Employment of Some Aquatic Plants for Removal of Cadmium, Lead, and Copper from the River Water

The world’s most valuable resource is water in addition to being essential to life, freshwater is also used in many other processes, including those that involve agriculture, industry, and human consumption due to interference with its quality, it continues to be a limited resource. Fresh potable water supply, particularly in urban areas, has been severely impacted by population increase, urbanization, and consumption. Therefore, the aim of this study was to understand the behavior of some heavy metals in the river waters via aquatic life represented by some aqua plants to achieve this three tanks of river water made from glass were prepared and injected with three heavy metals each which they are (copper, lead, and cadmium). The first tank represents the control (without any plants) while the second tank contains lentil plants moreover, the third tank contains the ceratophllum. The removal of heavy metals from river waters is enhanced by the presence of these plants using lentil plants and Ceratophyllum plants, respectively, led to removals of roughly 77% and 73% of the copper (Cu) content compared to the regular operation (control tank). For lead (Pb) removal, the Ceratophyllum removed about 72.6%, and the presence of lentil plant removes 52% of the Pb and only around 20% of the substance has been removed in the control tank. With ceratophullum present, there was a higher removal percentage of cadmium (45.9%)compared to tanks without aqua plants or lentil plants, which had removal rates of 21% and 42.3%, respectively. In general, necessary action to minimize the impact of discharging polluted wastewater must be taken to save aquatic life and the environment.


Introduction
The presence of toxic substances in the environment is growing, which is a source of significant concern for the people who live in the area.A wide variety of contaminants are continually being introduced into the aquatic environment.This is primarily the result of increased industrialization, the development of technological technologies, a growing human population, the exploitation of natural resources, and the runoff from agricultural and domestic waste.Because of the pervasive nature of these pollutants, heavy metals are one of the classes that are considered to be among the most harmful.Some of the most prevalent forms 1232 (2023) 012062 IOP Publishing doi:10.1088/1755-1315/1232/1/012062 2 of pollution in the environment are trace elements, particularly heavy metals.The occurrence of trace elements in water and living organisms indicate the presence of either natural or human-made sources [1].
The sources of heavy metals can be released into the aquatic environment naturally through geological processes, including erosion processes.These minerals come from the natural source of origin, namely rocks, and sediments, to the aquatic environment, and they are released as dissolved or in water.Rain drifting on the surface of the earth or suspended in the air to be carried by the wind from one place to another are other examples of natural sources.Volcanic activity is also one of the natural factors that contaminate the aquatic environment.Pollutants, such as elements, and these rains can dissolve the soil and release heavy elements into the water [8].The other sources of heavy metals can be released by human activities as industrial development is a significant source of pollution.Heavy in the environment as many businesses, including the petroleum sector, oil refineries, iron, steel, copper, glass, and aluminium companies, tanning factories, fertilizer, pesticide, and fuel sector found that heavy metals can reach the water through pollution with industrial or consumer waste [9].
The most ubiquitous toxic metal in drinking water is lead [5] Lead poisoning results in 0.6% of the disease globally.Long-term exposure to lead causes colic-like abdominal pains, and nephropathy damages the brain and kidneys and causes death.Exposure to high levels of lead may cause miscarriage and reduce fertility in males [6].A Canadian-American study concluded that even at levels that are considered to pose little to no risk, lead may cause "adverse mental health outcomes.[4].Environmental Consequences Acute inhalation exposure to cadmium at concentrations above about 5 mg/m 3 may cause the destruction of lung epithelial cells, resulting in pulmonary edema, tracheobronchitis, and pneumonitis [7].
Many different mechanisms of remediating Heavy Metals such as Precipitation, Adsorption, Ion exchange, Biosorption, Membrane technologies, and Filtration were adopted in order to minimize the concentration of heavy metals in the aqueous solutions.Based on the employment of some aqua plants, phytoremediation is a realistic, sustainable, and encouraging approach for heavy metal removal from polluted waters [21,23, and 24].Many studies have been conducted to investigate the role of aquatic plants in removing heavy metals.Employing freshwater algae to remove heavy metals (Cr, Cd, Ni, and Pb).The three most prevalent native algal species, Ulothrix tenuissima, Oscillatoria tenuis, and Zygogonium ericetorum, were collected from freshwater channels.The results showed that algal inoculation drastically decreased the concentration of all heavy metals in the contaminated water [27].M. Ali Awan and his team studied the removal of four heavy metals i.e.Pb, Cr, Cu, and Zn from their aqueous solutions, using ordinary sand as an adsorbent studied at 20°C.The amount of metal adsorbed to form a monolayer on sand (a), obtained from Langmuir isotherm, exhibited the preference of metals for sand in the order Pb> Cr> Cu> Zn. [28] Therefore, the aim of the research is to study the impact of using water lentil plants or Ceratophyllum plants for removing the selected heavy metals.

2.1.Case study and Climate Condition
The river water sample were collected from the river of Al-Diwaniyah specifically in the south of the city of Al-Diwaniyah which is located mid-south of Iraq.The sample was taken in November when the temperature ranged between (30-35) °C during the day and (28-30) °C at night.There was no rain during or before the sampling session.

