Tag: biology

Freshwater molluscs--snails and bivalves--have been used frequently as bioindicator organisms. With increasing needs for research on contaminant effects in freshwater ecosystems, this kind of biomonitoring is likely to develop further in the future. Molluscs can be used effectively for studies of both organic and inorganic contaminants; this review focuses on studies involving bioaccumulation and toxicity of metals. Two important advantages of snails and bivalves over most other freshwater organisms for biomonitoring research are their large size and limited mobility.

The root zone process is a biological wastewater treatment method that uses plants and their root systems to filter and purify water, acting as a control measure against water pollution.

Sedimentation is a physical process used in the primary stage of water treatment to remove suspended solids by allowing them to settle out of the water.

The toxicity of many chemical pollutants increases with temperature because higher temperatures can increase the metabolic rate of organisms, leading to faster uptake of toxins, and can also decrease dissolved oxygen levels.

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen required by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. It is used to measure of the amount of organic waste in water.

Water pollution is the increase in the concentration of the undesirable harmful compounds in the water resources. The water pollution can be controlled by many ways. The sewage and the factory wastes which contain the pollutants and high number of microbes can be treated before letting the water discharged into water bodies. Biodegradable form of fertilizers and pesticides can be used for the reduction of the soil and water pollution, and eutrophication. 

Biological treatment of the waste water can be performed with the use of microbes. The bacteria and fungal cells are commonly used in the treatment of the water through activated sludge. Activated sludge refers to floc of microorganisms including bacterial cells and fungal filaments which are used in the process to break down organic matter into carbon dioxide, water, and other inorganic compounds and help in the clearing of the water. 

The methods that can be used to control water pollution are:
(i) Avoiding the use of chemical substances freely.
(ii) Educating society about the dangers of water pollution.
(iii) Using biological control in agricultural areas instead of using pesticides.

Drinking arsenic-rich water over a long period results in various health effects including skin problems (such as color changes on the skin, and hard patches on the palms and soles of the feet), skin cancer, cancers of the bladder, kidney and lung, and diseases of the blood vessels of the legs and feet, and possibly also diabetes, high blood pressure and reproductive disorders.