Spatial And Temporal Trends Of Organic Pollutants In Vegetation From Remote And Rural Areas

Combining Spatial, Genetic, and Environmental Risk Data to Define and Prioritize In Situ Conservation Units

In situ management aims to preserve species and their genetic integrity within their natural habitat. To achieve this, conservation strategies must strike a balance between safeguarding genetic diversity, mitigating environmental risks, and addressing practical management constraints. Here, we present a clear and reproducible framework that addresses these goals. We applied this framework to the Nightcap reserves in the Gondwanan Rainforests of Australia, a UNESCO World Heritage site impacted by the 2019/20 Black Summer fires. We analyzed the genetic diversity of 12 rainforest tree species, including three endangered species-Eidothea hardeniana, Uromyrtus australis, and Elaeocarpus sedentarius-and examined how fire risk, influenced by the presence of fire-dependent species such as eucalypts, impacts genetic diversity. To guide specific in situ management for the endangered species, we developed a flexible framework that uses clustering algorithms (DBSCAN and k-means) to define spatial management units while considering resource limitations (e.g., maximum perimeter or area). Our framework also incorporates a composite genetic value metric (combining Essential Biodiversity Variables heterozygosity, allelic richness, and genetic differentiation) and evaluates future fire risk based on vegetation flammability. This approach allowed us to identify priority management areas while adhering to resource constraints. We provide some reproducible examples of how the proposed framework can be applied, either partially or fully, to optimize in situ conservation efforts. Its flexibility allows for adjustments to fit different habitat types, species, and environmental threats, making it a valuable tool for enhancing conservation management across diverse conservation contexts.

Fungal endophytes modulate the negative effects induced by Persistent Organic Pollutants in the antarctic plant Colobanthus quitensis

Antarctica has one of the most sensitive ecosystems to the negative effects of Persistent Organic Pollutants (POPs) on its biodiversity. This is because of the lower temperatures and the persistence of POPs that promote their accumulation or even biomagnification. However, the impact of POPs on vascular plants is unknown. Moreover, fungal symbionts could modulate the effects on host plants to cope with this stress factor. This study investigates the molecular and ecophysiological responses of the Sub-Antarctic and Antarctic plant Colobanthus quitensis to POPs in different populations along a latitudinal gradient (53°- 67° S), emphasizing the role of endophytic fungi. The results show that exposure of POPs in C. quitensis generates oxidative stress and alters its ecophysiological performance. Nevertheless, C. quitensis in association with fungal endophytes and POPs exposure, shows lower lipid peroxidation, higher proline content and higher photosynthetic capacity, as well as higher biomass and survival percentage, compared to plants in the absence of fungal endophytes. On the other hand, the antarctic plant population (67°S) with endophytic fungi presents better stress modulating upon POPs exposure. Endophytic fungi would be more necessary for plant performance towards higher latitudes with extreme conditions, contributing significantly to their general functional adaptation. We develop a transcriptomics analyses n the C. quitensis-fungal endophytes association from the Peninsula population. We observed that fungal endophytes promote tolerance to POPs stress through upregulated genes for the redox regulation based on ascorbate and scavenging mechanisms (peroxidases, MDAR, VTC4, CCS), transformation (monooxygenases) and conjugation of compounds or metabolites (glutathione transferases, glycosyltransferases, S-transferases), and the storage or elimination of conjugates (ABC transporters, C and G family) that contribute to detoxification cell. This work highlights the contribution of endophytic fungi to plant resistance in situations of environmental stress, especially in extreme conditions such as in antarctica exposed to anthropogenic impact. The implications of these findings are relevant for the biosecurity of one of the last pristine bastions worldwide.

