Visualizing Environmental Science

Amount of

DDT in tissue

75.5 ppm Tertiary consumer(ring-billed gull)

Secondary consumer

(Atlantic needlefish)

Secondary consumer

(American eel)

Primary consumer

(shrimp)

Producer and

primary consumer

(algae and other

plankton)

Water

2.07 ppm

0.28 ppm

0.16 ppm

0.04 ppm

0.00005 ppm

Trophic level

1,510,000

times

increase

DDE (ppm, dry weight)*

1966

Year

*DDT is converted to DDE in the birds’ bodies

Mean number of young per breeding area

1.3

1.0

0.7

0.4

0.1

130

100

70

40

10

1968 1970 1972 1974 1976 1978 1980

DDE residue in eagle eggs

Mean number of young

per breeding area

DDT ban

Reproductive

success

improved

after DDT

levels

decreased

Data from Grier, JW “Ban of DDT and subsequent recovery of reproduction in bald eagles.”

Science (1982)

Data from Woodwell, G. M., C. F. Worster Jr. and P. A. Isaacson. “DDT

residues in an east coast sanctuary: a case of biological concentration

of persistent insecticide,” Science 156 (May 12, 1967).

Klaus Nigge/NG Image Collection

James Hager/Robert Harding World Imagery/Getty Images

b. A bald eagle feeds its chicks.

a. A comparison of the number of successful bald eagle offspring

with the level of DDT residues in their eggs. (Grier, 1982).

d. Note how the level of DDT, expressed as parts per

million, increased in the tissues of various organisms

as DDT moved through the food chain from producers

to consumers (bottom to top of figure). The ring-billed

gull at the top of the food chain had approximately 1.5

million times more DDT in its tissues than the water

contained (Woodwell et al., 1967).

c. A ring-billed gull forages on a beach.

82 CHAPTER 4 Risk Analysis and Environmental Health Hazards

Environmental InSight ✓✓THE PLANNER

Bioaccumulation and

biomagnificationÊ UÊ ˆ}ÕÀiÊ{°n

Effects of DDT on birds

Biological magnification of DDT

on a Long Island salt marsh

Interpreting Data

In which year was the DDE level

in eagle eggs the highest? What

was the level in that year?