The environmental impact of packaging in food supply chains—does life cycle assessment of food provide the full picture?

Purpose

Due to the urgency and the magnitude of the environmental problems caused by food supply chains, it is important that the recommendations for packaging improvements given in life cycle assessment (LCA) studies of food rest on a balanced consideration of all relevant environmental impacts of packaging. The purpose of this article is to analyse the extent to which food LCAs include the indirect environmental impact of packaging in parallel to its direct impact. While the direct environmental impact of food packaging is the impact caused by packaging materials’ production and end-of-life, its indirect environmental impact is caused by its influence on the food product’s life cycle, e.g. by its influence on food waste and on logistical efficiency.

Methods

The article presents a review of 32 food LCAs published in peer-reviewed scientific journals over the last decade. The steps of the food product’s life cycle that contribute to the direct and indirect environmental impacts of packaging provide the overall structure of the analytical framework used for the review. Three aspects in the selected food LCAs were analysed: (1) the defined scope of the LCAs, (2) the sensitivity and/or scenario analyses and (3) the conclusions and recommendations.

Results and discussion

While in packaging LCA literature, there is a trend towards a more systematic consideration of the indirect environmental impact of packaging, it is unclear how food LCAs handle this aspect. The results of the review show that the choices regarding scope and sensitivities/scenarios made in food LCAs and their conclusions about packaging focus on the direct environmental impact of packaging. While it is clear that not all food LCAs need to analyse packaging in detail, this article identifies opportunities to increase the validity of packaging-related conclusions in food LCAs and provides specific recommendations for packaging-related food LCA methodology.

Conclusions

Overall, we conclude that the indirect environmental impact of packaging is insufficiently considered in current food LCA practice. Based on these results, this article calls for a more systematic consideration of the indirect environmental impact of packaging in future food LCAs. In addition, it identifies a need for more packaging research that can provide the empirical data that many food LCA practitioners currently lack. In particular, LCA practitioners would benefit if there were more knowledge and data available about the influence of certain packaging characteristics (e.g. shape, weight and type of material) on consumer behaviour.

     

How origin,packaging and seasonality determine the environmental impact of apples,magnified by food waste and losses

Purpose

Using apple consumption in Belgium as a case study, this study examines the environmental impacts associated with Belgian (BE) and New Zealand (NZ) apples, how impacts evolve throughout the year and how packaging affects this impact. Additionally, impacts associated with food losses and food waste along the chain are assessed. The study aims to delineate the most important factors in determining environmental impacts associated with apple.

Methods

The environmental impacts are calculated using the ILCD (International Reference Life Cycle Data System) approach. The functional unit is 1 kg of apples purchased by a consumer in the supermarket. Primary data was collected through players along the chain. Various scenarios are analysed for both the BE and NZ apples, based on the moment of purchase and packaging method. Food loss and waste impacts are assessed by splitting the impacts along the chain into three categories: apples lost along the supply chain, apples purchased and eaten by the consumer and apples purchased and wasted by the consumer.

Results and discussion

For all impact categories assessed, NZ apples come at a higher environmental cost than BE ones due to overseas transport. For both BE and NZ apples, minimum impacts are found for bulk apples at the beginning of the season, whereas maximum values are found for pre-packed apples at the end of the season. For BE apples, the choice of packaging method highly affects the impact, while it is negligible relative to shipping impacts for NZ apples. Altering secondary packaging materials of BE apples allows for impact reductions up to 50%. In the case of climate change, food waste and losses contribute up to 25% or 15% for BE or NZ apples, respectively, as all lost food travels in vain through the food chain and needs to be disposed of.

Conclusions

The study shows the importance of origin and packaging, whereas the moment of purchase hardly affects the environmental impact of apples. From a supply chain perspective, there is room for improvement as altering the use of secondary packaging greatly reduces impacts along the chain. The study further highlights how impacts are magnified by food waste and losses.

