Technological change in revitalization - Phytoremediation and the role of nonknowledge

Development of simplified probabilistic models for predicting phytoextraction timeframes of soil contaminants: demonstration at the DDX-contaminated Kolleberga tree nursery in Sweden

Phytoextraction, utilizing plants to remove soil contaminants, is a promising approach for environmental remediation but its application is often limited due to the long time requirements. This study aims to develop simplified and user-friendly probabilistic models to estimate the time required for phytoextraction of contaminants while considering uncertainties. More specifically we: i) developed probabilistic models for time estimation, ii) applied these models using site-specific data from a field experiment testing pumpkin (Cucurbita pepo ssp. pepo cv. Howden) for phytoextraction of DDT and its metabolites (ΣDDX), iii) compared timeframes derived from site-specific data with literature-derived estimates, and iv) investigated model sensitivity and uncertainties through various modelling scenarios. The models indicate that phytoextraction with pumpkin to reduce the initial total concentration of ΣDDX in the soil (10 mg/kg dw) to acceptable levels (1 mg/kg dw) at the test site is infeasible within a reasonable timeframe, with time estimates ranging from 48-123 years based on literature data or 3 570-9 120 years with site-specific data using the linear or first-order exponential model, respectively. Our results suggest that phytoextraction may only be feasible at lower initial ΣDDX concentrations (< 5 mg/kg dw) for soil polishing and that alternative phytomanagement strategies should be considered for this test site to manage the bioavailable fraction of DDX in the soil. The simplified modes presented can be useful tools in the communication with site owners and stakeholders about time approximations for planning phytoextraction interventions, thereby improving the decision basis for phytomanagement of contaminated sites.

The emergence of plastic-free grocery shopping: Understanding opportunities for practice transformation

Despite consumer concern for sustainability, avoiding plastic packaging, particularly in food shopping, is difficult due to its pervasiveness and usefulness. Yet achieving changes in consumer behaviour is an important part of environmental management approaches towards a circular economy and plastic reduction. This research explores how everyday food shopping practices might adapt and evolve to become more sustainable through consumers avoiding, reducing, or replacing plastic packaging in their grocery shopping. This qualitative research, based on eighteen semi-structured interviews with sustainably-oriented consumers, finds that plastic-free shopping practices are challenging for even committed practitioners. However, we illuminate four mechanisms representing 'bright spots' (i.e., points of optimism) that offer specific opportunities for environmental management. We define these as destabilisation, envisioning, emotional connection and adaptation. Destabilisation and envisioning help with recruitment of practitioners to plastic-free shopping, and emotional connection and adaptation help support practitioner loyalty and commitment. Further, consumer reflexivity and habituated sustainable-orientation supports practice recruitment, stabilisation and transition. We discuss the implications of our findings for environmental management approaches to 'behaviour change', focusing on the role of policymakers, social marketers, retailers, and manufacturers in fostering competitive, stable plastic-free grocery shopping.

Plant-Based Innovations for the Transition to Sustainability: A Bibliometric and in-Depth Content Analysis

Plants maintain the ecological equilibrium of the earth and stabilize the ecosystem. Today, traditional commodities and new value-added markets can be served simultaneously. There is significant biosource and bioprocess innovation for biobased industrial products. Furthermore, plant-based innovation is associated with the transition to sustainability. This study performed a bibliometric and in-depth content analysis to review plant-based innovations in the research field between 1995 and 2022. A set of 313 articles was identified from the Scopus and Web of Science databases. Different analytical scientometric tools (topic mapping and overlay visualization networks) were used to analyze 124 articles; the most influential countries, institutions, authors, journals and articles were identified. Through in-depth studies, based on the grounded theory approach, five leading research areas related to plant-based innovation were determined: (1) agricultural/environmental innovation, (2) plant-based food or feed innovation, (3) innovation within the medical/pharmaceutical research area, (4) technology-related innovation and (5) economic/business aspects of plant-based innovations. Future research directions include exploring less examined and new topics, such as the sustainability implications of incorporating various plant-based foods and Industry 4.0 in plant-based innovation, and linking and developing findings from different research areas.