Background of persistent organic pollutants in estuarine sediments from the Marajó Island, an Amazonian environmental protection area for sustainable use

Marajó Island, an environmental protection area for sustainable use in the Brazilian Amazon, was the first region in Brazil to apply the pesticide DDT, a persistent organic pollutant (POP), to control malaria outbreaks. This study investigated background levels of various POPs, including o,p'- and p,p'-DDT and their primary metabolites (o,p'- and p,p'-DDE, o,p'- and p,p'-DDD), as well as hexachlorocyclohexane (α-, β-, γ-, δ-HCH), using estuarine surface sediments and sediment cores from areas influenced by urbanization and agriculture. All samples were collected during the dry season (September 2014). Surface sediments exhibited ΣDDT concentrations up to 2.71 ng g⁻1, with isomeric ratios indicating past DDT application and contributions from dicofol. Sediment profiles revealed alternating aerobic and anaerobic degradation processes of DDT. Other organochlorinated contaminants were not detected. The presence of γ-HCH as the main isomer (0.24 to 0.90 ng g⁻1) in surface samples suggests recent lindane application as a wood preservative or cattle parasite treatment. A dated sediment core revealed historical contamination of early DDT tests in the Amazon during the mid-1940s. Increasing ΣDDT concentrations (up to 12.3 ng g⁻1) were identified in the 1970s, coinciding with the intensification of DDT use for public health campaigns, which lasted until 2009 and reached the highest ΣDDT flux. Legal restrictions on the use and commercialization of POPs, along with natural degrading processes, likely led to decreased accumulation and limited ecological risks. Furthermore, the low concentrations of POPs suggested biodegradation and dispersion from northeast to southeast.

Is Physical Activity an Efficient Strategy to Control the Adverse Effects of Persistent Organic Pollutants in the Context of Obesity? A Narrative Review

Obesity affects nearly 660 million adults worldwide and is known for its many comorbidities. Although the phenomenon of obesity is not fully understood, science regularly reveals new determinants of this pathology. Among them, persistent organic pollutants (POPs) have been recently highlighted. Mainly lipophilic, POPs are normally stored in adipose tissue and can lead to adverse metabolic effects when released into the bloodstream. The main objective of this narrative review is to discuss the different pathways by which physical activity may counteract POPs' adverse effects. The research that we carried out seems to indicate that physical activity could positively influence several pathways negatively influenced by POPs, such as insulin resistance, inflammation, lipid accumulation, adipogenesis, and gut microbiota dysbiosis, that are associated with the development of obesity. This review also indicates how, through the controlled mobilization of POPs, physical activity could be a valuable approach to reduce the concentration of POPs in the bloodstream. These findings suggest that physical activity should be used to counteract the adverse effects of POPs. However, future studies should accurately assess its impact in specific situations such as bariatric surgery, where weight loss promotes POPs' blood release.

Major latex-like proteins show pH dependency in their binding to hydrophobic organic pollutants

The Cucurbitaceae family accumulates hydrophobic organic pollutants in its aerial parts at high concentrations. Major latex-like proteins (MLPs) were identified in zucchini (Cucurbita pepo) as a transporting factor for hydrophobic organic pollutants. MLPs bind to hydrophobic organic pollutants in the roots, are secreted to xylem vessels as complexes, and are transported to the aerial parts. However, the suitable conditions for binding MLPs to hydrophobic organic pollutants remain elusive. In the present study, we show that MLPs bind to the hydrophobic organic pollutant pyrene with higher affinity under acidic conditions. Our results demonstrated that pH regulates the binding of MLPs to hydrophobic organic pollutants.

