Water Lecture 2

What is Total Dissolved Solids (TDS)?

The sum of all dissolved substances in water, expressed as mg/L or ppm.

How is concentration commonly expressed in water studies?

Concentration is typically expressed as milligrams per liter (mg/L) or parts per million (ppm).

What primarily influences rainwater composition?

Rainwater is nearly pure water with less than 10 ppm Total Dissolved Solids (TDS) and contains dissolved CO₂ from the atmosphere.

What are some minor sources of dissolved constituents in water?

Sea-salt aerosols, mineral dust particles, and particulate industrial pollutants.

Why do some regions have higher sulfate and nitrate concentrations in rain and snow?

Higher sulfate and nitrate concentrations are often due to industrial pollutants.

What is the pH variation range observed in rain and snow samples?

The pH can range from 4.6 to greater than 10.14, indicating both acidic and alkaline samples.

What initiates chemical weathering in rocks?

Chemical weathering is initiated by reactions between oxygenated, acidic meteoric waters and Earth's materials.

What is the role of atmospheric CO₂ in chemical weathering?

Atmospheric CO₂ dissolves in water to form carbonic acid (H₂CO₃), which acts as an acid source in chemical weathering.

What effects does chemical weathering have on the environment?

Chemical weathering creates landforms, soils, new minerals, sediments, and regulates atmospheric CO₂ over geological time scales.

What waters are primarily sources for chemical weathering?

Meteoric precipitation, which includes rain and snow.