The intensification of agriculture has been distorting the perception of fertility, with a great attention on its chemical component, reinforced by the use of chemical fertilizers as a major option to manage soil fertility. The consequent decline in soil organic matter content is a threat to the sustainability of intensive agricultural systems. Improving soil quality by increasing soil organic carbon (SOC) is seen as a potential way of improving crop yield and quality. In this paper, we studied the effects of two compost-based fertilization strategies on soil fertility and on yields of the following seven vegetable crops: eggplant (Solanum melongena L.), Endive (Cichorium endivia L.), Tomato (Lycopersicon lycopersicum (L.) Karsten Exfarw), Cauliflower (Brassica oleracea L), Onion (Allium cepa L. var. cepa), Muskmelon (Cucumis melo L), Fennel (Pheniculum vulgare L). The results of a seven-year experiment carried out under open field conditions in Southern Italy are presented. Four different fertilization treatments were applied: a) unfertilized control (CNT) b) supplying of mineral N, P2O5 and K2O by chemical fertilizers (CF); c) biowaste compost amendment at 30 Mg ha−1 year−1 as dry matter (d.m.) (≈ 8.4 Mg ha−1 organic C) in the first three years, and 15 Mg ha−1 year−1 as d.m. (≈ 4.2 Mg ha−1 organic C) from the fourth year onwards (Com); d) biowaste compost application of 15 Mg ha−1 year−1 as d.m. integrated with ½ of mineral N supplied in the mineral fertilization (ComN). We demonstrated that the loss of the productive ability in unfertilized control corresponded to SOC concentration ≤ 1%, the same occurred with CF fertilization where, however, the addition of chemical fertilizers concealed soil degradation. On the contrary, SOC concentration ranging between 1.2 and 1.4% in compost amended treatments granted vegetable crops yields always higher than or similar to mineral fertilization. Such SOC concentrations were far from the 2% threshold considered as the minimum SOC concentration of not degraded soil. SOC content increased 8.1 and 5.7 Mg ha−1 due to Com and ComN strategies. The supplying of 4-5 Mg C ha−1 year−1 as in ComN resulted in a positive efficiency (15%) in stabilizing C in soil compared to the supplying of higher doses as in Com. As concerns the risks of groundwater pollution due to N-NO3 releases in amended soils, we ascertained in three annual monitoring campaigns that releases measured in the 0-30 cm soil layer did not exceed values of 20-25 mg kg−1 considered as the treshold above which vegetable crop response to additional fertilization was unlikely .

At the core of the adaptive ecosystem management paradigm, environmental monitoring, especially using biomonitors, mandates the search for tools and approaches to overcome its current limitations, both in terms of novel species and analytical techniques to extract information from the data. In this context, a large field bio-monitoring study was performed in order to validate a candidate active biomonitor, the macrophytic alga Chara gymnophylla, using a long-established biomonitor (the aquatic moss Fontinalis antipyretica) as reference, innovative spatial analysis approaches and the area of two of the main freshwater ecosystems of the "Cilento Vallo di Diano e Alburni" National Park as experimental setting. Specifically, the concentrations of 19 potentially toxic elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, V, Zn) in 3 alga and 3 moss bags placed in each of 41 sites along the Bussento and Calore Salernitano rivers were analyzed. The coherence of element gradients between biomonitors, the spatial heterogeneity in element distribution and their spatial scales were evaluated using robust multivariate approaches, random models and spectral decomposition of the spatial gradients. Results demonstrate the substantial uniformity in responses between the biomonitors, both showing similar element spatial distributions, within and between-site variability, the same spatial connectivity and spatial variations at similar scales. On the one hand, the approach adopted and the findings obtained allow definitely validating Ch. gymnophylla as a novel active biomonitor of potentially toxic elements in freshwater ecosystems and, on the other hand, deriving clear contamination scenarios, with indication of the alleged sources.

