3.1. Mo, Pb and Cu in acidic mining water
The principal anion and cation results of the acid mine water’s physicochemical characteristics are displayed in
Table 1. The temperature varied from 18.6 to 24.8
oC (mean: 22.6 ± 1.2
oC); the pH of the water altered to 5.84 from 5.62 (mean: 5.76±0.14); and the EC values were between 2.64 and 2.38 mS cm
-1 (mean: 2.55 ± 0.08 mS cm
-1)(taken from 35). Throughout the eight-day experiment, daily field samples of water were collected.
Table 1 displays the average concentrations of Mo, Pb, and Cu in the acid mine water, which were found to be 30±4, 260±12, and 15535±322 μg L−1, respectively (p < 0.5). The chemistry of acidic mine water is greatly influenced by several factors, including its distance from the recharge area, the length of time it spends in the flow system, the volume of acid mine water flowing through it, and the long-term rock-water interaction. According to the measured data, the chemistry and physicochemical properties of the waters originating from the ore location are generally comparable. Significant pollution near the Maden stream is caused by heavy metal pollution in the land and water.
The mean values of Mo, Cu and Pb in the acid mine fluids exceeded the US EPA’s [
15] and ATSDR’s [
32] limit levels, as indicated in
Table 1. The research area’s acid mine water included varying quantities of Mo (28.4 to 31.6 μg L
−1). Most natural waters have Mo concentrations of around 10 μg/L or less [
14]. The research area’s average Mo value was higher than the WHO-established threshold levels (10 mg L
-1) for drinking water [
13] (
Table 1). Average Pb levels in these natural waters according to US EPA [
15] have been recorded as 10– 15 µg/L [
16]. The environment’s soil and water are contaminated by the mine’s leaky water. It is extremely difficult to clean these contaminated soils and waterways [
39,
40,
41]. According to Ning et al. [
42], the average readings of WHO [
16] for heavy metal levels were not as high as those found in the water surrounding Pb resources. A median Mo content of 0.5 mg/L was reported by Reimann and de Caritat [
43] for streamwaters worldwide. The estimates for world rivers are 0.11-8.63 (mean 1.21 mg/L) [
44] and around 0.42 mg/L [
45]. Rivers from India can contain up to 20 mg/L [
46] and up to 8.6 mg/L [
47].
Based on the main cations and anions (Ca–Mg–HCO
3; Ca–Mg–Fe–SO
4; Na–F–NO
3), the waters in the research region were divided into three groups. The water kinds in the aquifer were identified by using Piper’s [
48] triangular drawing approach. Over 90% of the cations in the aquifer are found in the examined fluids, with Ca, Mg, Fe, Na, S, K and Mn being the most common. In the waters of the research area, bicarbonate and sulfate constituted 85–90% of all anions, making them the main anion species. Ca-Mg-Fe-Na-SO
4 HCO
3 water is one possible classification for the acid mining water in the Maden Cu mining.
Table 1.
Physicochemical characteristics, cation major anion and trace element results the acid mine water [
35].
Table 1.
Physicochemical characteristics, cation major anion and trace element results the acid mine water [
35].
