhalation of soil particles. The cancer risk mainly occurs from ingestion, whereas dermal exposure contributes to a minor extent to the total cancer risk. The risk associated with inhalation was found to be negligible. The total cancer risk for the studied OCPs were found to be p,p'-DDT ˃ p,p'-DDE ˃ p,p'-DDD ˃ α-HCH ˃ β-HCH ˃ γ-HCH.

Pesticides in persimmons, jujubes and soil from China: Residue levels, risk assessment and relationship between fruits and soils

Extreme and uncontrolled usage of pesticides produces a number of problems for vegetation and human health. In this study, the existence of organophosphates (OPs), organochlorines (OCs), pyrethroids (PYs) and fungicides (FUs) were investigated in persimmons/jujubes and their planted soils, which were collected from China. One OP (dimethoate), three OCs (DDT, quintozene and aldrin), six PYs (bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) and two FUs (triadimefon and buprofezin) were found in 36.4% of persimmons and 70.8% of jujubes, with concentrations from 1.0 μg/kg to 2945.0 μg/kg. The most frequently detected pesticides in the two fruits were fenpropathrin in persimmons and cypermethrin in jujubes, with the detection frequencies of 30.0% and 22.7%, respectively. The residues of 4.5% (persimmon) and 25.0% (jujube) of samples were higher than the maximum residue limits (MRLs) of China. Compared with the fruits, more types of pesticides and higher residues were observed in their planted soils. The most frequently detected pesticides were HCH in persimmon soil and DDT in jujube soil, with the detection frequencies of 10.9% and 12.7%, respectively. For the tested samples, 39.1% of fruit samples and 63.0% of soil samples with multiple residues (containing more than two pesticides) were noted, even up to 8 residues in fruits and 14 residues in soils. Except for cyhalothrin, the other short-term risks for the tested pesticides in the fruits were below 10%, and the highest long-term risk was 14.13% for aldrin and dieldrin. There was no significant health risk for consumers via consumption of the two fruits.

Occurrence of organochlorine pesticides in the environmental matrices from King George Island, west Antarctica

Antarctica is considered as a final sink of many persistent organic pollutants (POPs). This work aims to investigate the levels, distributions and potential sources of organochlorine pesticides (OCPs) with HRGC/HRMS technique. Twenty-three OCPs were measured in various environmental matrices from King George Island, west Antarctica. The total concentrations (Σ23OCPs) were at quite low levels, ranging 93.6-1260 pg g(-1) dry weight (dw) in soil and sediment, 223-1053 pg g(-1) dw in moss and 373-812 pg g(-1) dw in lichen. Hexachlorobenzene (HCB), dichloro-diphenyl-trichloroethane (DDT) and its metabolites (especially p,p'-DDE) and hexachlorocyclohexanes (HCHs) were the main contaminants in all samples. Lower α-HCH/γ-HCH and higher p,p'-DDE/p,p'-DDT ratios compared with the technical products indicated long-range atmospheric transport (LRAT) of recent lindane and aged technical DDT. Significant dependence of many OCPs concentrations on total organic carbon (TOC) was observed. Apart from LRAT, local biotic activities could also contribute and influence the spatial distribution of the contaminants.

Tree bark as a biomonitor for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers from Southern Jiangsu, China: levels, distribution, and possible sources

Tree bark was used as the passive air sampler to evaluate polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) pollution and possible sources in Southern Jiangsu. The concentrations of PCBs and Σ7PBDEs were in the range of 0.58-5.19 ng/g dry weight (dw; mean 1.79 ng/g dw) and 17.9-243 pg/g dw (mean 74.7 pg/g dw), respectively. Tri-PCBs were the major PCB homologs, and technical PCB product Ar1242 was identified as the main source. BDE209 concentrations (4.29-456 ng/g dw) were relatively high, indicating that BDE209 pollution was serious in this region. The deca-BDE commercial mixture was the predominant commercial PBDE product used in this region. A good correlation was found between tree bark and polyurethane foam (PUF) disks in Σ6PCB monitoring, suggesting that both of them respond well to the gas-phase PCB monitoring.

