Short abstract:

Wastewater is often portrayed as a mirror of society, its analysis promising insights on the spread of pathogens, illicit drug use, and increasingly also microplastics. I look at efforts to monitor microplastics in wastewater to explore how societies know, make sense of, and care for its residues.

Long abstract:

Over the past two decades, microplastics have emerged as an environmental concern, attracting increasing attention in scientific research as well as the political and legal realm. My paper, which is part of an ERC Advanced Grant project “Innovation Residues: Modes and infrastructures of caring for our longue-durée environmental futures” (PI: Ulrike Felt, GA 1010545), examines how societies know, make sense of, and care for innovation residues, in particular microplastics.

Wastewater is a key research site to investigate this question. It is often portrayed as a mirror of contemporary societies, promising real time and accurate knowledge about chemical pollution, the spread of pathogens, or patterns of illicit drug consumption. The EU, in its revision of the Urban Wastewater Treatment Directive, has now proposed to utilize the affordances of wastewater to govern microplastics pollution, tackling the issue through a mandatory monitoring.

Drawing on interviews with wastewater experts, this paper explores how the monitoring of microplastics is put into practice. Specifically, I investigate the frictions arising when microplastics, a previously unregulated, ambiguously defined, and materially heterogenous substance, is turned into a monitoring object. Doing so, I engage with the politics of monitoring, showing how this practice renders some aspects of microplastics pollution visible and others invisible. This shapes not only how microplastics become a problem but also possible ways to govern them, enabling some responses at the expense of others.