Parameter |
T |
pH |
EC |
HCO3-
|
NO3-
|
SO4
|
F-
|
Ca |
Mg |
K |
Na |
Fe |
( oC) |
|
(mS cm-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
(mgL-1) |
DL |
- |
- |
- |
- |
- |
- |
- |
0,05 |
0,05 |
0,05 |
0,05 |
10 |
Mining water |
22.6±1.6 |
5.76± 0.1 |
2.55± 0.2 |
282±16 |
1.86± 0.06 |
128±8 |
0.41±0.1 |
482±24 |
426±18 |
5.80± 0.3 |
115± 6 |
118±7 |
Parameter |
Mn |
S |
P |
B |
Zn |
Cr |
Ni |
Co |
As |
Mo |
Pb |
Cu |
(mg L-1) |
(mg L-1) |
(μg L-1) |
(μg L-1) |
(μg L-1) |
(μgL-1) |
(μg L-1) |
(μg L-1) |
(μg L-1) |
(μg L-1) |
(μg L-1) |
(μg L-1) |
DL |
0,05 |
1 |
10 |
5 |
0,5 |
0,5 |
0,2 |
0,02 |
0,5 |
0,1 |
0,1 |
0,02 |
Mining water |
6.4± 0.3 |
670±28 |
236± 12 |
850±45 |
2852± 84 |
202± 16 |
965± 58 |
1766±72 |
193±12 |
30±4 |
260±12 |
15535±322 |
3.2. Lemna gibba and Lemna minor
Cleaning and restoring contaminated areas can be done affordably, effectively, sustainably, and economically with phytoremediation. But before building a decontamination system, knowledge regarding the effects of heavy metals on plant physiology should be acquired to optimize the system [
49]. The uptake process of Mo, Pb, and Cu can be impacted by variables such the metal’s bioavailability, the contaminant’s chemical characteristics, organic matter contents, plant species, phosphorus, pH, and environmental factors of the contaminated environment [
50]. Numerous aquatic plants are employed successfully for the monitoring of contaminated settings and are recognized as heavy metal pollution indicators [
51]. Due to their ability to accumulate in biological systems, heavy metals like Mo, Ag, Pb, Au, Cu, As, Co, Hg, Zn, Tl and Cd are hazardous and poisonous.
Prior to the commencement of the experimental investigation, it was found that
L. minor (LM-0) and
L. gibba (LG-0) had Mo levels of 2.16 and 0.29 mg kg
-1, respectively (p < 0.05) (
Figure 4). These values are regarded as the values of the control group for these plants. A total of 2.89 and 0.97 mg kg
-1 of Mo were collected by
L. minor and
L. gibba on the first day of the experimental investigation. Over the first five-6 days of the experiment, both plants’ absorption of Mo from acidic mining water either marginally increased. On the fifth and sixth days,
L. gibba and
L. minor removed 84 and 77 times more Mo compared to the control from acid mine water.
L. gibba showed outstanding Mo accumulation ability between day 5 and day 7.
L. minor showed a high ability to accumulate rapidly after the 5th day until the end of the experiment, and on the 8th day it accumulated 169 ppm Mo, which corresponds to an approximately 77 times Mo accumulation compared to the control sample.
Even though the acidic mining water utilized in the study contained low values of Mo (30 µg L-1), by the end of the study. L. gibba removed molybdenum in 274 L of acidic mineral water at the end of the 6th day of the study, and L. minor accumulated molybdenum in 5561 L of acidic mineral water at the end of the 8th day.
Figure 4.
Mo accumulation ratios by L. gibba and L.minor.
Figure 4.
Mo accumulation ratios by L. gibba and L.minor.
Both
L. minor and
L. gibba showed comparable increases in Pb accumulation throughout the course of the first five days of the study. Both
L. minor and
L. gibba showed limited, comparable increases in Pb accumulation throughout the first five days of the experiment. Both plants showed a linear and extremely high accumulation ability from the fifth to the eighth day. On days 5 and 8,
L. gibba accumulated 30 times (78.2 mg kg
-1) and 109 times more Pb (189 mg kg
-1) from acidic water, respectively, compared to the control samples of each plant (
Figure 5).
By the end of the 8-day trial, Pb had been extracted to acidic mining water of 291 L and 720 L, respectively, by L. gibba and L. minor, despite the low content of lead (260 µg L-1) in the acidic mine water used for the study.
Figure 5.
Pb accumulation ratios by L. gibba and L. minor.
Figure 5.
Pb accumulation ratios by L. gibba and L. minor.
L. gibba regularly showed significant increases in copper accumulation throughout the experiment and accumulated 9866 ppm Cu on the last day of the experiment. This corresponds to a 495-fold copper accumulation compared to the control group.
L. minor showed incredible accumulation ability during the first four days of the experiment, and at the end of the 4th day, 12668 ppm copper was accumulated by this plant. This indicates 1150 times more accumulation compared to control samples. Between the 5th and 8th days, the accumulation values of
L. minor decreased due to the plant being sufficiently saturated with copper (
Figure 6).