Environmental monitoring in sensitive areas is crucial to develop and adapt governance policies. In this context, biomonitoring provides information not only on environmental contamination gradients, but also on the actual pollutant bioavailabilities and, using bioaccumulators, on their possible transfer through the food webs. The spatial distribution of suitable bioaccumulators, however, may limit the effectiveness of biomonitoring. To relieve this constraint, we investigated the usefulness of Mentha aquatica as a novel cosmopolitan biomonitor of potentially toxic elements (PTEs) in freshwater ecosystems, using Helosciadium nodiflorum, a widely recognized biomonitor, as a reference for environmental concentration gradients. The biomonitors were then employed in deriving spatial gradients of macronutrient (Ca, K, Mg, P, S), micronutrient (Co, Cr, Cu, Fe, Mn, Na, Ni, Si, V, Zn) and non-essential element (Al, As, Cd, Pb) concentrations in the area of one of the largest Italian national parks. Over two years and a large number of sites, M. aquatica roots provided PTE concentration gradients comparable to those obtained using H. nodiflorum roots, demonstrating their usefulness in PTE biomonitoring and widening the range of suitable biomonitors for freshwater ecosystems. At the same time, the joint use of M. aquatica and H. nodiflorum enhanced the accuracy of concentration gradients measured in two of the main freshwater ecosystems within the “Cilento, Vallo di Diano e Alburni” National Park (southern Italy). The study, performed for two consecutive years over 43 sites along the Bussento and Calore Salernitano rivers, pointed out several criticalities, attributable either to natural or anthropogenic sources. High natural concentrations of Al, As, Na, Si and V were mainly related to local characteristics (proximity to sea, sediment texture) or generalized lithological background (pyroclastic deposits on carbonates), whereas local high concentrations of Co, Fe and Mn were mainly related to direct or indirect anthropogenic sources (proximity to urban centers, wastewater treatment plants). Moreover, unusual high concentrations of Cd, Cr, Ni and Zn were observed at three spring mouths, suggesting changes in their bioavailability due to spring water physico-chemistry.

Reconstructing spatial and temporal pollution gradients in natural and anthropogenic areas is of paramount importance to undertake proper mitigation strategies. To this end, air biomonitoring based on chemical analysis of selected bioaccumulators, provides useful information not only on the pollutant concentration gradients, but also on their possible effects on biota and ecosystems. The analysis of 18 potentially toxic elements (PTEs), namely macronutrients (Ca, K, Mg, P, S), micronutrients (Co, Cr, Cu, Fe, Mn, Na, Ni, V, Zn) and non-essential elements (Al, As, Cd, Pb), in Quercus ilex leaves collected from 26 sites belonging to remote, residential, urban and industrial areas of Salerno, in the Mediterranean area, provided accurate information on spatial and temporal air pollution gradients, as well as on the plant nutritional status within the whole area. Despite the adequate nutritional status of plants in all the site typologies, several criticalities were highlighted. Specifically, on a natural background contamination by Na (due to the sea proximity), Al and V (due to the lithological characteristics) of the whole area, anthropogenic activities were responsible for relatively high concentrations of selected PTEs in the different site typologies. Remote sites were affected by high Cd concentrations, due to the transport of fine particulate from urban or industrial areas. Urban (and to a lesser extent residential) sites were affected by high concentrations of most PTEs, mainly released by diffuse sources, such as vehicular traffic. Exceedingly high concentrations of As, Mn, Ni and Pb were observed in industrial sites, in relation to local and specific emissions. Anyway, an overall decrease, consistent with the general temporal trends observed in Europe in the last years, was observed in several PTE concentrations for all the site typologies.

In statistics, the identification of environmental criticalities, one of the primary goals of environmental monitoring and management, translates into the detection of spatial outliers. Detected in relation to purposely defined sets of indicators, both global and local outliers are pivotal in the identification not only of the severity and spread of criticalities, but also of their nature and causes. The present research exemplifies a procedural framework to identify environmental criticalities, using two different approaches for the detection of spatial outliers in river ecosystems related to several sets of parameters (organic C, inorganic C, Ca, Co, Cr, Fe, K, Mg, Mn, N, Na, P, S, Si, V, Zn, Cl−, F−, NO3−, SO42−, chlorophyll a, chlorophyll b, pheophytin a, pheophytin b, total carotenoids, pH, and electrical conductivity), including emerging contaminants. To this end, indicator sets diagnostic for specific criticalities, derived from an empirical dataset of water quality parameters, were employed, using detection techniques based on geographically weighted principal component analysis and a modified pairwise Mahalanobis distance–based algorithm. Clear and accurate criticality scenarios were derived, highlighting both the strengths and the limitations of the proposed approach, especially in relation to the classic threshold-based methods.

