How can we measure national chemical footprints?

Chemicals feature in just about every manufacturing process and in almost every product we consume. In fact, the lives we lead would be impossible without them. But some chemicals can have serious – often unanticipated – impacts on ecosystems and human health. That is why we in the PRINCE project are looking into how to monitor the environmental costs of chemicals used in producing the goods and services consumed in Sweden.

Challenges of chemical footprints

Most of us are familiar with the idea of “footprints” – quantifications that try to represent some aspect of the environmental impacts of a country’s consumption. Footprints to date have mainly focused on carbon emissions, and on the use of energy, water and land to a country’s demand for goods and services. Much less work has been done on indicators for the use and emissions of hazardous chemicals.

There is a simple reason for this: it is very difficult to do. At the root of this difficulty is the multitude of chemicals in use today – over 100,000 by one estimate, and new substances are coming into use all the time. For a start, every one of these 100,000-plus chemicals might act, and react, differently in the environment. And they can reach ecosystems and human populations through many different pathways – airborne or waterborne, in household dust or packaging, in plastic waste, leaching from a landfill site or waste pond, bioaccumulated in the food chain – and in different phases of a product’s lifecycle, from manufacture to storage and use to disposal.

There are big unknowns in the data on what chemicals are being used, and for what purposes. It is a huge undertaking to register and monitor all of those different chemicals, so only a limited number tend to be registered. It might take years before we realize that a novel chemical has serious health or environmental impacts and is worth monitoring.

And even if we know what chemicals are used in manufacturing a product in one factory or country, it is risky to generalize. In particular, the environmental pressures linked to a particular use of a particular chemical might be much worse in a country with weak legislation and enforcement than in a country with stricter governance.

And that is just the chemicals that are intentionally used. Processes like combustion can create hazardous substances as by-products. Or two or more emitted chemicals may react with each other or with something in the environment, creating new hazards.

Five key questions

Inevitably, constructing indicators for a chemical footprint requires some major compromises and shortcuts. The challenge is to make the indicator(s) as simple as possible (both to measure and to understand), while still telling a broadly true story about a country’s chemical footprint.

It comes down to five key questions:

• How many indicators do we need to give a reliable picture?
• Should our indicators focus on the use of chemicals, on the chemicals that are emitted, on the potential impacts, on the state of the environment (as a measure of emissions that have already happened), or on a country’s policy responses to minimize chemical risks – or a combination?
• Should we try to capture risks through whole product lifecycles, or just one or two stages of it?
• Should we try to capture a broad spectrum of chemicals or use one or a few substances as proxy indicators for all the others?
• How do we compare and aggregate the different types of impacts from different chemicals?

How PRINCE is rising to the challenge

In PRINCE I am leading the work package dedicated to developing footprint indicators for hazardous chemicals. We have already taken some important decisions. For example, we have decided to look into several indicators instead of trying to compile a single, composite indicator, which would probably not give a meaningful picture.

One set of indicators will look at the use of hazardous chemical products. In earlier projects, we used data from the Swedish Chemicals Inspectorate to develop indicators on the total use of hazardous chemical products in Sweden. In this project we will explore the possibilities of finding similar data from other countries. Also the use of pesticides in agriculture could be a separate indicator. This is relevant since we are importing a lot of food products and the use of pesticides in agriculture can vary between different countries.

Another set of indicators will look at emissions of hazardous chemicals. As PRINCE is looking at Sweden’s global footprint, and hopes to set up a system for regular monitoring, we ideally want data that are international and regularly updated. In Europe, one such source is the European Pollutant Release and Transfer Register (E-PRTR), maintained by the European Environment Agency and containing data reported by more than 30,000 industrial facilities across Europe (not just the EU member states). Similar databases exist in other countries too. In a pilot study we used the E-PRTR database for Sweden and it will be further explored in PRINCE.

Several methods have been developed to weigh up and aggregate the impacts of different hazardous chemicals within the field of lifecycle assessment – which attempts to quantify the environmental impacts associated with a product throughout its lifecycle. One of these is USEtox. We have used it in pilot studies and expect to use it in PRINCE.

In attempting to build a broad and policy-relevant understanding of the changing global impacts of Swedish consumption, PRINCE will be trying to break new ground in many ways. The work on hazardous chemicals is far from the least of them. We know that whatever indicators for Sweden’s chemical footprint we develop will be imperfect; at best interim, exploratory, proxy indicators. But they will be a start, and that is long overdue.