In Silico Evaluation and Experimental Validation of Interfacial Properties in 3-5 Residue Peptides.

Predicting the interfacial properties of peptides is important for replacing oil-derived surfactants in cosmetics, oil, and agricultural applications. This work validated experimentally the estimations of surface tension at the critical micelle concentration (STCMC) of six peptides performed through a random forest (RF) model in a previous contribution. In silico interfacial tensions of the peptides were obtained in the system decane-water, and dilational experiments were applied to elucidate the foaming potential. The RF model accurately classified the peptides into high and low potential to reduce the STCMC. The simulations at the decane-water interface correctly identified peptides with high, intermediate, and low interfacial properties, and the dilational rheology allowed the estimation of the possible potential of three peptides to produce foams. This study sets the basis for identifying surface-active peptides, but future work is necessary to improve the estimations and the correlation between dilational properties and foam stabilization.

Transcriptome analysis of Acinetobacter calcoaceticus HX09 strain with outstanding crude-oil-degrading ability.

Microbial remediation plays a pivotal role in the elimination of petroleum pollutants, making it imperative to investigate the capabilities of microorganisms in degrading petroleum. The present study describes the isolation of a promising strain, Acinetobacter sp. HX09, from petroleum-contaminated water. GC-MS analysis revealed a remarkable removal efficiency for short and medium-chain alkanes, with a rate of approximately 64% after a 7-days incubation at 30 °C. Transcriptome analysis of HX09 exhibited a predominant upregulation in gene expression levels by the induce of crude oil. Notably, genes such as alkane 1-monooxygenase, dehydrogenases and fatty acid metabolic enzymes exhibited fold changes range from 3.16 to 1.3. Based on the alkB gene sequences in HX09, the Phyre2 algorithm generated a three-dimensional structure that exhibited similarity to segments of acyl coenzyme desaturases and acyl lipid desaturases. Furthermore, three biodegradation-related gene clusters were predicted in HX09 based on the reference genome sequence. These findings contribute to our understanding of the hydrocarbon-degrading mechanisms employed by Acinetobacter species and facilitate the development of effective remediation strategies for crude oil- polluted environments.

The MATH test. A three-phase assay?

This study aimed to investigating the possible interference caused by glass test tubes on the quantification of bacterial adhesion to hydrocarbons by the MATH test. The adhesion of four bacteria to hexadecane and to glass test tubes was evaluated employing different suspending polar phases. The role of the ionic strength of the polar phase regarding adhesion to glassware was investigated. Within the conditions studied, Gram-positive bacteria adhered to both the test tube and the hydrocarbon regardless of the polar phase employed; meanwhile, Escherichia coli ATCC 25922 did not attach to either one. The capacity of the studied microorganisms to adhere to glassware was associated with their electron-donor properties. The ionic strength of the suspending media altered the patterns of adhesion to glass in a strain-specific manner by defining the magnitude of electrostatic repulsion observed between bacteria and the glass surface. This research demonstrated that glass test tubes may interact with suspended bacterial cells during the MATH test under specific conditions, which may lead to overestimating the percentage of adhesion to hydrocarbons and, thus, to erroneous values of cell surface hydrophobicity.

GC-MS-based Metabolomics Unravels Metabolites across Larval Development and Diapause of a Specialist Insect.

Plant-insect interactions are a driving force into ecosystem evolution and community dynamics. Many insect herbivores enter diapause, a developmental arrest stage in anticipation of adverse conditions, to survive and thrive through seasonal changes. Herein, we investigated the roles of medium- to non-polar metabolites during larval development and diapause in a specialist insect herbivore, Chlosyne lacinia, reared on Aldama robusta leaves. Varying metabolites were determined using gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Sesquiterpenes and steroids were the main metabolites putatively identified in A. robusta leaves, whereas C. lacinia caterpillars were characterized by triterpenes, steroids, fatty acids, and long-chain alkanes. We found out that C. lacinia caterpillars biosynthesized most of the identified steroids and fatty acids from plant-derived ingested metabolites, as well as all triterpenes and long-chain alkanes. Steroids, fatty acids, and long-chain alkanes were detected across all C. lacinia instars and in diapausing caterpillars. Sesquiterpenes and triterpenes were also detected across larval development, yet they were not detected in diapausing caterpillars, which suggested that these metabolites were converted to other molecules prior to the diapause stage. Our findings shed light on the chemical content variation across C. lacinia development and diapause, providing insights into the roles of metabolites in plant-insect interactions.