     

Life cycle assessment of ferro niobium

Purpose

Ferro niobium (FeNb) is a metallic alloy whose industrial use has been increasing steadily in the last decades. This work aims to systematize the available information on FeNb production, provide its inventory data and generate its first technologically representative publicly available life cycle impact assessment (LCIA).

Methods

The production of 1 kg of FeNb from pyrochlore in the baseline year 2017 was modelled following a cradle-to-gate approach. Primary information on mass, energy and water flows was collected when possible from the Brazilian leading FeNb supplier, CBMM (80% of the world market). The CML method (CML-IA 4.7) was applied for the impact assessment including global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), abiotic depletion potential (fossil and elemental) (ADP_fossil and ADP_elemental) and photochemical ozone creation potential (POCP).

Results and discussion

The first stage of pyrochlore processing (pyrochlore ore extraction, mechanical processing and flotation) and the last stage (aluminothermic reaction) bear the highest impact in all analyzed CML impact categories. The primary aluminium consumption has the most important contribution in five out of seven impact categories (50% in ADP_fossil, 55% in AP, 35% in EP, 57% in GWP and 40% in POCP). In this sense, the industry should promote a higher share of secondary aluminium in the production process. Also, the impact from electricity consumption and processing chemicals showed to be relevant.

Conclusions

This work is the first LCIA on ferro niobium to be published with representative, high-quality data. A dataset was produced in order to enable ferro niobium to be incorporated to future LCIA-modelling.

     

Fate modelling within LCA

For an accurate assessment of the toxic effects of chemicals during their life cycle, LCA developers try more and more to include chemical fate into the life-cycle impact assessment (LCIA) procedure. In this study the application of multi-media partitioning models within LCIA is discussed. With the case of textile chemicals as an example, USES-LCA and a simple river model (box approach) are compared according to their practicability and the value added to the assessment results. It is shown that emissions from the supply and use of energy still dominate the LCIA results even if ecotoxicity is assessed with a rather complex fate model such as USES-LCA. Second, the treatment of modelling results is addressed for persistent substances with low or unknown toxicity. A possible approach to include such chemicals into valuation is to define an exposure-based impact category additionally to the existing effect-oriented ones (toxicity scores) or a combination of different methods. A combined presentation of results from complementary tools is proposed, providing a more detailed background for decision making while avoiding aggregation and leaving the final weighting between the categories to the user.     

USEtox human exposure and toxicity factors for comparative assessment of toxic emissions in life cycle analysis: sensitivity to key chemical properties

Purpose

The aim of this paper is to provide science-based consensus and guidance for health effects modelling in comparative assessments based on human exposure and toxicity. This aim is achieved by (a) describing the USEtox? exposure and toxicity models representing consensus and recommended modelling practice, (b) identifying key mechanisms influencing human exposure and toxicity effects of chemical emissions, (c) extending substance coverage.

Methods

The methods section of this paper contains a detailed documentation of both the human exposure and toxic effects models of USEtox?, to determine impacts on human health per kilogram substance emitted in different compartments. These are considered as scientific consensus and therefore recommended practice for comparative toxic impact assessment. The framework of the exposure model is described in details including the modelling of each exposure pathway considered (i.e. inhalation through air, ingestion through (a) drinking water, (b) agricultural produce, (c) meat and milk, and (d) fish). The calculation of human health effect factors for cancer and non-cancer effects via ingestion and inhalation exposure respectively is described. This section also includes discussions regarding parameterisation and estimation of input data needed, including route-to-route and acute-to-chronic extrapolations.

Results and discussion

For most chemicals in USEtox?, inhalation, above-ground agricultural produce, and fish are the important exposure pathways with key driving factors being the compartment and place of emission, partitioning, degradation, bioaccumulation and bioconcentration, and dietary habits of the population. For inhalation, the population density is the key factor driving the intake, thus the importance to differentiate emissions in urban areas, except for very persistent and mobile chemicals that are taken in by the global population independently from their place of emission. The analysis of carcinogenic potency (TD₅₀) when volatile chemicals are administrated to rats and mice by both inhalation and an oral route suggests that results by one route can reasonably be used to represent another route. However, we first identify and mark as interim chemicals for which observed tumours are directly related to a given exposure route (e.g. for nasal or lung, or gastrointestinal cancers) or for which absorbed fraction by inhalation and by oral route differ greatly.