Role of Microbes in the degradation of organic semivolatile compounds in polar ecosystems: A review

The Arctic and the Antarctic Continent correspond to two eco-regions with extreme climatic conditions. These regions are exposed to the presence of contaminants resulting from human activity (local and global), which, in turn, represent a challenge for life forms in these environments. Anthropogenic pollution by semi-volatile organic compounds (SVOCs) in polar ecosystems has been documented since the 1960s. Currently, various studies have shown the presence of SVOCs and their bioaccumulation and biomagnification in the polar regions with negative effects on biodiversity and the ecosystem. Although the production and use of these compounds has been regulated, their persistence continues to threaten biodiversity and the ecosystem. Here, we summarize the current literature regarding microbes and SVOCs in polar regions and pose that bioremediation by native microorganisms is a feasible strategy to mitigate the presence of SVOCs. Our systematic review revealed that microbial communities in polar environments represent a wide reservoir of biodiversity adapted to extreme conditions, found both in terrestrial and aquatic environments, freely or in association with vegetation. Microorganisms adapted to these environments have the potential for biodegradation of SVOCs through a variety of genes encoding enzymes with the capacity to metabolize SVOCs. We suggest that a comprehensive approach at the molecular and ecological level is required to mitigate SVOCs presence in these regions. This is especially patent when considering that SVOCs degrade at slow rates and possess the ability to accumulate in polar ecosystems. The implications of SVOC degradation are relevant for the preservation of polar ecosystems with consequences at a global level.

Analysis of water quality indexes and their relationships with vegetation using self-organizing map and geographically and temporally weighted regression

Natural vegetation has been proved to promote water purification in previous studies, while the relevant laws has not been excavated systematically. This research explored the relationships between vegetation cover and water quality indexes in Liaohe River Basin in China combined with self-organizing map (SOM) and geographically and temporally weighted regression (GTWR) innovatively and systematically based on the distributing heterogeneity of water quality conditions. Results showed that the central and northeast regions of the study area had serious organic and nutrient pollution, which needed targeted treatment. And SOM verified that high vegetation coverage with retention potential of organic and inorganic pollutants as well as nutrients improved water quality to some degree, while the excessive discharges of pollutants still had serious threats to nearby water environment despite the purification function of vegetation. GTWR indicated that the waterside vegetation was beneficial for dissolved oxygen increasing and contributed to the decreasing of organic pollutants and inorganic pollutants with reducibility. Natural vegetation also obsorbed nutrients like TN and TP to some degree. However, the retential potential of nitrogen and organic pollutants became not obvious when there were heavy pollution, which demonstrated that pollution sources should be controlled despite the purification function of vegetation. This study implied that natural vegetation purified water quality to some degree, while this function could not be revealed when there was too heavy pollution. These findings underscore that the pollutant discharge should be controlled though the natural vegetation in ecosystem promoted the purification of water bodies.

Accumulations and temporal trends of polychlorinated biphenyls (PCBs) in olive tree components

In this study, ambient air samples, olive tree branches (1- and 2-year-old) and their leaves (particulate and dissolved phase) were collected simultaneously between January and December months at a suburban site of Bursa-Turkey. Total polychlorinated biphenyl (PCB) concentrations, sampled by employing passive air samplers, ranged from 0.03 to 0.08 ng/m³ in the atmosphere. The average annual total PCB concentrations belonging to the tree components were 1.14 ± 0.32 ng/g DM in dissolved phase in leaves, 0.71 ± 0.32 ng/g DM in particle phase on leaves, 1.06 ± 0.25 ng/g DM in 1-year-old branches, and 0.93 ± 0.23 ng/g DM in 2-year-old branches. It was determined that the correlation between PCB concentrations in olive tree components and the air was low. This result indicated that besides the tree-air exchange, other possible factors (such as soil-to-tree transitions, wind effect, etc.) affect the levels of PCB concentrations in the tree components. Total PCB concentrations decreased from summer to winter in all samples. The percentage ratio of PCB in the dissolved phase in the leaves was generally higher than other tree components in seasons. PCB homologous distributions indicated 5-CBs were dominant in the tree components and 3-CBs were dominant in the air samples. Highly chlorinated PCB congeners (8-CBs and 9-CBs) were found at low concentrations in both air and tree components samples. The samples indicated that the ratio of PCBs in tree components to the total (tree component+ambient air) PCBs slightly increased with increasing the chlorine number.

