Soil samples from a contaminated site in Sweden were analyzed to identify the presence of 78 polycyclic aromatic compounds (PACs) using gas chromatography coupled with mass spectrometry (GC-MS). The target analysis revealed large contributions not only from polycyclic aromatic hydrocarbons (PAHs), but also from alkylated- and oxygenated-PAHs (alkyl- and oxy-PAHs, respectively), and N-heterocyclics (NPACs). PAC profiles indicated primarily pyrogenic sources, although contribution of petrogenic sources was also observed in one sample as indicated by a high ratio of alkylated naphthalene compared to naphthalene. The aryl hydrocarbon receptor (AhR)-activity of the soil extracts was assessed using the H4IIe-pGudluc 1.1 cells bioassay. When compared with the calculated total AhR-activity of the PACs in the target list, 35–97% of the observed bioassay activity could be explained by 62 PACs with relative potency factors (REPs). The samples were further screened using GC coupled with Orbitrap™ high resolution MS (GC-HRMS) to investigate the presence of other PACs that could potentially contribute to the AhR-activity of the extracts. 114 unique candidate compounds were tentatively identified and divided into four groups based on their AhR-activity and environmental occurrence. Twelve substances satisfied all the criteria, and these compounds are suggested to be included in regular screening in future studies, although their identities were not confirmed by standards in this study. High unexplained bio-TEQ fractions in three of the samples may be explained by tentatively identified compounds (n = 35) with high potential of being toxic. This study demonstrates the benefit of combining targeted and non-targeted chemical analysis with bioassay analysis to assess the diversity and effects of PACs at contaminated sites. The applied prioritization strategy revealed a number of tentatively identified compounds, which likely contributed to the overall bioactivity of the soil extracts.

Antimicrobial resistance has become one of the main public health threats worldwide with anthropogenic activities driving the spread of resistance. Understanding and combatting the spread of resistant bacteria is a top priority for global health institutions, and it is included as one of the main goals of the One Health initiative. Giant tortoises (Chelonoidis spp.), some of the most iconic species on Earth, are widely distributed across the Galapagos archipelago and are thus perfect candidates to test the hypothesis that wildlife species in the Galapagos carry antimicrobial resistant genes (ARGs) associated with human activities. We sampled a total of 200 free-living Galapagos tortoises from western Santa Cruz Island (C. porteri), the most human-populated island of the archipelago, and 70 tortoises (C. vandenburghi) from the isolated Alcedo Volcano on Isabela Island, a natural area with minimal human presence. Fecal samples were analyzed by quantitative PCR for a panel of 21 ARGs conferring resistance for eight antimicrobial classes. We found ARGs in both Santa Cruz and Alcedo Volcano giant tortoises; however, both qualitative and quantitative results showed higher loads of ARGs in tortoises inhabiting the human modified environments of Santa Cruz. Moreover, Santa Cruz tortoises sampled in higher human-modified landscapes (i.e., farmlands and urban areas) presented a higher number of ARGs, antimicrobial classes, and multi-resistant microbiomes than those from less anthropized areas within the same island. Our findings suggest that human activities in Galapagos have a negative impact on ecosystem health through ARG dispersal. This research highlights a new threat for the health and conservation of the unique wildlife of the Galapagos, their ecosystems, and the humans inhabiting this World Heritage Site. Our recommendation to local policy makers is to control and reduce the use of antibiotics in both human and animal health, thus helping enforce antimicrobial regulations.

The high capacity of many ant species to accumulate trace metals raises the question of whether the metal concentration in ants’ bodies could reliably reflect the contamination of ecosystems. The idea of applying the metal accumulation in ants for bioindication purposes is tempting; however, the methods should consider that ants are unique organisms due to their social way of life. In this study, we describe the between-colony variation in the accumulation of Zn and Cd in workers of the common garden ant Lasius niger originated from the post-mining area of a zinc-and-lead smelter in southern Poland. We show that the accumulation of both metals differs significantly between colonies even within the same study site; at the maximum, we detected a three-fold difference in Zn accumulation and a six-fold difference in Cd. The results showed that in the study area, the capacity of L. niger to accumulate metals is highly colony-specific. If future studies on other ant species concur with our findings, this may suggest that incorporating the between-colony variation of metal accumulation in prospective bioindication protocols would provide a higher accuracy of the assessments on the contamination of impacted environments. We suggest that using ants for bioindication should be preceded by preliminary studies to assess representative samples of colonies that could reliably indicate the contamination of the investigated area.

