Positive impacts in social life cycle assessment: state of the art and the way forward

Purpose

Social life cycle assessment (SLCA) is a methodology under continuous development, which may be applied at different scales: from products to economic sectors up to systems at region (meso) and country (macro) scales. Traditionally, SLCA has been focusing on the assessment of negative social externalities, whereas also positive social impacts could be associated to human interventions. The purpose of the present study is to understand how positive impacts are defined in published literature and how they could be assessed through indicators. The aim is to clarify the concept among scholars and to support decision making in business and policy context.

Methods

The study uses a systematic review approach in order to analyse the types of indicators adopted. In the field of SLCA and according to Paragahawewa et al. (2009), “[I]ndicators are ‘pointers’ to the state of the impact categories (and/or subcategories) being evaluated by the SLCA”. Indicators can be quantitative, semi-quantitative or qualitative (UNEP/SETAC 2009). This review was carried out in order to identify and analyse positive impacts and indicators. After careful scrutiny, 47 papers containing theoretical frameworks were considered, as well as 46 papers presenting case studies.

Results and discussion

Compared to environmental life cycle assessment (E-LCA), where the presence of positive impacts is lower, evaluating benefits or positive impacts can still play a major role in SLCA (Benoît et al. 2010). A quarter of the analysed papers on theoretical frameworks take into account the topic of positive impacts and indicators. Results from case study analysis highlight as “workers”, was the most considered stakeholder (in 100 % of the analysed papers), and as the majority of positive indicators used in the case study analysed are recorded in relation to “other value chain actors”. Within the concept of “positive impacts”, no reference should be made merely to the utility of a product or service. In a broader sense, we could refer to solutions improving the conditions of one or various stakeholders involved. In other words, these are solutions that carry a positive contribution to one or more stakeholders without harming others.

Conclusions

So far, positive impacts are barely covered in literature. There is a clear need of streamlining definition and indicators, especially if they should be applied in a policy context complementing traditional—and often monetary-based, cost-benefit analysis (CBA).

     

Control of crops leaf growth by chemical and hydraulic influences

Three species of forage grasses (Festuca arundinacea, Eragrostiscurvula, Sporobolus stapfianus) commonly grown in the Mediterraneanregion were subjected to a soil drying treatment. Leaf growthrate in F. arundinacea was highly sensitive to soil drying andlow growth rates were associated with high laminar turgors.The production of ABA was stimulated by soil drying and therewas a clear relation between increasing ABA accumulation andreduction in leaf growth. Leaf growth of E. cutvula, a C⁴ warmseason grass, was relatively insensitive to soil drying whichwas not accompanied by a substantial increase in leaf ABA content.S. stapfianus, a resurrection plant, was highly sensitive todecreasing soil water availability. In these two latter species,leaf growth was substantially restricted before ABA accumulationoccurred. It is suggested that reductions in laminar turgorof E. curvula and S. stapfianus may be limiting leaf growthas soil dries. The results indicated a different mechanism ofsensing and responding to reduction in soil water availabilityfor the three species studied. The relative importance of thechemical and hydraulic control of leaf growth is discussed. Key words: Leaf growth, water relations, abscisic acid, Festuca arundinacea, Eragrostis curvula, Sporobolus stapfianus     

Expression of recombinant human granulocyte colony-stimulating factor in CHO dhfr cells: new insights into the in vitro amplification expression system

The in vitro amplification method for heterologous gene expression in mammalian cells is based on the stable transfection of cells with long, linear DNA molecules having several copies of complete expression units, coding for the gene of interest, linked to one terminal unit, coding for the selectable marker. DNA concatenamers containing additional expression units can also be prepared: we exploited this feature by co-polymerizing expression units coding for granulocyte colony-stimulating factor (G-CSF) with cassettes for dihydrofolate reductase (DHFR) and for neomycin (Nm) resistance, as selectable markers. We were thus able to obtain high level production of G-CSF in chinese hamster ovary (CHO) dhfr^- cells by combining in vitro amplification to just one step of in vivo amplification. This approach required a considerably shorter time than the classical, stepwise amplification by methotrexate.     