Genome-wide identification and characterization of major latex-like protein genes responsible for crop contamination in Cucurbita pepo

BACKGROUND

Zucchini plants (Cucurbita pepo) accumulate persistent organic pollutants (POPs) at high concentrations in their aerial parts, and major latex-like proteins (MLPs) play crucial roles in their accumulation. MLPs bind to POPs in root cells, MLP-POP complexes are then translocated into xylem vessels, and POPs are transported to the aerial parts. We previously identified three CpMLP genes (MLP-PG1, MLP-GR1, and MLP-GR3) as transporting factors for POPs; however, other studies have shown that the genomes of several plant species contain more than 10 MLP genes, thus, further MLP genes responsible for POP accumulation may have been overlooked.

METHODS AND RESULTS

Here, we investigated the number of CpMLP genes by performing a hidden Markov model search against the C. pepo genome database and characterized their effects on POP accumulation by performing the expression analysis in the organs and in silico structural analysis. The C. pepo genome contained 21 CpMLP genes, and several CpMLP genes, including MLP-PG1 and MLP-GR3, were highly expressed in roots. 3D structural prediction showed that all examined CpMLPs contained a cavity with a hydrophobic region, which facilitated binding to POPs.

CONCLUSIONS

The present study provides insights regarding CpMLP genes responsible for POP accumulation.

Identifying emerging environmental concerns from long-chain chlorinated paraffins towards German ecosystems

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C_10-13), but also the current-use medium- and long-chain products (MCCPs, C_14-17; LCCPs, C_>17) as well as the very-short-chain impurities (vSCCPs, C_<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Selection of Endophytic Strains for Enhanced Bacteria-Assisted Phytoremediation of Organic Pollutants Posing a Public Health Hazard

Anthropogenic activities generate a high quantity of organic pollutants, which have an impact on human health and cause adverse environmental effects. Monitoring of many hazardous contaminations is subject to legal regulations, but some substances such as therapeutic agents, personal care products, hormones, and derivatives of common organic compounds are currently not included in these regulations. Classical methods of removal of organic pollutants involve economically challenging processes. In this regard, remediation with biological agents can be an alternative. For in situ decontamination, the plant-based approach called phytoremediation can be used. However, the main disadvantages of this method are the limited accumulation capacity of plants, sensitivity to the action of high concentrations of hazardous pollutants, and no possibility of using pollutants for growth. To overcome these drawbacks and additionally increase the efficiency of the process, an integrated technology of bacteria-assisted phytoremediation is being used recently. For the system to work, it is necessary to properly select partners, especially endophytes for specific plants, based on the knowledge of their metabolic abilities and plant colonization capacity. The best approach that allows broad recognition of all relationships occurring in a complex community of endophytic bacteria and its variability under the influence of various factors can be obtained using culture-independent techniques. However, for practical application, culture-based techniques have priority.

The Research Progress of the Influence of Agricultural Activities on Atmospheric Environment in Recent Ten Years: A Review

In recent years, the industrial emission of air pollution has been reduced via a series of measures. However, with the rapid development of modern agriculture, air pollution caused by agricultural activities is becoming more and more serious. Agricultural activities can generate a large amount of air pollutants, such as ammonia, methane, nitrogen oxides, volatile organic compounds, and persistent organic pollutants, the sources of which mainly include farmland fertilization, livestock breeding, pesticide use, agricultural residue burning, agricultural machinery, and agricultural irrigation. Greenhouse gases emitted by agricultural activities can affect regional climate change, while atmospheric particulates and persistent organic pollutants can even seriously harm the health of surrounding residents. With the increasing threat of agricultural air pollution, more and more relevant studies have been carried out, as well as some recommendations for reducing emissions. The emissions of ammonia and greenhouse gases can be significantly reduced by adopting reasonable fertilization methods, scientific soil management, and advanced manure treatment systems. Regarding pesticide use and agricultural residues burning, emission reduction are more dependent on the restriction and support of government regulations, such as banning certain pesticides, prohibiting open burning of straw, and supporting the recycling and reuse of residues. This review, summarizing the relevant research in the past decade, discusses the current situation, health effects, and emission reduction measures of agricultural air pollutants from different sources, in order to provide some help for follow-up research.