At the end of the study, L. minor and L. gibba accumulated, respectively, copper in 634 L and 815 L acidic mine water, despite the high amount of copper in acid mine water (15535 µg L-1) of the research region..
Figure 6.
Cu accumulations by L. minor and L. gibba.
Figure 6.
Cu accumulations by L. minor and L. gibba.
Sasmaz et al. [
21] examined the metal accumulation rates and the best time to harvest in gallery water using plants such as
L. minor and
L. gibba in waters from the Keban Pb-Zn mine. The pH of gallery water is 7.36 and has a neutral composition. It was observed that both plants achieved higher accumulations in acidic waters than in neutral mineral waters of Pb-Zn mining, Keban. The study determined the best time to harvest by monitoring daily changes in the amounts of metals in both plants. Based on the acquired data,
L. gibba and
L. minor accumulated Pb and Cu at 2888 and 3708 times and 108 and 147 times, respectively, greater than those found in the gallery water.
Sasmaz [
35]) examined the Ag, Au and As accumulation performances with the same plants in acidic mineral water in the same experiment setup. In comparison to control samples of these plants,
L. minor and
L. gibba showed effective and high abilities in accumulating As, Au and Ag from the acidic mine water of Cu mining area; respectively, 30 and 907 times for As; 336 and 394 times for Au; and. 240 and 174 times for Ag.
During the course of eight days, Sasmaz and Obek [
52] provided evidence of
L. gibba’s ability to extract As, U, and B from secondary-treated urban wastewater. During the first two days of the study,
L. gibba showed, respectively, the highest uptake ratio for B, U, and As with removal rates of 40%, 122%, and 133%. These results imply that
L. gibba may be useful as a natural strategy to lessen the amount of these pollutants in wastewater.
L. minor shows a higher capacity for collecting lower amounts of Cr and Ni, according to Goswami and Majumder [
17]. Furthermore, the uptakes of Au and Ag from secondary-treated municipal waste water by
L. gibba were examined by Sasmaz and Obek [
52]. Within six days of the experiment, the investigation showed that both Au and Ag were accumulated rapidly. But after day six, the concentrations of Ag and Au accumulation fluctuated, perhaps because the plant had reached saturation the greatest accumulations for Au and Ag on the 5th and 6th days of the study, were noted as 2303% and 247%, respectively. Uysal [
53] investigated
Lemna’s capacity to sorb Cr at various pH and concentration levels and found that despite being subjected to harmful consequences, the plants were still able to absorb Cr from the water. During the course of the 12-day experiment, Abdallah [
54] noted that
L. gibba did remarkably well, accumulating over 84% of the Cr in the solution.
L. minor is a viable choice for repairing habitats damaged with Pb and Cr because of its ability to absorb these metals fast and efficiently, according to Ucuncu et al. [
55]. According to Goswami et al. [
18],
L. minor worked well to correct low low concentration As-contaminated waters. The effectiveness of L. gibba and L. minor in extracting Y, La, and Ce from contaminated gallery water was ascertained by Sasmaz et al. [
56]. Comparing the results with the control samples, it was shown that
L. gibba accumulated more metals than in
L. minor.
Salvinia natans and
L. minor are two aquatic macropyhtes whose biological reactions and phytoremediation potential were examined by Leblebici et al. [
57]. They discovered that
L. minor was a better Cd accumulator than
S. natans, although
S. natans was a more effective Ni and Pb accumulator. According to Amare et al. [
58],
L. minor should be a moderately phytoaccumulator of Cd, Cu, Ni, and Cr but a high phytoaccumulator of Mn, Co, Zn, and Fe. According to Tatar et al. [
59],
L. minor has a high removed capacity for Ag, Hg, Mn, Pb, Zn, Fe, Ba, Sb, Co and P, while
L. gibba has a good uptake capacity for Mo, Cu, Ca, Na, Mg, Se and S.