Occurrence, risk assessment, and source apportionment of heavy metals in surface sediments from Khanpur Lake, Pakistan

Journal of Analytical Science and Technology

Table 5 Description of sediment classification and sediment quality guidelines in acid extract of sediments in two seasons

		Cd	Cr	Cu	Fe	Mn	Pb	Zn
Sediment classification	Non-polluted	-	<25	<25	<17,000	<300	<40	<90
	Moderately polluted	-	25 to 75	25 to 50	17,000 to 25,000	300 to 500	40 to 60	90 to 200
	Heavily polluted	>6	>75	>50	>25,000	>500	>60	>200
Sediment quality guidelines (SQGs)	LEL	0.6	26	16	20,000	460	31	120
	SEL	10	110	110	40,000	1,100	250	820
	ERL	5	80	70	-	-	35	120
	ERM	9	145	390	-	-	110	270
Percentage of samples (summer)	Non-polluted	100	-	-	100	23	63	67
	Moderately polluted	-	100	100	-	43	23	33
	Heavily polluted	-	-	-	-	34	14	-
	<LEL	13	-	-	100	63	63	100
	≥LEL and <SEL	87	100	100	-	37	37	-
	>SEL	-	-	-	-	-	-	-
	<ERL	100	100	100	-	-	63	100
	≥ERL and <ERM	-	-	-	-	-	37	-
	>ERM	-	-	-	-	-	-	-
Percentage of samples (winter)	Non-polluted	100	3.0	40	100	53	100	97
	Moderately polluted	-	97	57	-	44	-	3.0
	Heavily polluted	-	-	3.0	-	3.0	-
	<LEL	10	3.0	-	100	90	93	100
	≥LEL and <SEL	90	97	100	-	10	7.0	-
	>SEL	-	-		-	-	-	-
	<ERL	97	100	100	-	-	93	100
	≥ERL and <ERM	3.0	-	-	-	-	7.0	-
	>ERM	-	-	-	-	-	-	-

The units of metals are expressed in milligrams per kilogram. LEL, lowest effect level; SEL, severe effect level; ERL, effect range low; ERM, effect range median.