Suppression of the genes responsible for transporting hydrophobic pollutants leads to the production of safer crops

Hydrophobic pollutants have become widely distributed across the world. From an agricultural perspective, their accumulation in crops from contaminated soil threatens food security and quality, leading to many diseases in humans. The Cucurbitaceae family can accumulate high concentrations of hydrophobic pollutants in their aerial parts. The Cucurbitaceae family contains major latex-like proteins (MLPs) as transporting factors for hydrophobic pollutants. MLP genes are expressed in the roots in which the MLPs bind hydrophobic pollutants. MLPs transport these hydrophobic pollutants to the aerial parts of the plant through the xylem vessels. As a result, hydrophobic pollutant contamination occurs in the Cucurbitaceae family. In this study, we suppressed the expression of MLP genes in the roots and reduced the amounts of MLPs with pesticide treatments. First, the fungicides Benlate and Daconil that deceased the hydrophobic pollutant, perylene, concentration in the xylem sap of zucchini plants were selected. Daconil suppressed the transcription activity of MLP in the roots. In the Daconil treatment, the amount of MLPs in the roots and xylem sap of zucchini plants was decreased, and the concentrations of the hydrophobic pollutants, pyrene and dieldrin, were significantly decreased. Our research contributes to the production of safer crops.

Levels of persistent organic pollutants in pine tree components and ambient air

Pine needles are employed as alternative biomonitoring agents in atmospheric studies. In this study, pine (Pinus Pinea) components (needles and branches) and air samples were collected simultaneously to monitor polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from Gemlik, Turkey between January and December 2016. The relationship between ambient air and pine needles were examined to enlighten the usability of pine components as passive samplers for persistent organic pollutants (POPs) in the Marmara region. Average ∑₁₄PAH concentrations for the ambient air, pine needles, and pine branches were 23.1 ± 18.3 ng/m³, 626 ± 306 ng/g DW and 548 ± 261 ng/g DW respectively. PCB concentrations were 118 ± 74 pg/m³, 7.5 ± 2.1 ng/g DW and 6.8 ± 2.9 ng/g DW and ∑₁₀ OCP concentrations were 122 ± 89 ng/m³,1.3 ± 1.5 ng/g DW and 10.0 ± 3.8 ng/g DW in the same order. Levels of PAHs and PCBs were higher in needles than branches. PAH, PCB and OCP concentrations in pine components tended to decrease with increasing temperatures in spring. PAH compounds with medium and light molecular weighted ones were found to be dominant. On the other hand, the predominant PCB components were the medium-weighted congeners while γ-HCH, Heptachlor endo. Epox. Iso A, endrin aldehyde, and methoxychlor were the dominant OCP species.

Biological Traits and the Transfer of Persistent Organic Pollutants through River Food Webs

Freshwater organisms remain at risk from bioaccumulation and biomagnification of persistent organic pollutants (POPs), but factors affecting their transfer through food webs are poorly understood. Here, we investigate transfer pathways of polychlorinated biphenyls, polybrominated diphenyl ethers, and organochlorine through a river food web, assessing the distribution and flux between basal resources (n = 3), macroinvertebrates (n = 22), and fish (n = 1). We investigate the effects of biological traits on the observed patterns and use trait-based models to predict POP bioaccumulation. Transfer pathways differed among POPs and traits such as habitat affinity, feeding behavior, and body size explained some variation in POP burdens between organisms. Trait-based models indicated that relationships between POPs, trophic transfers, and traits were relatively well conserved across a wider array of river food webs. Although providing more consistent predictions of POP bioaccumulation than steady-state models, variability in bioaccumulation across food webs limited the accuracy of trait-model predictions. As some of the first data to illustrate how ecological processes alter the flux of pollutants through river food webs, these results reveal important links between POPs and contrasting energetic pathways. These data also show the utility of trait-based methods in the assessment of persistent contaminants, but further field validations are required.

