Per- and poly-fluoroalkyl substances (PFAS) are synthetic contaminants of global concern for environmental and public health. Perfluorooctanoic acid (PFOA) is an important PFAS, and considerable ...attention has been paid to its hepatotoxicity and reproductive and developmental impact, while potential nephrotoxic effects are largely ignored, especially in fish. This study documents the structural and ultrastructural effects on kidney of common carp Cyprinus carpio exposed to waterborne PFOA at an environmentally relevant concentration of 200 ng L−1 and at 2 mg L−1. Dilation of the glomeruli capillary bed, increased vesiculation in the proximal tubular segment, compromised mitochondria, apical blebbing, and sloughing of collecting duct cells occurred in exposed fish, primarily at 2 mg L−1. Perfluorooctanoic acid exposure resulted in higher numbers of rodlet cells (RC), putative immune cells exclusive to fish, mainly in the renal interstitium, than seen in controls, increased association with cells of myeloid lineage and modifications to ultrastructure. No differences in other cells of innate immunity were observed.
Despite the absence of severe histological lesions, PFOA was shown to affect both nephron and hemopoietic interstitium at high concentration, raising concern of the impact on renal and immune function in fish. The response of RCs to PFOA concentration of 200 ng L−1 suggests a potential role as a biomarker of PFOA exposure.
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•Perfluorooctanoic acid affects common carp nephron and renal hemopoietic tissue.•Evidence of glomerular hyperfiltration was observed mainly at 2 mg L−1.•Rodlet cell increase occurs at 200 ng L−1 (environmentally relevant concentration).•Rodlet cells are a candidate for a biomarker of PFOA exposure.•Fish kidney is useful to assess both PFOA nephrotoxicity and immunotoxicity.
•Bioenergy potential from agricultural residues was mapped in E-R region.•Potential was contrasted with plants distribution considering a 10 km buffer.•95% and 50% of total demand from biogas and ...woody biomass plants could be met.•Possible competition for residues among bioenergy plants have to be considered.•ES approach may help to solve trade-offs in agro-ecosystems.
Agro-ecosystems have large potentials for supporting human well-being and local development, also by providing large amounts of organic matter for bioenergy generation. The use of agricultural residues was proposed as a possible solution to support energy transition, while avoiding conflicts for the use of agricultural land destined to food production.
The present work uses an Ecosystem Services (ES) approach to map and estimate the potential availability of agricultural residues (potential ES supply) in the Emilia-Romagna region (Italy), where high productive croplands are present. The map was overlapped with the bioenergy plants currently present in the region (ES demand) that could be sustained by residues, considering a buffer area of 10 km radius for a sustainable supply chain and under the assumption of using only the 25% of total residues. Additionally, suitable areas for bioenergy development were mapped by means of a hotspot analysis.
The results showed that the Emilia-Romagna region has a large availability of agricultural residues to be potentially used for bioenergy generation. The 82.4% of the total installed power of biogas plants and the whole installed power of those using woody biomasses may be supported by using agricultural residues. When considering buffer areas for sustainable supply chains, agricultural residues could meet the 95% and 50% of total demand from biogas and solid biomasses plants, respectively. However, competition for agricultural residues among bioenergy plants could arise because of the overlap of their buffer zones. Moreover, hotspot analysis revealed large suitable areas for the development of environmental and cost-effective biogas plants.
Contrasting ES supply and demand may unveil unexplored forms of sustainable development in agro-ecosystems, thus contributing to a more rational use of agricultural production which supports renewable energies without competing for the agricultural land.
The effects of single macrofauna taxa on benthic nitrogen (N) cycling have been extensively studied, whereas how macrofaunal communities affect N-related processes remains poorly explored. In this ...study, we characterized benthic N-cycling in bioturbated sediments of the oligotrophic Öre Estuary (northern Baltic Sea). Solute fluxes and N transformations (N
2
fixation, denitrification and dissimilative nitrate reduction to ammonium DNRA) were measured in sediments and macrofauna-associated microbes (holobionts) to partition the role of three dominant taxa (the filter feeder
Limecola balthica
, the deep deposit feeder
Marenzelleria
spp., and the surface deposit feeder
Monoporeia affinis
) in shaping N-cycling. In the studied area, benthic macrofauna comprised a low diversity community with dominance of the three taxa, which are widespread and dominant in the Baltic. The biomass of these taxa in macrofaunal community explained up to 30% of variation in measured biogeochemical processes, confirming their important role in ecosystem functioning. The results also show that these taxa significantly contributed to the benthic metabolism and N-cycling (direct effect) as well as to sediments bioturbation with positive feedback to dissimilative nitrate reduction (indirect effect). Taken together, these functions promoted a reuse of nutrients at the benthic level, limiting net losses (e.g. denitrification) and effluxes to bottom water. Finally, the detection of multiple N transformations in macrofauna holobionts suggested a community-associated versatile microbiome, however, its role was of minor importance as compared to the activity of sediment-associated microbial communities. The present study highlights hidden and interactive effects among microbes and macrofauna, which should be considered analysing benthic functioning.
