As more water was diverted to irrigate land, the Aral Sea got smaller and saltier. In 1986, the sea got so shallow that it was divided into two separate seas, the North Aral Sea and the South Aral Sea. In 2005, the Kok-Aral dam was constructed to stop water from leaving the North Aral Sea.
This table shows data that describes how the Aral Sea changed from 1950 to 2010.
|
area of irrigated land
(square kilometers) |
area of the sea’s surface
(square kilometers) |
water level (meters) |
salinity
(grams per liter) |
fish catch (metric tons) |
| 1950 |
30,910 |
65,607 |
52.9 |
10.7 |
48,000 |
| 1960 |
34,930 |
68,478 |
53.5 |
9.9 |
43,430 |
| 1970 |
39,440 |
60,692 |
51.4 |
11.2 |
17,460 |
| 1980 |
51,140 |
51,743 |
45.8 |
16.8 |
11,940 |
| 1990 |
74,000 |
35,349 |
north: 40.6
south: 38.3 |
north: 29
south: 30 |
0 |
| 2000 |
-- |
24,266 |
north: 40.7
south: 33.6 |
north: 30
south: 70 |
1,290 |
| 2010 |
78,960 |
14,280 |
north: 42
south: 27 |
north: 8
south: 130 |
3,010 |
Note: The fish catch of 48,000 metric tons was the reported maximum from 1957. No data could be found for 1950. Also, data could not be found for the area of irrigated land in 2000.
This table shows data that describes some health conditions of school-age children living around the Aral Sea.
|
Kazalinsk district |
Zhanakorgan district |
| distance from the Aral Sea |
less than 200 kilometers |
about 500 kilometers |
| prevalence of cough |
8.1% |
4.6% |
prevalence of restrictive
pulmonary dysfunction |
10% |
3% |
| prevalence of diarrhea |
11.3% |
5.6% |
| prevalence of hypercalciuria |
38.6% |
12.8% |
| sodium concentration in urine |
3.54 |
2.89 |
| calcium concentration in urine |
0.75 |
0.33 |
| sodium concentration in hair |
738 |
471 |
| bromine concentration in hair |
9.57 |
6.22 |
| nickel concentration in hair |
1.61 |
0.85 |
| mercury concentration in hair |
1.31 |
0.88 |
Note: Units for urine concentrations are mmol uNa or uCA per mmol creatinine. Units for hair concentrations are μg of the element per g of hair.
Using the information in the tables, calculate at least 4 percentages of increase or decrease that describe the situation with the Aral Sea. For each percentage, write a sentence that clearly describes what the percent increase or percent decrease represents.