A Review of Plant Vacuoles: Formation, Located Proteins, and Functions

Vacuoles, cellular membrane-bound organelles, are the largest compartments of cells, occupying up to 90% of the volume of plant cells. Vacuoles are formed by the biosynthetic and endocytotic pathways. In plants, the vacuole is crucial for growth and development and has a variety of functions, including storage and transport, intracellular environmental stability, and response to injury. Depending on the cell type and growth conditions, the size of vacuoles is highly dynamic. Different types of cell vacuoles store different substances, such as alkaloids, protein enzymes, inorganic salts, sugars, etc., and play important roles in multiple signaling pathways. Here, we summarize vacuole formation, types, vacuole-located proteins, and functions.

Evaluation of the airborne pollution by emerging contaminants using bitter orange (Citrus aurantium) tree leaves as biosamplers

In this work, an analytical method has been applied to biomonitor airborne emerging pollutants in urban areas using bitter orange (Citrus aurantium) tree leaves, which is an evergreen species widely extended in the Mediterranean region, as biosampler. Leaves, from trees located in 20 different locations from Seville City (South of Spain) were sampled during one year period. Sampling sites were located in six highly populated areas, in seven lowly populated areas, in six urban parks and in one industrial area. Fifteen of the target compounds were detected in the analysed samples. The highest concentrations corresponded to plasticizers (up to 852ng/g dry matter (dm)) and surfactants (up to 752ng/gdm), especially di(2-ethylhexyl)phthalate and nonylphenol. Spatial distribution allowed assessing the influence of populated areas in the concentration of some of the studied compounds, such as plasticizers and perfluorinated compounds, and the influence of industrial areas, in the concentration of surfactants. No clear influence of the climatic conditions (temperature, solar radiation and rainfall) on the concentrations of studied compounds was observed. This fact could be due to the presence of diffuse sources of these compounds. In the case of the brominated flame retardant, the measured concentrations could be related with two fire episodes in the vicinity, but until now it has not been possible to rigorously demonstrate a causal relationship. This fact could reveal the suitability and valuable use of Citrus aurantium tree leaves for biomonitoring atmospheric pollutants, especially from unexpected emissions in atmospheric pollution episodes.

Exploration of environmental contaminants in honeybees using GC-TOF-MS and GC-Orbitrap-MS

This study reports an analytical approach by gas chromatography and high-resolution mass spectrometry (HRMS) intended to be used for investigation of non-targeted environmental contaminants in honeybees. The approach involves a generic extraction and analysis with two GC-HRMS systems: time-of-flight and Orbitrap analyzers, GC-TOF-MS, and GC-Orbitrap-MS operated in electron-impact ionization (EI) mode. The workflow for screening of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, molecular formula of representative ions (molecular and fragment ions) was provided for those with an accurate mass scoring (error < 5 ppm). This methology was applied for screening environmental contaminants in 75 samples of adult honeybee. This approach has provided the tentative identification of environmental contaminants belonging to different chemical groups, among them, PAHs, phthalates and synthetic musks. Residues of veterinary treatments used in apiculture were also detected in the honeybee samples.