7.1',8.3'- and 7.3',8.5'-Connected Bicyclo[3.2.1]octanoids and Oxabicyclo[3.2.2]nonane-Type Neolignans from Ocotea aciphylla: Structures and Absolute Configurations.

The phytochemical investigation of the leaves and trunk bark of a specimen of Ocotea aciphylla collected in the southern portion of the Amazon forest led to the isolation of an oxabicyclo[3.2.2]nonane-type neolignan and 15 bicyclo[3.2.1]octanoid neolignans, 14 of which are unreported compounds (2-15), including one with an unusual oxidation pattern of the side chain at C-1' and two rare 7.1',8.3'-connected bicyclo[3.2.1]octanoid derivatives. Their structures and relative configurations were determined by extensive spectrometric analysis based on 1D- and 2D-NMR spectroscopy and HRESIMS data, while their absolute configurations were unambiguously assigned using electronic and vibrational circular dichroism data assisted by density functional theory calculations. Additionally, known sesquiterpenes, phenylpropanoids, and phytosterols were also isolated.

Observations of ozone, acyl peroxy nitrates, and their precursors during summer 2019 at Carlsbad Caverns National Park, New Mexico.

Carlsbad Caverns National Park (CAVE) is located in southeastern New Mexico and is adjacent to the Permian Basin, one of the most productive oil and natural gas (O&G) production regions in the United States. Since 2018, ozone (O3) at CAVE has frequently exceeded the 70 ppbv 8-hour National Ambient Air Quality Standard. We examine the influence of regional emissions on O3 formation using observations of O3, nitrogen oxides (NOx = NO + NO2), a suite of volatile organic compounds (VOCs), peroxyacetyl nitrate (PAN), and peroxypropionyl nitrate (PPN). Elevated O3 and its precursors are observed when the wind is from the southeast, the direction of the Permian Basin. We identify 13 days during the July 25 to September 5, 2019 study period when the maximum daily 8-hour average (MDA8) O3 exceeded 65 ppbv; MDA8 O3 exceeded 70 ppbv on 5 of these days. The results of a positive matrix factorization (PMF) analysis are used to identify and attribute source contributions of VOCs and NOx. On days when the winds are from the southeast, there are larger contributions from factors associated with primary O&G emissions; and, on high O3 days, there is more contribution from factors associated with secondary photochemical processing of O&G emissions. The observed ratio of VOCs to NOx is consistently high throughout the study period, consistent with NOx-limited O3 production. Finally, all high O3 days coincide with elevated acyl peroxy nitrate abundances with PPN to PAN ratios > 0.15 ppbv ppbv-1 indicating that anthropogenic VOC precursors, and often alkanes specifically, dominate the photochemistry.Implications: The results above strongly indicate NOx-sensitive photochemistry at Carlsbad Caverns National Park indicating that reductions in NOx emissions should drive reductions in O3. However, the NOx-sensitivity is largely driven by emissions of NOx into a VOC-rich environment, and a high PPN:PAN ratio and its relationship to O3 indicate substantial influence from alkanes in the regional photochemistry. Thus, simultaneous reductions in emissions of NOx and non-methane VOCs from the oil and gas sector should be considered for reducing O3 at Carlsbad Caverns National Park. Reductions in non-methane VOCs will have the added benefit of reducing formation of other secondary pollutants and air toxics.

Hydrocarbon markers for assessing the influence of human activities in the tropical semi-arid region (Acaraú River, state of Ceará, Brazil).

