In the context of circular economy, biosolids from three WWTPs (WWTP1, 2 and 3) in Northern Greece were tested for their metal content (pseudo-total and leachate content) and their ecotoxicity on D. magna neonates, as part of a risk assessment strategy. Results showed metal concentration much lower than the limits of Greek legislation for use in agriculture. Low but nonnegligible toxicity on D. magna was detected, irrespective of biosolids' origin or seasonality. Biosolids from WWTP1 were applied against Verticillium wilt of pepper plants caused by the fungus Verticillium dahliae. These biosolids had undergone additional processing in relation to previous research in 2018-2019, but this did not alleviate D. magna toxicity whilst it affected metal leachate in the following ways: in the EN-12457-2 leaching test, Ni and Zn content were increased in relation to previous research; Cu leaching was variable, while Pb, Cd (and Hg) remained undetectable. A correlation between D. magna toxicity and Cr concentration in the leachates was observed but it did not reach statistical significance. Regarding their ability to act as phytoprotective agents, biosolids incorporation at 2 % w/w reduced wilt severity caused by V. dahliae on pepper. Similar results have previously been observed for Fusarium root rot of tomato. Plant growth characteristics were not enhanced in healthy plants. However, several growth parameters characteristics were promoted in the presence of the pathogen as also noted in our previous research. The results encourage research into novel agronomic uses of biosolids, including their use to produce novel plant growth boosters.

The amended Waste Framework Directive (WFD) highlights the circular use of resources and the minimization of solid waste. To align with these concepts, the Greek Law is now implementing pay-as-you-throw (PAYT) systems and Rewarding Recycling (RR) schemes and establishing incorporated Green Points (GPs) and Recycling Corners (RCs). These additions aspire to enhance source separation and to facilitate recycling so that materials can be re-used. In order to assess the public opinion on these measures, a web-based questionnaire aimed at citizens of 5 municipalities of Thessaloniki Regional Area in Northern Greece was answered by 1614 respondents. The questionnaire assessed their degree of knowledge on PAYT, RR and GPs RCs, as well as their attitude on the usefulness of these schemes. Results showed in general a lack of knowledge of these schemes, however many interviewees agreed that these governmental policies will increase recycling and will contribute to sustainable waste management (WM). Older people (56–65 years old) were more favorably inclined towards some of these policies; women rather than men were more favorably inclined towards GPs and RCs, while young people were generally more indifferent. These results show that: 1) the expected time-related goals of the new Greek WM policies should urgently be re-evaluated 2) the social participation aspect should urgently be enhanced via targeted informative campaigns 3) campaigns aimed specifically at young people should be created, aspiring to instigate, engage, educate and inform.

Appropriate solid municipal waste management is an important topic in the EU. Abiding by the amended EU Waste Framework Directive and the amended EU Landfill Directive, Greece has set ambitious goals for waste reuse and recycling and for landfill minimization in its recent National Waste Management Plans. These goals however can only be reached through the improvement of the mixed recyclable waste scheme (the "blue bin" scheme for paper/carton, plastic and metal) and the establishment of collection containers for separate waste streams (separately for biodegradable waste, for glass, for paper/carton and for the rest). Active participation of citizens in waste source separation is paramount for this program. As such, the determinants that favor waste source separation intention were measured in approximately 1600 residents in the city of Thessaloniki in Northern Greece, through the application of the Theory of Planned Behavior (TPB). The determinant of Moral Norms (MN) was included in the basic model [that contains the determinants Attitude (ATT), Subjective Norms (SN) and Perceived Behavioral Control (PBC)]. Each determinant was measured through four or five declarations while the Behavioral Intention (BI) contained ten subsections. The model was able to satisfactorily predict the intention of the respondents to perform waste source separation. Specifically, the model successfully predicted respondents' intention to engage in waste source separation, explaining 36 % of the variance, indicating that a moderate amount of variance can be explained by the constructs. There was a significant direct effect of ATT (β = 0.486, p < 0.001), SN (β = 0.091, p < 0.05), and PBC (β = 0.091, p < 0.05) on BI. Additionally, MN showed statistically significant mediating effects; a mediating effect on BI via ATT (β = 0.479; p < 0.01), via SN (β = 0.046; p = 0.015), and via PBC (β = 0.057; p = 0.017) was noted. Implications of these results on waste separation policies include the following: launching comprehensive public education campaigns to reshape positive attitudes, improving infrastructure to strengthen the real or perceived behavioral control of citizens experience, increasing "peer pressure" via community engagement activities, such as recycling workshops, clean-up drives, and competitions. The important role of moral obligations in the community should be underlined and it may be the long-term key solution; educational programs and campaigns should emphasize the moral obligation of waste separation and integrating environmental ethics into school programs can instill these values from a young age.