Microbial degradation is the main responsible for polycyclic aromatic hydrocarbons (PAHs) removal from contaminated soils, and the understanding of this process is pivotal to define effective bioremediation approaches. To evaluate the contribution of several microbial groups in soil anthracene and benzo[a]pyrene degradation, the analysis of phospholipid fatty acid (PLFA) profiles and machine learning techniques were employed. To this end, PLFAs and PAH concentrations were analysed, along 274 days of incubation in mesocosms, in soils artificially contaminated with anthracene and benzo[a]pyrene, subjected to different treatments: untreated soil and soils treated with biowaste compost or fungal consortium. Random forest models, figuring anthracene or benzo[a]pyrene concentrations as dependent variables and PLFAs as predictors, were then built to evaluate the contribution of each variable in PAH degradation. PLFA profiles varied substantially among soil treatments and along time, with the increase of Actinomycetes in soils added with fungi and other Gram+ bacteria in compost amended soils. The former, together with fungi, are primarily responsible for anthracene and benzo[a]pyrene degradation in both treated soils, a process in which also metanotrophs and other Gram+ and Gram- bacteria participate. In untreated soil, the cooperation of a multitude of different microorganisms was, instead, responsible for PAH removal, a process with lower efficiency in respect to treated soils.

The effect of plant cover on soil microbial community structure and activity was investigated in forest ecosystems dominated by holm oak (Quercus ilex), Turkey oak (Quercus cerris) and beech (Fagus sylvatica), in two seasons (autumn and early summer). Microbial community structure was investigated by phospholipid fatty acid (PLFA) profile and ergosterol determination. Microbial community activity was assessed by fluorescein diacetate hydrolisys, beta-glucosidase and cellulase activities. The Turkey oak forest showed the lowest soil microbial biomass, both as total and specific PLFA markers. PLFA profile showed a different microbial community structure among forest soils, mainly between the two oak systems. Enzyme activities were affected by soil organic carbon content, with the lowest values measured in Turkey oak. A seasonal effect both on microbial biomass and on enzyme activity was generally observed. Among the investigated forest systems, the beech forest appeared to store more carbon both in aboveground biomass and in soil.

The effects of long-term soil fertilizations on nutrient and non-essential element concentrations in edible parts of three crops important in human diet were investigated repeating four treatments (biowaste compost, biowaste compost plus mineral nitrogen, mineral NPK, unfertilized control) for seven consecutive years (2007–2014). Fruits of Solanum lycopersicum cv San Marzano collected in 2011 and 2012, bulbs of Allium cepa cv Bianca di Pompei collected in 2012 and 2013, and bulbs of Foeniculum vulgare cv Orbit collected in 2014 were analyzed. Wide variations in element concentrations were observed along time and among species, with Ca, K, Mg, and Na higher in fennel bulbs and Cd, Cr, Mn, Ni, Pb, and Zn higher in tomato fruits, where Cd reached concentrations up to ninefold higher than the permitted values (EU Regulation n. 488/2014). Despite the enrichments in soil total Cu and available Cd, Fe, K, Mn, and Zn concentrations due to long-term fertilization with biowaste compost (alone or with mineral fertilizers), plants showed lower micronutrient and non-essential element concentrations in respect to those on unfertilized soils. Considering the potential toxicity for human beings of these mobile and persistent elements, the obtained findings reassure on the safe use of biowaste compost in agriculture. Overall, this study suggests the use of compost as the most advisable fertilization practice and highlights the need of multiple crops analysis in evaluating the effects of long-term soil fertilization on their chemical composition.