Coastal ecosystems are facing increasing anthropogenic stressors, including rapid urbanization rates and extensive fossil fuel usage. Nevertheless, the distribution of hydrocarbons in the Brazilian semi-arid region remains relatively uncharacterized. In this study, we analyzed ten surface sediment samples (0-2 cm) along the banks of the Acaraú River to assess the chronic contributions of aliphatic and aromatic hydrocarbons. The Acaraú River is a crucial riverine-estuarine area in the semi-arid region of Northeast Brazil. Ultrasound-assisted extraction and gas chromatograph coupled to a mass spectrometer were used to identify target compounds: 45 PAHs, 27 n-alkanes (C10-C38), and two isoprenoids. At most stations, the predominant grain size was sand, and the organic carbon content was less than 1%. The total n-alkanes concentration ranged from 14.1 to 170.0 µg g-1, while individual pristane and phytane concentrations ranged from not detected (nd) to 0.4 µg g-1 and nd to 0.7 µg g-1, respectively. These concentrations resemble those found in unpolluted sediments and are lower compared to samples from urbanized coastal areas. The total USEPA PAHs concentration varied from 157.8 to 1364 ng g-1, leading to the characterization of sediment samples as moderately polluted. Based on diagnostic ratios calculated from both alkane and PAH concentrations, the sediment samples were predominantly deriving from pyrolytic sources, with some contribution from petrogenic sources. The most abundant group was 5-ring PAHs (mean: 47.3 ± 36.7%), followed by 3-ring PAHs (mean: 17.9 ± 13.7%). This predominance indicates a pyrolytic origin of hydrocarbons in the Acaraú River. The concentrations reported here were representative of the level of background hydrocarbons in the region. Regarding the sediment quality assessment, BaP TPE calculated for the Acaraú River ranged from 13.2 to 1258.4 ng g-1 (mean: 409.3 ± 409.4 ng g-1). When considering site-specific sediment quality values for the coast of the state of Ceará, half of the stations are classified as strongly contaminated, and toxic effects are expected to occur (SQGq >0.25) for the ∑16 PAHs measured in the samples, especially due to dibenz [a,h]anthracene concentrations.

Assessment and identification of bioactive metabolites from terrestrial Lyngbya spp. responsible for antioxidant, antifungal, and anticancer activities.

Lyngbya from fresh and marine water produces an array of pharmaceutically bioactive therapeutic compounds. However, Lyngbya from agricultural soil is still poorly investigated. Hence, in this study, the bioactive potential of different Lyngbya spp. extract was explored. Intracellular petroleum ether extract of L. hieronymusii K81 showed the highest phenolic content (626.22 ± 0.65 µg GAEs g-1 FW), while intracellular ethyl acetate extract of L. aestuarii K97 (74.02 ± 0.002 mg QEs g-1 FW) showed highest flavonoid content. Highest free radical scavenging activity in terms of ABTS•+ was recorded in intracellular methanolic extract of Lyngbya sp. K5 (97.85 ± 0.068%), followed by L. wollei K80 (97.22 ± 0.059%) while highest DPPH• radical scavenging activity observed by intracellular acetone extract of Lyngbya sp. K5 (54.59 ± 0.165%). All the extracts also showed variable degrees of antifungal activities against Fusarium udum, F. oxysporum ciceris, Colletotrichum capsici, and Rhizoctonia solani. Further, extract of L. wollei K80 and L. aestuarii K97 showed potential anticancer activities against MCF7 (breast cancer) cell lines. GC-MS analyses of intracellular methanolic extract of L. wollei K80 showed the dominance of PUFAs with 9,12,15-octadecatrienoic acid, methyl ester, (Z,Z,Z) as the most abundant bioactive compound. On the other hand, the extracellular ethyl acetate extract of L. aestuarii K97 was rich in alkanes and alkenes with 1-hexyl-2-nitrocyclohexane as the most predominant compound. Extracts of Lyngbya spp. rich in novel secondary metabolites such as PUFAs, alkanes, and alkenes can be further explored as an alternative and low-cost antioxidant and potential apoptogens for cancer therapy.

Microaerobic degradation of crude oil and long chain alkanes by a new Rhodococcus strain from Gulf of Mexico.