Processing Waste of Electrical and Electronic Equipment (WEEE) causes serious environmental problems, especially when WEEE is processed in uncontrolled conditions. WEEE recycling under controlled conditions consists of the following major steps: disassembly, upgrading and refinement. Disassembly is usually done manually, and, at this stage, certain components (cases, external cables, cathode ray tubes [CRTs], printed circuit boards [PCBs], batteries etc.) are separated. This activity releases coarse and fine particles, which may also contain additional noxious substances, into the atmosphere. The current study determines the concentration of indoor PM10 in a Greek plant for the dismantling and temporary storage of WEEE, based on a short-term sampling campaign. Elemental concentrations in the PM10 have also been determined. Results show that the indoor PM10 concentration in the disassembly area did not exceed the time-weighted average (TWA) for total particles set by Greek legislation or the 8-h TWA for total particles set by the Occupational Safety and Health Administration (OSHA). Nevertheless, these concentrations were higher than those measured in the ambient air of Greek cities. Regarding the measured elements, Zn, As, Br, Pb and Cd were quite enriched in PM10, indicating significant indoor sources. Factor analysis of elements of possible anthropogenic origin showed a clear distinction between cathode ray tubes (CRT) and other possible sources. Finally, the risk assessment for metals of toxicological concern showed a non-negligible lifetime risk for 8-h workers. This is the first report of WEEE indoor air pollution in Greece and its associated origins and effects.

Effective recycling is the key issue for the sustainable management of Municipal Solid Wastes (MSW), to achieve the substantial decrease of their amounts requiring further management and landfilling. The basic concepts related to the effective management of MSW and recyclable materials (RM) are analyzed in this study, in order to find out the key factors for achieving increased recycling rates. A survey was developed and distributed to citizens of the Prefecture of Central Macedonia (PCM), the 2nd major prefecture of Greece. The now used recycling process for the collection of RMs in PCM, based on the Blue Bin system and the collection of mixed RMs, was tried to be evaluated in terms of the achievement of the recycle target goals. The main factors responsible for the low recycling yields (< 20

Lake Koronia in Greece, a wetland of ecological significance, benefits from dual protection under the Ramsar Convention and the Natura 2000 network and serves as a thriving habitat for diverse plant and animal species. Regrettably, this crucial European biotope has experienced a substantial decline in environmental quality over the last 30 years, primarily due to the continuous extraction of groundwater for irrigation and the subsequent deterioration of water quality. This situation has resulted in water scarcity, environmental degradation, and a loss of biodiversity. The central objective of this research was to document the perspectives and attitudes of local farmers operating within the Lake Koronia basin concerning environmental preservation and agricultural practices. To achieve this, we employed structured questionnaires utilizing a Likert scale during one-on-one interviews. These findings were directly compared to previous research outcomes, providing insight into whether there have been shifts in opinions, particularly in light of the gradual implementation of restoration efforts in the area. While most farmers acknowledge Lake Koronia's international protection status, many do not readily accept responsibility for its deterioration stemming from excessive water extraction and nitrogen pollution. However, there is a notable willingness among the surveyed farmers to transition to alternative fertilization methods, cultivate less water-intensive crops, adopt improved agricultural practices, and even explore opportunities in ecotourism. This study's significance lies in the fact that any effective water management plan relies heavily on the acceptance and active engagement of the individuals dependent on the water resource. As part of an updated water management plan for Lake Koronia, the results from this study can form a valuable database concerning social parameters and considerations, facilitating more informed decision-making and sustainable practices in the region.