Restoring HCHs polluted land as one of the priority activities during the UN-International Decade on Ecosystem Restoration (2021-2030): A call for global action

The United Nations General Assembly has recently declared 2021-2030 as the 'International Decade on Ecosystem Restoration' for facilitating the restoration of degraded and destroyed terrestrial and marine systems for regaining biodiversity and ecosystem services, creating job opportunities and also to fight against climate change. One of the prime focus is the restoration of ~350 mha of degraded land across the world for attaining the UN-Sustainable Development Goals. Pesticides are one of the major causes of land pollution and hexachlorocyclohexanes (HCHs, including technical-HCH and γ-HCH) is one of the widely used organochlorine pesticides during the past seven decades before α-, β-, and γ-HCH was listed in the Stockholm Convention in 2009. The widespread pollution of HCHs has been reported from every sphere of the environment and ~7 Mt of HCHs residues have been dumped worldwide near the production sites. HCHs isomers have higher volatility, water solubility and long-range atmospheric transport ability which further facilitates its entry into various environmental compartments. Therefore, the restoration and management of HCHs polluted land is urgently required. Despite various pilot-scale studies have been reported for the remediation of HCHs polluted land, they are not successfully established under the field conditions. This is mainly due to the high concentration of HCHs residues in the contaminated soil and also due to its toxicity and highly persistent nature, which increases the complexity of the onsite remediation. Here we provide a novel approach i.e. sequential and integrated remediation approach (SIRA) for the restoration of HCHs contaminated land by the integrated use of agroresidues along with the application of HCHs degrading microorganisms and chemical amendments followed by the plant-based clean-up techniques using grasses, herbs, shrubs and trees in a sequential manner. SIRA provides cost effective solution with enhanced ecological and socioeconomic benefits for the sustainable restoration of HCHs contaminated sites.

Intermittent lead-induced stress on antioxidant enzyme activity and subcellular distribution of Pb in Pogonatherum crinitum seedlings

Pogonatherum crinitum is a promising lead (Pb) hyperaccumulator due to its high Pb tolerance and accumulation ability. However, the mechanisms that support Pb accumulation and tolerance in P. crinitum are not yet clearly understood. An indoor hydroponic experiment was conducted by cultivating P. crinitum seedlings exposed to intermittent Pb stress for 60 days, divided into four stages (T1, T2, T3 and T4), with a 15-day duration per stage. The following concentrations of Pb were used: 0, 500, 0, 500 mg·l^-1 and 0, 1000, 0, 1000 mg·l^-1 ). Antioxidant enzyme activity, Pb concentration and subcellular distribution of Pb were measured at each of the above stages. The results showed that superoxide dismutase (SOD) activity in shoots, and SOD, peroxidase (POD) and malondialdehyde (MDA) activity in shoots and roots significantly increased from T1 (no Pb stress) to T2 (Pb stress) in both 500 mg·l^-1 and 1000 mg·l^-1 treatments; however, no significant difference was noted between stages T3 (no Pb stress) and T4 (Pb stress). There was no obvious effect of Pb stress on catalase (CAT) activity in shoots and roots among different stages. The Pb concentration in shoots was up to 5090.90 mg·kg^-1 and 7573.57 mg·kg^-1 , and the bioconcentration factor (BFC) was 10.18 and 7.57 for the 500 mg·l^-1 and 1000 mg·l^-1 treatments, respectively, which confirmed the Pb hyperaccumulator characteristics of P. crinitum. For plants under Pb stress, most of the Pb was fixed in the cell walls, with a smaller amount in leaves and root vacuoles. Both SOD and POD scavenging of reactive oxygen radicals and fixing and compartmentalisation of Pb in the cell wall might play important roles in detoxification of P. crinitum seedlings in response to Pb stress. There was no phased response of P. crinitum to intermittent Pb stress and the physiological response to Pb stress may be contiguous.