Bacterial degradation of crude oil is a promising strategy for reducing the concentration of hydrocarbons in contaminated environments. In the first part of this study, we report the enrichment of two bacterial consortia from deep sediments of the Gulf of Mexico with crude oil as the sole carbon and energy source. We conducted a comparative analysis of the bacterial community in the original sediment, assessing its diversity, and compared it to the enrichment observed after exposure to crude oil in defined cultures. The consortium exhibiting the highest hydrocarbon degradation was predominantly enriched with Rhodococcus (75%). Bacterial community analysis revealed the presence of other hydrocarbonoclastic members in both consortia. In the second part, we report the isolation of the strain Rhodococcus sp. GOMB7 with crude oil as a unique carbon source under microaerobic conditions and its characterization. This strain demonstrated the ability to degrade long-chain alkanes, including eicosane, tetracosane, and octacosane. We named this new strain Rhodococcus qingshengii GOMB7. Genome analysis revealed the presence of several genes related to aromatic compound degradation, such as benA, benB, benC, catA, catB, and catC; and five alkB genes related to alkane degradation. Although members of the genus Rhodococcus are well known for their great metabolic versatility, including the aerobic degradation of recalcitrant organic compounds such as petroleum hydrocarbons, this is the first report of a novel strain of Rhodococcus capable of degrading long-chain alkanes under microaerobic conditions. The potential of R. qingshengii GOMB7 for applications in bioreactors or controlled systems with low oxygen levels offers an energy-efficient approach for treating crude oil-contaminated water and sediments.

Toxicity evaluation of Pinus radiata D.Don bark wax for potential cosmetic application.

Radiata pine bark is a widely available organic waste, requiring alternative uses due to its environmental impact on soil, fauna, and forest fires. Pine bark waxes could be used as cosmetic substitutes, but their toxicity requires evaluation since pine bark may contain toxic substances or xenobiotics, depending on the extraction process. This study evaluates the toxicity of radiata pine bark waxes obtained through various extraction methods on human skin cells grown in vitro. The assessment includes using XTT to evaluate mitochondrial activity, violet crystal dye to assess cell membrane integrity, and ApoTox-Glo triple assay to measure cytotoxicity, viability, and apoptosis signals. Pine bark waxes extracted via T3 (acid hydrolysis and petroleum ether incubation) and T9 (saturated steam cycle, alkaline hydrolysis, and petroleum ether incubation) exhibit non-toxicity up to 2% concentration, making them a potential substitute for petroleum-based cosmetic materials. Integrating the forestry and cosmetic industries through pine bark wax production under circular economy principles could promote development while replacing petroleum-based materials. Extraction methodology affects pine bark wax toxicity in human skin cells due to the retention of xenobiotic compounds including methyl 4-ketohex-5-enoate; 1-naphthalenol; dioctyl adipate; eicosanebioic acid dimethyl ester; among others. Future research will investigate whether the extraction methodology alters the molecular structure of the bark, affecting the release of toxic compounds in the wax mixture.

Application of Pyrolysis for the Evaluation of Organic Compounds in Medical Plastic Waste Generated in the City of Cartagena-Colombia Applying TG-GC/MS.

In this study, the thermal degradation and pyrolysis of hospital plastic waste consisting of polyethylene (PE), polystyrene (PS), and polypropylene (PP) were investigated using TG-GC/MS. The identified molecules with the functional groups of alkanes, alkenes, alkynes, alcohols, aromatics, phenols, CO and CO2 were found in the gas stream from pyrolysis and oxidation, and are chemical structures with derivatives of aromatic rings. They are mainly related to the degradation of PS hospital waste, and the alkanes and alkenes groups originate mainly from PP and PE-based medical waste. The pyrolysis of this hospital waste did not show the presence of derivatives of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, which is an advantage over classical incineration methodologies. CO, CO2, phenol, acetic acid and benzoic acid concentrations were higher in the gases from the oxidative degradation than in those generated in the pyrolysis with helium. In this article, we propose different pathways of reaction mechanisms that allow us to explain the presence of molecules with other functional groups, such as alkanes, alkenes, carboxylic acids, alcohols, aromatics and permanent gases.