Sustainable patterns of production and consumption dictate waste elimination and the modest use of resources in uncontaminated environments. However, this is not always possible, especially in urban settings, since soils may be enriched with various metals and metalloids, and this may pose a threat to the city’s residents. Urban soils have not received the same degree of interest as agricultural soil, where crops are cultivated, but the risk of exposure of humans to soil pollutants is real in urban settings. For this reason, in the present study, soil samples from public green spaces in Thessaloniki, Northern Greece, were collected in March 2022. Soil physicochemical characteristics (% of sand, silt and clay, pH and electrical conductivity) as well as the pseudo-total concentrations of Cu and of Zn (mg/kg dry weight soil) were determined for 50 distinct sites in the city. The risk to inhabitants was determined for the oral and dermal routes in both adults and children. The pseudo-total concentrations of Cu and of Zn were variable, with some sites exhibiting concentrations higher than the EU set limits for soil treated with municipal sludge or than the Canadian Soil Quality Guidelines. The risk to adults and children was acceptable in every case. The high correlation between the Cu and Zn pseudo-total concentrations as well as the locations of the most polluted sites point to input from anthropogenic activities. These activities may include train and automobile traffic, as well as operations within the city's commercial and passenger port. Even though it is not as well studied as soil pollution in agriculture, soil pollution in cities should be given proper attention.

Industry is an integral part of the economic activity of any country [...]

Considering the main objectives of a circular economy, Lemnaceae plants have great potential for different types of techniques to valorize their biomass for use in biofuel production. For this reason, scientific interest in this group of plants has increased in recent years. The aim of this study was to evaluate the effects of salt stress on the growth and development of S. polyrrhiza and the valorization of biomass for biofuel and energy production in a circular economy. Plants were grown in a variety of culture media, including standard 'Z' medium, tap water, 1% digestate from a biogas plant in Piaszczyna (54° 01′ 21″ N, 17° 10′ 19″ E), Poland) and supplemented with different concentrations of NaCl (from 25 to 100 mM). Plants were cultured under phytotron conditions at 24 °C. After 10 days of culture, plant growth, fresh and dry biomass, as well as physio-chemical parameters such as chlorophyll content index, gas exchange parameters (net photosynthesis, transpiration, stomatal conductance and intercellular CO 2 concentration), chlorophyll fluorescence measurements were analyzed. After 10 days of the experiment, the percentage starch content of Spirodela shoot segments was determined. S. polyrrhiza was shown to have a high starch storage capacity under certain unfavorable growth conditions, such as salt stress and nutrient deficiency. In the W2 (50 mM NaCl) series, compared to the control (Control2), starch levels were 76% higher in shoots and 30% lower in roots. The analysis of the individual growth and development parameters of S. polyrrhiza plants in the experiment carried out indicates new possibilities for the use of this group of plants in biofuel and bioethanol production.

The European Green Deal proposes the reuse of any kind of waste that can be safely repurposed; sludge may also be reused as a biosolid. The present research aims to evaluate a biosolid made from sludge, originating from a wastewater treatment plant (WWTP) for its effect on tomato growth and enhancement of tolerance against the phytopathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici (Forl). Peat and/or two soil types were amended with biosolid (0, 80 and 160 tons/ha) to form substrates on which tomato plants were grown either under controlled conditions, in a growth chamber or outdoors, in a net protected area. Plant growth and disease parameters were recorded 4–7 weeks after application of Forl inoculum in the substrates. Results showed that biosolid addition enhanced plant growth and increased tolerance against tomato foot and root rot caused by Forl. Specifically, fresh weight, root weight, stem height and leaf number of tomato plants in Forl-inoculated soils that had received biosolid, were increased when compared to Forl-inoculated control soils. Forl resulted in higher disease severity on plants grown outdoors in biosolid plus clay soil than in biosolid plus sandy soil, while the opposite occurred under controlled conditions where higher disease index was recorded on plants grown in peat plus sandy soil than in peat plus clay soil. These findings strongly suggest that this biosolid may act as an organic fertilizer and possible stimulant of tomato tolerance against Forl, and the effect is soil type dependent. Therefore, this biosolid should be considered for its possible use in agriculture according to the principles of circular economy and waste minimization. • Biosolid addition enhances tomato growth in different substrates and conditions. • Disease is less severe on plants grown on soil mixed with biosolid. • In the outdoors trial biosolid renders higher disease tolerance in sandy soil. • Fusarium disease is less aggressive on tomato plants grown on biosolid mix. • Tolerance to disease is higher in sandy soil+biosolid than in clay soil+biosolid.