Assessment of POPs in air from Spain using passive sampling from 2008 to 2015. Part I: Spatial and temporal observations of PBDEs

The Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) calls for the Parties' effectiveness evaluation of those measures taken to meet the reduction and eventual elimination of POPs from the environment. With that goal, air concentrations of different POP families have been measured uninterruptedly since 2008 under the Spanish Monitoring Program (SMP) by means of passive air sampling. This work focuses on data for polybrominated diphenyl ethers (PBDEs) determined in a total of 321 samples collected seasonally each year in 5 urban and 7 background sites. Neither significant temporal trends nor significant seasonal variations for total PBDE air burdens were detected. In contrast, significant variations were found among PBDE congeners. Those related to the octa-PBDE formulation significantly decreased in the study period. However, PBDEs related to the penta-formulation showed steady concentrations while PBDE-209, the congener found at the greatest levels, showed increasing or steady levels in most sampling sites. Seasonal variations were also markedly different among congeners. Concentrations of the lightest PBDEs (tri- to penta-substituted) were highly influenced by ambient temperature (T), showing maximum values in summer probably due to higher volatilization rates compared to those of heavier PBDEs. Contrarily, no clear seasonal trends were found for hexa- to deca-PBDEs, which were negatively related to precipitation; thereby, indicating an efficient atmospheric wash out by wet deposition episodes. Regarding spatial patterns, overall significant greater PBDE levels were found in cities compared to background areas, pointing out the role of highly populated areas as sources for these pollutants in Spain. Yet and especially in the case of PBDE-209, our results suggested the presence of significant unknown sources of PBDEs in some background sites. Further monitoring efforts are needed to assess potential unknown sources in the sampling network as well as to ensure temporal trends of these pollutants in Spain.

Vacuolar Transporters for Cadmium and Arsenic in Plants and their Applications in Phytoremediation and Crop Development

Soil contamination by heavy metals and metalloids such as cadmium (Cd) and arsenic (As) poses a major threat to the environment and to human health. Vacuolar sequestration is one of the main mechanisms by which plants control toxic materials including Cd and As. Understanding the mechanisms of heavy metal tolerance and accumulation can be useful for both phytoremediation and safe crop development. In this review, we summarize recent advances in deciphering the molecular mechanisms underlying vacuolar sequestration of Cd and As, and discuss potential biotechnological applications of this knowledge and efforts towards attaining these goals.

Distribution, fate and risk assessment of PAHs in water and sediments from an aquaculture- and shipping-impacted subtropical lake, China

The spatial-temporal distribution of polycyclic aromatic hydrocarbons (PAHs), their source, and potential health risks were determined in overlying water and surface sediments from Chinese Lake Guchenghu, adjacent commercial mitten crab ponds and the connected Wushen Canal to assess the contamination profile of the area. The total PAHs concentrations in sediment and water were 86.7-1790 ng g^-1 dry weight (dw) and 184-365 ng L^-1 in summer and 184-3140 ng g^-1 dw and 410-1160 ng L^-1 in winter. Two- and 3-ring PAHs were the predominant compounds in water, while PAHs with 4-6 rings dominated in the sediment at both upstream and downstream sites. PAHs concentrations in water and sediment correlated significantly. Diagnostic ratios and positive matrix factorization (PMF) analyses indicated a strong influence of pyrogenic sources, principally biomass combustion and vehicle emission, on the concentrations of PAHs. The distribution, source identification, and mean effects range median quotients (mERMQ) analyses suggested that the most contaminated area was located downstream and upstream of the Wushen Canal, followed by Lake Guchenghu and a commercial crab pond area. From an ecological point of view, PAHs posed a potential risk to drinking water sources as the concentrations exceeded the guideline value of 0.05 μg L^-1. The risk posed by sediment PAHs appeared to be low except for the downstream sites, which showed a low to medium ecotoxicological risk. The total incremental lifetime cancer risks ranged between 10^-7 and 10^-5, indicating a potential health risk for the local population when exposed to sediment from the area.

