The usability of Juniperus virginiana L. as a biomonitor of heavy metal pollution in Bishkek City, Kyrgyzstan

Figures & data

Figure 1. Bishkek Province and its location in Kyrgyzstan.

Table 1. Concentrations of Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn (mg/kg DW) in the parts of J. virginiana and co-located soil samples.

	Stations	Unwashed leaf	Washed leaf	Bark	Soil
Ca (mg/kg DW)	1	3852.293 ± 72.541**^a	3790.553 ± 49.63**^b	2613.153 ± 27.610**^b	14975.337 ± 272.477**^b
	2	4161.037 ± 87.499**^a	4092.177 ± 62.140**^a	2841.166 ± 32.800**^a	16283.677 ± 295.393**^a
	3	3489.033 ± 58.513**^b	3433.224 ± 40.617**^c	2350.522 ± 17.598**^c	13472.505 ± 209.339**^c
	4	2461.592 ± 26.845**^e	2369.536 ± 25.577**^f	1657.342 ± 16.733**^f	9296.613 ± 100.847**^f
	5	2994.733 ± 52.58**^cd	2925.125 ± 36.064**^d	2016.403 ± 15.137**^d	11558.009 ± 156.818**^de
	6	3295.527 ± 49.82**^bc	3220.165 ± 42.179**^c	2219.999 ± 14.746**^c	12633.847 ± 164.162**^cd
	7	2643.794 ± 36.262**^e	2562.732 ± 28.432**^e	1779.923 ± 17.303**^e	10054.827 ± 114.360**^ef
	8	2784.333 ± 47.15**^de	2720.055 ± 35.931**^de	1874.731 ± 12.45**^de	10668.55 ± 127.972**^e
Cd (mg/kg DW)	1	1.496 ± 0.025**^f	1.369 ± 0.028**^f	1.640 ± 0.019**^e	5.396 ± 0.069**^f
	2	1.405 ± 0.023**^f	1.278 ± 0.023**^f	1.542 ± 0.019**^e	5.032 ± 0.062**^f
	3	1.603 ± 0.023**^e	1.456 ± 0.026**^e	1.758 ± 0.022**^d	5.782 ± 0.074**^e
	4	2.128 ± 0.023**^a	1.935 ± 0.021**^a	2.333 ± 0.024**^a	7.531 ± 0.082**^a
	5	1.801 ± 0.022**^cd	1.623 ± 0.020**^cd	1.973 ± 0.014**^c	6.455 ± 0.089**^cd
	6	1.681 ± 0.024**^de	1.527 ± 0.023**^de	1.842 ± 0.017**^d	6.061 ± 0.093**^de
	7	1.974 ± 0.021**^b	1.786 ± 0.021**^b	2.171 ± 0.019**^b	7.006 ± 0.095**^b
	8	1.862 ± 0.022**^bc	1.685 ± 0.016**^bc	2.047 ± 0.012**^c	6.653 ± 0.091**^bc
Cr (mg/kg DW)	1	5.332 ± 0.072*^f	4.396 ± 0.023**^e	2.821 ± 0.026**^e	35.003 ± 0.659**^e
	2	5.012 ± 0.065*^f	4.100 ± 0.033**^f	2.630 ± 0.024**^f	32.913 ± 0.572**^f
	3	5.717 ± 0.080*^e	4.675 ± 0.029**^de	2.999 ± 0.021**^de	37.504 ± 0.627**^de
	4	7.595 ± 0.083*^a	6.117 ± 0.066**^a	3.920 ± 0.040**^a	49.418 ± 0.536**^a
	5	6.370 ± 0.095*^cd	5.213 ± 0.065**^c	3.341 ± 0.035**^c	42.124 ± 0.616**^c
	6	5.946 ± 0.094*^de	4.903 ± 0.051**^d	3.119 ± 0.027**^d	39.319 ± 0.597**^d
	7	7.012 ± 0.087*^b	5.646 ± 0.054**^b	3.648 ± 0.032**^b	45.995 ± 0.538**^b
	8	6.612 ± 0.083*^bc	5.366 ± 0.048**^bc	3.440 ± 0.034**^c	43.717 ± 0.610**^bc
Cu (mg/kg DW)	1	13.166 ± 0.099**^e	11.251 ± 0.137**^f	11.338 ± 0.163**^f	48.074 ± 0.516**^e
	2	12.379 ± 0.092**^f	10.500 ± 0.144**^f	10.657 ± 0.134**^f	44.829 ± 0.402**^f
	3	14.003 ± 0.080**^d	11.965 ± 0.159**^e	12.156 ± 0.184**^e	51.111 ± 0.727**^d