Abstract
Temperature is one of the most fundamental drivers governing microbial nitrogen (N) dynamics in rivers; however, the effect of climate change-induced warming on N processing has not been ...sufficiently addressed. Here, annual, and seasonal (spring and summer) N loads exported from the Po River watershed (Northern Italy), a worldwide hotspot of eutrophication and nitrate pollution, are investigated in relation to water temperature trends over the last three decades (1992–2019). Despite large inter-annual variations, from the early 1990s, the Po River experienced a significant reduction in total N loads (−30%) represented mainly by nitrate, although agricultural N surplus in croplands and other watershed conditions have remained constant. In parallel, the Po River water is steadily warming (+0.11 °C yr
−1
, for average annual temperature) and the number of warm days is increasing (+50%, in the spring–summer period). The inverse relationship between water temperature and N loads strongly indicated that the higher temperatures have boosted the denitrification capacity of river sediments along the lowland reaches. Overall, over the last three decades, annual total N loads declined by around one-third due to a near 3 °C increase in temperature and this evidence was even more marked for the summer season (−45% for total N loads and +3.5 °C for temperature). Based on these observations, it is suggested that near-term effects of climate change, i.e. warming and an increase in the duration of low-flow periods in rivers, may have negative feedback on eutrophication, contributing to partially buffer the N export during the most sensitive period for eutrophication.
Denitrification is a key process buffering the environmental impacts of agricultural nitrate loads but, at present, remains the least understood and poorly quantified sink in nitrogen budgets at the ...watershed scale. The present work deals with a comprehensive and detailed analysis of nitrogen sources and sinks in the Burana–Volano–Navigabile basin, the southernmost portion of the Po River valley (Northern Italy), an intensively cultivated (> 85% of basin surface) low-lying landscape. Agricultural census data, extensive monitoring of surface–groundwater interactions, and laboratory experiments targeting N fluxes and pools were combined to provide reliable estimates of soil denitrification at the basin scale. In the agricultural soils of the basin, nitrogen inputs exceeded outputs by nearly 40% (~ 80 kg N ha
−1
year
−1
), but this condition of potential N excess did not translate into widespread nitrate pollution. The general scarcity of inorganic nitrogen species in groundwater and soils indicated limited leakage and storage. Multiple pieces of evidence supported that soil denitrification was the process that needed to be introduced in the budget to explain the fate of the missing nitrogen. Denitrification was likely boosted in the soils of the studied basin, prone to waterlogged conditions and consequently oxygen-limited, owing to peculiar features such as fine texture, low hydraulic conductivity, and shallow water table. The present study highlighted the substantial contribution of soil denitrification to balancing nitrogen inputs and outputs in agricultural lowland basins, a paramount ecosystem function preventing eutrophication phenomena.
Abstract
We analyzed the large-scale drivers of biological invasions using freshwater fish in a Mediterranean country as a test case, and considering the contribution of single species to the overall ...invasion pattern. Using Boosted Regression Tree (BRT) models, variation partitioning and Redundancy Analysis (RDA), we found that human factors (especially eutrophication) and climate (especially temperature) were significant drivers of overall invasion. Geography was also relevant in BRT and RDA analysis, both at the overall invasion and the single species level. Only variation partitioning suggested that land use was the second most significant driver group, with considerable overlap between different invasion drivers and only land use and human factors standing out for single effects. There was general accordance both between different analyses, and between invasion outcomes at the overall and the species level, as most invasive species share similar ecological traits and prefer lowland river stretches. Human-mediated eutrophication was the most relevant invasion driver, but the role of geography and climate was at least equally important in explaining freshwater fish invasions. Overall, human factors were less prominent than natural factors in driving the spread and prevalence of invasion, and the species spearheading it.
Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants, with perfluorooctanoic acid (PFOA) being a prominent member. PFOA poses a risk to aquatic ecosystems and human ...health due to its presence in water, environmental persistence, and bioaccumulation. Since rodlet cells (RCs) have emerged as potential biomarkers for chemical stressors, this study aimed to investigate the effects of sub-chronic PFOA exposure on RCs in the renal hematopoietic tissue of common carp. Three groups of fish were used: an unexposed control group and two groups exposed to environmentally relevant (200 ng L−1) and elevated (2 mg L−1) PFOA concentrations. Light and transmission electron microscopy were employed to assess RCs’ distribution patterns and exocytosis, while biometry quantified RCs in the hematopoietic tissue. The results showed that, even at environmentally relevant concentrations, PFOA significantly influenced RCs’ distribution patterns, leading to increased occurrence and cluster formation, as well as heightened exocytosis activity. This research highlights PFOA’s immunotoxicity in fish and suggests the potential of RCs as sentinel cells in the immunological response to environmental contaminants. These findings enhance our understanding of PFAS toxicity and emphasise the importance of monitoring their impact on fish as representative vertebrates and reliable animal models.
Bighead carp (Hypophthalmichthys nobilis) have been introduced throughout Europe, mostly unintentionally, and little attention has been given to their potential for natural reproduction. We ...investigated the presence of young-of-the-year bighead carp in an irrigation canal network of Northern Italy and the environmental conditions associated with spawning in 2011-2015. The adult bighead carp population of the canal network was composed by large, likely mature, individuals with an average density of 45.2 kg/ha (over 10 fold more than in the main river). The 29 juvenile bighead carp found were 7.4-13.1 cm long (TL) and weighed 9.5-12.7 g. Using otolith-derived spawning dates we estimated that these juveniles were 94-100 days old, placing their fertilization and hatch dates in mid-to-end-June. Using this information in combination with thermal and hydraulic data, we examined the validity of existing models predicting the onset of spawning conditions and the viability of egg pathways to elucidate spawning location of the species. While evidence of reproduction was not found every year, we determined that potentially viable spawning conditions (annual degree-days and temperature thresholds) and pathways of egg drift suitable for hatching are present in short, slow-flowing canals.
Near-Infrared Spectroscopy is a cost-effective and environmentally friendly technique that could represent an alternative to conventional soil analysis methods, including total organic carbon (TOC). ...Soil fertility and quality are usually measured by traditional methods that involve the use of hazardous and strong chemicals. The effects of physical soil characteristics, such as moisture content and particle size, on spectral signals could be of great interest in order to understand and optimize prediction capability and set up a robust and reliable calibration model, with the future perspective of being applied in the field. Spectra of 46 soil samples were collected. Soil samples were divided into three data sets: unprocessed, only dried and dried, ground and sieved, in order to evaluate the effects of moisture and particle size on spectral signals. Both separate and combined normalization methods including standard normal variate (SNV), multiplicative scatter correction (MSC) and normalization by closure (NCL), as well as smoothing using first and second derivatives (DV1 and DV2), were applied to a total of seven cases. Pretreatments for model optimization were designed and compared for each data set. The best combination of pretreatments was achieved by applying SNV and DV2 on partial least squares (PLS) modelling. There were no significant differences between the predictions using the three different data sets (
< 0.05). Finally, a unique database including all three data sets was built to include all the sources of sample variability that were tested and used for final prediction. External validation of TOC was carried out on 16 unknown soil samples to evaluate the predictive ability of the final combined calibration model. Hence, we demonstrate that sample preprocessing has minor influence on the quality of near infrared spectroscopy (NIR) predictions, laying the ground for a direct and fast in situ application of the method. Data can be acquired outside the laboratory since the method is simple and does not need more than a simple band ratio of the spectra.
Bivalves aquaculture is already considered a very sustainable for of food production and might become an essential pillar on which to develop future global food security. However, with the increase ...in production, a correspondingly great amount of waste will be produced all around the earth, principally in the form of shells, which can represent up to 90% of the fresh mollusk weight. Nowadays, shell waste has no notable use and is commonly regarded as waste, often dumped in landfill, or thrown back into the sea, causing a significant level of environmental concern, and resulting in a loss of natural and valuable resources. Bivalve shells are mainly formed by CaCO3, giving them the potential to become a promising secondary raw material for several applications, from a circular economy perspective. This paper aims to review the scientific literature of the last twenty years and the principal recent trends in shell waste reuse, describing applications that are already in place on a large scale in agriculture and livestock, soils, water and wastewater remediation, biodiesel production and biofilters, as well as niche applications that now simply have the potential to be scaled up.
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