Risk Assessment of Trace Element Contamination in Drinking Water and Agricultural Soil: A Study in Selected Chronic Kidney Disease of Unknown Etiology (CKDu) Endemic Areas in Sri Lanka

Table 4

Descriptive statistics on concentrations of environmental toxicants including toxic metals/metalloids and phosphates of paddy soil samples (CKDu hotspots: Eppawala (EP) and Ambagaswewa (AM) GNDs, and the reference: Dambethalawa (RE) GND).

Variable	Sample	Mean	SE mean	Minimum	Median	Maximum
Cr (mg/kg)	EP	49.9	2.12	32.6	49.9	64.2
	AM	33.0	2.01	19.6	30.6	48.4
	RE	8.87	1.19	3.59	7.80	24.1
Mn (mg/kg)	EP	302	29.9	164	273	611
	AM	590	203	173	397	3325
	RE	125	24.6	18.5	96.3	417
Fe (mg/kg)	EP	23765	1142	15052	24075	30728
	AM	30461	5103	12995	25735	95805
	RE	7117	1178	2627	5799	22581
Co (mg/kg)	EP	8.08	0.51	4.73	7.81	12.0
	AM	13.8	1.50	5.90	14.1	21.6
	RE	3.35	0.64	0.93	2.90	11.5
As (mg/kg)	EP	5.03	0.12	4.04	5.08	5.65
	AM	3.30	2.23	0.57	0.97	34.4
	RE	0.48	0.04	0.22	0.45	0.84
Cd (mg/kg)	EP	0.11	0.01	0.08	0.09	0.25
	AM	0.10	0.01	0.04	0.10	0.22
	RE	0.04	0.000	0.02	0.04	0.08
Ca (mg/kg)	EP	4290	171	3090	4376	5355
	AM	2288	1895	136	268	28762
	RE	59.35	9.71	28.7	50.0	177
Mg (mg/kg)	EP	2359	103	1495	2339	2827
	AM	1659	185	710	1654	3190
	RE	651	165	209	497	2870
Pb (mg/kg)	EP	9.88	0.32	6.60	10.2	11.2
	AM	6.80	1.20	3.52	6.26	22.7
	RE	36.5	8.14	1.35	35.9	107
Cu (mg/kg)	EP	24.6	0.87	15.7	25.0	28.5
	AM	36.4	19.9	7.70	17.8	313
	RE	2.90	0.38	1.20	2.10	5.66
Zn (mg/kg)	EP	34.6	1.95	27.4	32.4	59.8
	AM	39.4	8.74	15.1	32.3	156
	RE	14.6	2.43	8.32	11.2	39.6
Na (mg/kg)	EP	288	14.6	207	294	383
	AM	337	161	84.0	186	2581
	RE	58.5	5.23	30.1	54.8	90.9
Al (mg/kg)	EP	26866	974	17959	28426	30312
	AM	22735	2322	9511	19625	44042
	RE	1276	509	ND	ND	4971
K (mg/kg)	EP	1106	46.9	539	1125	1350
	AM	625	167	235	394	2799
	RE	320	62.7	135	245	1155
Ni (mg/kg)	EP	16.9	0.63	11.1	17.4	20.2
	AM	11.9	1.23	5.07	10.4	24.2
	RE	1.03	0.36	ND	ND	3.21
(mg/kg)	EP	110	6.24	61.0	111	141
	AM	8.19	0.90	3.62	7.56	16.6
	RE	7.94	1.48	3.00	4.96	20.5