Leukocyte Esterase. Leukocyte esterase is an enzyme present in most white blood cells (WBCs). A few white blood cells are normally present in urine and usually give a negative chemical test result. When the number of WBCs in urine increases significantly, this screening test will become positive.
Land subsidence occurs when large amounts of groundwater have been withdrawn from certain types of rocks, such as fine-grained sediments. The rock compacts because the water is partly responsible for holding the ground up. When the water is withdrawn, the rocks falls in on itself.
How does erosion occur? Erosion occurs when the soil breaks because of strong water discharge during heavy storm. Wind is also a primary cause of erosion when it blows hard enough on unprotected so â¦ il to lift and move it away. Ocean waves, river currents, and glacial movement also erode large amounts of rock and soil.