A distance-to-target weighting method for Europe 2020

Purpose

Distance-to-target (DTT) methods are weighting methods aimed at assessing the distance of an existing situation from a desired state (the target). Weighting factors in DTT methods could be based on calculation which is performed on normalization factors (NFs) developed for life cycle assessment (LCA). At present, some DTT weighting sets have been developed. However, there is no DTT weighting set assessing the distance of EU domestic impacts from the desired state set by EU binding or non-binding policy targets (e.g., those related to the “Climate and Energy Package” and the “Roadmap to a Resource Efficient Europe”).

Methods

In the present work, a methodology to derive target references from policy-based targets in 2020 (TRs2020), both binding (A) and non-binding (B), is presented. Resulting target factors and DTT weighting factors are then compared to the current normalisation factors (based on 2010 normalization references). The resulting weighting factor (WF) sets are presented and discussed in light of their use for decision support in policy and business contexts. We applied the WF sets to characterization results to an example (the EU energy mix process) aiming at illustrating key differences and effects on the results.

Results and discussion

The three reference sets (NRs2010, TRs2020A, and TRs2020B) show, in some impact categories, a relatively small difference. WFs referred to set A and set B result to be quite similar, with the only exception of water depletion impact category, for which a very relevant change is foreseen when considering the effect of the non-binding target of limiting the abstraction of water resource to 20 % of the available renewable water resources. This is mainly due to the higher difficulty in deriving quantitative targets from non-binding strategies and policies rather than from binding ones.

Conclusions

The resulting weighting sets present strengths and limitations. The translation of policy targets into quantitative modifications to the baseline inventories appeared to be not a straightforward task, due to several reasons discussed in the paper (e.g., not all the policy targets are expressed in quantitative terms or can be translated into quantitative reductions and modifications of the elementary flows in the existing baseline inventories). Aiming at improving the effectiveness in supporting policies, further development of the methodology may be the integration with other DTT approaches such those based on carrying capacity, developed to integrate Earth’s carrying capacity concept and planetary boundaries.

     

Humic substances biological activity at the plant-soil interface: From environmental aspects to molecular factors

Humic substances (HS) represent the organic material mainly widespread in nature. HS have positive effects on plant physiology by improving soil structure and fertility and by influencing nutrient uptake and root architecture. The biochemical and molecular mechanisms underlying these events are only partially known. HS have been shown to contain auxin and an “auxin-like” activity of humic substances has been proposed, but support to this hypothesis is fragmentary. In this review article, we are giving an overview of available data concerning molecular structures and biological activities of humic substances, with special emphasis on their hormone-like activities.Key words: auxin, humic substances, root, soil, sustainable agriculture     

Identification of horizontally transferred genes in the genus Colletotrichum reveals a steady tempo of bacterial to fungal gene transfer

Background

Horizontal gene transfer (HGT) is the stable transmission of genetic material between organisms by means other than vertical inheritance. HGT has an important role in the evolution of prokaryotes but is relatively rare in eukaryotes. HGT has been shown to contribute to virulence in eukaryotic pathogens. We studied the importance of HGT in plant pathogenic fungi by identifying horizontally transferred genes in the genomes of three members of the genus Colletotrichum.

Results

We identified eleven HGT events from bacteria into members of the genus Colletotrichum or their ancestors. The HGT events include genes involved in amino acid, lipid and sugar metabolism as well as lytic enzymes. Additionally, the putative minimal dates of transference were calculated using a time calibrated phylogenetic tree. This analysis reveals a constant flux of genes from bacteria to fungi throughout the evolution of subphylum Pezizomycotina.

Conclusions

Genes that are typically transferred by HGT are those that are constantly subject to gene duplication and gene loss. The functions of some of these genes suggest roles in niche adaptation and virulence. We found no evidence of a burst of HGT events coinciding with major geological events. In contrast, HGT appears to be a constant, albeit rare phenomenon in the Pezizomycotina, occurring at a steady rate during their evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-16-2) contains supplementary material, which is available to authorized users.     

