Garden-to-gaia, urban sustainability, disasters 323surge could have been reduced 4.7 cm for each kilometer of marsh in front of
the city, due to the presence of both vegetation and shallow water (Farber 1987,
Danielsenet al.2005, Costanzaet al.2006). A 6 km wide protective marsh would
have dropped the approaching seawater by 30 cm (a foot).
Industrial air pollution
The sudden release of toxic substances into the city air by industries
has been a chronic problem, though periodically the type and amount of pol-
lutant is considered a disaster (e.g., in Mexico City, Bangkok, Kuala Lumpur).
Industries tend to aggregate close to cities where workers live. The effects on
human health and on the survival of wildlife populations in the urban region
of course depend on the substance emitted. As perhaps the worst case, in 1984
apesticide-producing industry in the heart ofBhopal(India), a city of 1.5 mil-
lion, released 40 tons of a toxic gas (methyl isocyanate or MIC), which is heavier
than air. Some 3000 people are reported to have died quickly, perhaps another
15 000 over the following two decades, and the total continues to climb. Reports
suggest that a third of the city’s population was exposed to the chemicals and
asignificant portion had related health problems. Contamination is apparently
still present at the factory site and its dumping grounds, as well as in drink-
ing water. Incentives for heavy industries to relocate away from water bodies
and dense human populations, to heavy-industry centers with efficient energy,
water, and waste disposal (Chapter 10 ), should pay manifold dividends.
Radiation releases from nuclear power plants
The 38 urban regions analyzed are in 32 nations worldwide, over half of
which have operating nuclear-power reactors (John P. Holdren, personal commu-
nication). Most are in France, Japan, USA, United Kingdom, and Russia. Releases
of radioactivity into the air and water apparently are not infrequent, and no safe
level or threshold exists. Because the radioactivity often accumulates through
the food chain, insect-eaters and meat-eaters are generally most affected. The
radioactivity is incorporated into tissue and damages proteins and DNA, which
leads to radiation disease and death. Altered DNA can be passed to future gener-
ations with consequent genetic and health problems. Occasionally large releases
of radiation have occurred, such as at Windscale (United Kingdom) in 1957 and
Three-Mile-Island well west of Philadelphia in 1979. A massive 1986 release at
Chernobylnear the small city of Prypyat and 130 km north of Kiev (USSR, now
Ukraine) resulted in elevated rates of many illnesses, especially cancer, that con-
tinue to appear two decades later. A 27 km radius (17 mile) ‘‘exclusion zone”
exists (including the former city of Prypyat) where radioactivity levels are high
and access is highly restricted; three other nuclear reactors still operate there.