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Ecological and human health risk assessment of metals leached from end-of-life solar photovoltaics
Abstract
Photovoltaic industry has shown tremendous growth among renewable energy sector. Though, this high installation rate will eventually result in generation of large volume of end-of-life photovoltaic waste with hazardous metals. In present study, reported leached metal contents from different photovoltaics in previous investigations were utilized for (i) potential fate and transport analysis to soil and groundwater and, (ii) estimating ecological and human health risks via dermal and ingestion pathways for child and adult sub-populations. The results indicate that the children are at highest risk, mainly due to lead (hazard quotient from 1.2 to 2.6). Metals, such as cadmium, lead, indium, molybdenum and tellurium pose maximum risks for child and adult sub-populations via soil-dermal pathway followed by soil-ingestion pathway. This is further proved by calculated high values of contamination factor and geo-accumulation index for cadmium (102.4), indium (238.9) and molybdenum (16.12). The estimated soil contamination is significant with respect to aluminium, silver, cadmium, iron, lead, however, groundwater contamination was insignificant. Exposure to polluted soils yields an aggregate hazard index (for non-cancer effects) > 1 for all four pathways, with soil dermal pathway as the major contributor. Lead poses significant cancer risk for all scenarios (average risk: 0.0098 to 0.047 (soil) and 2.1 × 10⁻⁵ to 3.5 × 10⁻⁵ (groundwater)), whereas acceptable non-cancer risk was observed for other metals from groundwater exposure. Further, variance contribution and spearman correlation coefficient analysis show that metal concentration, exposure frequency and ingestion rate are the main contributors towards overall uncertainty in risk estimates. More detailed assessment for environmentally-sensitive metals should be carried out by considering other field breakage scenarios also, although the assessment suggests low risk for majority of metals examined.
... Figure 1 shows samples of malfunctioned PV panels that are disposed of sporadically in the northern region of Jordan at the Al-Albayt 3.2 MW PV energy facility location. The EoL of PV modules has been studied from different perspectives such as economic analyses [4,5], impact on the environment [6][7][8][9][10][11][12][13], impact on water resources [14], impact on human health [15][16][17], soil contamination [8,18,19], and waste management methods [10,[20][21][22]. Different scenarios in different countries have proposed or implemented management and mitigation approaches to PV panel waste [21,[23][24][25][26][27]. ...
... Different scenarios in different countries have proposed or implemented management and mitigation approaches to PV panel waste [21,[23][24][25][26][27]. PV panels are composed of several materials that can seep into the environment and water resources and prominently affect them, such as heavy metals [17]. Therefore, these impacts on the The EoL of PV modules has been studied from different perspectives such as economic analyses [4,5], impact on the environment [6][7][8][9][10][11][12][13], impact on water resources [14], impact on human health [15][16][17], soil contamination [8,18,19], and waste management methods [10,[20][21][22]. ...
... PV panels are composed of several materials that can seep into the environment and water resources and prominently affect them, such as heavy metals [17]. Therefore, these impacts on the The EoL of PV modules has been studied from different perspectives such as economic analyses [4,5], impact on the environment [6][7][8][9][10][11][12][13], impact on water resources [14], impact on human health [15][16][17], soil contamination [8,18,19], and waste management methods [10,[20][21][22]. Different scenarios in different countries have proposed or implemented management and mitigation approaches to PV panel waste [21,[23][24][25][26][27]. ...
Even though the Kingdom of Jordan is moving in the right direction and adopting clean energy sources such as PV plants, the waste problem will eventually emerge within a few decades and will be an overwhelming issue if not addressed early on. According to reports, the installed PV capacity worldwide was around 410 GW in 2017 and is projected to increase to 5000 GW by 2050. Global solar PV waste is anticipated to reach between 5% and 15% of total generation capacity by 2030, with a 25-year average panel lifespan. This study aims to provide an estimation of the amount of PV waste expected within the next decade, and finally expand on the economic and environmental effects. Moreover, this paper’s target is to explore the possible effects of PV waste materials in the northern part of Jordan, and the obtained results can be applied to other regions in Jordan. Information about renewable energy in Jordan, retrieved from databases of electricity companies, is utilized to reach an accurate estimation of the amounts of materials that will occur at the end of life. The solar PV panel end of life (EOL) management is a developing field that necessitates additional research and development The obtained findings, figures, and facts about the photovoltaic solar energy sector presented in this study highlight the urgency to develop a suitable system for the collection and management of photovoltaic modules at their end of life.
... Therefore, ten dermal contact scenarios covering over three sub-population groups were considered for the dermal contactsoil pathway. In this study, commercial activities, i.e., construction work, etc., were also considered along with the residential activities, i.e., children playing in wet and dry soil, farmers working in the field, in dermal contact exposure scenarios, otherwise neglected in most of the studies (Johar et al., 2020;Nain and Kumar, 2020;Zhou et al., 2018). A detailed list of all the commercial and residential activities, including values and distribution types of different input parameters used in this study, is given in Table 1. ...
... In several risk assessment studies, the probabilistic approach was found as efficient in quantifying the uncertainty associated with exposure model parameters (Kubicz et al., 2018;Nain and Kumar, 2020;Rajasekhar et al., 2020Rajasekhar et al., , 2018. MCS has been widely used to determine the probabilistic estimates of the risk index Chakma, 2021b, 2021a;Mukherjee et al., 2020Mukherjee et al., , 2019. ...
... The effects of variability of input parameters on the estimated risk indexes were quantified by computing correlation and variance contribution, as proved to be an efficient approach in previous studies Chakma, 2021a, 2021b;Kumar and Xagoraraki, 2010;Nain and Kumar, 2020). In the oral ingestion scenario -water pathway, variability in the five input variables viz. ...
In this study, ecological and human health risk assessment (HHRA) of the subsurface environment was performed due to the presence of six different contaminants, i.e., Cr(VI), U, F⁻, As, NO3⁻, and Mo, in the proximity of chromite ore processing residue (COPR) dumping sites of Northern India. The analysis covered a probabilistic risk assessment approach comprised of 10,000 Monte Carlo simulations (MCS) for multi-exposure scenarios following soil and water pathways. The results of ecological risk indexes indicated considerable (contamination factor (CF) = 5.6) to very high (maximum CF ~11.0) contamination of soil near the Rania contaminant site. The maximum and 95th percentile of CF obtained due to Cr(VI) were 4.547 and 11.129, respectively, during the monsoon season. Cancer risk (CR) value for dermal contact exposure via soil pathway for the Rania site was > 1 - 2 orders higher than the safe limit, posing a serious threat to human health. Further, oral ingestion and skin dermal exposure to groundwater in the proximity of Chhiwali dumping site were posing the highest risk with CR = 18.5 and 54.9 (>10−6), respectively to the adult population. Overall, the study recommends an urgent need to take intensive remediation action for these COPR dumpsites to ensure human health safety.
... Table 1 General knowledge of research on TCEs in groundwater (GW) systems in the last 2 years (2019-2021). An [4,6] Beh [5,54,55] CS [7,[9][10][11] Rev [4,52] Mine [53] Remed [56] Pre-concentration techniques, Tracer of interactions between surface water and groundwater, weathering studies Less-studied TCEs Indium (In) Heart, kidney, liver damage, potentially teratogenic [49] Toxicity and lung damage [50] e-waste [49,50], industrial effluents Expected GW conc. affected by leaching from broken solar modules: 10 000 ng L −1 [50] Hea [50,57] Phytoaccumulation and estimations of health risk assessment Gallium (Ga) Ga(III): Irritation, breathing difficulties and chest pain [49] Toxicity and lung damage [50] Ga is exempted from WHO standard limits for drinking water [41] Fertilizer plants [24] Hard and sedimentary rock aquifers in the K/T boundary (India): max. ...
... Table 1 General knowledge of research on TCEs in groundwater (GW) systems in the last 2 years (2019-2021). An [4,6] Beh [5,54,55] CS [7,[9][10][11] Rev [4,52] Mine [53] Remed [56] Pre-concentration techniques, Tracer of interactions between surface water and groundwater, weathering studies Less-studied TCEs Indium (In) Heart, kidney, liver damage, potentially teratogenic [49] Toxicity and lung damage [50] e-waste [49,50], industrial effluents Expected GW conc. affected by leaching from broken solar modules: 10 000 ng L −1 [50] Hea [50,57] Phytoaccumulation and estimations of health risk assessment Gallium (Ga) Ga(III): Irritation, breathing difficulties and chest pain [49] Toxicity and lung damage [50] Ga is exempted from WHO standard limits for drinking water [41] Fertilizer plants [24] Hard and sedimentary rock aquifers in the K/T boundary (India): max. ...
... An [4,6] Beh [5,54,55] CS [7,[9][10][11] Rev [4,52] Mine [53] Remed [56] Pre-concentration techniques, Tracer of interactions between surface water and groundwater, weathering studies Less-studied TCEs Indium (In) Heart, kidney, liver damage, potentially teratogenic [49] Toxicity and lung damage [50] e-waste [49,50], industrial effluents Expected GW conc. affected by leaching from broken solar modules: 10 000 ng L −1 [50] Hea [50,57] Phytoaccumulation and estimations of health risk assessment Gallium (Ga) Ga(III): Irritation, breathing difficulties and chest pain [49] Toxicity and lung damage [50] Ga is exempted from WHO standard limits for drinking water [41] Fertilizer plants [24] Hard and sedimentary rock aquifers in the K/T boundary (India): max. 80-6400 ng L −1 [41] Non-specified source in the Carpathian Mountains (Romania): 1380-121 000 ng L −1 [47] Influence from fertilizer plant in the area of the Dead Sea (Israel): 3200-172 000 ng L −1 [24] CS [41,47] CS [24,41] Hea [41,47] Mobility, punctual health risk assessment Germanium (Ge) May be essential in micro-doses though not officially stablished. ...
Groundwater is a crucial resource for humans, used as drinking, agricultural, or industrial water. While aquifer pollution may cause dramatic loss of water supply, currently increasing pressure is exerted on these systems. Technology Critical Elements (TCEs) are a group of naturally occurring elements gaining recent attention regarding their extensive use in various technological applications. Growing emissions into the environment classify them as emerging contaminants, though scarce information is yet available in the literature. Ongoing advances in analytical methods have provided some TCE environmental levels but very little is known about their distribution, behavior, and fate, particularly for subsurface waters. This review summarizes the latest research on TCEs in groundwater resources and highlights the gaps of knowledge remaining in this field.
... Potential ecotoxicity and human health risks of PV module waste's material leaching in landfills were investigated by Nain and Kumar and identified possible exposure scenarios from leachates [37]. It is vital that the direct disposal of PV waste to landfills should be prevented due to their detrimental effects on nearby communities and ecosystems. ...
... In relation to structural damage, PV modules are no exception to this because of their delicate, brittle nature. In fact, PV module breakage is a common theme even in its transport [37]. ...