Insights about levels and source appointment of petroleum hydrocarbons in Brazilian semi-arid coastal: baseline status assessment for ocean decade targets.

The Ocean decade (2021-2030) for sustainable development proclaimed in 2017 by the UN, seeks to promote and conserve the sustainable use of oceans, seas, and marine resources. For this, the distribution of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and biomarkers, in sediments from the Fortaleza coastal zone (Mucuripe harbor (MH) and Inner Continental shelf (ICS)) were used to assess the impacts of anthropogenic activities in the area. The concentrations of total n-alkanes (Σ16 n-alkanes) in MH and ICS sediments varied from 35.9 to 94.9 and 17.9 to 197.3 µg g-1, respectively, while the isoprenoids phytane and pristane in MH and ICS sediments ranged from 0.1 to 1.69 ug g-1 and from 0.14 and 1.20 µg g-1, respectively. Most of the sediment samples presented carbon preference index (CPI) values close to unity, indicating that the area is submitted to petroleum-related sources. The concentrations of Σ16 PAHs in MH and ICS sediments varied from 87.0 to 562.0 and 98 to 288.0 ng g-1. This work presents the first investigation of the petroleum biomarkers hopanes and steranes in the Fortaleza coastal zone, in which ΣBiomarkers varied from 0.10 to 1.79 and 0.02 to 0.24 ug g-1 in MH and ICS sediments, respectively. The presence at stations of biomarkers also indicates petrogenic input. The diagnosis of the distribution of pollutants in the investigated zones of the Fortaleza coast suggests contamination from urban areas and oil spills and vessel traffic.

Weathering impacts on petroleum biomarker, aromatic, and polar compounds in the spilled oil at the northeast coast of Brazil over time.

After the wide oil spill reached the northeast of Brazil, the resurgence of oil was recorded and to evaluate this oil in detail, two samples collected in the state of Pernambuco in 2019 and 2021 were submitted to multiple analytical techniques. For both, we have found similar saturated biomarkers and triaromatic steroid ratios, implying that they are from the same spilled source. The n-alkanes, isoprenoids, and cycloalkanes were almost completely degraded due to evaporation, photooxidation, and/or biodegradation processes. The preferential loss of less alkylated PAHs than the more alkylated ones suggests that biodegradation was the most active process. This hypothesis is reinforced by the formation of mono and dicarboxylic acids assessed by GC × GC-TOFMS and ESI(-) FT-ICR MS high-resolution techniques. Furthermore, based on the ESI(-) FT-ICR MS results, three new ratios were proposed to evaluate the progress of the biodegradation process over time: Ox>2/O, SOx/SO, and SOx/N.

Efficient implementation of time-dependent auxiliary density functional theory.

The random phase approximation of time-dependent auxiliary density functional theory (TDADFT) is rederived from auxiliary density perturbation theory. Our exhaustive validation of TDADFT reveals an upshift of the excitation energies by ∼0.1 eV with respect to standard time-dependent density functional theory. For the computationally efficient implementation of TDADFT, floating point operation optimized three-center electron repulsion integral recurrence relations and their double asymptotic expansions are implemented into the Davidson solver. The computational efficiency of TDADFT is benchmarked with four sets of molecules comprising alkanes, fullerenes, DNA fragments, and zeolites. The results show that TDADFT has a computational scaling between 1.3 and 1.9 with respect to the number of basis functions, which is lower than the scaling of standard time-dependent density functional theory. Due to its computational simplifications, TDADFT is particularly well suited for Born-Oppenheimer molecular dynamics simulations. As illustrative examples, we present the temperature effects on the gas-phase absorption spectra of benzene, naphthalene, and anthracene.

Microplastics and hydrocarbons in soils: Quantification as an anthropic carbon source.

