(303f) Integra LCA: An Innovative Tool for Health Risk Assessment of Plastic Waste

Authors: 
Karakitsios, S., Aristotle University of Thessaloniki
Sarigiannis, D., Aristotle University of Thessaloniki
Gypakis, A., Ministry of Education
Gotti, A., Aristotle University of Thessaloniki
Plastic waste management and the associated risks to human and ecosystem health are recognized as key issues in sustainable waste and resource management worldwide. The plastic crisis, has induced a number of jurisdictions to pose bans on use of plastic bags and enhance plastic recycling in the respective municipal waste management systems. Still to date, however, landfilling remains the most common waste management practice in Greece in spite of enforced regulations aimed at increasing recycling, pre-selection of waste and energy and material recovery.

Especially with regard to plastic waste, a lot of studies have exemplified the adverse effects of low-biodegradability plastic material on the health and sustainability of natural ecosystems, disrupting the food web and inducing endocrine disruption and eventually gender alteration (feminization) in sensitive species such as fish. This effect in turn endangers biodiversity and ecosystem sustainability.

As yet, there is a much more limited number of studies focusing on the adverse human health effects of plastic products and waste, the ubiquitous nature of plastic material notwithstanding. Thus, in this study we have developed an innovative tool for integrated health risk assessment of plastic waste. The INTEGRA LCA software couples the integrated external and internal exposure assessment capabilities of the INTEGRA computational platform (Sarigiannis et al, 2014) with life cycle impact assessment (Clift et al, 2000). The integrated software platform allowed us to perform a first-of-its-kind analysis of adverse health outcomes attributable to chronic exposure to persistent organic pollutants associated with plastic material use and disposal.

Our analysis focused on plastic waste generated in the two main metropolitan centers in Greece, Athens and Thessaloniki. A comprehensive review of up-to-date information on plastic products and plasticizers used by the urban population was performed in order to build up the application-specific release/emissions inventory. This review included both plastic products (e.g. PET bottles, PVC material, polycarbonate products) and plasticizers used in food packaging. The latter is of particular importance when considering the total human exposure to persistent toxic compounds found in plastic matrices, such as plasticizers found in the interior of cans, baby bottles, pacifiers and other products coming in contact with the oral route of exposure (Luz, 2012). Compounds of interest in this regard include bisphenol A, phthalates such as DEHP and its metabolites, DINCH, di-(2-ethylhexyl)adipate (Ehlert et al, 2008). The environmental fate analysis performed, included both multi-media contamination of POPs found in plastic waste and contamination of the food web including seafood.

Integration of all human exposure routes and pathways to the toxic compounds contained in plastic was done at the level of systemic internal dose using the intake fraction methodology (Sarigiannis and Karakitsios, 2016). We then parameterized properly the state-of-the-art generic physiology-based biokinetic (PBBK) model in the INTEGRA platform for these compounds and used it to reckon the biologically effective dose (BED) at the target tissues more closely associated with the putative adverse health outcomes considered in our study. Thus, we estimated the level of homeostatic perturbation induced by the BED at the target tissues. The extent of the perturbation was then used as the fundamental metric that was linked with adverse health outcomes reported in the literature to quantitatively assess the related health risk.

Bisphenol-A is characterised by low environmental concentrations, as a result of the limited environmental emissions. In Greece, BPA concentration in urban PM has been estimated equal to 0.06 ng/m3, which is in a very good accordance with the predictions of the multimedia model incorporated in INTEGRA. Exposure to BPA mainly occurs through exposure to specific consumer products. As expected, children are exposed to higher amounts of BPA, and the mean urinary concentration in Greece have been identified equal to 1.2 and 2.1 μg/g creatinine for adults and children respectively. Using the exposure reconstruction module of the INTEGRA platform, the respective external exposure levels correspond to 0.06 and 0.156 μg/kg_bw/d, which is far below the t-TDI of 4 μg/kg_bw/d set by EFSA. Although DEHP is produced in lower volumes compared to BPA, overall exposure is significantly higher. The measured urinary levels of MEHP, the major metabolite of DEHP have been identified as 7.6 and 2.8 μg/g creatinine for adults and children respectively. Similarly to BPA, contribution of DEHP exposure originates from consumer exposure (mainly use of PVC flooring and use of various plastic toys and equipment, as well as food conduct materials), however, these exposure levels (10 μg/kg_bw/d are in the same order of magnitude with the respective TDI. DEHA is considered one of the major DEHP substitutes. Based on the LCA and considering its broad applications, the estimated daily intake is in the range of 1 μg/kg_bw/d. In Europe, the estimated intake for children based on biomonitoring data, has been estimated within the same range. DINCH is another of the DEHP substitutes. Based on the respective LCA, the predicted exposure estimates of DINCH are close to 0.7 μg/kg_bw/d; this value is within the range the one (0.5 μg/kg_bw/d) estimated from biomonitoring data collected in daycare centers in Germany. Contribution from consumer applications is similar a few orders of magnitude higher that the rest of contributing pathways.