The drastic increase in solar energy dependency would yield a tremendous amount of waste worldwide, and sustainably managing the emerging PV waste prevents potential environmental impacts and harm to humanity. This paper presents a systematic review of literature to identify strategies for PV module waste management and an internet-based assessment of PV module waste regulations in the Philippines. The systematic review utilized four key phrases to identify relevant articles. The title and abstract of the resulting articles from 2012 to 2022 were screened based on selection criteria and relevance, and 54 articles were selected. In addition, an internet-based assessment was conducted to determine the regulations of PV module waste in the country. Several key themes were also discussed that include waste assessment, global regulatory framework and policies, and end-of-life management encompassing monitoring, collection, recycling, and supply chain for recovered secondary materials. In addition, strategies for the various stages of the life cycle of PV modules were presented in the review. The identified waste management strategies include carefully designed PV modules to withstand breakage, utilization of recovered secondary materials, correct installation procedures, regular PV waste assessment and monitoring, efficient collection and fast classification of PV module waste, and sustainable recycling and recovery methods and technologies. Furthermore, the assessment shows that there is no specific regulation in the country that deals with PV module waste. Policies for PV module waste monitoring, take-back scheme, and subsidization should be explored. Indeed, PV module waste management strategies and regulations in the Philippines are critical to managing emerging waste effectively.
... In the persulfate activation systems, the application of highly efficient metal-based catalysts is accompanied by the leaching of heavy metal, which puts pressure on the secondary sludge purification and ecosystem [22,23]. Consequently, carbonaceous materials (such as graphite, graphene, fullerene, and carbon nanotubes) were repeatedly introduced in persulfate activation [24]. ...
As a rising branch of advanced oxidation processes, persulfate activation has attracted growing attention. Unlike catalysts that have been widely studied, the selection of persulfate is previously overlooked. In this study, the affecting factors of persulfates were studied. The effect of target pollutant properties on superior persulfate species (the species with a higher degradation efficiency) was investigated by multiwalled carbon nanotube (MWCNT)/persulfate catalytic systems. Innovatively, the EHOMO (or vertical ionization potential (VIP)) value of the target pollutant was proposed to be an index to judge the superior persulfate species, and the threshold is VIP= 6.397-6.674 eV, EHOMO= -8.035∼- 7.810 eV, respectively. To be specific, when the VIP of phenolic compounds is higher (or EHOMO of phenolic compounds is lower) than the threshold, the catalytic performance of peroxymonosulfate would be higher than that of peroxydisulfate. Moreover, the effects of coexisting cations on peroxydisulfate superior species were further investigated. It was illustrated that the hydrated cation radius of coexisting cations would influence the pollutant degradation efficiency under some circumstances. This study provides a new approach to improve the cost of persulfate activation systems and promotes the underlying downstream application of persulfate activation systems.
... The government should provide incentives for industry led initiatives to also come up with innovative recycling technologies. Without proper control measures, the broken panels in the landfills may percolate and leach into the ground water (Nain & Kumar, 2020a, 2020b which will cause several environmental and health issues. ...
The growth of solar photovoltaic (PV) waste in the coming years requires implementation of effective management options. Australia, with one of the highest rates of rooftop solar PV, is still developing policy options to manage these panels when they reach their end-of-life. This study evaluates the environmental impacts of three options for mono and multi crystalline silicon (c-Si) solar panel waste modules. The impact of transport distance from transfer stations to the recycling centre is also assessed. The life cycle assessment revealed that, -1 E+06 kgCO2eq and -2 E+06 kgCO2eq are associated with the mandatory product stewardship scenarios under global warming potential for mono and multi c-Si solar modules, respectively. However, the non-existence of a product stewardship will produce a global warming impact of 1 E+05 kgCO2eq for both modules. The global warming effects revealed that, collecting and recycling most of the multi c-Si panels were not effective (−365.00 kg CO2-eq, −698.40 kg CO2-eq, −1032.00 kg CO2-eq) compared to keeping them away from the landfills and fully recycling (-2 E+06 kg CO2-eq) them. It was also highlighted that, the highest environmental impact regarding the transport distances was the scenario of one recycling centre serving over 107 transfer stations with a global warming potential of 1 E+06 kgCO2eq. This research model serves as the first conceptual and methodological framework for life cycle assessment (LCA) in policy and transport related analysis. Since transport is incredibly significant in PV recycling processes, it is recommended that, to further reduce these impacts, other forms of low-impact modes of transportation should be explored.
... The initial domain concentrates on the dimension of connection between domestic climatic degradation and socio-economic amelioration. It includes the bond between climatic variations and progress in economic activities (Fan et al., 2023;Rao and Yan, 2020) and the impression of climatic vulnerability on human health (Gehrsitz, 2017;Gu et al., 2019;Haseeb et al., 2019;Nain and Kumar, 2020). For instance, Rao and Yan (2020) preliminarily highlighted the primal parameters influencing economic progress in environmental contamination indicators through the lens of the LARS-LASSO (Least Angular Regression -Least Absolute Shrinkage and Selection Operator) approach and step-by-step regression. ...
In response to China's burgeoning environmental pollution, since 2010, Chinese policymakers have implemented a low-carbon city pilot policy (LCCP) and expanded the pilot project's dimension since then. An accurate evaluation of the consequences of this environmental intervention is vital for the further promotion and extension of this pilot project. In this milieu, we develop a framework to put credibility on this newly intervened policy by harnessing robust econometric approaches. To achieve this objective, we garner integrated data from 2006 to 2014, sourced from two distinct databases: the Chinese Industrial Enterprise database and the China Enterprise Pollution Emissions database. This paper deploys a time-varying Difference in Difference (DID) approach to scrutinize the influence of LCCP on China's emissions reduction agenda from a micro-perspective. The findings reveal that: (1) LCCP significantly reduces enterprise pollution by promoting eco-friendly technologies and innovation capacity; (2) LCCP promotes healthy urbanization and restores the urban ecosystem by abating emissions intensities significantly (i.e., for every one percentage point increase in LCCP, firm-level emissions plummet by 1.87%); (3) LCCP efficacy in controlling emissions varies in terms of ownership, type and location of the firms (i.e., LCCP policy is more efficacious in controlling emissions if the firm is foreign or private-owned if it is a capital and technology intensive high polluting firm and if the firm is located in eastern and western zones of the country). The findings are robust after replacing the explained variables, changing the estimation method, excluding the interference of outliers, considering the lagged term, and excluding other policy interference. Based on the findings, this study touts the Chinese Government's LCCP policy by providing firm-level theoretical support and empirical evidence for China to boost the revamping strategy of carbon-neutral cities. Therefore, the benefits of pilot cities should be further harnessed to guide enterprises in low-carbon pilot cities so that they can engage in cleaner production activities and achieve green transformation through policy preferences and other incentives. Further policy suggestions have been made in the relevant section.
... The initial domain concentrates on the dimension of connection between domestic climatic degradation and socio-economic amelioration. It includes the bond between climatic variations and progress in economic activities (Fan et al., 2023;Rao and Yan, 2020) and the impression of climatic vulnerability on human health (Gehrsitz, 2017;Gu et al., 2019;Haseeb et al., 2019;Nain and Kumar, 2020). For instance, Rao and Yan (2020) preliminarily highlighted the primal parameters influencing economic progress in ...
In response to China's burgeoning environmental pollution, since 2010, Chinese policymakers have implemented a low-carbon city pilot policy (LCCP) and expanded the pilot project's dimension since then. An accurate evaluation of the consequences of this environmental intervention is vital for the further promotion and extension of this pilot project. In this milieu, we develop a framework to put credibility on this newly intervened policy by harnessing robust econometric approaches. To achieve this objective, we garner integrated data from 2006 to 2014, sourced from two distinct databases: the Chinese Industrial Enterprise database and the China Enterprise Pollution Emissions database. This paper deploys a time-varying Difference in Difference (DID) approach to scrutinize the influence of LCCP on China's emissions reduction agenda from a micro-perspective. The findings reveal that: (1) LCCP significantly reduces enterprise pollution by promoting eco-friendly technologies and innovation capacity; (2) LCCP promotes healthy urbanization and restores the urban ecosystem by abating emissions intensities significantly (i.e., for every one percentage point increase in LCCP, firm-level emissions plummet by 1.87%); (3) LCCP efficacy in controlling emissions varies in terms of ownership, type and location of the firms (i.e., LCCP policy is more efficacious in controlling emissions if the firm is foreign or private-owned if it is a capital and technology-intensive high polluting firm and if the firm is located in eastern and western zones of the country). The findings are robust after replacing the explained variables, changing the estimation method, excluding the interference of outliers, considering the lagged term, and excluding other policy interference. Based on the findings, this study touts the Chinese Government's LCCP policy by providing firm-level theoretical support and empirical evidence for China to boost the revamping strategy of carbon-neutral cities. Therefore, the benefits of pilot cities should be further harnessed to guide enterprises in low-carbon pilot cities so that they can engage in cleaner production activities and achieve green transformation through policy preferences and other incentives. Further policy suggestions have been made in the relevant section.
... Based on the composition of the multiple layers of these cells, the valuable and critical elements Ag, In and Ga can be present [10]. At the same time, Ag, Al, Cu, In, Mo, Ni, Zn as well as Fe and Cr (in case of stainless steel substrate), are considered hazardous for health if they contaminate the soil and/or groundwater [11][12][13]. ...
The increase in the manufacturing of copper-indium-gallium-diselenide (CIGS) thin film photovoltaics is accompanied by a growing amount of production waste, which contains a mixture of valuable, critical and hazardous elements. However, industrial recovery and reuse processes of these elements for production of new photovoltaics are still absent. In this paper, the possibility of using benign leaching conditions for recovering mainly silver and indium from production waste flexible CIGS solar cells was investigated, along with the contamination levels from other industrial elements in the leachate. At the same time, the prospect of selective leaching of contaminants was assessed, aiming to purer streams of the valuable metals and thus their reuse in new products. The results show an increase in the leaching yields of Ag and In when acid concentration and surface to liquid ratio (A:L) increase, however, this is also true for contamination. A complete Ag recovery and 85% recovery of In was achieved with 2 M HNO3 and A:L equal to 1:3 cm²/ml after 24 h of leaching at room temperature. Under the same conditions, leaching with 0.5 M HNO3 extracts 85% Ag and 30% In, with correspondingly reduced contamination levels. Finally, leaching with 0.1 M HNO3 proved to be promising for achievement of higher Ag purity through an initial step of Zn selective leaching for 1 h.
... Les panneaux photovoltaïques en fin de vie constituent une préoccupation mondiale émergente, avec une estimation de 78 millions de tonnes de déchets photovoltaïques dans le monde d'ici 2050 (Chowdhury et al. 2020). En plus de la crise mondiale actuelle des déchets électroniques, ils représentent une grave menace pour l'environnement dans certains pays où ils ne sont pas recyclés, notamment en raison des risques de ruissellement dans l'eau potable et de la dégradation des sols due à la libération 27 potentielle de matériaux toxiques (Nain et Kumar 2020). Le recyclage et l'utilisation efficace (upcycling) des déchets issus des parcs photovoltaïques sont essentiels pour assurer la durabilité (à long terme) de cette filière en tant que source propre d'énergie renouvelable (Kumar et Mani 2021). ...
Cette synthèse bibliographique passe en revue les publications scientifiques françaises et internationales les plus récentes afin de fournir aux acteurs de la filière photovoltaïque, aux services de l’Etat et aux différents organismes engagés pour la protection de l’environnement un état des lieux le plus complet possible sur le niveau de connaissance des incidences potentielles sur les milieux naturels des centrales photovoltaïques au sol et flottantes, les mesures d’atténuation des incidences existantes et leurs modalités de suivi.
... The vast amount of materials mined and processed for the rapidly expanding solar PV industry has become a basis for social and environmental concern. A range of environmental depredations and environmental distribution conflicts along the PV supply chain are now affecting vulnerable communities and groups, primarily in the Global South (Dubey et al., 2013;Yenneti et al., 2016;Stock and Birkenholtz, 2019;Nain and Kumar, 2020;Temper et al., 2020;Sonter et al., 2020). ...
