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## Why is the water cycle important to all life on the earth?

Kate M.
Featured 7 months ago

The water cycle is important to all life on earth for many reasons.

#### Explanation:

The water cycle is important to all life on earth for many reasons. All living organisms require water and the water cycle describes the process of how water moves through the planet.

Plants wouldn't grow without precipitation (and thus anything consuming the plants wouldn't survive and so forth). Infiltration of water filters and cleans our water. Glaciers, ice, and snow can act as stores of freshwater for both humans and other organisms. Runoff contributes to rivers, other freshwater bodies, and eventually the ocean, sustaining freshwater and marine life.

All of these process sustain life and create the ecosystems around us. Some organisms are very sensitive to changes in the water cycle. A prolonged drought can destroy a population of plants or a certain salamander species may require a set amount of soil saturation in order to avoid desiccation.

See this question on how humans use water in everyday life, this webpage from NASA on the water cycle, and this PDF on how the natural world filters water for more information on why the water cycle is so important.

## Toxicology is highly linked with human development. Its development is directly related to industrialization, urbanization, and green revolution. Explain by citing relevant examples?

G_Ozdilek
Featured 2 months ago

Minamata Disease, Taiwan and Japan rice, Love Canal, etc.

#### Explanation:

I use only one reference for this assay (LaGrega et al., 1994).

Mercury salts, which were used to form felt in the Dutch hat industry, caused neurulogic disorder renowned as being "mad as a hatter." Organic forms of mercury (e.g. methyl mercury) have proven to be more pernicious, having caused hundreds of cases of paralysis and sensory loss at Minamata Bay area in Japan. Inorganic mercury discharged from a chemical plant became methylated in sediments and then bioaccumulated in shellfish. Due to the fact that shellfish are the principal protein source of the local people, this situation was an epidemic waiting to happen. In the late 1960s, this poisoning (itai itai disease) heightened global awareness of industrial pollution.

Two cases of accidental contamination of rice cooking oil in Japan and Taiwan in the late 1960s and mid-1970s exposed thousands of Asians to hşgh concentrations of PCBs (poly chlorinated biphenlys). Miscarriages and birth defects increased within the exposed populations. Although later it would be shown that these prenatal health problems resulted not from PCBs themselves but from polychlorinated dibenzofurans (PCDFs) that formed when heating the contaminated rice cooking oil, the riveting environmental journalism made the World population vividly aware of the adverse human effects of "PCB" exposure.

Nearly the same time in the United States, the contamination of Michigan cattle feed by polybrominated biphenyls (PBBs) not only caused widespread human exposures via milk and other dairy products, but also followed more complex pathways to reach humans.

Afflicted cattle were rendered and then used to prepare chicken feed; thousands of human consumers were exposed to PBBs through eggs and egg products. One incident involved 24 thousand crates of PBB-contaminated shorthcakes which were confiscated in Alabama. PBBs were found in some Michigan mothers' breast milk.

Love Canal is the symbol of environmental contamination by hazardous wate. Not useful as a canal, this canal was sealed off at the ends and used in the 1940s and 1950s by Hooker Chemical Company and others as a hazardous waste disposal site. Later, this site was sold to the Niagara Falls, New York, School Districts. The School District built an elementary school on the site despite the fact that a warning was made against any excavation and underground construction.

Later the developed area caused sickness in children and some residents. You can get details: https://www.geneseo.edu/history/love_canal_history

Reference:

LaGrega, M. D., Buckingham, P. L., and Evans, J. C. (1994). Hazardous Waste Management. McGraw Hill, Inc. New York, NY. USA.

## What is a good method to locate underground water for a well?

G_Ozdilek
Featured 1 month ago

Resistivity technique

#### Explanation:

Resistivity is defined as the resistance to current flow as a result of an applied electrical potential. In geophysical surveys resistivity is determined as the electrical resistance per length of a unit cross section area (such as $\frac{\frac{o h m s}{m}}{m} ^ 2$. Resistivity of underground is a function of material type, porosity (void volume), water content, and concentration of dissolved impurities in the pore water. Generally, dry solids and rock have very high resistance to electrical flow whereas saturated (filled with water) underground has a relatively low resistance.

Resistivity surveys are performed by applying an electrical current across two electrodes into the earth. Measuring the change in voltage across two receiving electrodes provides results.

## Where can one find underground water?

G_Ozdilek
Featured 3 weeks ago

By using geophysical methods (such as resistivity)

#### Explanation:

There are some methods to detect groundwater. One is resistivity. Resistivity is defined as the resistance to current flow as a result of an applied electric potential. Resistance is measured in ohms. Resistivity is resistence times legnth (such as $o h m \times m$).

In geophysical surveys resistivity is determined as the electrical resistance per length of a unit cross section area ($o h m s \times L$).

Resistivity below ground zero is a function of material type, porosity, water content and concentration of dissolved (such as TDS) contaminants in the pore water. Generally, dry soils and rock have very high resistance to electrical flow whereas inorganically contaminated saturated soils have a relatively low resistance.

## Where does most of the oil that pollutes the ocean come from?

G_Ozdilek
Featured 3 weeks ago

Oil tankers and newly drilled or old wells uncontrolled

#### Explanation:

Oil tankers, if they are not careful, pollute sea environment due to spills of oil on ports (loading and unloading operations), deliberately cleaning up operations of their loading areas, and accidents. Some sunken tankers also pollute sea/ocean environment too.

Another pollution issue is new wells drilled. These wells cause pollution if they are not careful enough. One of the worst disasters occurred a couple of years ago in South of the USA. (I do not want to give the name of the company and location).

Old wells, if they are not taken care properly, cause oil pollution too.

## How does ground water move underground?

G_Ozdilek
Featured 1 week ago

Groundwater moves in pore space. The flow in a porous medium (subsurface) occurs between particles (sand, silt, gravel, etc. or a mix of these).

#### Explanation:

Groundwater moves in pore space. The flow in a porous medium (subsurface) occurs between particles (sand, silt, gravel, etc. or a mix of these).

If porosity (porous volume in a given subsurface volume) is high, groundwater moves fast as a rule of thumb. A simple velocity definition is provided for groundwater flow analysis. It is discharge velocity or specific discharge. It is defined as water discharge through a representative area of porous medium/representative total area.

Similar to surface flow, water flows from higher elevations to lower elevations in the subsurface as groundwater flow.

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