The Wood mouse (Apodemus sylvaticus) is a widespread mammalian species that acts as a reservoir host for multiple infections, including zoonotic diseases. Exposure to immunotoxins, like for instance trace metals, may reduce the ability of the host to mount proper responses to pathogens, potentially increasing the transmission and prevalence of infections. Antibody-mediated responses are crucial in preventing and limiting infections, and the quantification of the primary antibody response is considered a sensitive predictor of immunosuppression. The current study aims to investigate effects of cadmium exposure on the antibody-mediated responses of wood mice inhabiting polluted and non-polluted areas in the Netherlands. Wood mice were captured alive at different locations and immunized to sheep red blood cells (SRBC) to induce a primary antibody response. SRBC-specific antibody-producing cells, or plaque forming cells (PFC), were quantified and related to kidney cadmium levels. Differential circulating main leukocyte populations were also characterised. Cadmium concentrations in mice kidneys differed between mice captured at different locations, and increased with individual body mass, likely associated with age-related time of exposure. Effect of cadmium was apparent on the percentages of B cell counts in blood. Because of potential natural immune heterogeneity between wild rodent populations, mice immune responses were analysed and compared grouped by captured locations. Capture location had significant effect on the total counts of white blood cells. Increasing cadmium exposure in wood mice captured from polluted sites was associated with a decrease of splenic PFC counts. This field research shows that wood mice antibody responses can be impaired by cadmium exposure, even at low environmental levels, by affecting B cell functioning mainly. Impaired B cell function can make exposed mice more susceptible to infections, potentially increasing the reservoir function of their populations. It also shows that immunomodulatory effects in the field should be assessed site specifically.

Considering that pesticides have been used in Europe for over 70 years, a system for monitoring pesticide residues in EU soils and their effects on soil health is long overdue. In an attempt to address this problem, we tested 340 EU agricultural topsoil samples for multiple pesticide residues. These samples originated from 4 representative EU case study sites (CSS), which covered 3 countries and four of the main EU crops: vegetable and orange production in Spain (S–V and S–O, respectively), grape production in Portugal (P-G), and potato production in the Netherlands (N–P). Soil samples were collected between 2015 and 2018 after harvest or before the start of the growing season, depending on the CSS. Conventional and organic farming results were compared in S–V, S–O and N–P. Soils from conventional farms presented mostly mixtures of pesticide residues, with a maximum of 16 residues/sample. Soils from organic farms had significantly fewer residues, with a maximum of 5 residues/sample. The residues with the highest frequency of detection and the highest content in soil were herbicides: glyphosate and its main metabolite AMPA (P-G, N–P, S–O), and pendimethalin (S–V). Total residue content in soil reached values of 0.8 mg kg−1 for S–V, 2 mg kg−1 for S–O and N–P, and 12 mg kg−1 for P-G. Organic soils presented 70–90% lower residue concentrations than the corresponding conventional soils. There is a severe knowledge gap concerning the effects of the accumulated and complex mixtures of pesticide residues found in soil on soil biota and soil health. Safety benchmarks should be defined and introduced into (soil) legislation as soon as possible. Furthermore, the process of transitioning to organic farming should take into consideration the residue mixtures at the conversion time and their residence time in soil.

Microplastics (MPs) are becoming an environmental growing concern, being the sewage sludge applied to agriculture fields one of the most important inputs to the environment. To date, there is no standardized protocol for their extraction and changes in vegetative growth and fruit maturation on cultivated plants induced by sludge containing MPs have not been studied yet. Sewage sludge from three different wastewater treatment plants located in Murcia, Spain, were studied. First, the microplastic concentration was estimated and, then, the effects of the sewage sludge in the development of tomato plants and fruit production was analyzed. The measured parameters in tomato plants were both, biomass and length, for shoot and root part, as well as, stem diameter and tomato production. The present work has developed and validated a protocol for the extraction and quantification of MPs comprising several shapes, materials and sizes from samples of sewage sludges, which offers a good compromise for the extraction of different types of microplastic. The protocol used for MPs extraction had a recovery efficiency of 80 ± 3% (mean ± SE) and used bicarbonate, to maximize MPs extraction. The mean abundance of MPs in the studied sewage sludge samples was 30,940 ± 8589 particles kg⁻¹ dry weight. Soils with sludge containing MPs fostered the growth of tomato plants, while delaying and diminished fruit production. However, other factors or their interactions with MPs could have influenced the outcomes. Further studies are necessary to corroborate these findings and explain the mechanisms of possible effects of MPs on plants.