Global installations of solar photovoltaic (PV) technology have reached unprecedented levels and is expected to further rise in the coming decades. Conventional interpretations have neglected international trade flows and the globally uneven valuation of labor and resources as relevant for the commercialization of solar PV technology. This study challenges these interpretations by assessing whether the rapid increase in solar power was based an uneven flow of resources in the world economy. The study relies on an LCA-based account of ecologically unequal exchange in two focal PV commodities between Germany and China 2002–2018. The results show how this trade was characterized by an intensifying rate of ecologically unequal exchange, which gradually improved Germany's prospect of installing solar PV modules at the expense of increasing environmental loads in China. This environmental load displacement contributed to 15 times lower production costs per watt and considerably higher EROI (from 2.2:1 to 77:1) and power density (from 4.3 W/m² to 143 W/m²) in Germany. The study concludes that ecologically unequal exchange may have been integral to the global rise of solar power and cautions that environmental load displacements may be inherent to the success of social metabolisms reliant upon solar energy harnessed through PV technology.
... where C (mg·kg −1 ) is the dermal bioaccessible concentration of heavy metals; SA is the surface area of skin exposed (5700 cm 2 for adults and 2800 cm 2 for children) (Luo et al., 2012); SAF is the skin adherence factor (0.07 mg·cm −2 for adults and 0.2 mg·cm −2 for children); EF is the exposure frequency (350 days year −1 for residents and 75 days year −1 for recreation); ED is the exposure duration (30 years for adults and 6 years for children); ABS is the dermal absorption factor (0.03 for As and 0.001 for other metals): BW is average body weight (16.2 kg for children and 61.8 kg for adults); AT is averaging time (AT = ED × 365 days); and CF is conversion factor (10 −6 kg·mg −1 ). At present, there is no available reference on dose values for dermal exposure (Nain and Kumar, 2020). Thus, oral reference dose (RfD O ) and gastrointestinal absorption factor (ABS GI ) were used to calculate the dermal reference dose values (RfD ABS ) of heavy metals in soils as follows: ...
The dermal exposure of heavy metals in contaminated urban soils poses huge environmental health risks globally. However, their dermal bioaccessibility and adverse effects on human skin cells were not fully understood. In this study, we measured the total and dermal bioaccessibility of Cr, As, Cd, Pb, and Cu in four selected urban soil samples from Kunming, Yunnan, China, and evaluated the cellular responses of these bioaccessible extracts on human keratinocytes (HaCaT). Among all the metals, only As in Soil-3 (S3) exceeded Chinese risk screening and Yunnan background values at 38.2 mg/kg. The average concentrations of Cr, As, Cd, Pb, and Cu in all soil samples were 47.79, 15.50, 3.11, 104.27, and 180.29 mg/kg respectively. Although relatively high concentrations of heavy metals were detected in soil samples, the highest dermal bioaccessibility of Cd was 3.57% with others' being lower than 1%. The bioaccessible dermal-absorbed doses (DADs) of Cr, As, Cd, Pb, and Cu from soils reflected acceptable health risks since all DADs were below the corresponding derived dermal reference values. However, the toxic data showed the extracts of S3 and S4 presented certain cytotoxicity in HaCaT cells, indicating the existing models based on dermal bioaccessibility and DADs may be not accurate enough to assess their human health risk. Taken together, the human health risk assessment should be modified by taking their skin cytotoxicity into account.
... Ecological and health risk assessments have previously been well integrated to evaluate the effects of chemical exposure on ecosystems and human health (Nain and Kumar, 2020). Bioconcentrations factor (BCF) can indicate levels of bioaccumulation of heavy metals in plants from polluting sources (e.g., soil and water), which can be further applied to calculate average daily intake (i.e., ingestion) and evaluate against the reference dose (RfD) in health risk assessment (Atikpo et al., 2021). ...
In bioponics, although chicken manure is an efficient substrate for vegetable production and nitrogen recovery, it is often contaminated with high Cu and Zn levels, which could potentially cause bioaccumulation in plants and pose health risks. The objectives of this study were to assess nitrogen recovery in lettuce- and pak choi-based bioponics with Cu (50–150 mg/kg) and Zn (200–600 mg/kg) supplementation, as well as their bioaccumulation in plants, root microbial community, and health risk assessment. The supplementation of Cu and Zn did not affect nitrogen concentrations and plant growth (p > 0.05) but reduced nitrogen use efficiency. Pak choi showed higher Cu and Zn bioconcentration factors than lettuce. Bacterial genera Ruminiclostridium and WD2101_soil_group in lettuce roots and Mesorhizobium in pak choi roots from Cu and Zn supplemented conditions were significantly higher (p < 0.05) than controls, suggesting microbial biomarkers in plant roots from Cu and Zn exposure bioponics depended on plant type. Health risk assessment herein revealed that consumption of bioponic vegetables with Cu and Zn contamination does not pose long-term health risks (hazard index <1) to children or adults, according to the US EPA. This study suggested that vegetable produced from chicken manure-based bioponics has low health risk in terms of Cu and Zn bioaccumulation and could be applied in commercial-scale system for nutrient recovery from organic waste to vegetable production; however, health risk from other heavy metals and xenobiotic compounds must be addressed.
... An ecological assessment of the study area was performed using the land accumulation index (I geo ) and potential ecological risk index (PER), which are effective tools for analyzing and quantifying environmental pollution (Nain and Kumar, 2020). Fig. 5 shows that the highest mean value of the combined ecological risk result was obtained for Cd, followed by Hg and As. ...
... It indicates the possibility of only small amount of Cd release from Cd-related compounds used in PVs which may not pose high risk. This could also be seen from one of the previous studies by author on risk assessment for PV disposal in environment [31]. The average hazard quotient values of Cd for all exposure scenarios were found to be <1 indicating insignificant health risk. ...
In last two decades, solar photovoltaic industry has shown tremendous growth among all renewable energy sectors, as a result, the concern of their end-of-life waste management increased. This study reviews the current state -of- art on end-of-life photovoltaics in terms of the materials used during manufacturing, their fate in environment, short-term & long-term leaching behaviour, applicability of current standard waste characterisation methods, possible human & ecological risk, manufacturers & consumers perspective towards management and recycling. A comprehensive comparative analysis of various findings from recent studies regarding the subject of end-of-life photovoltaic waste was done. Special emphasis was given on understanding the material release from first and second generation photovoltaics as per various theoretical and experimental studies to identify knowledge gaps. The findings from review shows that metals, such lead, copper, iron and aluminium have the potential to exceed hazardous waste limits, though a majority of them do not exceed the standard waste methods limit. Among the various modules, the highest material release was observed from crystalline-silicon modules. Further, if solar modules are disposed in landfills, the increase in leachate pollution index is mainly due to the leached heavy metals such as lead and chromium as the effect due to other parameters is negligible. At present, solar photovoltaics are generally grouped with electronic waste and is not classified under any waste category (hazardous or non-hazardous) except the United States of America and Europe. Amendments in existing waste characterization tests considering the complexity of photovoltaic waste and disposal mode should be considered. Further, as per various studies, progressing research is needed to establish standardized methods for recycling of photovoltaics. Present study gives a summary and future outlook on end-of-life solar photovoltaics with recommending the future directions for researchers and public policymakers.
... The PEV is defined as the concentration at which tolerable risk levels for noncarcinogenic risk (>1.0) would be exceeded for a child (<2 years) exposed to trace metals in vacuum dust, which can then be used to estimate probable exceedance. 139 The PEV calculations rely on generic input parameters that may not capture likely regional trace metal and lifestyle variations. ...
People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb−Zn−As factor related to legacy Pb sources, a Zn−Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.
... It also offers a qualitative and quantitative ranking of dangerous scenarios that can be utilized as safety analysis top occurrences (Kim et al., 2003). The goal of risk identification is to identify the potentially dangerous elements, such as hazardous sources, derivative incidents, etc. (Nain and Kumar, 2020). According to the United States Environmental Protection Agency (US-EPA), a population's exposure to heavy metals in water can occur either through direct ingestion (through drinking) or indirect ingestion (through use in foods and drinks made with contaminated water). ...
Industrial wastewater treatment is of paramount importance considering the safety of the aquatic ecosystem and its associated health risk to humankind inhabiting near the water bodies. Microalgae-based technologies for remediation of environmental pollutants present avenues for bioenergy applications and production of value-added biochemicals having pharmaceutical, nutraceutical, antioxidants, carbohydrate, phenolics, long-chain multi-faceted fatty acids, enzymes, and proteins which are considered healthy supplements for human health. Such a wide range of products puts up a good case for the biorefinery concept. Microalgae play a pivotal role in degrading complex pollutants, such as organic and inorganic contaminants efficiently removed from environments. Microalgal species such Botryococcus braunii, Tetraselmis suecica, Phaeodactylum tricornutum, Neochloris oleoabundans, Chlorella vulgaris, Arthrospira, Chlorella, and Tetraselmis, etc. are reported for the generation of value-added products. This review presents a holistic view starting from cultivation and harvesting of microalgae, the potential for remediation of environmental pollutants, bioenergy application, and production of value-added biomolecules. This review summarizes the current understanding of microalgae-based technologies for removal of contaminants risk, bioeconomy, and outlines future research directions.
... For human health risk assessment (Hum-T), the nature and probability of adverse health effects in humans who may be exposed to chemicals in contaminated environmental media, now or in the future, are estimated (Ancione et al., 2020;Nain and Kumar, 2020). As suggested by the Integrated Risk Information System (IRIS) conducted by the USEPA, the non-cancer toxicity of a single chemical and the carcinogenic risk were evaluated based on the average daily dose (ADD) values. ...
Screening priority pollutants from vast anthropogenic contaminants discharged into aquatic environment is urgent for protecting water quality definitely. The multi-criteria scoring method involved in the occurrence (O), persistence (P), bioaccumulation (B), ecological risk (Eco-T), and human health risk (Hum-T), was established for pollutants prioritization in waters and applied in Dongping Lake, the final impoundment reservoir along the eastern route of China's South-to-North Water Diversion Project (SNWDP). A total of 170 chemicals including heavy metals (HMs), volatile organic chemicals (VOCs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), phthalate esters (PAEs), and antibiotics (ANTs) were investigated as the candidates. Accordingly, 42 chemicals including 8 PAEs, 7 OCPs, 7 PCBs, 5 PAHs, 13 HMs, and 2 VOCs were made up the list of priority pollutants for Dongping Lake, suggesting the necessity of routine monitoring high priority groups and revising the existing list. Multiple risk assessment indicated higher ecological and human health risks induced by HMs than by organic pollutants. Spatial distribution of risks stressed the retention of toxic organic chemicals by the lake body and the accumulation of HMs along the transfer route, respectively, thus triggering ecosystem responses and potential effects on the water-receiving areas as expected.
... Some of the influencing factors in risk estimation include ingestion rate, frequency of consumption, duration of food consumption, the weight of people consuming food (vary from place to place; Sharafi et al., 2019b), and the average lifetime of the risk group. Acute or chronic metal exposures can cause severe disorders and extreme damage due to oxidative stress (Nain and Kumar, 2020). Numerous studies (Traina et al., 2019;Anandkumar et al., 2020;Alipour et al., 2021;Peng et al., 2016;Sharafi et al., 2019b) evaluated the human health risks from the consumption of various foods to inform the public, support policy changes, and improve food quality. ...