The literature on the presence of microplastics (MPs) and their potential impact on terrestrial ecosystems is still scarce. Interestingly, soil MPs are detected as organic carbon (SOC) using traditional quantification methods (e.g., loss on ignition [LOI]), although its dynamics in the environment will be different. The objective of this study was to quantify the carbon (C) contribution of MPs to the SOC in superficial soil samples from a coastal urban wetland (Avellaneda, Buenos Aires, Argentina) with the features of a humid subtropical forest and compare with hydrocarbon contribution. Soil samples were split for analysis of moisture content; texture (sieve and pipet method); organic matter as a LOI (8 h at 450 °C); total hydrocarbons (THCs; gravimetry of solvent extractable matter); n-alkanes (solvent extraction and gas chromatography-flame ionization detection analysis); and extraction of MPs (floatation in NaClaq , filtration, H2 O2 digestion, and visual sorting under a stereomicroscope). The superficial soil was a sandy clay loam with a large organic matter content (19%-30%). The THC averaged 2.5 ± 1.9 g kg and the marked predominance of odd-numbered carbon n-alkanes maximizing at C29 and C31 show the contribution of the terrestrial plant waxes. The average number of MPs was 587 ± 277 items kg of dry soil, predominantly fibers. Taking account of the C content, THCs and MPs add to the soil 1.23 ± 1.10 ton C ha and 0.10-0.97 ton C ha, respectively. Therefore, in this system with humid forest characteristics, the MPs represent between 0.12% and 1.25% of soil estimated carbon, in a magnitude similar to the C contribution of THCs (0.6%-4.2%). This preliminary study shows the relevance of discriminating MPs from other carbon sources and presents a description of their impact on soils to advance future research or tools for decision-makers. Integr Environ Assess Manag 2023;19:698-705. © 2022 SETAC.

Chemical Variability of Hexane Extracts from Five Subspecies of Calendula suffruticosa from Spain.

The chemical profile of the hexane extracts of the subspecies carbonellii, greuteri, marginata, trialata, and vejerensis of Calendula suffruticosa growing in Spain, herein described for the first time, were studied to access their value as a chemo taxonomical tool and search for potentially useful compounds. The subsp. greuteri and carbonellii showed higher extract yields. Terpenoids were the most abundant chemical class in subsp. carbonellii, greuteri, trialata, and vejerensis, while alkanes were the most abundant in subsp. marginata. Differences in chemical constituents were identified among the subspecies of C. suffruticosa analysed, which the PCA can prove. The subsp. trialata and greuteri showed more significant phytochemical similarity, which might indicate genetic proximity between these two subspecies. C. suffruticosa subsp. marginata presented the fewest number of compounds and in the smallest quantities, and C. suffruticosa subsp. vejerensis presented the largest number, however, both showed no alcohols. Furthermore, some of the compounds found in significant amounts are known for their pharmacological and nutraceutical properties, denoting potential use.

Biosynthesis of alkanes/alkenes from fatty acids or derivatives (triacylglycerols or fatty aldehydes).

This review summarizes the most relevant advances in the biological transformation of fatty acids (or derivatives) into hydrocarbons to be used as biofuels (biogasoline, green diesel and jet biofuel). Among the used enzymes, the fatty acid decarboxylase from Jeotgalicoccus sp. ATCC 8456 (OleTJE) stands out as a promising enzyme. OleTJE may be coupled in cascade reactions with metalloenzymes or reductases from the Old Yellow Enzymes (OYE) family to perform the hydrogenation of α-olefins into paraffins. The photodecarboxylase from Chlorella variabilis NC64A (CvFAP) is an example of coupling biocatalysis and photocatalysis to produce alkanes. Besides the (photo)decarboxylation of free fatty acids and/or triacyclglycerols to produce alkanes/alkenes, by enzymes has also been employed. The cyanobacterial aldehyde decarbonylase (cAD) from Nostoc punctiforme is an outstanding example of this kind of enzymes used to produce alkanes. Overall, these kinds of enzymes open up new possibilities to the production of biofuels from renewable sources, even if they have many limitations on the current situation. The possibilities of improving enzymes features via immobilization or coimmobilization, as well as the utilization of whole cells haves been also reviewed.