	4	18.614 ± 0.203**^a	15.647 ± 0.169**^a	16.030 ± 0.162**^a	66.380 ± 0.720**^a
	5	15.740 ± 0.179**^c	13.226 ± 0.167**^cd	13.546 ± 0.172**^cd	56.964 ± 0.527**^c
	6	14.682 ± 0.115**^d	12.443 ± 0.127**^de	12.740 ± 0.170**^de	53.167 ± 0.678**^d
	7	17.183 ± 0.196**^b	14.558 ± 0.126**^b	14.796 ± 0.189**^b	61.757 ± 0.745**^b
	8	16.337 ± 0.188**^bc	13.727 ± 0.161**^bc	13.952 ± 0.184**^bc	58.683 ± 0.525**^bc
Fe (mg/kg DW)	1	161.093 ± 1.949**^e	159.095 ± 2.924**^f	146.887 ± 0.999**^e	5048.900 ± 83.690**^ef
	2	151.495 ± 1.859**^e	148.456 ± 2.986**^f	136.965 ± 1.154**^f	4709.262 ± 89.406**^f
	3	172.647 ± 1.554**^d	169.147 ± 2.503**^e	157.412 ± 1.174**^d	5369.232 ± 70.951**^e
	4	227.941 ± 2.485**^a	222.829 ± 2.406**^a	205.649 ± 2.077**^a	7082.566 ± 76.833**^a
	5	192.619 ± 1.502**^c	188.379 ± 1.802**^cd	175.391 ± 1.298**^c	5986.523 ± 54.426**^cd
	6	179.821 ± 1.409**^d	177.240 ± 2.338**^de	164.967 ± 1.498**^d	5624.969 ± 65.306**^de
	7	210.428 ± 2.622**^b	205.638 ± 1.964**^b	191.321 ± 2.038**^b	6539.235 ± 71.347**^b
	8	198.398 ± 1.881**^c	195.478 ± 2.053**^bc	181.811 ± 1.625**^c	6167.583 ± 69.240**^bc
K (mg/kg DW)	1	4636.786 ± 50.53**^ef	4593.056 ± 67.514**^f	2066.705 ± 33.048**^ef	3481.076 ± 70.339*^f
	2	4367.447 ± 81.429**^f	4283.108 ± 67.058**^f	1926.898 ± 27.676**^f	3272.380 ± 53.557*^f
	3	4951.234 ± 48.74**^de	4881.540 ± 53.605**^e	2215.151 ± 29.99**^de	3700.708 ± 72.041*^e
	4	6399.985 ± 69.776**^a	6332.632 ± 68.364**^a	2898.119 ± 29.259**^a	4876.444 ± 52.903*^a
	5	5513.633 ± 64.056**^c	5441.238 ± 60.505**^cd	2468.761 ± 23.905**^c	4122.692 ± 58.971*^cd
	6	5226.286 ± 75.3**^cd	5120.686 ± 76.165**^de	2303.319 ± 25.676**^d	3879.320 ± 60.661*^de
	7	5905.813 ± 67.924**^b	5892.380 ± 50.959**^b	2674.034 ± 26.204**^b	4538.063 ± 52.894*^ab
	8	5614.711 ± 71.61**^bc	5601.267 ± 45.480**^bc	2542.455 ± 27.76**^bc	4279.190 ± 66.510*^bc
Mg (mg/kg DW)	1	3773.573 ± 46.606**^b	3737.924 ± 56.095**^b	1030.036 ± 17.781*^b	4760.417 ± 51.953**^b
	2	4102.298 ± 39.340**^a	4035.245 ± 53.629**^a	1119.747 ± 19.933*^a	5140.642 ± 58.703**^a
	3	3418.436 ± 45.836**^c	3384.950 ± 40.666**^c	926.243 ± 16.198*^c	4311.615 ± 57.127**^c
	4	2392.733 ± 26.092**^f	2369.531 ± 25.577**^f	653.213 ± 6.596*^f	2995.992 ± 32.503**^f
	5	2932.133 ± 41.263**^d	2903.939 ± 38.310**^d	794.656 ± 9.834*^d	3698.019 ± 48.984**^d
	6	3227.945 ± 48.702**^c	3175.087 ± 39.196**^c	874.758 ± 13.471*^c	4043.568 ± 55.120**^c
	7	2569.992 ± 29.02**^ef	2544.965 ± 34.343**^ef	701.502 ± 6.824*^ef	3240.584 ± 42.924**^ef
	8	2706.571 ± 37.59**^de	2700.309 ± 37.942**^de	738.823 ± 8.735*^de	3438.054 ± 47.236**^de