Farmed crustaceans are an important component in addressing the rising animal protein demand. The present study determined the concentrations of fourteen elements (Ag, As, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Sn, Pb, and Zn) in the edible abdominal muscle of cultured freshwater crayfish species (Faxonius virilis; Procambarus acutus acutus) from Missouri. Also, this paper describes the dietary intake and the human health risks from the consumption of crayfish muscle in the adult population. Overall, 172 animals were captured between February 2017 and January 2018 for assessment. Concentrations of metals (Ag, Be, Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb, Sn, Mo, and Zn) and metalloid (As) in the muscle tissue were determined after microwave-assisted acid digestion by ICP - OES. Health indices (EDI/EWI: estimated daily/weekly intakes; THQ: target hazard quotient; TTHQ: total target hazard quotient; ILCR: incremental lifetime cancer risk; and ∑ILCR: cumulative lifetime cancer risk) were calculated and compared to thresholds. Of all samples, the highest concentrations (mg kg ⁻¹ wet weight) of metal(loid)s in muscle were Ag (0.11), As (3.15), Be (0.21), Cd (0.11), Co (0.32), Cr (1.22), Cu (107), Fe (23.0), Mn (8.54), Mo (0.62), Ni (2.65), Pb (1.76), Sn (5.91), and Zn (19.2). In both species, the average As, Cd, and Zn concentrations were below the legal limits. However, the levels of Cu, Pb, and As, in some samples, were in exceedance of the maximum levels. In both species, a significant correlation (p < 0.05) was observed between the carapace length (CL) and animal body weight (BW). In P. acutus, CL, BW, and animal total length were homogenous (p > 0.05) among the sexes. Non-parametric Kruskal–Wallis test results indicated significant differences (p < 0.05) in the levels of As, Be, and Zn in F. virilis, and Be and Cr in P. a. acutus among the genders. Significant inter-species differences (p < 0.05) were observed in the levels of Be, Ni, and Pb and the growth factors. The EDI/EWI values were below the permissible limits. THQ and TTHQ values, being below 1.0, indicated no probabilistic health risk. Regarding carcinogenic risk, only As and Ni indicated cancer risk (ILCR >10⁻⁵ and ∑ILCR >10⁻⁵) to the adult population. High metals/metalloid exposure from crayfish muscle consumption posed potential health hazards to the adult population.
... It indicates the possibility of only small amount of Cd release from Cd-related compounds used in PVs which may not pose high risk. This could also be seen from one of the previous studies by author on risk assessment for PV disposal in environment [31]. The average hazard quotient values of Cd for all exposure scenarios were found to be <1 indicating insignificant health risk. ...
With rapid growth in solar industry, the potential fate and management of solar modules has raised concerns due to the presence of few toxic metals. Present work addressed this issue by (i) estimating potential release values or solubility (Ksp at pH 7) of various compounds used in different layers of emerging solar cells in neutral water and landfill leachate conditions, and (ii) further comparing their metal release values (termed as loss factors, LFs) with that of first and second generation photovoltaics. Top five compounds with highest metal release probability (probability>0.5%) were found to be: Lead iodide (highest LF)> Copper iodide> Cadmium hydroxide> Copper thiocyanate> Cadmium oxide (smallest LF). Also, identified compounds with lowest risk were: Lead selenide <Antimony trisulfide <Cadmium selenide <Aluminium oxide <Tin sulphide (lowest probability: 1*E-10 to 1*E-16). With respect to solar cells, perovskite was ranked first in terms of hazard as it mostly contains compounds like Lead iodide, Copper thiocyanate, Copper iodide, Nickel oxide, and Aluminium oxide. Quantum dot solar cells were ranked second due to presence of category II compound (i.e., ZnO). Further, organic and dye-sensitized solar cells are of least concern as they do not contain compounds with high LF values. With respect to different layers of an emerging PV, electron- and hole- transport layers were found to be with highest risk for material release. With respect to third generation solar cells, metal LFs for first generation solar cells were less for lead, cadmium and copper. Following the conservative approach, the calculated conversion factors for metal loss values from neutral water (pH7) to landfill leachate (i.e., CFs =LFMSW leachate/LFpH7) for Pb(0.075), Cu(0.263), Ni(0.426), Zn(0.591) were used for estimating metal loss values from emerging solar cells in landfill leachate conditions. Among all generation solar PVs, mostly lead- containing compounds were found to be exceeding the LF cut-off values. Thus, perovskites solar cells with lead–based compounds might pose risk to groundwater or surface runoff due to lead.
... • In the global commodity chains, there are negative and unequally distributed health effects and environmental consequences of renewable energy technologies (Dubey et al., 2013;Yue et al., 2014;Mulvaney, 2013Mulvaney, , 2019Nain and Kumar, 2020). These effects include toxicity and environmental pollution in the manufacturing, transportation, and end-of-life processes. ...
Solar photovoltaic (PV) technology is one of the most favored means of mitigating climate change. At the same time, there is a growing concern over how this technology is both environmentally harmful and unevenly distributed in the world economy. Researchers and environmentalists differ on whether a global relation of power is inherent in solar technology. This thesis investigates to what extent the global, social and material conditions of solar PV technology contrast with conventional conceptions of it. Building on insights from ecological economics and the philosophy of technology, it offers an interdisciplinary approach to solar PV technology. Its central question is whether ‘ecologically unequal exchange’ is a necessary condition for large-scale solar PV development. The theory of ecologically unequal exchange explains how wealthier nations rely on net imports of resources to sustain their levels of consumption and technological development, while displacing much of their work and environmental loads to poorer nations. This theory is tested in an LCA-based account of ecologically unequal exchange between Germany and China during the emergence of the global solar PV market (2002-2018). It is also tested through an application of the concept of ‘power density’ to four leading solar nation’s PV ambitions (China, Germany, India, Italy). The findings demonstrate how large-scale development of solar PV technology may require global asymmetries as much as polysilicon, electrical components, engineers, or direct sunshine. To the extent that decisionmakers disregard this, it may be a symptom of ‘machine fetishism,’ which masks the global asymmetries of the emerging energy regime while also preventing us from grasping what modern technology ultimately is.
... To date, the estimated global cumulative installed capacity of PV modules has dramatically increased from 40 GW in 2010 to 715 GW in 2020 [1]. In this regard, the limited lifetime (~25 years) of PV modules will lead to a significant amount of EoL PV modules, which has been defined as a new waste of electrical and electronic equipment [2], becoming a severe challenge to the sustainable energy generation system and an increasingly serious environmental issue [3][4][5][6][7][8][9]. Thus, it is necessary to develop novel technologies for PV modules waste disposal, particularly for crystalline silicon (c-Si) solar panels, which dominate 85-90% market share [10]. ...
End-of-life (EoL) photovoltaic (PV) waste is becoming a severe environmental issue worldwide. Developing technologies to reclaim nondestructive and reusable silicon wafers (Si-wafers) is the most appealing way to solve this problem, saving ∼40% on PV module production costs, but it remains a great challenge. Herein, we develop a novel method of coupling solvothermal swelling with thermal decomposition (SSTD) for structure-intact Si-wafers recovery. Laboratory-scale studies reveal that undamaged Si-wafers can be easily obtained by conducting a solvothermal swelling process in advance to build channels for the quick, horizontal release of ethylene-vinyl acetate (EVA) thermal decomposition gas. Using scaling-up equipment, 86.11% of Si-wafers in commercial PV module are reclaimed without any damage, nearly 10-fold higher than that of thermal decomposition alone (9.26%). Moreover, PV backsheet can be depolymerized with specially designed solvents (toluene-ethanol), greatly facilitating swelling by exposing EVA directly to toluene vapor and reducing the emission of fluorine-containing gas pollutants. The reclaimed Si-wafers are comparable to the originals, with the following properties: interstitial oxygen, <6 × 10¹⁷ atoms·cm⁻³; substitutional carbon, <5 × 10¹⁷ atoms·cm⁻³; resistivity, 1.84 Ω·cm; and minority carrier lifetime, 3.92 μs.
... End-of-life PV panels are an emerging global concern, with an estimated 78 million tonnes of PV waste globally by 2050 [53]. They pose a severe environmental threat in addition to the existing global e-waste crisis, such as leaching into drinking water and land degradation due to toxic materials [54]. Recycling and effective utilization (upcycling) of PV waste are crucial to ensure (long-term) sustainability of solar PV as a clean source of renewable energy. ...
Sustainability assessment in manufacturing has predominantly focused on environmental dimensions without accounting for absolute (consumption and or pollution) limits and has remained limited to efficiency-based improvements. Efficiency-based assessments are increasingly yielding counterintuitive results. An effectiveness-based approach could integrate local and global absolute pollution limits in the sustainability assessment and ensure resource-effectiveness using circularity indicators. Circularity is increasingly viewed as a viable approach to achieving sustainability by discerning the underlying interconnected, diverse systems. This paper presents a preliminary systems-based framework for effective sustainability assessment in manufacturing. Steps to understand and identify effectiveness indicators have been discussed. A case study of photovoltaic manufacturing industry has been discussed in the context of the framework.
... Further, non-carcinogenic probabilistic human risk assessment (PHRA) was also done for Pb, Cd, Cr, and Ni. The methodology and all the parameter values used for probabilistic risk were followed from a recent study by Nain and Kumar (2020b). Monte Carlo simulation was used to generate ten thousand random numbers for leachate metal concentration and dilution factor (range 1 to 1000) were used to estimate metal concentration in groundwater. ...
The present study investigated the variation in leachate pollution index (LPI) of four municipal solid waste (MSW) dumping sites: non-engineered (Okhla, Ghazipur, Bhalswa) and engineered (Narela-Bawana) of Delhi, India. A review of 142 screened studies from Google Scholar database was done for synthesis of information on LPI parameters. Further, the rate constant determination and human health risk assessment for various leachate parameters was done. Results showed the following LPI trends: Okhla landfill: irregular with exceedance to threshold value; Bhalswa landfill: exponential increase; and Narela-Bawana landfill: linear increase. Parameters such as pH, dissolved solids, copper, nickel, zinc, and chromium of Bhalswa landfill, exhibited an exponential decay with LPI variation. Whereas, for Narela-Bawana’s leachate BOD and COD parameters, an exponential decay in LPI vs zinc and linear increase for LPI vs lead was observed. For all dumping sites, a positive correlation was observed between heavy metals and LPI. In case of human health risk assessment, order of oral risk posed by Okhla’s metals was cadmium > chromium > nickel > lead, with maximum hazard quotient (HQ) of 1.61 for cadmium. For Ghazipur and Bhalswa landfills, cancer risk values for both adult and child sub-populations were observed to be maximum for cadmium followed by nickel, chromium, and minimum for lead. For Narela-Bawana landfill, the order of cancer risk was as follows: chromium > nickel > lead. HQ for Pb-contaminated groundwater exceeded the threshold limit in Ghazipur and Bhalswa landfills. For dermal groundwater exposure, cadmium for Okhla (adult 2.3 × 10⁻⁴ and child 1.4 × 10⁻⁴), Ghazipur (adult 9 × 10⁻⁵ and child 5.2 × 10⁻⁵), and Bhalswa (adult 1.5 × 10⁻⁴ and child 8.6 × 10⁻⁵) was observed to have maximum cancer risk. The analyzed year-wise LPI trend, calculated rate constants, and human health risk values from present study provide a basis to waste managers and regulators for understanding various waste sources.