The effect of bioaugmentation of petroleum-contaminated soil with Rhodococcus erythropolis strains on removal of petroleum from soil

The aim of the study was to assess the impact of inoculation of petroleum-contaminated soil with the hydrocarbon-degrading bacterial strains Rhodococcus erythropolis CD 130 and CD 167 or their consortium on the removal of hydrocarbons from the soil. Additionally, changes in the activity and structure of soil autochthonous bacterial communities were studied. At the end of the experiment, the fastest hydrocarbon removal was seen in the soil treated with the CD 167 strain (38.40%) and was statistically higher compared to the removal of total petroleum hydrocarbons (TPH) observed in soils inoculated with strain CD 130 (29.8%) or bacterial consortium CD 130 + CD 167 (29.72%). The rifampicin-resistant CD 130 and CD 167 strains, introduced as single strains or a consortium, survived in the soil for 42 days. The introduction of gram-positive strains of R. erythropolis primarily caused an increase in the biomass of branched phospholipid fatty acids (PLFAs), characteristic for gram-positive bacteria. Nevertheless, changes in the concentrations of gram-positive and gram-negative PLFA markers were periodic, and at the end of the experiment, significant changes were observed only in the case of the soil bioaugmented with the CD 167 strain. After the bioaugmentation, higher values of substrate-induced respiration (SIR) were observed in all the inoculated soils compared to the non-inoculated control. Nonetheless, after 91 days of incubation, a significant decrease in soil respiration was observed in the soil treated with single CD 130 or CD 167 strains or with their consortium. The number of transcripts of the CYP153 gene obtained on days 91 and 182 reflected the results of the hydrocarbon loss. The level of expression of the alkH gene in experimental soil was estimated and found to be higher than the level of expression of the CYP153 gene but did not coincide with the loss of hydrocarbons. The introduction of strains CD 130, CD 167, or CD 130 + CD 167 caused temporary changes in the composition of the soil autochthonous bacterial community, but it seems that these changes were needed for the enhanced removal of hydrocarbons from this soil.

Biosurfactant-assisted phytoremediation of multi-contaminated industrial soil using sunflower (Helianthus annuus L.)

This study evaluated the use of commercial rhamnolipid biosurfactant supplementation in the phytoremediation of a soil via sunflower (Helianthus annuus L.) cultivation. The soil, obtained from an industrial area, was co-contaminated with heavy metals and petroleum hydrocarbons. The remediation tests were monitored for 90 days. The best results for removal of contaminants were obtained from the tests in which the sunflower plants were cultivated in soil with 4 mg kg^-1 of the rhamnolipid. Under these conditions, reductions of 58% and 48% were obtained in the total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) concentrations, respectively; reductions in the concentrations of the following metals were also achieved: Ni (41%), Cr (30%), Pb (29%), and Zn (20%). The PCR-DGGE analysis of soil samples collected before and after the treatments verified that the plant cultivation and biosurfactants supplementation had little effect on the structure of the dominant bacterial community in the soil. The results indicated that sunflower cultivation with the addition of a biosurfactant is a viable and efficient technology to treat soils co-contaminated with heavy metals and petroleum hydrocarbons.

A Methodology to Evaluate Ecological Resources and Risk Using Two Case Studies at the Department of Energy's Hanford Site

An assessment of the potential risks to ecological resources from remediation activities or other perturbations should involve a quantitative evaluation of resources on the remediation site and in the surrounding environment. We developed a risk methodology to rapidly evaluate potential impact on ecological resources for the U.S. Department of Energy's Hanford Site in southcentral Washington State. We describe the application of the risk evaluation for two case studies to illustrate its applicability. The ecological assessment involves examining previous sources of information for the site, defining different resource levels from 0 to 5. We also developed a risk rating scale from non-discernable to very high. Field assessment is the critical step to determine resource levels or to determine if current conditions are the same as previously evaluated. We provide a rapid assessment method for current ecological conditions that can be compared to previous site-specific data, or that can be used to assess resource value on other sites where ecological information is not generally available. The method is applicable to other Department of Energy's sites, where its development may involve a range of state regulators, resource trustees, Tribes and other stakeholders. Achieving consistency across Department of Energy's sites for valuation of ecological resources on remediation sites will assure Congress and the public that funds and personnel are being deployed appropriately.