2.2.Materials
x Tanks Three tanks were made from glass were used, each tank has a dimensions of (70 * 50 * 40) cm.Glass tanks were used to avoid any absorption effect of other materials and also to increase the impact of sunlight on plants.
x Pumps Three pumps were used for these three tanks with a head of 1.8 m and a flow of 1000 l/h with power 25w.The submerged pump is made of high-quality stronger ABS, which has axle cores and casing made of high-quality ceramics and non-corrosive.
x Heavy metals About 25 mg of lead, copper, and cadmium oxides have been prepared and diluted in order to have about 50ppm to be added in each tanks.
x Plants A sample of natural aquatic plants was used, water lentils, and Ceratophyllum.These plants were collected from Shatt Al-Hamza, Al-Diwaniyah city.Plant samples were collected and washed from river water to get rid of mud and suspended materials presented in the roots and then kept in plastic bags until reaching the treatment system to plant them in tanks.
x Instruments The instrument that used for measuring the concentrations of heavy metals is the Atomic Absorption Spectrophotometer with a model NO.AA-7000 from Shimazdu -Japan.

Sampling
The experiment was designed in an outdoor area, as three tanks were designed, two for the experiment and another used as a control tank.The tanks were made from glass.The tanks were arranged horizontally, and exposed to a natural light source represented by the sun.Each of the tanks received an adequate quantity of air due to the impact of the electric pump that keep the water in circulation and provide air to the water.A heavy metal of an initial concentration of 50ppm for each heavy metal for each tank that has about 60L of river water.Samples were taken from each tank at days 1,4,7,10,13 and 16 from the initial reading which was taken at day 1 (before adding the plants).Create a specific calibration curve for each component using reference solutions at 1 ppm, 2 ppm, and 3 ppm before using an atomic absorption equipment.

Copper (Cu)
Figure 1 shows the degradation of Cu in the three tanks (Control, lentil plant and cerotophellum) during the period of study (16 days).It can be seen that about 37% removal was achieved in the control tank dropping from 48.3 to 30.2 mg/l. in tank No.2, about 77% removal was obtained via using lentil plants dropping from 49.7 to 12 mg/l.for tank No.3, there is about 73% removal was achieved by using ceratophyllum plants where the concentration changed from 51.1 to 13.8 mg/l.

Lead (pb)
Figure 2 displays the degradation of Pb in the three tanks (Control, lentil plant and cerotophellum) during the period of study (16 days).It can be seen that about 20% removal was achieved in the control tank dropping from 51.2 to 40.9 mg/l. in tank No.2, about 52% removal was obtained via using lentil plants dropping from 49.1 to 23.4 mg/l.for tank No.3, there is about 73% removal was achieved by using ceratophyllum plants where the concentration changed from 48.7 to 13.3 mg/l.It is clear that ceratophyllum has improved the removal of Pb comparing to the other aquatic plants.3) during the period of study (16 days).This figure revealed that about 21.6% removal was achieved in the control tank dropping from 49.9 to 39.1 mg/l.In tank No.2, about 42.3% removal was obtained via using lentil plants dropping from 50.8 to 29.3 mg/l.for tank No.3, there is about 45.9% removal was achieved by using ceratophyllum plants where the concentration changed from 48.3 to 26.1 mg/l.although there is a removal in the concentration of Cd, however, these aquatic plants were less effective in removing Cd comparing to the other heavy metals conducted in this study.

Conclusions and Recommendations
The conclusions obtained throughout this study are: x There is the challenge to remediate hazardous metal-containing water and wastewater, nationally and internationally.x The presence of these plants improves the removal of heavy metals from river waters.
x Although there was a removal in the concentration of copper in the normal operation (without any plants), however, about 75% and 72% removal were achieved via using lentil plants and ceratophyllum plants respectively.x The presence of Ceratophyllum, improve the removal efficiency of lead for about 73% which is higher than that one of lentil plants that achieved about 52%.The control tank has only accomplished a removal of about 20%.x The removal percentage in the concentration of cadmium with the present of Ceratophyllum (45.9%) which higher comparing to the other tanks that has no aqua plants or lentil plants with a rate of 21.6% and 42.3%.x It can be concluded that, the Copper was the most elements removed within these three pollutants while Ceratophyllum seem to be more efficient to be able to remove the selected heavy metals.

Recommendations
x Take the necessary activities to minimize the impact of effluent on the water bodies.It also important to study the feasibility to treat these types of metals that responsible for the severe damage to the aquatic environment.
x Commence another study to increase the time of study and the number of samples in order to have a clearer picture of the behavior of the aqua plants and the heavy metals as well.
x Increase of environmental awareness and the creation of basic environmental knowledge in order to improve positive environmental behavior is a basic requirement that citizen can effectively play their role in saving the environment.

Figure 1 .
Figure 1.Degradation of Cu in mg/l in Three Tanks

Figure 3 .
Figure 3. Degradation of Cd in (mg/l) In Three Tanks