Graphical abstract
Concerns about decreasing urban water supplies and environmental degradation caused by existing water infrastructure have prompted research on more resilient and long-term water delivery systems. Greywater reuse has been proposed to expand local water supply portfolios while minimizing stress on existing ecosystems and infrastructure. Researchers have developed several technologies for greywater reusability and recycling. There are three primary treatment technologies for greywater treatment: physical, chemical, and biological. Besides traditional treatment methods, numerous advanced technologies have attracted interest in recent years, like membrane-based technology, improved electrocoagulation, nature-based solutions (constructed wetlands), and solar-based approaches. The cost comparison of existing technologies has also been examined. The current review focuses on the relevance of various technologies and their readiness level, global scenario, risks possibilities and modeling systems for greywater reuse. The issues and hurdles of greywater reuse sustainably have also been evaluated. This in-depth review study will set the basis for future research in greywater reusability.Graphical abstract
The booming demands for energy and the drive towards low-carbon energy sources have prompted a worldwide emerging constructions of photovoltaic (PV) solar energy facilities. Compared with fossil-based electrical power system, PV solar energy has significantly lower pollutants and greenhouse gases (GHG) emissions. However, PV solar technology are not free of adverse environmental consequences such as biodiversity and habitat loss, climatic effects, resource consumption, and disposal of massive end-of-life PV panels. This review highlights the benefits and potential environmental impacts of implementing PV technologies. To the end, some proposals are recommended to improve this new technology's sustainability.
Building on insights from ecological economics and philosophy of technology, this book offers a novel, interdisciplinary approach to understand the contradictory nature of Solar photovoltaic (PV) technology.
Solar photovoltaic (PV) technology is rapidly emerging as a cost-effective option in the world economy. However, reports about miserable working conditions, environmentally deleterious mineral extraction and toxic waste dumps corrode the image of a problem-free future based on solar power. Against this backdrop, Andreas Roos explores whether ‘ecologically unequal exchange’ – an asymmetric transfer of labour time and natural resources – is a necessary condition for solar PV development. He demonstrates how the massive increase in solar PV installation over recent years would not have been possible without significant wage/price differences in the world economy - notably between Europe/North America and Asia- and concludes that solar PV development is currently contingent on environmental injustices in the world economy. As a solution, Roos argues that solar technology is best coupled with strategies for degrowth, which allow for a transition away from fossil fuels and towards a socially just and ecologically sustainable future.
This book will be of great interest to students and scholars of solar power, philosophy of technology, and environmental justice.
Black shale is rich in potentially toxic elements (PTEs) that migrate through rock weathering or rainfall, adversely affecting human health and the environment. In this study, simulated rainfall leaching experiments were used to investigate the migration patterns and leaching kinetics of PTEs in black shale from the Lower Cambrian Hetang Formation and to analyze the water quality index (WQI) of PTEs in the leachate. A comparison between the risk of PTEs in the leachate and those in the soil was also made to determine the risk sources, risk status, and distribution characteristics of PTEs in the study area. The WQI of the indoor column experimental leachate indicated the highest As contamination. The geo-accumulation index (Igeo) and potential ecological risk (Er) of soils in the entire region revealed that the risk of Cd was the highest. Furthermore, by mapping the distribution of Igeo and Er in soils, the risk level in the region where black shale is located was found to be significantly higher than that in other areas. Comparing the leaching rate of PTEs with the WQI from leaching experiments, the risk associated with As in soil can be inferred to originate mainly from the leaching of black shale. Previous studies on PTEs in black shale in the study area tended to focus on Cd; however, this study found that the risk of As was not negligible. The health risk assessment also showed that the risk at the location of black shale was beyond the accepted range. Overall, this study provided a new and important evaluation law for the level of pollution by PTEs and health risks in typical black shale regions.
The present study highlighted the issue of end-of-life photovoltaic waste before government, policy makers, waste regulators and fills the gaps between various stakeholders by exploring their perceptions towards end-of-life solar waste management. Respondents’ waste handling practices, willingness to pay towards recycling, and their mindset towards problematic situation of upcoming photovoltaic waste were investigated via a survey-based study. Findings indicated that consumers are less concerned about photovoltaic waste as 60% of them are planning to sell their used panels to rag-pickers, however, willing to pay a part of recycling/handling cost, if required. Majority of respondents (> 80%) never considered fate of end-of-life photovoltaics, though willing to pay 15% of handling costs. In terms of responsibility for recycling, 60% consumers think that it is government’s responsibility, whereas 51% manufacturers think that it is a common responsibility of government, consumer, seller/manufacturer. In respect to ranking of drivers, barriers and enablers towards solar waste management, consumers scored factors more moderately than manufacturers, highlighting the less apprehension and thoughtfulness concerning the issue. The most critical barrier identified was high recycling cost, and can possibly be overcome by implementation of research & development on feasible and economically sound recycling processes. Statistical analysis shows that the respondent category and their respective regions significantly affect the ranking of factors and point-of-view towards various aspects. The findings clearly indicate that self-take-back collection and recycling facilities, material recovery and recycling incentives are the main factors affecting end-of-life panels handling. As an input to policy makers, it is necessary to understand the findings presented in present study on consumers and manufacturers’ mindsets regarding photovoltaic waste issue and their willingness to participate in recycling activities.
Graphical abstract
The global exponential increase in annual photovoltaic installations and the resulting levels of photovoltaic waste is a growing concern. It was verified in recent literature how the production, management and recovery of residues from photovoltaic energy generation systems is being treated and the proposals for solutions to these problems. In the ScienceDirect database, 30 articles were found on the subject for the period 2012-2020. The evaluated articles were classified into four categories: environmental impacts, circular economy, recycling and/or recovery of inputs and projection of the amount of waste in countries. In the “environmental impacts” theme, five articles showed the environmental impact assessment of the end-of life phase of photovoltaic solar panels and the Circular Economy theme presented three researches. As for the projection of photovoltaic waste, five surveys showed this projection in the United States of America, in Australia; in Spain; in Mexico and Italy. Recycling and/or recovery of inputs was the topic that presented the most research, with seventeen articles, 14 on processes for removal/recovery of inputs and three literature reviews. The articles showed both the concern with the environmental impacts that the use of technology will bring in the future and the suggestions for making this technology a source of raw materials, whether within a circular economy or suggesting processes for extracting inputs after the end of the useful life of the equipment.
As the use of fossil fuels for energy production and in motor vehicles is gradually replaced by wind power, solar power, and electric cars, there is a corresponding increase in a newer form of waste – e-waste – and the chemical pollutants released from this waste. There is increasing evidence, from the effects on wildlife and from those involved in the recycling of this waste, that pollutants released from e-waste may be harmful.
Column experiments were conducted to investigate the effects of ion type, ion strength, humic acid (HA), and nanometer alumina (NA) particles on the transport of hexavalent chromium (HC) in saturated porous media. A one-dimensional model is developed to simulate the migration of HC affected by NA particles. The results show that nano-alumina particles would enhance the mobility of HC in saturated porous media. However, the influence of NA on the migration of HC in porous media is complex. When the concentration of NA reaches 30 mg/L, HC has minimum retention parameter and best mobility. The transport of HC also is affected by ion strength and ion type. Higher ionic strength would decrease the retention of HC and enhance its mobility. Compared with sodium ion, calcium ion has larger effects on the transport of HC. Moreover, HA can improve the mobility of HC in saturated porous media, but the corresponding promoting effect decreases with the increase of HA concentration. As nanometer contaminants and HC come into the subsurface environment, findings from this study elucidate the key factors and processes controlling the transport of HC in porous media, which can promote the prediction and assessment of HC in the groundwater system.
O aumento exponencial global nas instalações fotovoltaicas anuais e os níveis resultantes de resíduos fotovoltaicos é uma preocupação crescente. Verificou-se na literatura recente como está sendo tratada a produção, o gerenciamento e a valorização de resíduos dos sistemas fotovoltaicos de geração de energia e as propostas de solução para esses problemas. Na base ScienceDirect, foram encontrados 30 artigos sobre o tema referentes ao período 2012-2020. Os artigos avaliados foram classificados em quatro categorias: impactos ambientais, economia circular, reciclagem e/ou recuperação de insumos e projeção da quantidade de resíduos nos países. No tema “impactos ambientais”, cinco artigos mostraram a avaliação do impacto ambiental da fase de final de vida dos painéis solares fotovoltaicos e o tema Economia Circular apresentou três pesquisas. Quanto à projeção dos resíduos fotovoltaicos, cinco pesquisas mostraram essa projeção nos Estados Unidos da América, na Austrália; na Espanha; no México e na Itália. Reciclagem e/ou recuperação de insumos foi o tema que apresentou mais pesquisas, com dezessete artigos, sendo 14 sobre processos para retirada/recuperação de insumos e três revisões de literatura. Os artigos mostraram tanto a preocupação com os impactos ambientais que o uso da tecnologia trará no futuro quanto as sugestões para tornar essa tecnologia uma fonte de matérias-primas, seja dentro de uma economia circular ou sugerindo processos de extração dos insumos após o término da vida útil dos equipamentos.
The upcoming end-of-life solar photovoltaics (PV) waste stream is a huge concern before solid waste professionals due to presence of hazardous metals like lead or cadmium. The objective of present study was to understand the metal dissolution from PVs under four standard waste characterization regulatory tests of U.S., Germany, and Japan and their representativeness with actual landfill leachate. Modules were exposed to real municipal solid waste landfill leachate for extended extraction duration, agitation and diluted leachate to investigate the effect of various parameters on metal dissolution. The results indicated that extractions using landfill leachates resulted in lower metal release than standard methods. The leached concentration was within the threshold limit except for cadmium, copper, lead and selenium, with maximum lead release from amorphous-PV of 8.68 mg/L and 6.91 mg/L with respect to TCLP and WET tests, respectively. Arsenic showed negligible release with maximum concentration of 0.046 mg/L from copper indium gallium de-selenide (CIGS) PV. Regardless of small size (1-2 cm pieces) and agitation, Germany and Japan’s standard tests resulted in minimal release except copper from CIGS PV. Leaching without agitation, showed negligible release from all photovoltaics whereas when agitation is applied to diluted leachate, significant release was observed with aluminum and copper leached up to 145.32 mg/L (multi-silicon) and 139.01 mg/L (amorphous-photovoltaic), respectively. CIGS was most hazardous with Metal Hazard Score (calculated on the basis of magnitude of leached metals with respect to their threshold limit and subsequent health effects) of 23.19, when exposed to standard tests. For all scenarios, increased metal release was observed with decrease in sample size and increase in dilution factor and thus, leaching in highly acidic conditions are by no means representative for modules dumping in realistic conditions.
Study on the elemental composition of soils at dumpsites was conducted by analysing samples of soil at
different dumpsites located within Ikot Ekpene, South Eastern Nigeria. The samples were analysed for the
concentration of Na, Ca, Pb, Ni, Mn, Mg, Fe, P, N, Cu and Zn. Control soil samples were taken at 10km
away from the dumpsites and were also analysed for the present of these elements. The result of the
analysis shows a significant difference between the concentration of these elements in the dumpsites and
10km away from the dumpsite (p>0.05). Correlations between them were negative in some cases and
positive in some cases. The dumpsites were found to contained significant amount of toxic and essential
elements hence remediation processes were suggested.
