Pesticides can reach water-bearing aquifers below ground from
applications onto crop fields, seepage of contaminated surface water, accidental spills and leaks, improper disposal, and even through injection waste material into wells
.
How do pesticides enter the environment?
Pesticides
may become airborne, get into soil, enter bodies of water, or be taken up by plants and animals
. The environmental fate of pesticides depends on the physical and chemical properties of the pesticide as well as the environmental conditions.
How do pesticides interact with water?
Pesticides have the potential to
contaminate drinking water supplies
. They are applied to farmlands, gardens and lawns and can make their way into ground water or surface water systems that feed drinking water supplies.
How does pesticides affect groundwater?
Pesticides reach groundwater
through runoff and leaching
. Runoff carries pesticides over the ground in rain or irrigation water. Runoff is the movement of chemicals in water over a sloping surface. Runoff can carry pesticides mixed in water or bound to eroding soil.
How do pesticides end up in the ocean?
Pesticides typically enter a waterbody
through surface water runoff
, often from a farm field or from neighborhoods where they are applied on lawns.
How do pesticides cause water pollution?
Water from excessive rainfall and irrigation cannot always be held within the soil structure. Therefore,
pesticides and residues (also nitrates and phosphates) can be quickly transported to contaminate ground water and freshwater supplies over a large geographical area
.
Do pesticides dissolve in water?
Like sugar and salt,
some pesticides are very soluble in water
. They dissolve easily. Their molecules bond to water molecules. Highly soluble pesticides will travel with water as it moves in the environment.
How are pesticides absorbed?
Pesticides can be absorbed by plants
through the leaves and roots
. Pesticides that are taken up by plants can move (translocate) to other parts of the plant. Herbicides that are taken up by the plant (systemic herbicides) often are designed to interfere with the plants development by mimicking plant hormones.
What is pesticide adsorption?
Pesticide adsorption
The adsorption process
binds pesticides to soil particles, similar to iron filings or paper clips sticking to a magnet
. Adsorption often occurs because of the attraction between a chemical and soil particles.
How do pesticides and fertilizers cause water pollution?
The usage of organic fertilizers results in the discharge of nitrate, potassium and phosphates that pollute the water
. The contamination of groundwater occurs as a result of leaching due to nitrate. The ground and surface waters are infested with heavy metals, whose concentration poses a threat to humans and animals.
How do chemicals get into the ocean?
Once chemical pollutants are sprayed on land, water molecules, via rain, watering or groundwater flows
, act as vehicles that pick up and transport chemical substances from land, into the water cycle, and eventually the ocean.
Where do pesticides end up?
Pesticides reach
creeks and rivers through storm drains and household drains
. When you apply a pesticide or fertilizer outdoors, some of the material may move to other locations. Storm drains are frequently located in streets.
How do pesticides get into soil?
Pesticides in soil
may be taken up by plant roots and moved to other plant tissues, including the fruit
. Pesticides applied to sandy or course-grained soils are more likely to leach through the soil and contaminate groundwater.
How does insecticides pesticides enter the insect’s body explain?
Insecticides in this class kill pests by contacting and entering their bodies either
directly through the insect integument (skin) into the blood or by entering the respiratory system through the spiracles
(air valves along the side of an insect’s body which control gas exchange).
How does a pesticide work?
Most pesticides work
by affecting the nervous system of the insect
. The pesticide interrupts the information being sent by neurotransmitters in the synapses. The chemical produced by the body used to send information through the synapses is called acetycholine.
How do herbicides work?
Herbicides
kill plants by causing a build up of a toxic substance, where the toxic compounds stay at reasonably low levels
. By inhabiting the target site (enzyme), herbicides cause substances to build up and damage the plant. This is how the herbicide glyphosate works.
