Seafood are a cornerstone in designing food systems for the next generations because they are a rich source of nutrients, have a low environmental footprint in many systems, are essential for supporting livelihoods in vulnerable communities, may displace the consumption of less healthy meat, among other reasons (Golden et al., 2021; Tigchelaar et al., 2022). Costello et al. (2020) calculated that food from the sea represents 17% of the globally produced edible meat by 2017, which will increase between 36% and 74% by 2050. However, this substantial growth might depend on factors such as policy reforms, technology improvements, or shifts on the demand side. This variation in demand can be led, among many other reasons, by concerns related to emergent pollutants that could compromise food security.
One of the seafood sectors with the highest production potential is bivalve mariculture because it is not constrained by feed limitations (Costello et al., 2020), and poses a high nutritional potential at a lower environmental impact than other species (Koehn et al., 2022). Bivalves are filter feeders that capture food particles by water filtration. Unfortunately, this mechanism also bioaccumulates other types of particles, including pollutants such as metals (Waykar & Deshmukh, 2012), dumped munitions (Strehse & Maser, 2020), or microplastics (MP, plastic debris with a diameter below 5mm), which is an emerging pollutant that might harmfully affect plants, soils, wildlife, or even humans. This bioaccumulation feature could challenge food security (Willer et al., 2021). Particularly, mussels are a subgroup of bivalves that have been proposed as a global bioindicator of coastal MP pollution because of their wide distribution, vital ecological niches, susceptibility to MP uptake, and close connection with marine predators and human consumption (Li et al., 2019). Although we have certainty about the presence of MP in bivalves, the degree of its riskiness is still largely uncertain and controversial. For instance, Garrido Gamarro et al. (2020) argue that the contribution of hazardous chemicals from MP to bivalves is minimal compared to other pollutants; consequently, no evidence suggests risks to bivalves' safety due to MP exposure. However, the same authors point out that the total exposure to MP from different sources may pose a concern, but further research is needed. For these and other reasons, mussels are a dominant species used for field research on MP pollution.
The widespread presence of MP in the environment and the already confirmed exposure of humans through inhalation or ingestion of these particles (Danopoulos et al., 2021; Waring et al., 2018) could generate risks to food security and human health (De la Torre, 2020). Recent studies have identified MP in human stools (Schwabl et al., 2019; Zhang et al., 2021), blood (Leslie et al., 2022), placenta (Braun et al., 2021; Ragusa et al., 2021), lung tissue (Jenner et al., 2022), and colon (Ibrahim et al., 2021). Nevertheless, the direct impacts of these MP particles on human health are still largely unknown, and further research is needed (Koelmans et al., 2017; Leslie et al., 2022; Smith et al., 2018; Wright & Kelly, 2017). However, an increasing number of publications on social media have awakened public concern about MP contamination in food products, which can discourage the consumption of essential products in terms of food security, such as seafood. Consequently, researchers have begun investigating technologies that could reduce MP contamination in food products. Particularly in shellfish, such as mussels, researchers have proposed depuration as an additional step that could significantly reduce the MP content (Birnstiel et al., 2019; Fernández & Albentosa, 2019; Li et al., 2021). The depuration technique consists of placing the harvested shellfish into (treated or untreated) water tanks until they meet the criteria needed to put them on the market (Sun et al., 2022). However, the depuration process in practice is mainly used to eliminate microbiological content (e.g., escherichia coli), so most mussels in the market likely still contain MP.
No study has examined how consumers would value this emergent technology to reduce the presence of MP in food products. This is important since technology adoption can significantly be influenced by consumers’ willingness to pay (WTP) for it. This is the focus of this study. Moreover, we test how information about the potential health and environmental effects of MP can impact: 1) consumers' WTP for mussel’s attributes, 2) consumption avoidance behavior, and 3) MP riskiness perception. We also offer additional analyses for those consumers with high certainty about their answers, high perceived policy consequentiality, and with previous knowledge about MP. Evaluating consumers' preferences for technology to reduce MP pollution is tricky, as most of these technologies are in the research and development stages, and we cannot access market prices for them. In such cases, stated preference (SP) methods rise as an ad hoc tool to estimate consumer preferences as they can create a hypothetical market and elicit respondents' preferences for particular characteristics of the relevant good. Consequently, we conducted an online discrete choice experiment (DCE) in Chile about mussel purchasing decision-making, interviewing over 2,000 mussels’ consumers. The attributes presented in the DCE were mussel’s format, certified depuration efficiency, producer size, and price. To estimate the effect of information, we used a between-subjects design by randomly assigning respondents to four subgroups. The first group included additional information about the potential health effects of MP on human health (HEA), the second group included information about the potential environmental effects of MP (ENV), the third group is a combination of the potential health and environmental effects (HEA-ENV), and finally, the fourth group will be the control which does not include any additional information (CONTROL). We chose the Chilean mussel as the product of interest given its popularity. It is also one of the most important export industries in Chile, even leading the prices in the European mussel market (Avdelas et al., 2021; Salazar & Dresdner, 2022).
Our research hypotheses are: 1) consumers’ will highly value depuration as a technology to reduce MP from mussels, 2) the WTP for depuration will vary across information treatments; specifically, WTP in the control group will be the lowest, followed by the ENV treatment, then the HEA treatment, and the highest WTP for depuration certification should be found in the HEA-ENV treatment. 3) information treatments will increase the probability of choosing no-purchase alternative as a preventive behavior, following the same order as the WTP for certified depuration. Finally, our 4) research hypothesis indicates that information treatments will affect the perceived riskiness of microplastics on human health and the environment, but the effect will be higher for riskiness on human health.
In general, we found that the included attributes in our DCE were relevant for consumers. That is, consumers have a negative preference for canned formats compared to fresh mussels, while frozen format preferences are heterogeneous, certificate depuration reports an important WTP premium, which increases as the efficiency increases, and, in general, consumers prefer mussels produced by small-scale producers. In terms of the information effects, we show that information treatments can affect consumers' decision-making in several ways. First, information about MP pollution effects on human health implied a higher WTP for depuration than the information about potential environmental effects, but the combination of health and environmental information does not necessarily present the highest WTP. Second, information treatments affected the probability of choosing no-purchase alternative among respondents, with the HEA-ENV treatment having the highest effect. Third, information treatments impacted the risk perception of MP on human health but not on the environment. Additionally, our complementary analyses show that consumers with previous knowledge about MP strongly prefer fresh format over frozen or canned, and a higher WTP for depuration in CONTROL and ENV treatments but lower in ENV and HEA-ENV treatments.
The remainder of the article proceeds as follows: In the background section, we describe the relevance of MP pollution, its links with food products, and the related literature using SP methods. Next, we describe the DCE design, survey procedure, and how we plan to analyze the resulting data. The results section is divided into three main outcomes: WTP, no-purchase probability, and riskiness perception of MP pollution. After that, we discuss the results, comparing them with related literature and highlighting the main takeaways from our study. We finalize the article with the conclusions, policy suggestions, main limitations, and recommendations for further research on this topic.