Biosolid application is an effective strategy, alternative to synthetic chemicals, for enhancing plant growth and performance and improving soil properties. In previous research, biosolid application has shown promising results with respect to tomato resistance against Fusarium oxysporum f. sp. radicis-lycopersici (Forl). Herein, we aimed at elucidating the effect of biosolid application on the plant–microbiome response mechanisms for tomato resistance against Forl at a molecular level. More specifically, plant–microbiome interactions in the presence of biosolid application and the biocontrol mechanism against Forl in tomato were investigated. We examined whether biosolids application in vitro could act as an inhibitor of growth and sporulation of Forl. The effect of biosolid application on the biocontrol of Forl was investigated based on the enhanced plant resistance, measured as expression of pathogen-response genes, and pathogen suppression in the context of soil microbiome diversity, abundance, and predicted functions. The expression of the pathogen-response genes was variably induced in tomato plants in different time points between 12 and 72 h post inoculation in the biosolid-enriched treatments, in the presence or absence of pathogens, indicating activation of defense responses in the plant. This further suggests that biosolid application resulted in a successful priming of tomato plants inducing resistance mechanisms against Forl. Our results have also demonstrated that biosolid application alters microbial diversity and the predicted soil functioning, along with the relative abundance of specific phyla and classes, as a proxy for disease suppression. Overall, the use of biosolid as a sustainable soil amendment had positive effects not only on plant health and protection, but also on growth of non-pathogenic antagonistic microorganisms against Forl in the tomato rhizosphere and thus, on plant–soil microbiome interactions, toward biocontrol of Forl.

Biosolids made from municipal sludge are an attractive solution instead of chemical fertilization. Nevertheless, their effects on the ecosystem should always be considered. In the present study, anaerobically digested sludge was subjected to two leaching methods (EN 12457-2 and NEN 7341) and the main physicochemical parameters were measured in the leachates. The aquatic organisms Daphnia magna and Vibrio fischeri were exposed to the leachates in order to test for adverse effects. Mixtures of biosolid/solid, simulating the high dose of 80 tn/ha, were also created, and the same parameters were measured for EN 12457-2 leachates. The results show a strong seasonal variation for the results for the municipal sludge, even though the sludge did not originate from a touristic area. The biosolid/solid mixtures did not produce toxic responses to the organism tested. Nevertheless, the parameters nitrites and nitrates in the leachates were increased in relation to control and they continued to increase even at Day 40 post-application. This increase was soil-type-dependent. The biosolids in question could be used for field fertilization, however measures should be taken against underground water nitrate pollution.

Sludge-based biosolids can be used for crop fertilization and for soil enrichment with organic matter. The prerequisites for their application are laid out in 86/278/EEC which sets limits for metals of toxicological concern in the biosolid and in the recipient soil. In this context, three kinds of sludge-based biosolids from a municipal wastewater treatment plant were submitted to the leaching tests EN 12457-2 and ΝΕΝ 7341. The leachates were examined for their physicochemical, chemical, and ecotoxicological characteristics four times within a year. Even in the more aggressive metal leaching method (ΝΕΝ 7341), results were much lower than the limits set in Council Directive 86/278/EEC. Correlations were noted between numerous parameters and principal component analysis grouped them in 3 components explaining 76% of total variation. These leaching tests were also performed on soil-biosolid samples from another investigative research in which two of the three kinds of biosolids had been incorporated in corn fields at doses 0, 20, and 40 tn/ha. EN 12457-2 leaching tests indicated that Ni and Cd leaching was affected by biosolid incorporation in soil, in relation to the type of the receiving soil (clay or sand). The leachates from the soil-biosolid mixtures were practically not toxic for the organisms tested (D. magna, V. fischeri, higher plants). In summary the biosolids were considered of low environmental risk when utilized in the field. A detailed risk assessment encompassing both chemical and ecotoxicological analysis is necessary for integrated evaluation of biosolids.

The status of waste of electrical and electronic equipment (WEEE) recycling in a middle-sized industrialized city in Greece has been investigated, through the application of structured questionnaires to 310 citizens from the municipal units of Volos and Nea Ionia, asking for their habits and opinions on this kind of recycling. The underlying factors affecting the intention of these citizens to perform WEEE recycling were investigated, applying aspects of the Theory of Planned Behavior (TPB). Results show that there is an underperformance of WEEE recycling with 57% of the sample answering that they have never participated in WEEE recycling. A number of behavioral factors, based on TPB predictors, affect the intention of these citizens to participate in WEEE recycling schemes, namely total attitude, willingness to pay, information status regarding WEEE recycling and subjective norm. These findings may aid in improving marketing strategies for WEEE recycling of the general public. Investigation into pro-environmental incentives in Greece and in other countries with similar WEEE recycling management is urgently needed.