Among the various waste management options, incineration contributes to a higher amount of exposure through air and dust for the local population, as a result of the higher emissions in air from the incinerator. Among the various waste management options, incineration contributes to a higher amount of exposure through air for the local population, due to the higher emissions occurring from the incinerator. Similarly, exposure to dust is also slightly higher. On the contrary, landfilling contributes to slightly higher exposure through food (and drinking water) from the leachates ending up to the ground underwater and eventually to drinking water.

The estimated risks of the plasticizers investigated above seem to be relatively low, with the exception of DEHP, where the estimated intake is in the same order of magnitude with the respective TDI. Beyond that, the cumulative effect of these compounds has to be taken into account, as well as the presence of additional plasticizers (beyond the ones investigated herein) within the plastic matrix. Among the various steps of the respective life cycle, waste remaining in the environment is expected to be particles/fragments abraded from end-use products during their service life and during disposal (e.g. particles abraded from car undercoating, coil coating, shoe soles and fragments of plastic bags etc.). These particles are primarily released to the urban/ind. soil compartment in landfills. However, the smallest fraction may also be distributed to the air compartment or to the surface water environment ending up in the sediment. Overall, the comprehensive analysis of the waste management options indicated that incineration contributes significantly to increased levels of exposure through inhalation for the population living close to the incinerator facility, while on the other hand recycling results in lower exposure from all environmental exposure pathways.

The coupled integrated exposure and life cycle assessment methodology developed in this study and translated into the INTEGRA LCA platform is a significant step towards the direction of comprehensive, precise and transparent estimation potential health risks associated with use, management and disposal of plastics in urban settings. Our first results in the two major Greek metropolitan centers indicate the need to optimize the management of plastic waste in the country and to enhance the awareness of consumers with regard to the long-term adverse health effects of chronic exposure to plastic components. The incorporation of life cycle analysis produces different conclusions than a simple environmental impact assessment based only on estimated or measured emissions. Taking into account the overall life cycle of both the waste streams and of the technological systems and facilities envisaged under the plausible scenarios analyzed herein, alters the relative attractiveness of the solutions considered and enhances the robustness of the health impact assessment.

References

Clift, R., Doig, A., Finnveden, G., 2000. The Application of Life Cycle Assessment to Integrated Solid Waste Management: Part 1-Methodology. Process Safety and Environmental Protection 78, 279-287.

Ehlert, K.A., Beumer, C.W.E., Groot, M.C.E., 2008. Migration of bisphenol A into water from polycarbonate baby bottles during microwave heating. Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment 25, 904-910.

Luz C, 2012. Our food packaging and public health, Environmental Health Perspectives, 120(6): A232-A236.

Sarigiannis D.A. and Karakitsios S.P. Complex exposure modeling. In: Mixtures toxicology and risk assessment. J.E. Simmons and C. Rider (eds.), Springer (2016).

Sarigiannis, D.A., Karakitsios, S., Gotti, A., Loizou, G., Cherrie, J., Smolders, R. De Brouwere, K., Galea, K., Jones, K., Handakas, E., Papadaki, K., Sleeuwenhoek, A. 2014. INTEGRA: From global scale contamination to tissue dose, 7th International Congress on Environmental Modelling and Software (iEMSs), San Diego (California), USA, 15-19/6/2014.