Mn (mg/kg DW)	1	13.952 ± 0.066**^e	12.002 ± 0.207*^f	12.568 ± 0.125**^e	222.782 ± 2.478**^f
	2	13.116 ± 0.103**^e	11.287 ± 0.237*^f	11.727 ± 0.137**^e	209.407 ± 2.994**^f
	3	14.837 ± 0.051**^d	12.860 ± 0.195*^e	13.465 ± 0.127**^d	238.673 ± 3.379**^e
	4	19.282 ± 0.210**^a	16.687 ± 0.180*^a	17.739 ± 0.179**^a	314.397 ± 3.410**^a
	5	16.411 ± 0.065**^c	14.220 ± 0.202*^cd	15.115 ± 0.129**^c	265.816 ± 2.456**^cd
	6	15.435 ± 0.085**^d	13.376 ± 0.157*^de	14.112 ± 0.161**^d	250.041 ± 3.181**^de
	7	17.931 ± 0.157**^b	15.522 ± 0.136*^b	16.370 ± 0.119**^b	290.194 ± 3.266**^b
	8	16.903 ± 0.085**^c	14.641 ± 0.168*^bc	15.564 ± 0.093**^c	275.814 ± 2.350**^bc
Na (mg/kg DW)	1	215.687 ± 3.285*^f	208.262 ± 1.980**^f	110.895 ± 1.536**^f	121.309 ± 1.506**^f
	2	202.015 ± 2.887*^f	194.174 ± 1.535**^f	104.663 ± 1.000**^f	113.094 ± 1.057**^f
	3	231.132 ± 4.211*^e	221.477 ± 2.247**^e	118.860 ± 2.002**^e	128.995 ± 1.933**^e
	4	304.500 ± 3.320*^a	291.988 ± 3.152**^a	155.531 ± 1.571**^a	168.633 ± 1.829**^a
	5	257.592 ± 4.655*^cd	246.841 ± 2.191**^cd	132.474 ± 1.477**^cd	143.721 ± 1.977**^cd
	6	240.383 ± 4.814*^de	232.241 ± 2.309**^de	123.617 ± 1.717**^de	135.225 ± 1.936**^de
	7	281.051 ± 3.532*^b	271.769 ± 3.636**^b	143.510 ± 1.038**^b	156.900 ± 1.163**^b
	8	265.164 ± 3.920*^c	256.249 ± 3.132**^c	136.391 ± 1.157**^bc	149.160 ± 1.624**^bc
Pb (mg/kg DW)	1	19.057 ± 0.171**^e	16.008 ± 0.110*^e	12.794 ± 0.201**^ef	92.688 ± 1.309*^f
	2	17.776 ± 0.152**^f	15.045 ± 0.152*^f	11.934 ± 0.211**^f	86.459 ± 1.247*^f
	3	20.278 ± 0.169**^d	17.160 ± 0.130*^d	13.712 ± 0.260**^e	98.620 ± 1.179*^e
	4	26.576 ± 0.290**^a	22.370 ± 0.241*^a	17.871 ± 0.180**^a	129.484 ± 1.404*^a
	5	22.617 ± 0.101**^c	19.037 ± 0.166*^c	15.277 ± 0.294**^cd	110.077 ± 1.409*^cd
	6	21.116 ± 0.160**^d	17.882 ± 0.116*^d	14.267 ± 0.296**^de	103.387 ± 1.356*^de
	7	24.725 ± 0.212**^b	20.645 ± 0.181*^b	16.809 ± 0.294**^ab	120.318 ± 1.346*^b
	8	23.470 ± 0.183**^c	19.621 ± 0.158*^c	15.854 ± 0.270**^bc	113.459 ± 1.311*^bc
Zn (mg/kg DW)	1	60.547 ± 0.844**^ef	56.650 ± 0.670*^f	18.790 ± 0.212**^e	269.939 ± 4.738*^ef
	2	56.603 ± 0.792**^f	52.919 ± 0.691*^f	17.534 ± 0.204**^f	255.476 ± 2.858*^f
	3	63.931 ± 1.061**^de	60.797 ± 0.621*^e	20.061 ± 0.115**^d	289.624 ± 3.650*^de
	4	84.323 ± 0.919**^a	79.504 ± 0.858*^a	26.435 ± 0.267**^a	381.125 ± 4.134*^a
	5	71.162 ± 0.853**^bc	67.261 ± 0.648*^cd	22.351 ± 0.168**^c	326.118 ± 2.370*^c
	6	66.835 ± 0.782**^cd	63.200 ± 0.650*^de	20.844 ± 0.138**^d	304.448 ± 3.195*^d
	7	77.786 ± 1.002**^b	73.381 ± 0.702*^b	24.588 ± 0.287**^b	354.436 ± 4.046*^b
	8	73.340 ± 0.954**^b	69.811 ± 0.758*^bc	23.183 ± 0.227**^c	336.565 ± 2.929*^bc

