Environmental pollution loads on surface water chemistry and potentially ecological risks of inland aquatic ecosystem in South-Eastern State, Nigeria

Environmental Systems Research

Table 6 Comparison of Heavy metals concentration of Nworie surface water to global regulatory standards limits

Station	Cd (mgL⁻¹)	Cr (mgL⁻¹)	Cu (mgL⁻¹)	Fe (mgL⁻¹)	Ni (mgL⁻¹)	Pb (mgL⁻¹)	Zn (mgL⁻¹)
Upper River (UR)	0.078 ± 0.011^b	0.014 ± 0.006^b	0.020 ± 0.004^b	0.152 ± 0.00^b	0.037 ± 0.006^a	0.995 ± 0.179^a	0.024 ± 0.006^b
Middle River (MR)	0.062 ± 0.002^b	0.019 ± 0.015^b	0.078 ± 0.021^b	0.232 ± 0.064^b	0.033 ± 0.013^a	0.925 ± 0.099^a	0.024 ± 0.015^b
Lower River (LR)	0.178 ± 0.63^a	0.115 ± 0.074^a	0.805 ± 0.167^a	0.947 ± 0.153^a	0.003 ± 0.001^b	0.443 ± 0.073^b	0.129 ± 0.025^a
Mean	0.106	0.049	0.301	0.443	0.024	0.787	0.059
%Cv	12.7	86.7	37.1	21.5	33.5	16.0	31.2
Se	0.007	0.043	0.112	0.096	0.008	0.126	0.018
WHO LIMIT	0.003	0.10	1.00	0.03	0.02	0.01	3.0
SON	0.003	0.050	1.00	0.300	0.020	0.010	3.000
WPCL	0.003	0.020	1.00	0.450	0.020	0.010	4.250
EPA	0.010	0.050	1.00	0.500	0.020	0.050	5.000
EC	5.000	50.00	–	–	20.00	10.00	–

WHO, 2003/2011; SON 2007; WPCL 2004; EPA 2002; EC, 1998
WHO World Health Organization, SON Standard Organisation of Nigeria, WPCL Water Pollution Control Legislation, EPA Environmental Protection Agency (US), EC European Commission