Conclusions

A documentation of the human exposure and toxicity models of USEtox? is provided, and key factors driving the human health characterisation factor are identified. Approaches are proposed to derive human toxic effect factors and expand the number of chemicals in USEtox?, primarily by extrapolating from an oral route to exposure in air (and optionally acute-to-chronic). Some exposure pathways (e.g. indoor inhalation, pesticide residues, dermal exposure) will be included in a later stage. USEtox? is applicable in various comparative toxicity impact assessments and not limited to LCA.     

Reviewing the potential for including habitat fragmentation to improve life cycle impact assessments for land use impacts on biodiversity

Purpose

The biosphere is progressively subjected to a variety of pressures resulting from anthropogenic activities. Habitat conversion, resulting from anthropogenic land use, is considered the dominant factor driving terrestrial biodiversity loss. Hence, adequate modelling of land use impacts on biodiversity in decision-support tools, like life cycle assessment (LCA), is a priority. State-of-the-art life cycle impact assessment (LCIA) characterisation models for land use impacts on biodiversity translate natural habitat transformation and occupation into biodiversity impacts. However, the currently available models predominantly focus on total habitat loss and ignore the spatial configuration of the landscape. That is, habitat fragmentation effects are ignored in current LCIAs with the exception of one recently developed method.

Methods

Here, we review how habitat fragmentation may affect biodiversity. In addition, we investigate how land use impacts on biodiversity are currently modelled in LCIA and how missing fragmentation impacts can influence the LCIA model results. Finally, we discuss fragmentation literature to evaluate possible methods to include habitat fragmentation into advanced characterisation models.

Results and discussion

We found support in available ecological literature for the notion that habitat fragmentation is a relevant factor when assessing biodiversity loss. Moreover, there are models that capture fragmentation effects on biodiversity that have the potential to be incorporated into current LCIA characterisation models.

Conclusions and recommendations

To enhance the credibility of LCA biodiversity assessments, we suggest that available fragmentation models are adapted, expanded and subsequently incorporated into advanced LCIA characterisation models and promote further efforts to capture the remaining fragmentation effects in LCIA characterisation models.

     

Tackling the toxics in plastics packaging

The widespread use of plastic packaging for storing, transporting, and conveniently preparing or serving foodstuffs is significantly contributing to the global plastic pollution crisis. This has led to many efforts directed toward amending plastic packaging’s end of life, such as recycling, or alternative material approaches, like increasingly using paper for food packaging. But these approaches often neglect the critical issue of chemical migration: When contacting foodstuffs, chemicals that are present in packaging transfer into food and thus unwittingly become part of the human diet. Hazardous chemicals, such as endocrine disrupters, carcinogens, or substances that bioaccumulate, are collectively referred to as “chemicals of concern.” They can transfer from plastic packaging into food, together with other unknown or toxicologically uncharacterized chemicals. This chemical transfer is scientifically undisputed and makes plastic packaging a known, and avoidable, source of human exposure to synthetic, hazardous, and untested chemicals. Here, I discuss this issue and highlight aspects in need of improvement, namely the way that chemicals present in food packaging are assessed for toxicity. Further, I provide an outlook on how chemical contamination from food packaging could be addressed in the future. Robust innovations must attempt systemic change and tackle the issue of plastic pollution and chemical migration in a way that integrates all existing knowledge.

The widespread use of plastic packaging for storing, transporting, and conveniently preparing or serving foodstuffs is significantly contributing to the global plastic pollution crisis. This Essay exhorts us to change the conversation about plastic packaging and address the chemicals that migrate into food.     