Iron Oxide Powder as Responsible for the Generation of Industrial Polypropylene Waste and as a Co-Catalyst for the Pyrolysis of Non-Additive Resins.

For the synthesis of polymeric resins, it is of great importance to review the raw materials and the equipment to be used to avoid the presence of compounds that may affect the effectiveness of the polymerization and the characteristics of the plastic to be obtained. Iron oxide is a compound that can be present in reactors after maintenance due to the techniques used and the cleaning of this equipment, and it can affect the characteristics of the resins, reducing their quality. In this study, the presence of FeO in different concentrations was evaluated to determine its effects on the properties and pyrolysis of polypropylene resins by using X-ray refraction to determine the elements of the samples, evaluating thermal degradation by TGA, the variation in molecular weight by measuring the MFI, and the compounds obtained from pyrolysis by chromatography. The results showed that the thermal degradation decreased as the FeO concentration increased, while for the MFI, the relationship was directly proportional. The evaluation of the compounds obtained from pyrolysis showed an increase in the production of alcohols, alkynes, ketones, and acids, and a decrease in alkanes and alkenes, showing that FeO affects the properties of polypropylene and the compounds that are produced during pyrolysis.

Particulate matter-bound organic compounds: levels, mutagenicity, and health risks.

Increased industrialization and consumption of fossil fuels in the Metropolitan Region of São Paulo (MRSP), Brazil, have caused a growth of the particulate matter emissions to the atmosphere and an increase in population health problems. Particulate and gaseous phase samples were collected in different short campaigns (2015, 2016, and 2017) near an urban-industrial area. Organic carbon (OC), elemental carbon (EC), polycyclic aromatic hydrocarbons (PAH), and its derivatives (nitro and oxy-PAH), n-alkanes, hopanes, and pesticides were determined. The Salmonella/microsome test confirmed the mutagenic activity of these samples. Among PAH, benzo(a)pyrene was detected as one of the most abundant compounds. Benzo(a)pyrene equivalent concentrations for PAH and nitro-PAH, and the associated risk of lung cancer, showed values above those recommended in the literature. The profile of n-alkanes confirmed the predominance of anthropogenic sources. Pesticide concentrations and estimated risks, such as the daily inhalation exposure and hazard quotient, suggest that exposure to these compounds in this area may be dangerous to human health.

Detailing the organic matter in suspended sediments as a tool to assess the impact of land occupation in water bodies: a case of Barigui Watershed (Southern Brazil).

Suspended sediments were collected to examine the organic carbon content and n-alkanes in order to assess the impact on water bodies caused by soil and land occupation. For this, samples from distinct areas based on the level of land occupation of the Barigui Watershed and different areas under the influence of human activities were examined. The number of industries increasing along the river was also considered. Twenty-two sediment samples were collected using a time-integrated sediment sampler. Samples were extracted with dichloromethane:methanol (DCM:methanol) (2:1) in an ultrasound bath, treated and injected using gas chromatography coupled with mass spectrometry (GC-MS) for separation and quantification. Twenty-one n-alkanes were identified and were used to track both biogenic and anthropogenic inputs. The concentration of total n-alkanes varied from 38.72 to 222.76 µg g-1, due to the impact of urbanization. Diagnostic indexes indicated high numbers of plants, bacteria and petroleum as n-alkanes sources. The following results were obtained using: carbon preference index (CPI), 1.96-2.22 (rainy season) and 2.12-5.80 (summer season); average chain length (ACL), 30.37-31.17 (rainy season) and 30.05-30.50 (summer season) and terrigenous aquatic ratio (TAR), 0.39-5.47 (rainy season) and 2.98-5.06 (summer season); n-alkanes had two main sources: terrestrial plant and petroleum. It is clear that the source of n-alkanes is different in each season (rainy and dry) demonstrated by n-alkanes occurrence. During the rainy season, there was an increase in organic matter of oil origin which was mainly associated with the increased runoff and rain drainage. Finally, the input of organic matter associated with land occupation and erosion can be distinguished by higher concentration in the most urbanized site (PB).