One of the report’s case studies concludes that restrictions placed on tributyl tin (TBT) in the mid-1980s have brought the UK benefits worth at least £46 million per year. The annual cost to small boat owners, who used the compound as an antifoulant, is estimated to be no more than £36 million.
Other case studies looked at polychlorinated biphenyls (PCBs), the insecticide DDT and methiocarb, which is still used to kill snails. The UK’s bans on these substances have, or would have in the case of methiocarb, racked up benefits ranging from a few hundred thousand pounds a year for methiocarb to more than £1 billion for PCBs.
DEFRA commissioned the study from a team of academics at Lancaster University and the Centre for Ecology and Hydrology in the wake of discussions about the costs and benefits of the forthcoming REACH regime. "It was partly as a justification for the new legislation as the costs of implementing REACH are pretty high," said Peter Matthiessen, one of the study’s authors.
Most estimates put REACH’s total cost to the EU economy at around €2-4 billion for the 11-year phase-in period; although some industry estimates were several orders of magnitude higher. The possible benefits have been put at anywhere between ¤4.8 billion and more than €200 billion.
While the DEFRA study’s headline figures are impressive, the calculations they are based on are somewhat shaky: "We’d be the first to admit that this was a crude first attempt, but if nothing else it shows the environmental cost of some chemicals can be very high," said Professor Matthiessen. "The economics tools we have available are fairly crude. It’s pretty certain the final results underestimate the true values."
"It could be argued that you can’t monetise the environment, but we have to place a value on it somehow and at the moment we’re operating in a market economy that only measures money."
Complex ecosystem processes such as nutrient cycling proved particularly hard to monetise. But the team did find figures for TBT, concluding that its UK ban restored marine invertebrate communities - and hence nutrient cycling - worth £43 million annually.
Easier to quantify are direct effects on commercially harvested organisms. In TBT’s case, the ban was thought to have brought fishery improvements worth £7 million per year - although the figure shrinks if other factors potentially affecting shellfish yields are taken into account.
The final ‘benefit’ figure takes into account these direct and indirect ecosystem uses, plus - where possible - a measure of future value, for example to the pharmaceutical industry. People’s ‘willingness to pay’ to preserve a particular species or ecosystem was also calculated for some case studies.
The researchers were hampered by the limited information available on dose-response relationships, which link particular chemical concentrations to environmental and human health impacts. Data on environmental effects were particularly scarce.
The £1 billion-plus figure arrived at for PCBs was based only on there being fewer cancer cases. Little information is available on the environmental damage avoided or on more subtle epidemiological effects such as hormone disruption.
The most visible effect of banning DDT in the UK was on birds of prey. Saving the three main species at risk of extinction has brought £57 million in annual benefits, the researchers estimate. They also calculated the perceived benefits of protecting polar bears and other charismatic species beyond the UK, but did not include them in their final total because of the high level of uncertainty.
Methiocarb breaks down relatively quickly, reducing its toxicity. It has a minor effect on wood mouse populations, which recover quickly. Cases of larger mammals being poisoned are occasionally reported, but are only expensive when they concern pets.
The study concludes that the benefits of regulation are generally greatest for widely dispersed toxic, persistent and bioaccumulative substances. Unfortunately, these have often proved to be cases where the benefits of restrictions have only become apparent in hindsight.