The present study addresses the aspect of upcoming stream of solar photovoltaics waste. The aim of this study was to understand the possibility of material release from end-of-life solar modules using an integrated approach of literature review and stakeholders survey. it involved (i) identification of failure events responsible for degradation of photovoltaic modules were identified from literature review , (ii) evaluation of these events by a survey of stakeholders of photovoltaic industry and (iii) investigation of their perceptions on events responsible for generation of end-of-life modules, present management and recycling practices, (iv) conducting of fault tree analysis and risk priority number analysis for finding severe failure events responsible for dumping and material leaching from solar modules. Assessment indicates that environmental factors, like high UV irradiation, humidity, temperature play significant role in module degradation. As per survey, more than 90% of manufacturers were involved in crystalline-silicon photovoltaic business. Only 20% manufacturers replied when asked on the aspect of end-of-life modules, showing that the photovoltaic waste is comparatively a new subject and not enough discussion have been devoted to it. Lack of recycling infrastructure, incentives, and environmental awareness significantly influence recycling and recuse practices. With worst-case scenarios, the maximum probability of the material release from dumped solar panels was found to 0.053. As per manufacturer’s opinion, the most critical factors resulting in modules failure are glass breakage and encapsulant degradation. Among various events, the module breakage during operation event have highest probability value (i.e., 0.313). Risk priority number analysis suggests that generation of end-of-life photovoltaic and environmental damage resulting to metal leaching as the most significant events. Damage during manufacturing and installation were least significant events resulting in degradation. At present, 76% producers do not recycle or reuse photovoltaic waste material, preferably sell them to informal waste recyclers or rag pickers. Findings from the present study highlight the urgency to develop a suitable system for collection and management of end-of-life photovoltaic modules.
The issue of recycling waste solar cells is critical with regard to the expanded use of these cells, which increases waste production. Technology establishment for this recycling process is essential with respect to the valuable and hazardous metals present therein. In the present study, the leaching potentials of Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans, Penicillium chrysogenum, and Penicillium simplicissimum were assessed for the recovery of metals from spent solar cells, with a focus on retrieval of the valuable metal Te. Batch experiments were performed to explore and compare the metal removal efficiencies of the aforementioned microorganisms using spent media. P. chrysogenum spent medium was found to be most effective, recovering 100% of B, Mg, Si, V, Ni, Zn, and Sr along with 93% of Te at 30 °C, 150 rpm and 1% (w/v) pulp density. Further optimization of the process parameters increased the leaching efficiency, and 100% of Te was recovered at the optimum conditions of 20 °C, 200 rpm shaking speed and 1% (w/v) pulp density. In addition, the recovery of aluminum increased from 31 to 89% upon process optimization. Thus, the process has considerable potential for metal recovery and is environmentally beneficial.
The rapid growth of new electronics and energy technologies requires the use of rare elements of the periodic table. For many of these elements, little is known about their environmental behavior or human health impacts. This is true for indium and gallium, two technology critical elements. Increased environmental concentrations of both indium and gallium create the potential for increased environmental exposure, though little is known about the extent of this exposure. Evidence is mounting that indium and gallium can have substantial toxicity, including in occupational settings where indium lung disease has been recognized as a potentially fatal disease caused by the inhalation of indium particles. This paper aims to review the basic chemistry, changing environmental concentrations, potential for human exposure, and known health effects of indium and gallium.
The study assessed the levels of some heavy metals in soils in the vicinity of a municipal solid waste dumpsite with a view to providing information on the extent of contamination, ecological risk of metals in the soils and human health risk to the residents in Uyo. Soil samples were collected in rainy and dry seasons and analyzed for metals (Pb, Cd, Zn, Mn, Cr, Ni and Fe) using atomic absorption spectrometry. The concentrations of heavy metals (mg/kg) at the dumpsite in rainy season were Pb (9.90), Zn (137), Ni (12.56), Cr (3.60), Cd (9.05) and Mn (94.00), while in dry season, the concentrations were Pb (11.80), Zn (146), Ni (11.82), Cr (4.05), Cd (12.20) and Mn (91.20). The concentrations of metals in the studied sites were higher than that of the control site (P < 0.05). Pollution indices studies revealed that soil samples from dumpsite and distances from 10 and 20 m east of the dumpsite were highly polluted with cadmium. Ecological risk assessment carried out showed that cadmium contributed 98–99 % of the total potentially ecological risk. No probable health risk was observed as the total hazard index of all the metals was less than one. However, children were found to be more susceptible to heavy metal contamination than adult.
Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects.
Cadmium telluride (CdTe) and cadmium selenide (CdSe) are increasingly being applied in photovoltaic solar cells and electronic components. A major concern is the public health and ecological risks associated with the potential release of toxic cadmium, tellurium, and/or selenium species. In this study, different tests were applied to investigate the leaching behavior of CdTe and CdSe in solutions simulating landfill leachate. CdTe showed a comparatively high leaching potential. In the Toxicity Characteristic Leaching Procedure (TCLP) and Waste Extraction Test (WET), the concentrations of cadmium released from CdTe were about 1500 and 260 times higher than the regulatory limit (1 mg/L). In contrast, CdSe was relatively stable and dissolved selenium in both leaching tests was below the regulatory limit (1 mg/L). Nonetheless, the regulatory limit for cadmium was exceeded by 5- to 6- fold in both tests. Experiments performed under different pH and redox conditions confirmed a marked enhancement in CdTe and CdSe dissolution both at acidic pH and under aerobic conditions. These findings are in agreement with thermodynamic predictions. Taken as a whole, the results indicate that recycling of decommissioned CdTe-containing devices is desirable to prevent the potential environmental release of toxic cadmium and tellurium in municipal landfills.
Copyright © 2015 Elsevier Ltd. All rights reserved.
Grid-connected solar photovoltaic (PV) power is currently one of the fastest growing power-generation technologies in the world. While PV technologies provide the environmental benefit of zero emissions during use, the use of heavy metals in thin-film PV cells raises important health and environmental concerns regarding the end-of-life disposal of PV panels. To date, there is no published quantitative assessment of the potential human health risk due to cadmium leaching from cadmium telluride (CdTe) PV panels disposed in a landfill. Thus, we used a screening-level risk assessment tool to estimate possible human health risk associated with disposal of CdTe panels into landfills. In addition, we conducted a literature review of potential cadmium release from the recycling process in order to contrast the potential health risks from PV panel disposal in landfills to those from PV panel recycling. Based on the results of our literature review, a meaningful risk comparison cannot be performed at this time. Based on the human health risk estimates generated for PV panel disposal, our assessment indicated that landfill disposal of CdTe panels does not pose a human health hazard at current production volumes, although our results pointed to the importance of CdTe PV panel end-of-life management.
Energy payback time and carbon footprint of commercial roof-top photovoltaic systems are calculated based on new 2011 manufacturers' data; and on 2013 equipment manufacturers' estimates of "micromorph" silicon photovoltaic modules. The energy payback times and carbon footprints are 1.96, 1.24, 1.39, 0.92, 0.68, and 1.02 years and 38.1, 27.2, 34.8, 22.8, 15.8, and 21.4 g CO2-eq/kWh for monocrystalline silicon, multicrystalline silicon, amorphous silicon, "micromorph" silicon, cadmium telluride and CIGS roof-top photovoltaic systems, respectively, assuming a poly-silicon production with hydropower; ingot-, wafer-, solar cell and module production with UCTE electricity; an irradiation on an optimized-angle of 1700 kWh/(m 2×year); excluding installation, operation and maintenance and end-of-life phase. Shifting production of poly-silicon, ingots, wafers, cells and modules to China results in similar energy payback times but increases the carbon footprint by a factor 1.3-2.1, depending on the electricity intensity of manufacturing.
The aim of this work has been to penetrate one of many possible avenues towards a potential ecological risk index to be used as a diagnostic tool for water pollution control purposes, i.e. to sort out which lakes/basins and substances should be given special attention. The work is based on the thesis that a sedimentological risk index for toxic substances in limnic systems should at least,account for the following four requirements.
Most estuaries receive a high heavy-metal input from industries. This is reflected in the relatively high levels found in
numerous estuarine organisms and in sediments. Many indicators have been suggested for facilitating the detection of heavy-metal
pollution, but the problems in using these indicators to evaluate the metal loading of estuaries are considerable. Variations
in species composition, and conditions at different sites, differences in season of sampling, and age of organism, as well
as different metal levels in different parts of the organism, make the interpretation of results difficult. The levels reported
here, similar to those in other unpolluted estuaries, have been used to suggest a baseline concentration for heavy metals
in estuaries. The concept of a baseline is fundamental to the formation of a “Biological Quality Index” and “Pollution Load
Index,” and a formula for such an index is suggested and tested at a preliminary level against published data for an English
and a European estuary.
A total of 92 samples of street dust were collected in Luanda, Angola, were sieved below 100 μm, and analysed by ICP-MS for 35 elements after an aqua-regia digestion. The concentration and spatial heterogeneity of trace elements in the street dust of Luanda are generally lower than in most industrialized cities in the Northern hemisphere. These observations reveal a predominantly “natural” origin for the street dust in Luanda, which is also manifested in that some geochemical processes that occur in natural soils are preserved in street dust: the separation of uranium from thorium, and the retention of the former by carbonate materials, or the high correlation between arsenic and vanadium due to their common mode of adsorption on solid particles in the form of oxyanions. The only distinct anthropogenic fingerprint in the composition of Luanda's street dust is the association Pb–Cd–Sb–Cu (and to a lesser extent, Ba–Cr–Zn). The use of risk assessment strategies has proved helpful in identifying the routes of exposure to street dust and the trace elements therein of most concern in terms of potential adverse health effects. In Luanda the highest levels of risk seem to be associated (a) with the presence of As and Pb in the street dust and (b) with the route of ingestion of dust particles, for all the elements included in the study except Hg, for which inhalation of vapours presents a slightly higher risk than ingestion. However, given the large uncertainties associated with the estimates of toxicity values and exposure factors, and the absence of site-specific biometric factors, these results should be regarded as preliminary and further research should be undertaken before any definite conclusions regarding potential health effects are drawn.
This study developed a comprehensive ranking system, for the first time as per authors' knowledge, for prioritizing the monitoring of pharmaceuticals and personal care products and endocrine-disrupting chemicals (together termed as EOCs, hereafter; a total of 100 EOCs considered) in U.S. stream water/source water and finished drinking water (termed as "EOCRank," hereafter). The EOCRank system was developed using a total of 4 criteria: (1) occurrence, (2) treatment in drinking water treatment plants, (3) ecological effects, and (4) health effects and characterized using 7 attributes: prevalence, frequency of detection, removal, bioaccumulation, ecotoxicity (for fish, daphnid, and algae aquatic indicator species), pregnancy effects, and health effects. The health effects attribute was characterized using 7 sub-attributes: carcinogenicity, mutagenicity, impairment of fertility, central nervous system acting, endocrine effects, immunotoxicity, and developmental effects. Rank scores of EOCs were calculated as summations of multiplications of importance weights and utility functions of multiple criteria and were arranged to highlight EOCs needing immediate attention. Two different ranking lists of EOCs were developed for U.S. finished drinking water and stream water/source water and observed to differ with each other, indicating the effect of water type on ranking of EOCs. A ranking list of priority EOCs, developed using a particular criterion, was observed to differ with that, developed using multiple criteria. Health effects and treatment criteria were observed to be important criteria influencing overall data gap rank scores and need further data collection. The generalized nature of the system could be customized for specific geographical locations (occurrence information and importance weights of different components). The developed database of the EOCRank system is available on: http://www.egr.msu.edu/~xagorara/research.html).