In order to validate the use of compost in soil PAH bioremediation, the degradation of anthracene and benzo(a)pyrene was monitored in soils artificially contaminated and incubated in mesocosms under controlled conditions. The dynamics observed in compost amended soil were compared to those observed in soil added with a fungal consortium and untreated soil. At the same time, three microbial enzyme activities usually involved in PAH degradation (laccase, o-diphenol oxidase and peroxidase activities) were monitored. Both PAHs decreased along the time in the three mesocosms, with anthracene, with lower molecular weight, degrading with a higher rate and reaching lower residual values than benzo(a)pyrene. Although at the end of incubation, the residual values of investigated PAHs are similar in the three mesocosm types, PAH dynamics showed a higher degradation rate in the early stage in mesocosms added with the fungal mycelium and amended with compost. Among the three enzyme activities, only peroxidase showed higher values in treated than untreated mesocosms. Considering the ameliorating effects of compost on degraded soils, its use can be suggested in PAH bioremediation.

Choosing native vascular plants as nutrient and toxic element accumulators for passive biomonitoring of urban river quality is not an easy task in Mediterranean rivers, due to the particular climate determining high variations in river hydrology. To identify potential biomonitors for this area, the roots of seven species (Angelica sylvestris, Apium nodiflorum, Tradescantia fluminensis, Nasturtium officinale, Persicaria lapathifolia, Arctium lappa, Typha latifolia), growing in seven sites along the River Irno (Southern Italy), were collected in July 2010 and analyzed regarding their capability to accumulate Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, and Zn through atomic absorption spectrometry. Notwithstanding the expected different accumulation degree among the species, they highlighted similar spatial contamination gradients, and all of them appeared suitable, alone or in combination, for river passive biomonitoring. A. nodiflorum, in particular, appeared the best biomonitor for the River Irno, where severe anthropogenic impacts were detected: high Cu and Cd contamination from vine cultivation in the upper stretch, and Pb, Zn, and Mn contamination in the medium stretch from airborne dusts coming from a cast iron foundry.

Agricultural soils of semi-arid Mediterranean areas are often subjected to depletion of their chemical, physical, and biological properties. In this context, organic fertilization, in addition to providing nutrients for a longer time in respect to mineral fertilization, improves many other characteristics related to soil fertility. Moreover, the combined use of organic and mineral fertilizers may promote a more sustainable crop production. However, a concern on the long-term use of organic fertilizers arises in relation to the possible accumulation of toxic elements in soil and their transfer to human beings. For this reason, a long-term study on nutrient and toxic element total concentrations and availabilities during fertilization treatments was carried out. In particular, mineral NPK fertilized soils, soils amended with biowaste compost, soils amended with biowaste compost plus mineral nitrogen, and unfertilized soils were analyzed for 11 chemical elements. The results highlighted that temporal variations in total and bioavailable concentrations of both nutrients and toxic elements, occurring also in unfertilized soils, are wider than those related to fertilization treatments. Anyway, soil amendments with biowaste compost, alone or in combination with mineral fertilizers, reduce Cu bioavailability but improve K, Fe, Mn, and Zn availabilities, excluding at the same time a long-term accumulation in soil. Total and bioavailable toxic element concentrations (apart from available Cd) do not vary in relation to fertilization treatments.

Leafy vegetables have a relatively high potential for Cd uptake and translocation, and are thus considered Cd accumulators. For this reason, leaves and roots of lettuce (Lactuca sativa L.) and endive (Cichorium endivia L.) plants, grown on different agricultural soils in Campania region (southern Italy), subjected to different fertilisation treatments (unfertilisation, compost amendment and mineral fertilisation), were analysed for Cd concentrations. Moreover, to clarify if the highest concentrations found are linked to older and inedible or to younger and edible leaves, external and internal endive leaves were separately analysed. All the leafy vegetables analysed showed on average 2-fold higher Cd concentrations in leaves than in roots. Leaf Cd concentrations in both lettuce and endive plants significantly differed among fertilisation treatments, with values highest in the plants grown on mineral fertilised soils. Apart from the soil fertilisation treatments, however, Cd leaf concentrations were often higher (up to 4-fold) than the threshold deduced by the EU 420/2011 Regulation, although the plants grew on unpolluted soils. Anyway, external leaves of endive plants showed significantly higher concentrations than internal leaves (in some cases the values were 3-fold higher), partly reassuring on the consumption of the younger leaves. Moreover, this study points out two major drawbacks in the Italian and European regulatory frameworks: (1) metal concentration (as total and/or available fraction) limits in agricultural soils are lacking; (2) metal concentration thresholds (currently existing only for Cd and Pb in crops) reported in the EU 420/2011 Regulation, expressed on the fresh weight basis rather than on the dry weight basis, appear not suitable.

