Water Pollution Treatment: Function of Large Aquatic Plants

This report provides a comprehensive overview of the function of large aquatic plants in water pollution treatment. It begins with an executive summary and an introduction highlighting the global water pollution problem, the limited availability of freshwater, and the impact of industrialization and urbanization on water quality. The report then delves into the objective and hypothesis, followed by a literature review that examines the current state of water pollution in China, detailing the pollution levels in major river basins. It also covers the historical development of pollution control using aquatic plants, including phytoremediation techniques. The report explores the mechanisms of phytoremediation, the types of aquatic plants used, and their application in removing heavy metals, organic pollutants, and other contaminants. The report also includes tables summarizing plant species and their effectiveness in treating different pollutants. Finally, it discusses the selection principles of aquatic plants, and the safe disposal of used aquatic plants. The report concludes with a discussion of the effectiveness and future prospects of this environmentally friendly approach.

Running head: FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION
TREATMENT
Function of Large Aquatic Plants In Water Pollution Treatment
Name of the Student:
Name of the University:
Author note:

1FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Executive Summary
Being a worldwide problem, water pollution has a huge impact on the mankind. The
world has invested a lot of manpower and material resources after the environmental
governance. Environmental pollution control has a new breakthrough with the emergence of
phytoremediation technology that has the characteristics of low cost, more ecological and
environmental friendly. This paper summarizes the mechanism of large aquatic plants in
water pollution treatment, the status of water pollution, and the application of large aquatic
plants in order to minimize the content of pollution from water. Moreover, the discussion is
also based on the selection principle of aquatic plants to decrease the water pollution and safe
disposal to used aquatic plants.

2FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Table of Contents
Executive Summary.........................................................................................................................1
Introduction......................................................................................................................................3
Objective and Hypothesis................................................................................................................7
Literature Review............................................................................................................................7
MATERIALS AND METHODS...................................................................................................13
RESULT........................................................................................................................................14
DISCUSSION................................................................................................................................26
CONCLUSION..............................................................................................................................30
List of Tables
Table 1-----------------------------------------------------------------------------------------------------5
Table 2-----------------------------------------------------------------------------------------------------6
Table 3----------------------------------------------------------------------------------------------------11
Table 4----------------------------------------------------------------------------------------------------11
Table 5----------------------------------------------------------------------------------------------------17
Table 6----------------------------------------------------------------------------------------------------18
Table 7----------------------------------------------------------------------------------------------------19
Table 8----------------------------------------------------------------------------------------------------21
Table 9----------------------------------------------------------------------------------------------------23
Table 10--------------------------------------------------------------------------------------------------24
Table 11--------------------------------------------------------------------------------------------------26

3FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Introduction
The earth is said to be as a “blue planet”, as 70% of its surface is covered with water.
However, in reality, 97.5% of it is salt water and the fresh water accounts for only 2.5%.
Moreover, nearly 70% of the fresh water is fixed in the Antarctic and Greenland glaciers, the
rest in the soil moisture or deep groundwater, which cannot be used by humans. Hence, less
than 1% of the earth's fresh water is there to consume by humans directly. These waters are
provided through lakes, rivers, reservoirs and shallow groundwater sources. In other words,
water is the most precious and limited resource for mankind. Furthermore, there are
numerous activities such as erosion, climatic changes, evaporative cooling, hydropower,
promotion of the cycling of inorganic and organic matter and so on. However, with the rapid
development of industrialization and urbanization, many toxic substances like pesticide and
some organic pollution have entered the water system. This has made the problem of water
pollution the most serious environmental problem that the world is facing today. About 42
billion cubic meters of sewage is discharged into the rivers and lakes every year, polluting 5.5
trillion cubic meters of fresh water, which is equivalent to more than 14 percent of global
runoff. Human activities such as mining, metal smelting, chemical industry, coal combustion,
automobile exhaust emissions, domestic wastewater discharge, pesticide and chemical
fertilizer application and atmospheric deposition are the main factors causing pollution in the
water bodies.
Water pollution can cause effect of water ecological system function. Some harmful
substances, like Heavy metal ions and organic pollutants, can keep in water over one hundred
years. These toxic substances are consumed by humans through the food chain. For example,
the little fishes eat the tiny organic particles; big fishes eat those tiny fishes; and human in
turn eats the big fishes. Hence, ultimately the health is getting affected.

4FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Everyone is aware of the fact that water pollution is a serious problem that is effecting
the human survival and sustainable development. It is negatively affecting human health,
agricultural productivity and the stability of natural ecosystems. The establishment and
development of strategies and technologies for the removal of water pollution has become an
important area of scientific and technological research. Compared with the physical
technology and strategy of mechanical decontamination method, the strategy of using green
plants to remove pollutants is a very promising approach to water pollution.
Phytoremediation is a generic term that uses plants for remediating soils, sludge,
sediments and water contaminated with organic and inorganic contaminants. It can be defined
as “the efficient use of plants to remove, detoxify or immobilize environmental contaminants
in a growth matrix (soil, water or sediments) through the natural biological, chemical or
physical activities and processes of the plants”. Plants are unique organisms equipped with
remarkable metabolic and absorption capabilities, as well as transport systems that can take
up nutrients or contaminants selectively from the growth matrix, soil or water.
Phytoremediation involves growing of plants in a contaminated matrix, for a required period
of time in order to remove contaminants from the matrix, or facilitate immobilization
(binding/containment) or degradation (detoxification) of the pollutants. The plants can be
subsequently harvested, processed and disposed (Wang S M, 2006).
Aquatic plants in the ecosystem are primary consumers. They are autotrophic
organisms. They play a key role in maintaining a virtuous cycle of aquatic ecosystems. The
examples include- aquatic plants can store short-term nutrients such as N P K, which inhibits
the growth of lower aquatic plants such as algae, purify contaminants in water, provide
habitat for some organisms, as well as to promote water production, nitrogen cycle.
Pollution factor Phytormediation Plant

5FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Cd Iris, Canna, Rushes, Barracude, Ipomoea,
Metzyllum
Pb Oriental cattail, Cape health Chara, Canna,
Rushes
Cu Reed, Eichhornia crassipes, Algae
Zn Reed, Eichhornia crassipes, Algae
As Eichhornia crassipes, Algae,
Mn Eichhornia crassipes, Algae, Acours calamus
Hg Algae, Progency Chara
Cr Algae, Progency Chara
Co Algae,
N P Eichhornia crassipes, Canna, Calla
COD Eichhornia crassipes, Calamus, Water Iily
BOD5 Eichhornia crassipes, Reed, Cat-tail
Phenol Rush,
Pesticide Canna, Chrysanthemum
Table 1: Common ecological restoration of aquatic plants
Aquatic plants are mainly composed of three major categories: aquatic vascular
plants, aquatic mosses and higher algae. Global application in the sewage treatment is more k
borne vascular plant developed mechanical process. The plant individuals are relatively tall,
usually can be divided into Algae, Emerged plants, Floating leaves plants and submerged
species (Chong, Hu and Qian. 2003).
Life type Growth characteristic Represent plants

6FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Garden Greenland
plants
Rhizome was born in
the sediment Reed, cattails
Potted flowers
The plant body is
completely floating on
the surface of the water,
with a specialized adapt
to the floatinglife of the
organizational structure
Eichhorniacrassipes, Duckweed
Cut flowers
Rhizome was born in
the mud, the leaves
floating in the water
Water Lily, Nymphoides
Indoor water tank
Soil or muddy water
interface following the
services
Cryptomeria
Table 2：Four kinds of life type of aquatic plants ：source：Chong：Hu and Qian. 2003)
Objective and Hypothesis
Due to its cheap and environment friendly nature, phytoremediation technology is a widely
used technology in recent years. With the discovery of some aquatic plants, the control
treatment of heavy metals and organic pollutants in water environment system has been a top
most research topic in the world. Due to this, the aquatic plants have the same characteristic
of hyperaccumulation plants. In this paper, some normal aquatic plants will be discussed, and
aquatic plants mechanism analysis, practical application, control treatment effectiveness and

7FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
developing prospect will be explored. Furthermore, some factors that influence the ability of
aquatic plants to clean water pollution will be listed down and discussed.
Literature Review
1. The Current Situation of Water Pollution In China
The information related to water pollution is reported by the National Environmental
Protection Agency every year. According to the published data, surface water quality in the
seven major rivers of China is outlined as- In the Songhua River and the Liaohe River
systems, the organic pollution is very serious. The polluted river that reaches accounted for
about 50 percent of the evaluated river reaches in length in the year 1986. Currently, organic
pollutants, ammonia N, phenols and nitrate N contents all have a tendency to rise. The water
quality in the Liaohe River is deteriorating ：Mei and Feng 1993). In the Haihe River basin,
water quality is the worst. In a comprehensive pollution index, among the seven major river
basins, the organic pollution and heavy metal pollution comprise of the first and second place
respectively. The principal components of heavy metal pollution are cadmium, mercury and
copper. Phenol, COD and ammonia N concentrations are in excess of the standards. In the
Huanghe River basin, natural water quality is not high. Suspended matter content exceeds the
standard at all monitoring cross-sections. Total ion and chloride contents are at high levels.
Currently, organic pollution is rather serious; amm onia N pollution is growing, while arsenic
pollution is lightening. In the Huaihe River basin, comprehensive water pollution index is in
the second place below the Haihe River, but heavy metal pollution is in the first place. The
dominant pollution results from organic chemicals, and the polluted river reaches was up to
55.8 percent of the evaluated river. Presently water quality of the Huaihe River is getting
worse, especially during the low-flow periods. The contamination from ammonia N, phenols,
nitrite N and lead, mercury, cadmium and chromium is becoming heavier. In the Changjiang

8FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
(Yangtze) River basin, the water quality of the main stream appears to be rather better but
some tributaries, lakes and urban river reaches have been polluted seriously. The annual
average value of suspended matter exceeds the water standard and the ammonia N pollution
is spreading. In the Pear River basin, water quality is good as well and there, the water
pollution is mainly caused due to organic pollutants. In addition, iron concentration is a bit
high. Furthermore, the pollution from ammonia N, organic chemicals nitrite N is becoming
heavier in specific river reaches.
2. Development History of cleaning pollution By Aquatic Plants In China.
The ecological function of aquatic plants in the water body makes it a very useful
component in the prevention and control of water pollution. Due to the increase of water
pollution, an efficient and low cost water pollution treatment technology had started to grab
people’s attention towards itself. Many of the substances resistance to pollution and
management capabilities studies have founded that a variety of large-scale aquatic pollution
control as the core of sewage treatment and water restoration of ecological engineering
technology has been developed.
In the1990s, scientists used floating island in order to carry out repairing work in Wuli
Lake of Wuxi City. They founded that N, P removal efficiency is high and in 2002, by using
the technology of phytoremediation brake Lake, the Yongding River and other polluted water
bodies in Beijing have gained better phytoremediation results. In 2002, the study of Jianjun
Shi showed that the aquatic plants were used to enrich the radioactive elements in the water.
In 2005, the study of Yi wang showed that there was a negative absorption of heavy metal
contaminants in the water environment or reduces the toxicity of heavy metal pollutants
through the system, thus weaken the water toxicity and repair the water body. The general

9FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
root enrichment coefficient of aquatic plants is greater than that of stems and leaves.
Furthermore, the submerged plant is larger than the floating leaves and the floating leaves are
larger than that of water.
China began to improve the environment by restoring the experiment work of aquatic
plants, and hence developed Tai lake, Dianchi Lake, and the East Lake’s eutrophication
control and ecological restoration demonstration research in the early 1990s. The study found
that the disappearance of the Donghu Lake’s cyano-bacteria populations was related to the
stocking filter-feeding fishes. The later researches and tests were based on using silver carps
such as predatory fish, as filters to control the eutrophication for lake water’s phytoplankton
(algae) quantity and improve water quality. Chinese Academy of Sciences, Nanjing lakes
Geography, set up a pilot area of the demonstration project in Wuli Lake Shore, for
establishing the associations among emergent aquatic plants, floating-leaved plants and
submerged plants. During the project, the aquatic plants’ diversity index reached up to 40%,
and the dominant plant in lake water was changed from algae to large aquatic plants. The area
later on found improvement on its water quality and became clear water.
3. Some Information about Aquatic Plants
Plant adsorption is the direct occurrence of roots (or stems and leaves) surface is
considered to be the most rapid removal of heavy metals, NP and organic ion from the water.
It is by chelation ion exchange, selective absorption and other physical and chemical
processes result (Reddy and Debusk, 1987), that plants can be used for cleaning water
pollution and they must have the following characteristics (Yan 2003：:
 Plants have a higher rate of accumulation even in the lower concentration of
pollutants

10FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
 They can be enriched in high concentrations of pollutants in their body (they can live
in water who content high concentration of pollutants)
 They can absorb the accumulation of several heavy metals, N P and the organic ion
pollution (Samecka and Kemper. 2004)
 They can contribute to fast growth, large biomass (height), along with insect
resistance.
Heavy metal
ion
Hg Cu Cd Zn Pb
Ottelia - 15.4 0.10 4.00 40.3
Hornwort 1.00 7.80 5.00 - -
Water hyacinth 0.06 20.0 5.00 10.0 30.2
Nymphoides
Levin
- - 0.20 0.50 -
scirpus
tabernaem-
ontani
- - 30.0 - -
Algae - 5.00 10.0 - -
Table 3: Upper limit of tolerance of some aquatic plants to heavy metals (mg/L) （source（
He（Geng and Luo. 2008)
It is to be mentioned that aquatic plants can clean water pollution as they can absorb
the heavy metal ion and N P from the water bodies. However, if the pollution is very serious,
the heavy metal ion, N P and the organic pollution content in the water is out the upper limit
of tolerance for some of the aquatic plants. In the table 3, the upper limit of tolerance of some
aquatic plants to the heavy metals are listed, the highest upper limit of tolerance to Pb is

11FUNCTION OF LARGE AQUATIC PLANTS IN WATER POLLUTION TREATMENT
Ottelia, it can live in the water whose Pb content is 40.3mg/L. Most aquatic plants can live in
the water which is polluted by Cd, and the scirpus tabernaemontan even can live in the
30mg/L Cd of polluted water. However, a quite large amount of aquatic plants cannot live in
the Hg polluted water as the Hg ions are able to destroy the cell structure of the aquatic
plants：Jia. 2005).
Plant name Maximum height（m（ Nitrogen content Phosphorus Content
Coix 2 24.1-25.6 4.2-5.6
Reed 3 18-21 2.0-3.0
Mosaic reed 2 17.2-35.1 1.7-6.2
Trapa incisa var. sieb. 1 10.9-25.1 1.3-6.9
Incisa var. sieb 1.8 16.8-27.9 4.4-5.3
Chrysanthemum 0.8 12.3-29.9 1.61-5.94
cat-tail 2 5.0-24 0.5-4.0
Rush 1 15 2
Iris 0.5 4.7-25.3 2.3-4.7
Calamus 1.2 11-35 2.3-5.7
Algae - 12.0-48 1.5-11.5
Duckweed - 25-50 4.0-15.0
Eichhornia crassipes - 10-40 1.4-12
Salvinia - 20-48 1.8-9.0
Vallisneria 0.5 16.9-30.5 2.2-4.7