Implications of considering metal bioavailability in estimates of freshwater ecotoxicity: examination of two case studies

Purpose  

Previous methods of estimating characterization factors (CFs) of metals in life cycle impact assessment (LCIA) models were based on multimedia fate, exposure, and effect models originally developed to address the potential impacts of organic chemicals. When applied to metals, the models neglect the influence of ambient chemistry on metal speciation, bioavailability and toxicity. Gandhi et al. (2010) presented a new method of calculating CFs for freshwater ecotoxicity that addresses these metal-specific issues. In this paper, we compared and assessed the consequences of using the new method versus currently available LCIA models for calculating freshwater ecotoxicity, as applied to two case studies previously examined by Gloria et al. (2006): (1) the production of copper (Cu) pipe and (2) a zinc (Zn) gutter system.     

Effect of methodological choice on the estimated impacts of wool production and the significance for LCA-based rating systems

Purpose

One aim of LCA-based rating tools developed by the apparel industry is to promote a change in demand for textiles by influencing consumer preferences based on the environmental footprint of textiles. Despite a growing consensus that footprints developed using attributional LCA (aLCA) are not suitable to inform decisions that will impact supply and demand, these tools continue to use aLCA. This paper analyses the application of the LCA methods to wool production, specifically the application of aLCA methods that provide a retrospective assessment of impacts and consequential (cLCA) methods that estimate the impacts of a change.

Methods

Attributional and consequential life cycle inventories (LCIs) were developed and analysed to examine how the different methodological approaches affect the estimated environmental impacts of wool.

Results and discussion

Life cycle impact assessment (LCIA) of aLCI and cLCI for wool indicates that estimated global warming and water stress impacts may be considerably lower for additional production of wool, as estimated by cLCIA, than for current production as estimated by aLCIA. However, fossil resource impacts for additional production may be greater than for current production when increased wool production was assumed to displace dedicated sheep meat production.

Conclusions

This work supports the notion that the use of a retrospective assessment method (i.e. aLCA) to produce information that will guide consumer preferences may not adequately represent the impacts of a consumer’s choice because the difference between aLCIA and cLCIA results may be relatively large. As such, rating tools based on attributional LCA are unlikely to be an adequate indicator of the sustainability of textiles used in the apparel industry.

     

Could the recycled yarns substitute for the virgin cotton yarns: a comparative LCA

Purpose

Cotton yarns spun from natural fibers are widely used in the apparel industry. Most of waste cotton goods are now disposed by incineration or landfill, which brings resource and environmental challenges to the society. Using the waste cotton to spin yarns is an alternative way to forward a more sustainable future. In this research, two scenarios for the environmental impacts of yarns spun from corresponding fibers are investigated, including recycled cotton fibers and virgin cotton fibers.

Methods

The life cycle assessment (LCA) has been conducted according to the collected data from on-site investigation of typical production factories. The life cycle for the recycled cotton yarn production is divided into five stages, i.e., raw material acquisition, transportation, breaking, mixing, and spinning. The life cycle of virgin cotton yarn production is been divided into four stages, i.e., raw material acquisition, transportation, mixing, and spinning. The functional unit is 1000 kg produced yarns which are used for weaving into the fabrics. Notable impacts on climate change, fossil depletion, water depletion, and human toxicity were observed.

Results

The life cycle impact assessment (LCIA) results show that environmental impacts of recycled cotton yarns are far less than those of virgin cotton yarns, except for climate change and water depletion. The reason is that the land occupation and irrigation water have great impact on environmental impacts of cotton cultivation. In spinning, the electricity is the key factor whose environmental impacts account for the most in the virgin cotton yarn scenario, while the electricity and water consumptions are the key factors for the recycled cotton yarn scenario in the life cycle of yarn production. The sensitivity analysis indicates that improving energy efficiency can significantly reduce environmental burdens for both the two scenarios. The uncertainty distribution of water depletion, human toxicity, fossil depletion, and climate change of the two scenarios were determined with a 90% confidence interval.