Alfalfa plant-derived biostimulant stimulate short-term growth of salt stressed Zea mays L. plants

Background & Aims

The effects of an alfalfa plant (Medicago sativa L.) hydrolysate-based biostimulant (EM) containing triacontanol (TRIA) and indole-3-acetic acid (IAA) were tested in salt-stressed maize plants.

Methods

Plants were grown for 2 weeks in the absence of NaCl or in the presence (25, 75 and 150 mM). On the 12th day, plants were supplied for 48 h with 1.0 mg L^?1 EM or 11.2 μM TRIA.

Results

EM and TRIA stimulated the growth and nitrogen assimilation of control plants to a similar degree, while NaCl reduced plant growth, SPAD index and protein content. EM or TRIA increased plant biomass under salinity conditions. Furthermore, EM induced the activity of enzymes functioning in nitrogen metabolism. The activity of antioxidant enzymes and the synthesis of phenolics were induced by salinity, but decreased after EM treatment. The enhancement of phenylalanine ammonia-lyase (PAL) activity and gene expression by EM was consistent with the increase of flavonoids.

Conclusion

The present study proves that the EM increases plant biomass even when plants are grown under salinity conditions. This was likely because EM stimulated plant nitrogen metabolism and antioxidant systems. Therefore, EM may be proposed as bioactive product in agriculture to help plants overcome stress situations.     

Life cycle assessment of bio-based products: a disposable diaper case study

Purpose

In this study, a life cycle assessment of a bioplastic based diaper was performed. The product has several innovative elements, due to the implementation of eco-design principles, such as: (1) introduction of biopolymers (namely polylactic acid (PLA) and Mater-bi®), (2) relevant reduction of petrochemical plastics, and (3) minimization of energy consumptions and use of renewable energy in manufacturing. The aim of the study is to evaluate the environmental benefits gained through eco-innovation, while identifying further areas of improvement.

Methods

The bio-based diaper has been evaluated using a “cradle-to-gate” analysis. The functional unit is one diaper, assuming an average size among the different commercial options. A case study of an enterprise in Italy (WIP S.p.A) was carried out to collect as much reliable primary data as possible. In order to highlight potential areas of improvement and to compare the environmental performance of the product, a sensitivity analysis based on three different impact assessment methods (adopting ReCiPe 2008, IMPACT 2002+ and Cumulative Energy Demand (CED)) and a comparison with a standard commercial diaper were performed. Finally, three possible end-of-life scenarios including composting of WIP diaper were hypothesized and tested.

Results and discussion

Contribution analysis suggested that sourcing and production of raw materials used in WIP diaper manufacturing contributed most significantly to the potential environmental impacts. Adopting ReCiPe method, pulp, and sodium polyacrylate present the highest environmental burdens in WIP diaper system. Applying IMPACT2002+ method, PLA relative contribution to the toxicity increases, due to the generation of the electricity used in corn production and in PLA production phases. For both methods, impacts related to energy consumption of the WIP diapers’ production process look to be negligible. WIP diaper performance has room for improvement, since critical points were detected in the life cycle stages of raw materials used. However, the results of the normalization step, according to ReCiPe method, state that WIP diapers can bring environmental benefits, compared to standard ones. Moreover, if composting end-of-life scenario is included in the assessment, there is a significant improvement in WIP diaper environmental performance compared to a standard diaper.

Conclusions

Integrating eco-innovation and eco-design principles in the production of the bio-based diaper leads to a better environmental profile, compared to the standard one. Nevertheless, there are several areas of concerns to be considered in order to further improve its environmental performance. So far, the possible improvements identified from the case study are: (1) the selection of biopolymers suppliers with better production systems from an environmental point of view, (2) the reduction of distances along the supply chain, and (3) the implementation of composting procedures for the end of life. In conclusion, the introduction of biopolymers in diaper composition could lead them to be preferable compared to standard diapers, but criticisms arise, which need to be solved, to avoid the risk of burdens shifting.