Polybrominated diphenyl ethers (PBDEs) in herbaceous Centaurium erythraea affected by various sources of environmental pollution

Polybrominated diphenyl ethers (PBDEs) are persistent xenobiotics with harmful effects on humans and wildlife. Their levels in the environment and accumulation in biota must be carefully controlled especially in species harvested from wild populations and commonly used as medicines. Our objective has been to determine PBDE concentrations (BDEs 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209) in Centaurium erythraea collected at sites with various levels of environmental pollution. PBDE congener profiles in C. erythraea were dominated by BDE209, which accounted for 47-89% of the total PBDE burden in the plants. Principal Component and Classification Analysis, which classifies the concentration of PBDEs in C. erythraea, allowed us to distinguish the pattern of these compounds characteristic for the origin of pollution: BDEs 28, 47, 66, 85, 99, 100 for lignite and general chemical industry and the vicinity of an expressway and BDEs 183 and 209 for a thermal power plant and ferrochrome smelting industry. Careful selection of sites with C. erythraea for medicinal purposes is necessary as this herb can accumulate PBDEs while growing at polluted sites.

Lichen, moss and soil in resolving the occurrence of semi-volatile organic compounds on the southeastern Tibetan Plateau, China

This study investigated a wide range of semi-volatile organic compounds (SVOCs), including 28 persistent organochlorine pesticides (OCPs), 18 polychlorinated biphenyls (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCD) congeners in lichen, moss and soil collected from the southeastern Tibetan Plateau, China. This allows research provides insight into elevation gradient distributions and possible cold trapping effects of SVOCs in this high mountain area, and compares lichens and mosses as air passive samplers for indicating SVOC occurrences. DDTs, endosulfans, HCHs and hexachlorobenzene predominated in all of the samples. Source analysis indicted that there were fresh inputs of DDTs and HCHs in the sampling region. Lichens and mosses shared commonalities in revealing the profiles and levels of SVOCs based on their lipid-content-normalized concentrations. The concentrations of 12 OCPs and 14 PCBs in lichens were significantly linearly correlated with altitudes, whereas the correlations for mosses and soil with altitudes were insignificant. Both a frequency distribution diagram and the Mountain Contamination Potential Model indicated that SVOCs with specific values of log KOA (8-11) and log KWA (2-4) had relative high mountain contamination potential on the Tibetan Plateau.

Distribution and transfer pattern of Polychlorinated Biphenyls (PCBs) among the selected environmental media of Ny-Ålesund, the Arctic: As a case study

Polychlorinated Biphenyls (PCBs) were analyzed in multi-environmental samples collected from Ny-Ålesund, the Arctic to explore their legacy and transfer patterns. PCBs were ubiquitously in the environmental media, within the ranges of 1.73-6.27 and 9.18-141.1 pg m(-3) in vapor and aerosol, 2.76-10.8, 3.09-8.32, 22.5-56.3, 35.4-51.4 and 31.8-39.6 ng g(-1) (dry weight) in soil, sediment, plant, bird guano and reindeer faeces, respectively. The spatial distribution patterns exhibited a general southward decline in soil and sediment from the bay entrance to the inner bay. The concentration ratios of plants to soil inferred that no distinguished selective adsorption of PCBs congeners by plants existed and PCBs were mainly attributed to the air deposition on plant surface. The fugacity ratios among vapor, aerosol and soil indicted that the equilibrium status has not been reached and the net transferring direction was air-soil.

Chiral signature of α-HCH and o,p'-DDT in the soil and grass of the Central Tibetan Plateau, China

Enantiomeric fraction (EF) of organochlorine pesticides (OCPs) has been used as a signature for tracing the source and following pathways. The chiral analysis was performed for α-HCH and o,p'-DDT in paired soil and grass samples from the Central Tibetan Plateau (CTP), a unique background region. In the case of α-HCH, excess of (-) α-HCH was predominant in 83.3% of soil samples, and 80% of grass samples showed excess of (+) enantiomer. For o,p'-DDT, 90.9% of grass samples showed excess of (-) o,p'-DDT while 50% of soil samples showed excess of the (-) enantiomer. A correlation between EFs of soil and grass was not observed for either compound. The EFs of both compounds were correlated with soil concentration and with change of sampling altitude, within EFs being lower than racemic. However, these trends were not found in grass. Our study provides a database of EFs and signatures for OCPs in the CTP, one background region of the world.

