It can be seen from Table 1 that the correlation coefficient value of Mg²⁺ and Ca²⁺ is 0.893, and the correlation coefficient value of and Na⁺ is 0.967, indicating that there is a strong correlation between some variables. The correlation coefficient values of and Na⁺, are 0.403 and 0.389, respectively, and the correlation coefficient values of Cl⁻ and Mg²⁺ is 0.213, indicating that some variables had moderate correlations. According to different PCA dimensions, the cumulative contribution rate of extracted principal components is shown in Table 2.

Table 2

The cumulative contribution rate of extracted principal components

Element .	Initial eigenvalues .			Extract the load sum of squares .
	Total .	Percent variance .	Cumulation % .	Total .	Percent variance .	cumulation % .
Ca2+	4.123	51.532	51.532	3.864	48.301	48.301
Mg2+	1.685	21.061	72.592	1.694	21.169	69.470
Na+	1.092	13.649	86.242	1.342	16.772	86.242
	0.486	6.074	92.316
	0.377	4.708	97.024
Cl−	0.171	2.138	99.163
PH	0.062	0.781	99.943
TH	0.005	0.057	100.000

Element .	Initial eigenvalues .			Extract the load sum of squares .
	Total .	Percent variance .	Cumulation % .	Total .	Percent variance .	cumulation % .
Ca2+	4.123	51.532	51.532	3.864	48.301	48.301
Mg2+	1.685	21.061	72.592	1.694	21.169	69.470
Na+	1.092	13.649	86.242	1.342	16.772	86.242
	0.486	6.074	92.316
	0.377	4.708	97.024
Cl−	0.171	2.138	99.163
PH	0.062	0.781	99.943
TH	0.005	0.057	100.000

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