Soil Contamination
Soil Contamination is when harmful stuff gets into the ground and makes it unsafe for plants or people.
A glass of clean water sits on a table. Someone drops dark dye into it, and it spreads through the whole glass. You cannot get the dye back out. Soil works the same way — harmful stuff mixes into the ground and spreads, making the whole area unsafe.
Explaining soil contamination by grade level
Sometimes bad things get into dirt. Old spray from farms can leave poison behind. Plants that grow in that dirt may get sick. People can test the soil to find out what is in it.
Projects that explore soil contamination
Harmful chemicals can get into the ground and stay there for decades after their original use ends. Arsenic-based pesticides sprayed on orchards in the 1940s still make the soil unsafe where schools now stand. This project collects soil samples from campuses with different land-use histories to measure how long those toxins linger.
When heavy metals like copper get into the soil, they make it unsafe for plants — damaging root systems and stunting growth. Yet some species can reverse this through phytoremediation, absorbing the harmful metals through their roots. This experiment tests how well different plants take up copper from soil treated with copper sulfate solution.
Not all soil types hold pollutants the same way. Clay traps far more spilled oil than sand does, making some ground more unsafe than others. This project pours equal amounts of oil, gasoline, and antifreeze through two soil types and measures absorption in 60 seconds.
Harmful metals that get into the ground make the soil unsafe, but the right plants can slowly remove them. Thlaspi absorbs zinc through its roots in a process called phytoremediation. This experiment plants 100 seeds in soil containing 600 parts per million of zinc and tracks how the level drops over four 30-day growing cycles.
Oil spills get harmful stuff into the ground and stop seeds from growing, making the soil unsafe. Special oil-absorbing polymers may reverse that damage. This project mixes motor oil into soil, treats it with polymers, and counts how many green bean seeds sprout over 10 days.