Wastewater is not a waste but a valuable resource that should be reused. Nevertheless, it should be devoid of physical, chemical, and microbiological parameters that can harm the consumer. Along with the multitude of possible pollutants found in wastewater treatment plants (WWTPs), emerging pollutants, such as Personal Care Products (PCPs), have arisen. The present research examines some of the main ingredients commonly found in PCPs, focusing on their toxicological profile on their occurrence in WWTPs influents and effluents worldwide and on their persistence and biodegradability. A small-scale market sampling of PCPs was performed in Athens, Greece, in June 2019, and their individual ingredients were recorded, coded according to their main activity, scanned for the presence of ingredients of important toxicological profile, and finally analyzed for the presence of other candidates of toxicological interest. Results show that some ingredients of concern (i.e., parabens and triclosan) are a decreasing trend. On the other hand, information on the presence of synthetic musks and perfume synthesis is scarce and encumbered by brand protection. Finally, UV filters are numerous, and they are used in various combinations, while other ingredients of toxicological interest are also present. Since the reclaimed water may well be used to cover irrigation needs in Greek areas with water deficiency or to enrich bodies of surface water, it is important to know what PCP ingredients are on the rise in the market, to monitor their presence in WWTPs influents and effluents and to extend research on their environmental fate and behavior.

Investigations on the fluctuation in PM10 air pollution in Volos, a medium-sized industrialized port city in the Mediterranean, are presented for the 5-year period between 2009 and 2014. The levels detected have been examined in relation to legislatively set limits, sampling year, and day of the week. A PM10 spring sampling campaign has been performed in 2014 and metals and other elements in the PM10 mass have been quantified. Source origin has been attempted for the latter sampling campaign and human health risk has been assessed. Results show compliance with the mean annual value of 40g m(-3) of 2008/50/EC for the city; however, exceedances of the daily quality standard of 50g m(-3) were frequently recorded. Shifts in PM10 concentrations and in contributing sources have been recorded; nevertheless, longer duration data series are needed for safe deductions. Element measurements have enabled source identification for early summer of 2014, with Earth's crust minerals and anthropogenic sources being the main factors. Cumulative non-carcinogenic risk may exceed the threshold value of 1. Possible involvement of sea salt aerosol and desert dust long-range transport has also been assessed. These results may furnish databases on PM pollution of Greek cities as well as other Mediterranean urban centers with similar characteristics.

A hybrid source-receptor modeling process was assembled, to apportion and infer source locations of PM10 and PM2.5 in three heavily-impacted urban areas of Greece, during the warm period of 2011, and the cold period of 2012. The assembled process involved application of an advanced computational procedure, the so-called Robotic Chemical Mass Balance (RCMB) model. Source locations were inferred using two well-established probability functions: (a) the Conditional Probability Function (CPF), to correlate the output of RCMB with local wind directional data, and (b) the Potential Source Contribution Function (PSCF), to correlate the output of RCMB with 72h air-mass back-trajectories, arriving at the receptor sites, during sampling. Regarding CPF, a higher-level conditional probability function was defined as well, from the common locus of CPF sectors derived for neighboring receptor sites. With respect to PSCF, a non-parametric bootstrapping method was applied to discriminate the statistically significant values. RCMB modeling showed that resuspended dust is actually one of the main barriers for attaining the European Union (EU) limit values in Mediterranean urban agglomerations, where the drier climate favors build-up. The shift in the energy mix of Greece (caused by the economic recession) was also evidenced, since biomass burning was found to contribute more significantly to the sampling sites belonging to the coldest climatic zone, particularly during the cold period. The CPF analysis showed that short-range transport of anthropogenic emissions from urban traffic to urban background sites was very likely to have occurred, within all the examined urban agglomerations. The PSCF analysis confirmed that long-range transport of primary and/or secondary aerosols may indeed be possible, even from distances over 1000km away from study areas.