Conclusions

The LCIA results reveal recycled cotton yarn is a viable alternative to relieve resource and environmental pressure. About 0.5 ha of agricultural land can be saved, 6600 kg CO₂ eq can be reduced, and 2783 m³ irrigation water can be saved by using 1000 kg of the recycled cotton yarns. It can be concluded that the recycled cotton fibers can be served as a substitute for virgin cotton fibers to reduce agricultural land and avoid environmental impacts generated from the cotton planting.

     

Life cycle assessment of California unsweetened almond milk

Purpose

Plant-based alternatives to dairy milk have grown in popularity over the last decade. Almond milk comprises the largest share of plant-based milk in the US market and, as with so many food products, stakeholders in the supply chain are increasingly interested in understanding the environmental impacts of its production, particularly its carbon footprint and water consumption. This study undertakes a life cycle assessment (LCA) of a California unsweetened almond milk.

Methods

The scope of this LCA includes the production of almond milk in primary packaging at the factory gate. California produces all US almonds, which are grown under irrigated conditions. Spatially resolved modeling of almond cultivation and primary data collection from one almond milk supply chain were used to develop the LCA model. While the environmental indicators of greatest interest are global warming potential (GWP) and freshwater consumption (FWC), additional impact categories from US EPA’s TRACI assessment method are also calculated. Co-products are accounted for using economic allocation, but mass-based allocation and displacement are also tested to understand the effect of co-product allocation choices on results.

Results and discussion

The GWP and FWC of one 48 oz. (1.42 L) bottle of unsweetened almond milk are 0.71 kg CO₂e and 175 kg of water. A total of 0.39 kg CO₂e (or 55%) of the GWP is attributable to the almond milk, with the remainder attributable to packaging. Almond cultivation alone is responsible for 95% of the FWC (167 kg H₂O), because of irrigation water demand. Total primary energy consumption (TPE) is estimated at 14.8 MJ. The 48 oz. (1.42 L) PET bottle containing the almond milk is the single largest contributor to TPE (42%) and GWP (35%). Using recycled PET instead of virgin PET for the bottle considerably reduces all impact indicators except for eutrophication potential.

Conclusions

For the supply chain studied here, packaging choices provide the most immediate opportunities for reducing impacts related to GWP and TPE, but would not result in a significant reduction in FWC because irrigation water for almond cultivation is the dominant consumer. To provide context for interpretation, average US dairy milk appears to have about 4.5 times the GWP and 1.8 times the FWC of the studied almond milk on a volumetric basis.

     

Life Cycle Impact assessment of pollutants causing aquatic eutrophication

In life cycle impact assessment (LCIA), limited attention is generally given to a consistent inclusion of a fate analysis in the derivation of aquatic eutrophication potentials. This paper includes fate and potential effects in the calculation of aquatic eutrophication potentials of NH₃ and NO_x emitted to the ait, N and P emitted to water, and N and P emitted to soil. These characterisation factors were calculated for the Netherlands, West-Europe and the world, respectively. Implementation in current LCIA practice is further facilitated by calculating normalisation scores for the Netherlands in 1997, West-Europe in 1995 and the world in 1990. Although the results presented may be a step forward, significant improvements are still needed in the assessment of pollutants causing aquatic eutrophication. In particular, the fate factors representing transport of NO_x and NH₃, air emissions via soils to the aquatic environment should be improved. In addition, differences in the biological availability of nutrients and differences in the sensitivity of aquatic environments should be included in the calculation of effect factors for aquatic eutrophication.     

Intermittent exposure to aquatic pollutants: assessment,toxicity and sublethal responses in fish and invertebrates