Note: Statistical analyses such as one-way analyses of variance with Tukey's post hoc HSD were performed. The mean differences are significant at P < 0.01 (**) and P < 0.05 (*) levels.

a, b, c, d, e, f: different letters indicate different averages within same column, which are significant in terms of averages (P < 0.05).

Table 2. Correlation matrix (R) data between soil and washed leaf (Leaf) obtained by Pearson correlation method.

Correlation matrix (R)
Pearson correlation	Ca (Soil)	Cd (Soil)	Cr (Soil)	Cu (Soil)	Fe (Soil)	K (Soil)	Mg (Soil)	Mn (Soil)	Na (Soil)	Pb (Soil)	Zn (Soil)
Ca (Leaf)	−0.931**	0.994**	0.988**	0.992**	0.989**	0.989**	−0.927**	0.994**	0.993**	0.984**	0.990**
Cd (Leaf)	−0.943**	0.968**	0.956**	0.980**	0.976**	0.956**	−0.936**	0.984**	0.969**	0.951**	0.981**
Cr (Leaf)	−0.957**	0.983**	0.980**	0.983**	0.988**	0.967**	−0.952**	0.991**	0.987**	0.977**	0.983**
Cu (Leaf)	−0.948**	0.986**	0.985**	0.987**	0.988**	0.977**	−0.938**	0.995**	0.986**	0.974**	0.989**
Fe (Leaf)	−0.938**	0.987**	0.978**	0.986**	0.995**	0.974**	−0.931**	0.991**	0.989**	0.971**	0.987**
K (Leaf)	−0.946**	0.992**	0.990**	0.988**	0.990**	0.983**	−0.937**	0.995**	0.991**	0.981**	0.990**
Mg (Leaf)	0.977**	−0.943**	−0.947**	−0.945**	−0.930**	−0.940**	0.989**	−0.942**	−0.944**	−0.958**	−0.945**
Mn (Leaf)	−0.934**	0.990**	0.984**	0.987**	0.991**	0.981**	−0.925**	0.993**	0.989**	0.974**	0.988**
Na (Leaf)	−0.946**	0.976**	0.960**	0.989**	0.977**	0.967**	−0.954**	0.980**	0.980**	0.970**	0.982**
Pb (Leaf)	−0.966**	0.968**	0.963**	0.978**	0.977**	0.953**	−0.965**	0.983**	0.974**	0.964**	0.977**
Zn (Leaf)	−0.948**	0.987**	0.979**	0.988**	0.993**	0.975**	−0.944**	0.991**	0.991**	0.977**	0.986**

