eutrophication

Eutrophication

Eutrophication refers to the process of enrichment of

watercourses or surface water bodies by inorganic plant nutrients.

Estimates indicate that more than 72% of the N entering  surface

waters originates from  a agricultural lands. Both N and P are

important in stimulating eutrophication. This artificial eutrophication

has already happened in many parts of the world including India.

Causes of eutrophication include natural run-off of nutrients from the

soil and the weathering of rocks, accelerated runoff of inorganic

fertilizer & manures (containing nitrates and phosphates) from

agricultural lands, runoff from areas following mining, construction

work or poor land use, discharge of detergents (containing

phosphates) through domestic wastewater.

 Weed infestation  of water  bodies is driven  by 

nutrient  enrichment

 Effects of eutrophication

• Excessive growth of phytoplankton and filamentous algae

• Increase in aquatic plant life

• Increase in turbidity (cloudiness) of water

• Increase in rate of sedimentation

• Development of anoxic conditions (low oxygen levels)

• Decrease in species diversity, and an

• Increase in the frequency of algae blooms causing a dearth

of oxygen and a change in fish species composition

 Measures to reduce artificial eutrophicaion

• Reducing the use of phosphates as builders in detergents

• Reducing the use of nitrate containing fertilizers

• Using tertiary sewage treatment methods to remove

phosphate and nitrate before discharging the effluent into

rivers and lokes

• Directing waste water away from  lakes to safe treatment

& disposal sites

• Aerating lakes and reservoirs to prevent oxygen depletion

particularly during algal blooms

• Removing phosphate- rich plant material from affected

lakes

• Removing phosphate rich sediments by dredging