To investigate the after end-of-life (EoL) concerns of solar panels, four commercially available photovoltaics of 1515cm2 size in broken and unbroken conditions were exposed to three synthetic solutions of pH 4, 7, 10 and one real municipal solid waste (MSW) landfill leachate for one-year. Encapsulant degradation and release, probability of metals exceeding their surface water limit, and change in pollution index of leachate after dumping of solar panels were investigated. Rainwater stimulating solution was found to be predominant for metal leaching from silicon-based photovoltaics, with Ag, Pb and Cr being released to 683.26 mg/L (26.9%), 23.37 mg/L (17.6%), and 14.96 mg/L (13.05%) respectively. Copper indium gallium (de) selenide (CIGS) photovoltaic was found to be least vulnerable in various conditions with negligible release of In, Mo, Se and Ga with value ranging between 0.2 and 1 mg/L (0.30%-0.74%). In contrast, minimal metals were released to MSW leachate compared to other leaching solutions for all photovoltaics. Positive correlation was observed between encapsulant release and metal dissolution with a maximum encapsulant release in silicon-based photovoltaics in rainwater conditions. Probability of exceedance of leached metals to their respective surface water limits for Al (multi and mono crystalline-silicon (c-Si)), Ag (amorphous photovoltaic) and In (CIGS) has shown the maximum exceedance of 92.31%. The regression analysis indicated that conditions of the modules and pH of the leaching solution play significant roles in the leaching of metals. The increase in leachate contamination potential after one-year of photovoltaics dumping was found to be 12.02%, 10.90%, 15.26%, 54.19% for amorphous, CIGS, mono and multi c-Si photovoltaics, respectively. Overall, the maximum metal release observed in the present study is 30% of the initial amount under the most stressful conditions, which suggests that short-term leaching studies with millimeter sized sample pieces do not represent the realistic dumping scenarios.
Keywords: End-of-life, solar panel, photovoltaic, metal, leaching
Photovoltaic (PV) technology such as solar cells and devices convert solar energy directly into electricity. Compared to fossil fuels, solar energy is considered a key form of renewable energy in terms of reducing energy-related greenhouse gas emissions and mitigating climate change. To date, the development and improvement of PV technologies has received substantial attention; however, their potential environmental risks remain unknown. Therefore, this review focuses on the potential risks of leachates derived from solar cell devices. We collect scientific literature on toxicity and leaching potential, tabulate the existing data, and discuss related challenges. Insufficient toxicity and environmental risk information currently exists. However, it is known that lead (PbI2), tin (SnI2), cadmium, silicon, and copper, which are major ingredients in solar cells, are harmful to the ecosystem and human health if discharged from broken products in landfills or after environmental disasters. Several research directions and policy initiatives for minimizing the environmental risks of PV technology are suggested. This review contributes to both solar energy and environmental science research.
The photovoltaic (PV) technology is one of the fastest growing renewable and environmental friendly sources of electricity. However, this huge deployment rate is associated with generation of end-of-life (EoL) PV waste containing particularly, carcinogenic metals, once their operation phase ends. This study attempted to address this upcoming waste issue by systematically reviewing about 300 review/theoretical/ case/research papers/books/patents published between 2000 and 2018. The information was compiled and synthesized on: (i) initial metal concentration/content (IMC) for silicon-PV, amorphous-PV, CIGS and CdTe PVs; ii) statistical characterization and distribution of compiled IMCs; iii) leached metal concentrations (mg/l) from various PVs in water-based leaching solutions, as per standard waste characterization methods, in acid leaching and landfill matrix; iv) metal leaching rate constants (LRC) by fitting exponential model on reported plots of leached metal concentration values versus time using the GetData software; v) feasible application of compiled IMC and LRC data for Leachate Pollution Index (LPI) determination of an MSW landfill dumped with solar-PV waste; vi) human health risk assessment (HHRA) for exposure to lead leached from solar PV waste in an MSW landfill; vii) data/knowledge gaps from literature review and highlight the required future research actions.
The ranges of IMC values for top three solar PV-associated carcinogens, arsenic, cadmium and lead (% weight) were obtained to be: 0.00-0.001, 0.0001-19.84, and 0.003-5.09, respectively. Further, the range of LRC of solar PV-associated leached arsenic, cadmium and lead were obtained to be (per day): 0.00-0.129, 0.001-0.031, and 0.003-0.041, respectively. Leaching of Cd, Pb and Se from PVs have been mostly studied in acidic conditions (pH 3.0-6.5), whereas, fate of solar PVs in landfill conditions was not observed to be studied much. The estimation of contribution of solar PV in leachate pollution potential of an existing MSW landfill at T90 values (i.e., time required for 90% leaching of metals) showed an increase of 5.15% in pollution potential of landfill if landfill were to be dumped with EoL PV waste as well. HHRA for exposure to groundwater contaminated with leachate from a landfill dumped with lead containing solar PV waste did not pose any significant risk, however, the carcinogenic effects due to other metals under this scenario cannot be neglected. Out of 85 studies selected for content analysis, only 2.39 % of them investigated the fate of PVs in landfill stimulating conditions. To address fate of EoL waste and reduce uncertainty in present work, following future research actions need to be initiated: (i) conduct experimental studies to obtain data on metal leaching under realistic dumping scenarios and landfill conditions (intact solar panels with bigger size in MSW landfill) ; (ii) revise the expression of LPI for including solar PV-based LPI with critical parameters, like carcinogenic metals (cadmium); (iii) investigate suitability of existing standard hazardous waste characterizing methods (TCLP or WET) for PV waste.
The present work was designed to study the pH, sand, silt, clay, lime, organic carbon (OC), cation exchange capacity and heavy metals (Fe, Mn, Cu and Zn) in agricultural soils of Mashhad plain, Northeastern Iran. Pearson’s correlation analysis showed that OC influenced the retention of Cu and Mn in both surface and subsurface agricultural soil samples. The results of contamination factor, pollution index and potential ecological risk (RI) indicated low pollution of Mn, Zn and Cu in the agricultural soil samples. The enrichment factor showed very high enrichment of heavy metals in surface (88.1%) and subsurface (79.1%) agricultural soil samples. The geoaccumulation index also indicated very high contamination of heavy metals in surface (87.5%) and subsurface (82.6%) soil samples. The modified potential ecological risk (MRI) showed 37.5% ecological risk in surface, and 32.5% ecological risk in subsurface soil samples of Mashhad plain, Northeastern Iran.
Abbreviation: Fe: Iron; Mn: Manganese; Cu: Copper; Zn: Zinc; PCA: Principal component analysis; CA: Cluster analysis; CF: Contamination factor; EF: Enrichment factor; Igeo: Geoaccumulation index; PI: Pollution index; MPI: Modified pollution index; RI: Potential ecological risk index; MRI: Modified potential ecological risk index
Hazardous elements like lead, cadmium etc. are growingly being used in solar photovoltaics (PV). The major distress is the risk related to the potential release of these constituents in the environment. This paper reviews the leaching behaviour of various metallic constituents in soil & water and compiles the latest literature on PV. Analysis shows that there is substantial release of various metallic components in the environment and exist data gaps in (1) lack of information for solar PV disposal, (2) standardized leaching tests representing actual landfill conditions (e.g., studies with actual landfill waste and leachate) (3) Life Cycle Inventories from cradle to grave (4) kinetics data for metal leaching (5) PV wastewater characterization. These identified data gaps need to be filled by conducting more research in this direction so that exposure to toxic metals can be estimated with more confidence and efforts for protecting them can be made.
Gallium arsenide (GaAs) is a material widely used in electronic devices. Disposal of electronic waste containing GaAs in municipal solid waste landfills raises concerns about the public health and ecological risks associated with the potential release of toxic arsenic (As) species. In this study, different tests were performed to investigate the leaching behavior of particulate GaAs in aqueous solutions. In the U.S. Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET), the concentrations of As released from the GaAs particles were about 2.6-2.8-fold higher than the regulatory limit (5 mg/L). A much higher As concentration (72 mg/L), accounting for as much as 15.4% of the initial As in GaAs, was solubilized in a pH-7.6 synthetic landfill leachate under ambient atmosphere after 120 days. Additional tests performed to evaluate the dissolution of GaAs under a range of redox conditions, pH levels, ionic strength, and presence of organic constituents commonly found in landfills revealed that oxic environments and mildly alkaline conditions (pH 8.1-8.5) promote release of As (chiefly arsenite) and gallium species to the surrounding aqueous environment. The rate of As release in long-term exposure experiments was initially constant but later progressively diminished, likely due to the formation of a passivating layer on the surface of GaAs consisting of corrosion products rich in poorly soluble gallium oxides (Ga2O3 and Ga(OH)3). This hypothesis was confirmed by surface analysis of GaAs particles subjected to leaching using X-ray photoelectron spectroscopy (XPS). These findings suggest that further research is needed to assess the potential release of toxic As from electronic waste in municipal landfills.
Some photovoltaic module technologies use toxic materials. We report long-term leaching on photovoltaic module pieces of 5 × 5 cm² size. The pieces are cut out from modules of the four major commercial photovoltaic technologies: crystalline and amorphous silicon, cadmium telluride as well as from copper indium gallium diselenide. To simulate different environmental conditions, leaching occurs at room temperature in three different water-based solutions with pH 3, 7, and 11. No agitation is performed to simulate more representative field conditions. After 360 days, about 1.4% of lead from crystalline silicon module pieces and 62% of cadmium from cadmium telluride module pieces are leached out in acidic solutions. The leaching depends heavily on the pH and the redox potential of the aqueous solutions and it increases with time. The leaching behavior is predictable by thermodynamic stability considerations. These predictions are in good agreement with the experimental results.
A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30 days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1 mg L⁻¹), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005 mg L⁻¹). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions.
End-of-Life (EoL) photovoltaic (P/V) modules, which are recently included in the 2012/19/EU recast, require sound and sustainable treatment. Under this perspective, this paper deals with 2nd generation P/V waste modules, known as thin-film, via applying chemical treatment techniques. Two different types of modules are examined: (i) tandem a-Si:H/μc-Si:H panel and, (ii) Copper-Indium-Selenide (CIS) panel. Panels’ pretreatment includes collection, manual dismantling and shredding; pulverization and digestion are further conducted to identify their chemical composition. A variety of elements is determined in the samples leachates’ after both microwave-assisted total digestion and Toxicity Characteristic Leaching Procedure (TCLP test) using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) analysis. The analysis reveals that several elements are detected in the two of panels, with no sample exceeds the TCLP test. Concentrations of precious and critical metals are also measured, which generates great incentives for recovery. Then, further experiments, for P/V recycling investigation, are presented using different acids or acid mixtures under a variety of temperatures and a stable S/L ratio, with or without agitation, in order to determine the optimal recycling conditions. The results verify that chemical treatment in P/V shredded samples is efficient since driving to ethylene-vinyl acetate (EVA) resin’s dissolution, as well as valuable structural materials recovery (P/V glass, ribbons, cells, P/V intermediate layers). Among the solvents used, sulfuric acid and lactic acid demonstrate the most efficient and strongest performance on panels’ treatment at gentle temperatures providing favorably low energy requirements.
The Dutch government has adopted a progressive risk assessment strategy. This strategy aims at determining risk levels in agreement with recent scientific developments. Currently evaluation and revision is taking place of both target values, representing a negligible risk level, and C-values, representing a ‘serious threat’ level. An important base for this evaluation are two studies on the ecotoxicity of several substances and actual risk assessment methods carried out by the National Institute of Public Health and Environmental Protection (RIVM). The results of this strategy are an important step in the implementation of ecotoxicological arguments in standard setting.
