Pollution Characteristics and Potential Risk Assessment of Heavy Metals in Tea Garden Soil Treated with Soil Conditioning Powder

doi:10.11924/j.issn.1000-6850.casb2021-0306

Abstract

Abstract:

In this paper, the characteristics of heavy metal content and pollution level of “waterfall Maofeng” tea garden soil under different soil conditioning powder treatments in Anshun, Guizhou Province were studied by means of sample test and physical and chemical analysis. The heavy metal content and pollution level of tea garden soil under CK treatment (0 kg/hm ²), A treatment (600 kg/hm²), B treatment (750 kg/hm²) and C treatment (900 kg/hm²) were discussed. The results showed that: under different soil conditioning powder treatments, the variation degree of heavy metal Cr, Hg, Pb, Cu, Zn, Ni, As and Cd in the study area were different, and the content of the eight heavy metals in the soil were also different. The pH and content of Cr, Pb and Ni were the highest in treatment C, the content of As, Hg and Cd were the highest in treatment A, and the content of Cu and Zn were the highest in treatment B. Correlation analysis showed that there was a significant correlation between Ni and Pb, indicating that they had high level of homology, while the correlation characteristics of other elements were not obvious. According to the comprehensive pollution index (P_综), treatment A was slightly polluted, CK, B and C were all moderately polluted. Cr in different soil treatments were within the scope of national class II standard (GB15618—2008), and the sample points were up to the standard and the rate was 100%. Among the selected pollution assessment factors, Cu was the most important factor, followed by Cd and Ni. As to the single potential ecological risk index ($E_{r}^{i}$) of heavy metals in the study area, Hg belonged to strong ecological risk, and the other seven heavy metals were in slight potential ecological risk level. The average value of the comprehensive potential ecological risk index (RI) was 196.79, which was generally at the level of medium potential ecological risk. Hg contributed the most to RI and was the most important ecological risk element.

Key words: soil conditioning powder, tea garden, heavy metals, pollution assessment, ecological risk assessment

CLC Number:

S156.2

Liu Xiaolan, Wei Fuxiao, Wang Daoping, Zhang Qinghai, Lin Shaoxia, Pan Weidong, Wang Ruoyan. Pollution Characteristics and Potential Risk Assessment of Heavy Metals in Tea Garden Soil Treated with Soil Conditioning Powder[J]. Chinese Agricultural Science Bulletin, 2021, 37(32): 108-115.

Figures/Tables 8

土壤pH	重金属限值(≤)
土壤pH	砷(As)	汞(Hg)	镉(Cd)	铬(Cr)	铜(Cu)	锌(Zn)	铅(Pb)	镍(Ni)
<5.5	40	1.3	0.3	150	50	200	70	60
5.5~6.5	40	1.8	0.3	150	50	200	90	70
6.5~7.5	30	2.4	0.3	200	100	250	120	100
>7.5	25	3.4	0.6	250	100	300	170	190

等级划分	Ⅰ	Ⅱ	Ⅲ	Ⅴ	Ⅳ
单项污染指数(P_i)	P_i≤0.7	0.7<P_i≤1.0	1.0<P_i≤2.0	2.0<P_i≤3.0	P_i>3.0
综合污染指数(P_综)	P_综≤0.7	0.7<P_综≤1.0	1.0<P_综≤2.0	2.0<P_综≤3.0	P_综>3.0
污染等级	清洁（安全）	尚清洁（警戒线）	轻度污染	中度污染	重度污染

	Cd	Cr	Cu	Zn	Pb	As	Hg	Ni
$T r i$	30	2	5	1	5	10	40	5
$C n i$	0.66	95.5	32	99.5	35.2	20	0.11	24.9

	Cd	Cr	Cu	Zn	Pb	As	Hg	Ni
$T r i$	30	2	5	1	5	10	40	5
$C n i$	0.66	95.5	32	99.5	35.2	20	0.11	24.9

风险级别	$E_{r}^{i}$	RI	潜在生态危害程度
Ⅰ	$E_{r}^{i}$<40	RI<150	轻微
Ⅱ	40≤$E_{r}^{i}$<80	150≤RI<300	中等
Ⅲ	80≤$E_{r}^{i}$<160	300≤RI<600	强
Ⅳ	160≤$E_{r}^{i}$<320	RI≥600	很强
Ⅴ	$E_{r}^{i}$>320	—	极强

处理	特征值	pH	Cr/(mg/kg)	As/(mg/kg)	Hg/(mg/kg)	Cd/(mg/kg)	Pb/(mg/kg)	Cu/(mg/kg)	Zn/(mg/kg)	Ni/(mg/kg)
CK	均值	4.53	73.07	38.03	0.30	0.26	33.99	114.11	116.33	71.97
	标准差(SD)	0.84	17.73	6.58	0.04	0.07	10.96	16.62	16.02	19.29
	变异系数CV/%	18.64	24.27	17.31	12.42	25.53	32.26	14.57	13.77	26.80
A处理	均值	4.70	71.87	41.07	0.34	0.48	39.03	104.83	131.96	76.66
	标准差(SD)	0.85	30.00	15.25	0.05	0.11	12.74	17.53	38.22	22.72
	变异系数CV/%	18.08	41.74	37.14	14.14	22.35	32.63	16.72	28.97	29.63
B处理	均值	4.54	74.78	35.17	0.33	0.36	40.16	135.77	164.55	76.27
	标准差(SD)	0.92	13.14	18.27	0.02	0.05	7.29	20.92	13.37	15.69
	变异系数CV/%	20.18	17.57	51.94	4.79	14.27	18.15	15.41	8.13	20.57
C处理	均值	5.29	79.60	38.67	0.31	0.44	47.65	134.60	158.52	80.30
	标准差(SD)	1.20	17.09	16.88	0.03	0.13	12.34	10.63	28.36	13.57
	变异系数CV/%	22.64	21.47	43.66	10.27	29.77	25.89	17.90	17.89	16.89
贵州省土壤背景值		—	95.50	20.00	0.11	0.66	35.20	32.00	99.50	24.90

