Table 1.

Environmental characteristics of the samples from five rivers in the four seasons throughout the year

Season	Locality	Temperature (°C)	pH	Oxygen saturation (%)	Chlorides (mg/L)	Dissolved particles (mg/L)	Phosphorus (mg/L)	Nitrogen (mg/L)	Sulphates (mg/L)	Nitrates (mg/L)	Nitrites (mg/L)	Turbidity (ZFn)	Dissolved oxygen (mg/L)
Winter	1	2.7	8.2	99	95.3	683	0.178	4.96	120	0.128	19.5	7.21	12.9
	2	2	7.9	102	54.3	324	0.149	8.81	45	0.145	38.1	17.8	13.6
	3	1.6	7.9	102	93.7	412	0.18	9.81	50.2	0.184	41.6	20.8	13.7
	4	2.2	8.2	104	120	778	0.214	6.45	88.1	0.105	28.6	4.83	13.7
	5	1.7	8.2	97	30.2	249	0.103	7.09	52	0.112	30.2	9.75	13
Spring	1	12	8	93	40	575	0.347	4.65	84.5	0.233	15.2	43.9	9.8
	2	11.3	8	104	28.7	266	0.198	3.52	42	0.115	19.5	44.2	11.1
	3	12	8	99	56	350	0.262	4.95	53.3	0.131	19.2	46.1	10.4
	4	11.5	8.2	98	60.9	557	0.265	4.94	79.5	0.118	18.8	71.8	10.4
	5	12.1	7.7	91	15.9	230	0.12	4.71	36.2	0.171	17.8	10.1	9.6
Summer	1	14.2	8.3	81	33	566	0.472	4	48	0.443	13.5	6.34	8.2
	2	14.5	8.2	97	23.7	248	0.194	3.53	44	0.062	14.1	7.38	9.7
	3	13.6	8.2	100	57.4	400	0.4	4.22	50.8	0.026	17.6	12.2	10.2
	4	14.8	8.4	103	22.6	695	0.599	5.75	55	0.082	24.7	23.5	10.2
	5	20	8.1	71	15.8	197	0.028	5.01	46.1	0.663	10.8	8.08	6.3
Autumn	1	7	8	90	70.5	648	0.278	4.56	98	0.2	18.5	16	10.7
	2	6.8	8.3	96	28	253	0.141	3.87	44.1	0.066	15.1	5.24	11.3
	3	6.2	8.3	100	53.8	362	0.183	5	53.9	0.069	20.5	5.1	11.8
	4	6.9	8	94	92	730	0.553	7.23	91.4	0.174	27.1	8.45	11.1
	5	7.5	8	82	19.6	205	0.053	2.81	44.5	0.099	10	6.52	9.6