Aquatic animals are often exposed to intermittent, variable poison concentrations during pollution incidents. However, current understanding of ecotoxicology has evolved primarily from continuous exposure studies. This review summarises the relatively dispersed toxicity literature on intermittent exposures. Methodologies used in existing continuous exposure toxicity tests may be adapted to intermittent regimes provided the exposure profile is known and “poison concentration” is defined to give toxicologically relevant lethality estimate. Such tests rely on assuming that continuous and intermittent exposures of equivalent dose have the same toxicity. This assumption is untrue for some chemicals. The toxicity of intermittent events may be assessed by correlating mortality with poison accumulation, biochemical, haematological or physiological response syndromes. Such bioassays can be performed without knowledge of the exposure profile, and are often sufficiently rapid to record short pollution events. Intermittent and continuous exposures of equivalent dose may not have the same toxicities. Intermittent exposures are less toxic than continuous events, but only when peak concentrations of pollutant are the same in each regime. Exceptionally, sulphuric acid, acid/Al and ammonia are much more toxic to fish when administered intermittently. Variations in intermittent exposure frequency or duration do not produce proportional changes in lethality, since apparently large changes in exposure dose may not significantly alter toxicity. The short-lived nature of intermittent exposures suggests that equilibriums in poison concentrations between the external environment and the body compartments of the test species are not achieved. The overall accumulation response depends particularly on the duration of peak concentrations and any “recovery periods” between multiple episodes relative to poison uptake and depuration rates respectively. Transient biochemical and physiological disturbances occur during intermittent exposures. Latent effects include reduced post-exposure growth and reproductive failure in the F₁ generation, or increased deformities in the F₂ generation of fish.     

An effect factor approach for quantifying the impact of plastic additives on aquatic biota in life cycle assessment

Purpose

Plastic pervades now almost every aspect of our daily lives, but this prosperity has led to an increasing amount of plastic debris, which is now widespread in the oceans and represents a serious threat to biota. However, there is a general lack of consideration regarding marine plastic impacts in life cycle assessment (LCA). This paper presents a preliminary approach to facilitate the characterization of chemical impacts related to marine plastic within the LCA framework.

Methods

A literature review was carried out first to summarize the current state of research on the impact assessment of marine plastic. In recent years, efforts have been made to develop LCA-compliant indicators and models that address the impact of marine littering, entanglement, and ingestion. The toxicity of plastic additives to marine biota is currently a less understood impact pathway and also the focus of this study. Relevant ecotoxicity data were collected from scientific literature for a subsequent additive-specific effect factor (EF) development, which was conducted based on the USEtox approach. Extrapolation factors used for the data conversion were also extracted from reliable sources.

Results and discussion

EFs were calculated for six commonly used additives to quantify their toxicity impacts on aquatic species. Triclosan shows an extremely high level of toxicity, while bisphenol A and bisphenol F are considered less toxic according to the results. Apart from additive-specific EFs, a generic EF was also generated, along with the species sensitivity distribution (SSD) illustrating the gathered data used to calculate this EF. Further ecotoxicity data are expected to expand the coverage of additives and species for deriving more robust EFs. In addition, a better understanding of the interactive effect between polymers and additives needs to be developed.

Conclusions

This preliminary work provides a first step towards including the impact of plastic-associated chemicals in LCA. Although the toxicity of different additives to aquatic biota may vary significantly, it is recommended to consider additives within the impact assessment of marine plastic. The generic EF can be used, together with a future EF for adsorbed environmental pollutants, to fill a gap in the characterization of plastic-related impacts in LCA.

     

A framework for implementing holistic and integrated life cycle sustainability assessment of regional bioeconomy

Purpose

Currently, social, environmental, and economic risks and chances of bioeconomy are becoming increasingly a subject of applied sustainability assessments. Based on life cycle assessment (LCA) methodology, life cycle sustainability assessment (LCSA) aims to combine or integrate social, environmental, and economic assessments. In order to contribute to the current early stage of LCSA development, this study seeks to identify a practical framework for integrated LCSA implementation.

Methods

We select possible indicators from existing suitable LCA and LCSA approaches as well as from the literature, and allocate them to a sustainability concept for holistic and integrated LCSA (HILCSA), based on the Sustainable Development Goals (SDGs). In order to conduct a practical implementation of HILCSA, we choose openLCA, because it offers the best current state and most future potential for application of LCSA. Therefore, not only the capabilities of the software and databases, but also the supported methods of life cycle impact assessments (LCIA) are evaluated regarding the requirements of the indicator set and goal and scope of future case studies.