Can coastline plant species be used as biosamplers of emerging contaminants? - UV-filters and synthetic musks as case studies

Personal care products, an important class of emerging contaminants, have been frequently detected in different environmental matrices. Included in this category are synthetic musks compounds (SMCs) and UV-filters. Their occurrence in the coastal environment has been poorly studied. Therefore, this work aimed to verify whether five coastline plant species (Carpobrotus edulis, Cakile maritima, Medicago marina, Elymus farctus borealis-atlanticus and Euphorbia paralias) have the ability to accumulate 11 SMCs (cashmeran, celestolide, phantolide, galaxolide, tonalide, exaltolide, musk moskene, tibetene, ambrette, xylene and ketone) and 2 organic UVB filters (3-(4'-methylbenzylidene) camphor and octocrylene), functioning as biosamplers. To accomplish this task, a QuEChERS technique ("Quick, Easy, Cheap, Effective, Rugged, and Safe") was employed to extract the target compounds from the plant material collected in 15 beaches of Matosinhos and Vila Nova de Gaia (Portugal). The resulting extracts were analysed by gas chromatography-mass spectrometry. Limits of detection ranged from 0.02 ng g^-1 for celestolide and tonalide to 1.32 ng g^-1 for musk ambrette. The obtained recoveries were around 93% and relative standard deviation was generally less than 15%. SMCs were detected at levels ranging from 1.56 to 350 ng g^-1 dw and UV-filters from 2.9 to 264 ng g^-1 dw. Galaxolide and 3-(4'-methylbenzylidene) camphor were the synthetic musk and UV-filter detected in higher concentrations, respectively. Plants with higher water content accumulate better SMCs (hottentot-fig), while those with higher lipid content retain better the UV-filters (sea spurge).

Pharmaceuticals and Personal-Care Products in Plants

Pharmaceuticals and personal-care products (PPCPs) derived from agricultural, urban, and industrial areas accumulate in plants at concentrations (ng to μg kg^-1) that can be toxic to the plants. Importantly, the dietary intake of these PPCP-contaminated plants may also pose a risk to human health, but currently little is known about the fate of PPCPs in plants and their effect on or risk to the ecosystem. In this Opinion article we propose that in-depth research on the use of plants as a monitoring device for assessing the use and environmental presence of PPCPs is warranted. The toxicity of PPCPs to plants and their microbiota needs to be established, as well as any toxic effects on herbivores including humans.

Carboxylesterase-involved metabolism of di-n-butyl phthalate in pumpkin (Cucurbita moschata) seedlings

Uptake and accumulation by plants is a significant pathway in the migration and transformation of phthalate esters (PAEs) in the environment. However, limited information is available on the mechanisms of PAE metabolism in plants. Here, we investigated the metabolism of di-n-butyl phthalate (DnBP), one of the most frequently detected PAEs, in pumpkin (Cucurbita moschata) seedlings via a series of hydroponic experiments with an initial concentration of 10 mg L^-1. DnBP hydrolysis occurred primarily in the root, and two of its metabolites, mono-n-butyl phthalate (MnBP) and phthalic acid (PA), were detected in all plant tissues. The MnBP concentration was an order of magnitude higher than that of PA in shoots, which indicated MnBP was more readily transported to the shoot than was PA because of the former's dual hydrophilic and lipophilic characteristics. More than 80% of MnBP and PA were located in the cell water-soluble component except that 96% of MnBP was distributed into the two solid cellular fractions (i.e., cell wall and organelles) at 96 h. A 13-20% and 29-54% increase of carboxylesterase (CXE) activity shown in time-dependent and concentration-dependent experiments, respectively, indicated the involvement of CXEs in plant metabolism of DnBP. The level of CXE activity in root subcellular fractions was in the order: the cell water-soluble component (88-94%) >> cell wall (3-7%) > cell organelles (3-4%), suggesting that the cell water-soluble component is the dominant locus of CXE activity and also the domain of CXE-catalyzed hydrolysis of DnBP. The addition of triphenyl phosphate, a CXE inhibitor, led to 43-56% inhibition of CXE activity and 16-25% increase of DnBP content, which demonstrated the involvement of CXEs in plant metabolism of DnBP. This study contributes to our understanding of enzymitic mechanisms of PAE transformation in plants.