The appropriateness of regulatory methods to characterise the toxicity of photovoltaic (PV) modules was investigated to quantify potential environmental impacts for modules disposed of in landfills. Because solar energy is perceived as a green technology, it is important to ensure that end-of-life issues will not be detrimental to solar energy's success. United States Environmental Protection Agency Method 1311, California waste extraction test, and modified versions of both were performed on a multi-crystalline silicon module and cells and a copper indium gallium diselenide (CIGS) module. Variations in metal leachate concentrations were found with changes in testing parameters. Lead concentrations from the multi-crystalline module ranged from 16.2 to 50.2 mg/L. Cadmium concentrations from the CIGS module ranged from 0.1 to 3.52 mg/L. This raises doubt that regulatory methods can adequately characterise PV modules. The results are useful for developing end-of-life procedures, which is a positive step towards avoiding an e-waste problem and continuing trends of increasing installation and cost reduction in the PV market.
Study on the elemental composition of soils at dumpsites was conducted by analysing samples of soil at different dumpsites located within Ikot Ekpene, South Eastern Nigeria. The samples were analysed for the concentration of Na, Ca, Pb, Ni, Mn, Mg, Fe, P, N, Cu and Zn. Control soil samples were taken at 10km away from the dumpsites and were also analysed for the present of these elements. The result of the analysis shows a significant difference between the concentration of these elements in the dumpsites and 10km away from the dumpsite (p>0.05). Correlations between them were negative in some cases and positive in some cases. The dumpsites were found to contained significant amount of toxic and essential elements hence remediation processes were suggested.
Information on the potentials of electronic waste (e-waste) leachate to induce genotoxicity in eukaryotic cells is scarce. In this study, we investigated the potential of raw and simulated e-waste leachates to induce cytotoxicity and DNA damage in Allium cepa. Roots of onion bulbs were grown in five concentrations: 1, 5, 10, 25 and 50% (v/v; leachate/tap water) of each of the leachate sample, tap water (negative control) and 0.25 ppm lead nitrate (positive control). Cytogenetic and root length inhibition analyses were evaluated at 48 and 72 hours respectively. There was concentration-dependent significant (p < 0.05) inhibition of root growth and cell proliferation compared to the negative control. The leachates also induced morphological modifications of the roots and cytological aberrations such as anaphase bridge, sticky chromosomes and binucleate cells. Fe, Cd, Mn, Cu, Ni, Cr As, Zn and Pb analysed in the samples were believed to play significant role in the observed cytogenotoxicity in A. cepa. These observations indicate that e-waste leachate contained substances capable of inducing cytotoxicity and somatic mutations in A. cepa. This is of environmental and public health importance in Nigeria and other developing nations whose populations are at risk of e-waste exposure.
The paper critiques a 1988 dissertation by Wong (1) of soil pica amongst Institutionalized children on the Island of Jamaica. The Wong dissertation presents the most extensive data yet of soil pica with respect to both numbers of children (six) displaying soil pica and the duration of study (4 months). Amongst children of normal mental capabilities with an average age of 3.1 years, 5 of 24 (20.8%) displayed soil pica behavior (i.e., > 1 g soil Ingested/day) on at least one occasion. In addition, 10.5% of all observations of these 24 children Involved soil Ingestion of > 1 gm/day. Emphasis is given to the Wong dissertation because It has essentially escaped notice amongst those researching and critiquing In the area of soil Ingestion most likely because its emphasis was directed toward exposure to parasites having a life‐cycle stage in soil and not chemical contaminants.
An Environmental Impact Study was carried mainly to assess the extent of groundwater contamination from a sanitary land fill (SLF) site, Hastsal, located in Western part of metropolitan city of Delhi. The characteristic of leachate generated from the site showed that it was acidic and yellowish in colour with very high concentration of dissolved solids, COD and BOD suggesting higher degree of inorganic and biodegradable organic materials. The results of groundwater analysis in term of BOD, TOC, COD, Conductivity revealed that the quality around the site upto a distance of 100 meter from the SLF boundary is being impacted due to infiltration of contaminated leachate. The bacteriological contamination also revealed that the water is not safe for public use. Impact on ambient air quality showed minor consequence. The level of hydrocarbon (HC), methane around the disposal site was found to be low. A management plan for the site for prevention of release of chemical contaminants to groundwater has been suggested.
This paper reviews recently derived toxicity data for Copper Indium Diselenide (CIS), Cadmium Gallium Diselenide (CGS) and Cadmium Telluride (CT), promising new materials on which a new generation of thin-film photovoltaic cells for generating electricity may be based. The new data deal with systemic and reproductive toxicity, acute pulmonary toxicity, and comparative pulmonary absorption, distribution and toxicity of these materials in laboratory rats. CT is shown to have higher lung toxicity than CIS, with the CGS toxicity being the lowest in the group. These data are extended to human exposure levels and exposure limits for CT are derived. The implications of these findings to the photovoltaic industry are also discussed. Published in 1999 by John Wiley & Sons, Ltd. This article is a U.S. Government Work and is in the public domain in the United States.
This paper presents a table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data.
The extraction and separation of cadmium, tellurium, and copper from CdTe PV module scrap was investigated. Several leaching technologies were assessed and the extraction of CdTe from samples of PV modules was optimized for maximum efficiency and minimum cost. A dilute aqueous solution of hydrogen peroxide and sulfuric acid was sufficient to completely leach out cadmium and tellurium from these samples. The same method successfully removed cadmium and tellurium from actual manufacturing scrap; copper was partially extracted. Subsequently, cation-exchange resins were used to separate cadmium and copper from tellurium. Complete separation (i.e., 99·99%) of Cd from Te was accomplished. The estimated costs of these processes for 10 MW/year processing are about 2 cents per W. Copyright © 2006 John Wiley & Sons, Ltd.
Potential ecological risk of cadmium (Cd), lead (Pb) and arsenic (As) in agricultural black soil in Jilin Province, China
was analyzed by the methods of risk assessment based on dose–effect relationships and ecological risk index. Heavy Cd-contamination
occurred mainly around the coal mine region. The accumulation area for Pb appeared mostly in the suburbs and roadsides, whereas
the higher As content was mainly found in the farmland of suburb and coal mine vicinity. In acute toxicity test, Cd, Pb and
As in the soil had adverse effects on both roots and shoots growth in soybean with the greatest toxicity of arsenic and the
least toxicity of lead at the same concentration levels. Exposed to Cd, Pb and As, the EC50 (50% effective concentration) values for the growth of soybean root (shoot) were 212.59 (376.70), 528.53 (828.69) and 194.60
(299.03) mg/kg, respectively. Results of potential ecological risk index showed that soil contamination from Cd in some samples
had very high potential ecological risk; Pb contamination for almost all sampling sites had moderate ecological risk; while
soil contamination from As had low ecological risk. With the present accumulation rate, concentrations of Cd, Pb and As in
agricultural black soil near coal mine would reach the threshold values in 68, 175 and 120years, respectively.
Fate and transport analysis has been performed to evaluate potential exposures to cadmium (Cd) from cadmium telluride (CdTe) photovoltaics (PV) for rainwater leaching from broken modules in a commercial building scenario. Leaching from broken modules is modeled using the worst-case scenario of total release of Cd, and residential screening levels are used to evaluate potential health impacts to on-site workers and off-site residents. A rooftop installation was considered rather than a ground-mount installation because rainwater runoff is concentrated via building downspouts in a rooftop installation rather than being dispersed across large areas in a ground-mount installation. Fate and transport of Cd from leachate to soil are modeled using equilibrium soil/soil-water partitioning. Subsequent migration to ambient air as windblown dust is evaluated with a screening Gaussian plume dispersion model, and migration to groundwater is evaluated with a dilution-attenuation factor approach. Exposure point concentrations in soil, air, and groundwater are one to six orders of magnitude below conservative (residential soil, residential air, drinking water) human health screening levels in both a California and southern Germany (Baden-Württemberg) exposure scenario. Potential exposures to Cd from rainwater leaching of broken modules in a commercial building scenario are highly unlikely to pose a potential health risk to on-site workers or off-site residents.
The mobility and bioavailability of heavy metals depends on the metal retention capacity of soil and also on the geochemical phases with which metals are associated. Laboratory batch experiments were carried out to study the sorption and distribution of Cd, Ni and Pb in 3 soils differing in their physicochemical properties from India: Oxyaquic Haplustalf (SL1), Typic Haplustalf (SL2) and Typic Haplustert (SL3). The heavy metal adsorption was studied by isotherms and the distribution coefficient (KD) for each metal was obtained from the linear regressions of the concentration of metal remaining in equilibrium solution and the amount adsorbed. In general, the sorption capacity for all the metals decreased in the order: SL3>SL2>SL1. Among metals, the sorption capacity in all the soils decreased in the order: Pb>>Ni>Cd. Distribution of sorbed metals at various equilibrating concentrations was studied by sequential extraction. Results showed significant differences in the distribution of metals in these soils. At higher additions (such as 200 μM l−1) most of the metals were extracted in their more mobile fractions, exchangeable and/or inorganic in contrast to their original partitioning in soils, where they were preferentially associated with the less mobile residual fraction. Largest percentages of metals extracted in the exchangeable fraction corresponded to those soil–metal systems with smaller KD values, e.g. Cd, Ni and Pb in SL1 and Cd and Ni in SL2. In neutral and alkaline soils (SL2, pH=7.1, and SL3, pH=8.6) Pb was predominantly extracted from the inorganic fractions and this corresponded to higher KD values for Pb in these soils. The predominance of metals associated with the exchangeable fraction together with low KD values indicates higher mobility of metals retained in the acidic soil (SL1, pH=5.2) compared with the others.
Urban and suburban road dust samples were collected in the most populated city of China, Shanghai. Size fractions of dust particles were analyzed; metal levels of the dust were also measured. Human exposure to individual toxic metals through road dust was assessed for both children and adults. The results showed that dust particles from urban and suburban road were presented similar size distribution pattern, with most particles in the range of 100–400 μm. Urban road dust consisted of higher proportions of inhalable, thoracic and respirable particles with increased risk of adverse effects to human. In general, mean grain sizes of urban road dust were smaller than suburban dust. Total organic carbon contents and levels of Pb, Cd, Cu, Zn, Ni, Cr in urban dust were higher than those of suburban dust. But the concentrations of As and Hg from suburban dust were higher, indicting a different main source. The exposure pathway which resulted in the highest level of risk for human exposed to road dust was ingestion of this material, which was followed by dermal contact. Except for some locations, risk values of both cancer and non-cancer obtained in this study were in the receivable range on the whole. Children had greater health risks than adults. The overall risks of non-cancer in urban area were higher than those in suburban area, but the values of cancer in the two areas were comparable. As for the aggregate noncarcinogenic risk, Pb was of most concern regarding the potential occurrence of health impacts. Of the three carcinogenic metals As, Cr and Cd, the only mean risk higher than 10−6 was Cr, accounting for a great percentage (95%) of the overall risk of cancer. Hence, potentially adverse health effects arising from Pb and Cr in road dust should arouse wide concern.
New best estimates for the solid-liquid distribution coefficient (K(d)) for a set of radionuclides are proposed, based on a selective data search and subsequent calculation of geometric means. The K(d) best estimates are calculated for soils grouped according to the texture and organic matter content. For a limited number of radionuclides this is extended to consider soil cofactors affecting soil-radionuclide interaction, such as pH, organic matter content, and radionuclide chemical speciation. Correlations between main soil properties and radionuclide K(d) are examined to complete the information derived from the best estimates with a rough prediction of K(d) based on soil parameters. Although there are still gaps for many radionuclides, new data from recent studies improve the calculation of K(d) best estimates for a number of radionuclides, such as selenium, antimony, and iodine.