Hexachlorocyclohexanes in tree bark across Chinese agricultural regions: spatial distribution and enantiomeric signatures

The environmental issue caused by atmospheric hexachlorocyclohexanes (HCHs) has been a worldwide concern due to their long-range transport potential. Tree bark is an excellent passive sampler for monitoring atmospheric pollutants. In this study, bark samples from agricultural regions across China were collected and analyzed to elucidate the contamination status of atmospheric HCHs and the enantiomeric composition of chiral α-HCH. Average contents of α-HCH, β-HCH, γ-HCH, δ-HCH, and ∑HCHs in bark were 1.16, 2.51, 1.67, 0.368, and 5.71 ng/g (dry basis), respectively. Jing-Jin-Tang region was identified as the "hot-spot" of bark HCHs in China. Their residues were likely from the combined sources of historical applications of technical HCHs and lindane through long-distance transport. HCH contents were found inversely correlated with annual precipitation and temperature, but positively correlated with PM10 or PM2.5 due to the bioaccumulation of both vapor- and particle-phase HCHs by tree bark. Most bark samples preferentially accumulated (+)-α-HCH, and the enantiomeric fractions (EFs) of α-HCH were positively correlated with α-HCH concentrations and the elevations of sampling locations. Compared to atmospheric analysis, tree bark analysis and enantiomeric signatures provide valuable time-integrated information on the spatial distribution and transport pathways of atmospheric HCHs on the national scale in China.

Air is still contaminated 40 years after the Michigan Chemical plant disaster in St. Louis, Michigan

The Michigan Chemical (also known as Velsicol Chemical) plant located in St. Louis, Michigan operated from 1936-1978. During this time, the plant manufactured polybrominated biphenyls (PBBs), hexabromobenzene (HBB), 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), and tris(2,3-dibromopropyl) phosphate (TDBPP), among other products. Due to widespread PBB contamination of Michigan, the plant eventually became a Superfund site, and despite years of cleanup activities, many of the compounds can still be found in the local ecosystem. To investigate the current atmospheric levels and to determine their spatial distributions, we collected tree bark samples from around Michigan and measured the concentrations of these pollutants. For comparison, other organic pollutants, such as polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs), which were not manufactured at the Michigan Chemical plant, were also measured in the same tree bark samples. Our results show levels of PBBs, DDT, and HBB in tree bark collected within 10 km of the Velsicol Superfund site (43, 477, and 108 ng/g lipid wgt., respectively) are 1-2 orders of magnitude higher than at sites located more than 10 km from the site (0.36, 28, and 0.36 ng/g lipid wgt., respectively). Levels of PBDEs and OPEs did not depend on distance from St. Louis. This is the first study on the atmospheric distribution of these chemicals around the Superfund site.

Biomonitoring persistent organic pollutants in the atmosphere with mosses: performance and application

Persistent organic pollutants (POPs) have aroused environmentalists and public concerns due to their toxicity, bioaccumulation and persistency in the environment. However, monitoring atmospheric POPs using conventional instrumental methods is difficult and expensive, and POP levels in air samples represent an instantaneous value at a sampling time. Biomonitoring methods can overcome this limitation, because biomonitors can accumulate POPs, serve as long-term integrators of POPs and provide reliable information to assess the impact of pollutants on the biota and various ecosystems. Recently, mosses are increasingly employed to monitor atmospheric POPs. Mosses have been applied to indicate POP pollution levels in the remote continent of Antarctica, trace distribution of POPs in the vicinity of pollution sources, describe the spatial patterns at the regional scale, and monitor the changes in the pollution intensity along time. In the future, many aspects need to be improved and strengthened: (i) the relationship between the concentrations of POPs in mosses and in the atmosphere (different size particulates and vapor phases); and (ii) the application of biomonitoring with mosses in human health studies.