Seed coating (‘seed treatment’) is the leading delivery method of neonicotinoid insecticides in major crops such as soybean, wheat, cotton and maize. However, this prophylactic use of neonicotinoids is widely discussed from the standpoint of environmental costs. Growing soybean plants from neonicotinoid-coated seeds in field, we demonstrate that soybean aphids (Aphis glycines) survived the treatment, and excreted honeydew containing neonicotinoids. Biochemical analyses demonstrated that honeydew excreted by the soybean aphid contained substantial concentrations of neonicotinoids even one month after sowing of the crop. Consuming this honeydew reduced the longevity of two biological control agents of the soybean aphid, the predatory midge Aphidoletes aphidimyza and the parasitic wasp Aphelinus certus. These results have important environmental and economic implications because honeydew is the main carbohydrate source for many beneficial insects in agricultural landscapes.

This paper analyzes a unique, aquatic phytobial biocenosis that has been forming naturally for over 20 years and operating as a filter for Cr(VI)-polluted groundwater. Our study presents a thorough taxonomic analysis of the biocenosis, including filamentous algae, vascular plants, and microbiome, together with the analysis of Cr accumulation levels, bioconcentration factors and other environmentally-significant parameters: siderophore production by bacteria, biomass growth of the plants or winter hardiness. Among 67 species identified in the investigated reservoir, 13 species were indicated as particularly useful in the bioremediation of Cr(VI)-polluted water and sediment. Moreover, three species of filamentous algae, Tribonema sp., and three easily culturable bacterial species were for the first time shown as resistant to Cr concentration up to 123 mg/dm³, i.e. 6150 times over the permissible level. The work presents a modern holistic phytobial consortium indispensable for the remediation of Cr(VI)-contaminated aquatic environment in temperate zones worldwide.

Agricultural use of organochlorine pesticides (OCPs) increased during the twentieth century but many of them have been progressively banned several decades after their introduction. Nevertheless, these lipophilic chemical compounds may persist in soils and sediments. From sediment deposits, it is possible to reconstruct the chronology of OCP releases in relation to former applications through time. Nevertheless, long-term fate of OCPs i.e. source, transfer, and storage through the watershed, is also related to the OCPs-sediment characteristics interactions, and our study showed the significant links between OCPs and labile or refractory organic matter. From sediment cores collected in a mainly agricultural watershed, the Eure River watershed (France), aldrin and lindane widespread applications during the 1950s–1970s have been recorded. While lindane applications declined after that date, according to the temporal trend of the stable isomer of hexachlorocyclohexane (β-HCH), α-, and γ-HCH have been recorded at significant levels in the 2000s, suggesting first local post-ban applications. Nevertheless, the relationships between these OCPs and labile organic matter resulted in an overestimation of the post-ban releases. Also, the detection of stable metabolites of dichlorodiphenyltrichloroethane (DDT) (i.e. 4,4′-DDE) and heptachlor (i.e. heptachlor epoxide) several decades after their ban, revealed the role of old deep soils erosion in the chronology of OCP releases and thus the reemergence of stable transformation products from historical OCPs.

Contaminant levels are lower in Antarctica than elsewhere in the world because of its low anthropogenic activities. However, the northern region of the Antarctic Peninsula, is close to South America and experiences the greatest anthropogenic pressure in Antarctica. Here, we investigated, in two Antarctic Peninsula islands, intra and interspecific factors that influence the concentrations of 17 trace elements (TEs) in blood and feathers of three penguin species breeding sympatrically in relation to their trophic ecology assessed via a stable isotopic approach (C, N and S). Geographical location, foraging zone (δ¹³C and δ³⁴S) and diet influences the interspecific difference, and sex and maturity stage diet influence the intraspecific difference of Pygoscelis penguins. Penguins from Livingston showed higher values (mean, ng. g⁻¹, dry weight - dw) of Zn (103), Mn (0.3), and Fe (95) than those from King George Island (Zn: 80, Mn: 1.9, and Fe: 11). Gender-related differences were observed, as males showed significantly higher values (mean, ng. g⁻¹, dw) of Rb (3.4) and δ¹⁵N in blood of gentoo, and Ca (1344) in Adélie feathers. Chicks of gentoo and Adélie presented higher Zn, Mg, Ca, and Sr and lower ¹³C values in blood than adults. The highest concentrations (mean, ng. g⁻¹, dw) of Cd (0.2) and Cu (26), and the lowest δ¹⁵N values were found in chinstrap. Geographical, intraspecific (i.e., ontogenetic and gender-related) and interspecific differences in feeding seemed to have influenced TE and stable isotope values in these animals. The TE bioaccumulation by penguins may have also been influenced by natural enrichment in environmental levels of these elements, which seems to be the case for Fe, Zn, and Mn. However, the high level of some of the TEs (Mn, Cd, and Cr) may reflect the increase of local and global human activities.