Flame retardants（阻燃剂） are chemical compounds added to fabrics¹ and plastics to keep them from burning easily, but these can be toxic². Now a team of researchers from Spain and Canada has detected some of these emerging pollutants³ for the first time in peregrine falcon⁴ (Falco peregrinus) eggs in both countries. "The presence of 'dechlorane plus' and other related, chlorinated compounds used as flame retardants have been detected for the first time in the European biota⁵ (flora and fauna⁶ of the region)", explains Ethel Eljarrat, co-author of the study and scientist at the Institute of Environmental Assessment⁷ and Water Studies (IDAEA-CSIC, Spain).

The researchers have found these substances in peregrine falcon (Falco peregrinus) eggs in both Spain and Canada. The flame retardants are often added to textiles, electronic circuits and other products to inhibit⁸ or resist the spread of fire, but can be transferred to the environment.

In nature these compounds are "bioaccumulating and bioconcentrating" all along the food chain, as evidenced by the research published in the Environmental Science & Technology journal. The international research team for this study was led by Begoña Jiménez of the Institute of Organic Chemistry (CSIC, Spain), and Environment Canada researchers, Kim Fernie and Mehran Alaee.

Having received the relevant permits, eggs that had failed to hatch from various active falcon nests in Canada and Spain, were collected. The collection involved 13 eggs from Spain (five in Guadalajara – a territory representative of an inland habitat of the Iberian Peninsula - and eight in Bilbao - representing a coastal⁹ environment), and 12 eggs from Canada (Great Lakes Region and Eastern provinces).

The levels of some of the measured contaminants have been found to be somewhat higher in Bilbao than in Guadalajara, and the authors believe this may be due partially¹⁰ to the difference in the falcons¹¹' diet: more aquatic¹²（水生的） in the former and more terrestrial（地球的，陆地的） in the latter. In fact, if fish is highly contaminated, peregrines would accumulate more of the harmful substances. While peregrine falcons do not eat fish, they prey¹³ upon other birds, some of which may eat fish.

Selecting the peregrine falcon（游隼） was no accident. This species was endangered in many areas of the northern hemisphere due to the use of organochlorinated pesticides¹⁴, particularly DDT, though when this was prohibited in the 1970s the populations recovered. Furthermore, falcons are at the top end of the food chain and accumulate substances carried by their prey.