**Correlation is significant at the level of 0.01 (2-tailed).

Table 3. The percentage changes (% removal) of heavy metal amounts found in the leaves of the plant before and after washing.

Stations	Ca	Cd	Cr	Cu	Fe	K	Mg	Mn	Na	Pb	Zn
1	1.60	8.51	17.56	14.55	1.24	0.94	0.94	13.98	3.44	16.00	6.44
2	1.65	9.08	18.21	15.18	2.01	1.93	1.63	13.95	3.88	15.36	6.51
3	1.61	9.16	18.23	14.56	2.03	1.41	0.98	13.33	4.18	15.38	4.90
4	3.74	9.06	19.46	15.94	2.24	1.05	0.97	13.46	4.11	15.81	5.71
5	2.32	9.89	18.16	15.97	2.20	1.31	0.96	13.35	4.17	15.83	5.48
6	2.29	9.17	17.54	15.25	1.44	2.02	1.64	13.32	3.39	15.31	5.44
7	3.07	9.50	19.48	15.28	2.28	0.23	0.99	13.44	3.30	16.50	5.66
8	2.31	9.54	18.84	15.98	1.47	0.24	0.23	13.38	3.36	16.40	4.81

Table 4. The results of paired samples t-test for unwashed and washed leaf samples.

		Paired differences
					Interval of the difference
		Mean	Std. deviation	Std. error mean	Lower limit	Upper limit	t	df	Significance (2-tailed)
Pair 1	UW Ca–W Ca	72.07100	12.10116	4.57381	60.87930	83.26270	15.757	6	0.000
Pair 2	UW Cd–W Cd	0.15914	0.02761	0.01044	0.13361	0.18468	15.248	6	0.000
Pair 3	UW Cr–W Cr	1.13343	0.21522	0.08135	0.93438	1.33247	13.933	6	0.000
Pair 4	UW Cu–W Cu	2.31100	0.40688	0.15379	1.93470	2.68730	15.027	6	0.000
Pair 5	UW Fe–W Fe	28.92857	66.54583	25.15196	−32.61606	90.47320	1.150	6	0.294
Pair 6	UW K–W K	65.22057	29.48401	11.14391	37.95241	92.48873	5.853	6	0.001
Pair 7	UW Mg–W Mg	37.92414	16.19741	6.12205	22.94403	52.90425	6.195	6	0.001
Pair 8	UW Mn–W Mn	2.14429	0.27319	0.10326	1.89162	2.39695	20.766	6	0.000
Pair 9	UW Na–W Na	9.37257	1.80264	0.68133	7.70541	11.03974	13.756	6	0.000
Pair 10	UW Pb–W Pb	3.42829	0.55025	0.20798	2.91939	3.93719	16.484	6	0.000
Pair 11	UW Zn–W Zn	3.92500	0.54755	0.20695	3.41860	4.43140	18.966	6	0.000

Note: Unwashed (UW); washed (W).