Results and discussion

This study presents an overview of available indicators and LCIAs for bioeconomy sustainability assessments as well as their link to the SDGs. We provide a practical framework for HILCSA of regional bioeconomy, which includes an indicator set for regional (product and territorial) bioeconomy assessment, applicable with current software and databases, LCIA methods and methods of normalization, weighting, and aggregation. The implementation of HILCSA in openLCA allows an integrative LCSA by conducting all steps in a single framework with harmonized, aggregated, and coherent results. HILCSA is capable of a sustainability assessment in terms of planetary boundaries, provisioning system and societal needs, as well as communication of results to different stakeholders.

Conclusions

Our framework is capable of compensating some deficits of S-LCA, E-LCA, and economic assessments by integration, and shows main advantages compared to additive LCSA. HILCSA is capable of addressing 15 out of 17 SDGs. It addresses open questions and significant problems of LCSAs in terms of goal and scope, LCI, LCIA, and interpretation. Furthermore, HILCSA is the first of its kind actually applicable in an existing software environment. Regional bioeconomy sustainability assessment is bridging scales of global and regional effects and can inform stakeholders comprehensively on various impacts, hotspots, trade-offs, and synergies of regional bioeconomy. However, significant research needs in LCIAs, software, and indicator development remain.

     

Comparison of two equivalency factor approaches with simplified risk assessment for lcia of toxicity impact potential

Three approaches recommended for characterization of toxicity impact potential in a life cycle impact assessment (LCIA) are tested on a case study and compared. The two equivalency factor methods are the Persistence, Bioaccumulation, and Toxicity (PBT) method and the Multimedia Fate Modeling (MFM) method using a Mackay Level III model with state-specific environmental data. The simplified risk assessment (SRA) method involved dispersion modeling using site-specific environmental data. The life cycle inventory information evaluated by all three methods was limited to manufacturing of the RDX-based explosive in Kingsport, Tennessee. The effort to collect site-specific environmental data and conduct air dispersion modeling for the SRA method required about 24 times more effort than the PBT method and about 4 times more effort than the MFM method. Direct comparison of impact potential scores for the three approaches were limited to inhalation toxicity scores for nine air pollutants modeled by SRA. Correlations were made on the rank order of the impact potential scores for the nine air emissions evaluated for all three LCIA methods. Although the number of chemicals compared is very limited, the best correlation coefficient (0.96) was between the rank orders for the MFM and the SRA methods. The minimal effort and reduced accuracy of the PBT approach make it best suited for screening large numbers of chemicals for further evaluation of the highest ranked chemicals. The intermediate effort and reasonable accuracy (includes transfers to other media) of the MFM approach make it well suited for LCIAs involving comparative assertions or governmental policy decisions. The maximum effort and assumption of highest accuracy make the SRA approach suitable only after limiting the locations of interest to a few sites by screening with the other two approaches.     

Microcystins: measuring human exposure and the impact on human health

Abstract

Context: Freshwater cyanobacterial toxins, microcystins, may be a contributing factor to the development of hepatocellular cancer and colorectal cancer.

Objectives: This review summarizes the toxicity data, exposure routes and the methodologies available to determine exposure to elucidate the relationship to liver and colorectal cancer.

Methods: Literature searches were conducted using Medline, PubMed and Web of Science.

Results: There is evidence of human poisonings resulting from exposure to microcystins, however current methods rely on targeted approaches only suitable for acute exposure. No methods exist for the determination of chronic exposure to microcystins.

Conclusions: With the growing evidence of exposure to microcystins and the possible links to cancer, methods to measure medium to long-term human exposure are needed. The identification and validation of candidate biomarkers are key to undertaking urgently required epidemiological studies.     

Identifying the species of copper that are toxic to plant roots in alkaline nutrient solutions

Background and aims

The pH of the growth medium influences Cu speciation in solution, the negativity of plasma membrane (PM) surface potential, and hence the rhizotoxicity of Cu.