BACKGROUNDTomato (Solanum lycopersicum L.) is one of the most important crops in the world and represents a key crop in southern Italy. With the aim to evaluate the nutritional characteristics of tomato fruits in relation to NPK and compost fertilisation, the concentrations of the main nutrients, toxic elements, primary metabolites and total phenols were determined in two varieties (Lido and San Marzano). Each variety was cultivated in a different experimental field, subjected to different agronomic techniques.RESULTSConcentrations of toxic elements (Cd and Pb) were below the limits indicated by the EU Regulation (2011) in all the fruits analysed. Moreover, fruits obtained from San Marzano plants grown on organic amended soils showed a better overall quality than those obtained on mineral fertilised soil, being characterised by lower N (attributed to lower nitrate and nitrite concentrations), lower Cd, and higher soluble sugar concentrations. Higher concentrations of soluble sugars in fruits from organic amended soils were also observed in the Lido variety.CONCLUSIONSThe agricultural use of quality compost represents an effective strategy to obtain high quality products in an economically and environmentally sustainable way. © 2016 Society of Chemical Industry.

A vegetation analysis was carried out on a degraded agricultural soil of the Mediterranean area (Campania region, southern Italy) in order to study the effects of different fertilization practices (quality compost, mineral fertilizers, mixed fertilization, and no fertilization) on the whole spontaneous vegetation community. The study was performed for two consecutive years at three different scales (species level, community structure, and community properties), using three different units of abundance (number of individuals, biomass, and cover of each species). The observations were carried out in spring, after 5 and 6 years of soil treatments, on a total area of 4 m(2) for each soil treatment and in each year. The different fertilization practices did not determine changes in species composition; however, the relative abundance of dominant species increased in compost and mixed fertilized soils, particularly in the second year of observation. Although the dominance and diversity were unaffected by the different fertilization practices, the total biomass and total number of individuals increased in compost-amended soils. These results indicate the effectiveness of soil quality compost amendments to enhance natural revegetation, a key step in the recovery of degraded areas.

Concentrations of four heavy metals (HMs) (Cd, Cr, Fe, Pb) and four polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, phenanthrene, chrysene, benzo[a]pyrene) in Quercus ilex L. leaves collected at the Campania Region (Southern Italy) in previous air biomonitoring studies were employed to (1) test the correspondence with an a priori site subdivision (remote, periurban, and urban) and (2) evaluate long temporal trends of HM (approximately 20 years) and PAH (approximately 10 years) air contaminations. Overall, Q. ilex leaf HM and PAH concentrations resulted along the gradient: remote < periurban < urban sites, reflecting the a priori subdivision based on human management. Over a long time, although a clear decrease of leaf Pb, chrysene, fluoranthene, and phenanthrene concentrations occurred at the urban sites, a high contamination level persists.

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) were analysed in topsoil and in Quercus ilex L. leaves from holm oak woodlands located along urbanization gradients (urban, periurban and extraurban sites) in two Italian regions (Campania and Tuscany). In each sampling site, the metal bioavailability factors (MBFs) and the pollutant bioaccumulation factors (BAFs) were calculated to estimate the fraction of each total metal concentration in soil potentially available to root uptake and to know the fate of both HMs and PAHs in the plant–soil system.In general, the results indicated a low atmospheric deposition of pollutants and, in some cases, leaves and soils accumulated higher HM and PAH concentrations in the most urbanized areas. Correlation analyses showed that in each sampling site topsoil and leaves were exposed to the same atmospheric inputs of HMs and PAHs, although to a different extent. Notwithstanding the MBFs and BAFs differed between the two regions for the most HMs, they did not show a clear pattern in relation to the urbanization gradient. However, some information could be deduced by these ratios: the high BAF calculated for Mn shows that the foliar uptake plays an important role in accumulation of this metal. Moreover, for PAHs the different values of BAFs among low and high molecular weight compounds suggest their different fate, the first accumulated in leaves by stomata and the latter preferentially deposited on topsoil.