处理	单因子污染指数(P_i)								综合污染指数 (P_综)	污染等级
处理	铬Cr	砷As	汞Hg	镉Cd	铅Pb	铜Cu	锌Zn	镍Ni	综合污染指数 (P_综)	污染等级
CK	0.65	1.16	1.15	0.80	0.68	2.68	0.68	1.11	2.02	中度污染
	0.50	0.98	0.98	1.17	0.52	2.19	0.60	1.50
	0.38	0.90	1.06	0.90	0.31	1.89	0.56	0.79
	0.42	0.77	0.85	0.63	0.43	2.37	0.49	1.40
均值	0.49	0.95	1.01	0.88	0.49	2.28	0.58	1.20
A处理	0.64	1.53	1.26	1.33	0.67	2.47	0.88	1.27	1.91	轻度污染
	0.51	1.06	0.94	1.97	0.55	1.99	0.75	1.51
	0.19	0.63	1.28	1.27	0.30	1.66	0.47	0.75
	0.57	0.89	1.06	1.87	0.71	2.27	0.54	1.58
均值	0.48	1.03	1.14	1.61	0.56	2.10	0.66	1.28
B处理	0.60	1.39	1.12	1.13	0.71	2.98	0.84	1.14	2.37	中度污染
	0.49	0.78	1.06	1.43	0.59	2.43	0.90	1.53
	0.38	0.31	1.06	1.10	0.48	2.30	0.80	0.97
	0.52	1.04	1.17	1.07	0.51	3.16	0.75	1.45
均值	0.50	0.88	1.10	1.18	0.57	2.72	0.82	1.27
C处理	0.68	1.55	1.14	1.40	0.82	2.85	0.94	1.26	2.20	中度污染
	0.49	0.81	1.10	1.80	0.65	2.89	0.89	1.38
	0.40	0.55	0.90	0.87	0.44	2.59	0.69	1.09
	0.55	0.96	1.04	1.77	0.81	2.44	0.65	1.63
均值	0.53	0.97	1.05	1.36	0.68	2.69	0.79	1.34

处理	单项潜在生态风险指数指数($E_{r}^{i}$)								综合潜在生态风险指数(RI)	风险等级
处理	铬Cr	砷As	汞Hg	镉Cd	铅Pb	铜Cu	锌Zn	镍Ni	综合潜在生态风险指数(RI)	风险等级
CK	2.03	23.23	125.54	10.91	6.80	20.94	1.36	13.34	204.15	中等
	1.58	19.51	107.11	15.91	5.13	17.09	1.21	18.12	185.67
	1.20	17.96	115.54	12.27	3.10	14.75	1.12	9.50	175.43
	1.31	15.36	93.17	8.64	4.28	18.54	0.98	16.85	159.13
均值	1.53	19.01	110.34	11.93	4.83	17.83	1.17	14.45	181.09
A处理	2.02	30.66	137.15	18.18	6.61	19.29	1.77	15.25	230.93	中等
	1.60	21.18	103.03	26.82	5.51	15.51	1.52	18.25	193.41
	0.60	12.56	139.42	17.27	3.01	12.99	0.94	9.01	195.80
	1.80	17.73	115.69	25.45	7.04	17.72	1.08	19.07	205.59
均值	1.51	20.53	123.82	21.93	5.54	16.38	1.33	15.39	206.43
B处理	1.88	27.90	122.02	15.45	7.11	23.32	1.69	13.68	213.05	中等
	1.55	15.51	115.10	19.55	5.84	18.95	1.82	18.44	196.75
	1.21	6.19	115.73	15.00	4.79	17.95	1.61	11.72	174.19
	1.63	20.75	127.26	14.55	5.08	24.65	1.50	17.42	212.84
均值	1.57	17.59	120.03	16.14	5.70	21.21	1.65	15.32	199.21
C处理	2.13	30.95	124.58	19.09	8.18	22.27	1.89	15.20	224.28	中等
	1.55	16.21	120.44	24.55	6.45	22.55	1.78	16.60	210.13
	1.27	11.03	97.96	11.82	4.41	20.20	1.39	13.10	161.20
	1.72	19.15	113.17	24.09	8.03	19.10	1.31	19.60	206.16
均值	1.67	19.33	114.04	19.89	6.77	21.03	1.59	16.12	200.44

相关系数	Cr	As	Hg	Cd	Pb	Cu	Zn	Ni
Cr	1
As	-0.23	1
Hg	-0.39	0.19	1
Cd	0.2	0.56	0.68	1
Pb	0.87	0.03	0.08	0.65	1
Cu	0.79	-0.75	-0.21	-0.07	0.63	1
Zn	0.66	-0.52	0.3	0.39	0.77	0.86	1
Ni	0.74	0.15	0.29	0.8	0.98^**	0.5	0.75	1

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