Methods

Solution culture experiments were conducted with wheat (Triticum aestivum L.) seedlings to examine the toxicity of various Cu species at pH values ranging from 4.50 to 8.25. The toxic species of Cu was identified, giving particular consideration to the electrical properties at the plant cell membrane and ion activities at the PM surface.

Results

The solution culture studies showed that at pH?<?6.60 (i.e., free Cu²⁺ >95 % of total Cu), the addition of cations (Ca²⁺ or H⁺) decreased the toxic effects of Cu by decreasing the negativity of the PM surface potential (and hence decreasing the activity of Cu²⁺ at the PM surface). For solutions with pH values from 7.50 to 8.25 (CuCO ⁰₃ >50 % of total Cu), an increase in pH significantly enhanced the toxicity of Cu, whilst the addition of Ca had negligible influence on toxicity.

Conclusions

Root growth in solution cultures was influenced primarily by the surface activities of free Cu²⁺ and CuCO ⁰₃ . Across all experiments, the data indicate that it was CuCO ⁰₃ , rather than CuOH⁺, that contributed Cu toxicity over pH?>?7.00. Although our data do not explore the mechanism of toxicity, we propose that CuCO ⁰₃ has an important role in Cu rhizotoxicity in alkaline growth media.

     

OMNIITOX - operational life-cycle impact assessment models and information tools for practitioners

This article is the preamble to a set of articles describing initial results from an on-going European Commission funded, 5th Framework project called OMNIITOX, Operational Models aNd Information tools for Industrial applications of eco/TOXicological impact assessments. The different parts of this case study-driven project are briefly presented and put in relation to the aims of contributing to an operational life cycle-impact assessment (LCIA) model for impacts of toxicants. The present situation has been characterised by methodological difficulties, both regarding choice of the characterisation model(s) and limited input data on chemical properties, which often has resulted in the omission of toxicants from the LCIA, or at best focus on well characterised chemicals. The project addresses both problems and integrates models, as well as data, in an information system- the OMNIITOX IS. There is also a need for clarification of the relations between the (environmental) risk assessments of toxicants and LCIA, in addition to investigating the feasibility of introducing LCA into European chemicals legislation, tasks that also were addressed in the project. Keywords: Case studies; characterisation factor; chemicals; environmental risk assessment; hazard assessment; information system; life cycle impact assessment (LCIA); potentially toxic substances; regulation; risk assessment; risk ranking     

Comparison of cholin- and carboxylesterase enzyme inhibition and visible effects in the zebra fish embryo bioassay under short-term paraoxon-methyl exposure

Abstract

The acute zebra fish embryo test (Danio rerio Hamilton–Buchanan, 1822) is an accepted bioassay to assess the toxicity of waste water that may be used for the replacement of testing with adult fish. It is also suggested for chemical hazard characterization and assessment, although only a few groups of substances have yet been studied. Specifically acting substances such as neurotoxic insecticides pose a potentially hazard for non-target fish. To establish whether the proposed zebra fish embryo test protocol and the inhibition of cholinesterases (acetylcholinesterase EC 3.1.1.7, propionylcholinesterase EC 3.1.1.8) and carboxylesterase (EC 3.1.1.1) enzymes can be used in a similar fashion for hazard characterization and risk assessment of chemicals and environmental samples, two types of experiments were conducted. Visual effects of exposure to the organophosphate metabolite paraoxon-methyl after 24 and 48 h in the zebra fish embryo test system were analysed with the use of an inverse microscope (rate of mortality, developmental disturbances, heart rate and others). The inhibition to cholinesterases and carboxylesterase was also measured. Enzyme inhibition as a biomarker of exposure was about 70 times more sensitive than the effects in the zebra fish embryo test with an IC₅₀ below 1.2?µmol compared with an EC₅₀ of 91?µmol. The dose–response relationships showed different curve characteristics with a linear increase of enzyme inhibition compared with a sigmoidal curve for the overt effects. Significant overt effects could only be seen at concentrations at which already 80% of the activities of the different esterases were inhibited.