Selected persistent organic pollutants (POPs) in water of River Niger: occurrence and distribution

Abstract

This study assessed the levels and distribution of selected persistent organic pollutants (POPs) in water of River Niger. The selected POPs of interest were organochlorine pesticides (OCPs). Fifteen representative sites along River Niger: three each from Gurara River (tributary) in Niger State, Lokoja (confluence) in Kogi State, Onitsha in Anambra State, Brass and Nicolas Rivers (tributaries) in Bayelsa State were selected for sampling quarterly over a 24-month period. A total of 240 surface and bottom water samples were collected using Van Dorn water sampler in the eight quarters of 2008-2009. At the Delta locations where tidal effects take place, high- and low-tide water samples were taken as compared to surface and bottom at the River Niger locations. For sample extraction, EPA method 3510c was employed with slight modifications. Certified reference standards from Accustandards USA was used for the instrument calibration and quantification of OCPs. The extracted samples were subjected to gas chromatography (GC/ECD) for identification/quantification. And Shimadzu GCMS QP2010 was used for confirmation. Chlordane, endosulfan, endrin and DDT metabolites were very prominent in the water samples, compared to HCH, dieldrin, and isomers which occurred at lower concentrations. The sequence in the concentration of the organochlorine pesticides were ∑chlordane > ∑DDT > ∑endosulfan > ∑endrine > ∑dieldrin > ∑HCH. The highest concentration of ∑OCPs in water samples of River Niger, 1138.0 ± 246.7 ng/L, with range 560.8-1629 ng/L was detected at Onitsha location, while the lowest concentration, 292.6 ± 74.9, with range 181-443.0 ng/L was detected at Nicolas River. Levels of OCPs in a larger percentage of the samples exceeded guidelines and therefore hold potential harmful effects on benthic fauna, fish, and man. Abstraction of water from the River for drinking water treatment should be discouraged. Because of the potential danger, this presents, continuous monitoring of the water body and if possible remediation, determination of the sources of the POPs is therefore very necessary.

Levels of Organochlorine Pesticides in Brackish Water Fish from Niger River, Nigeria

“…The details of sample preparation, extraction, extract concentration, lipid determination, extract cleanup, quality control, and quality assurance have been reported elsewhere [ 7 ]. In addition to the extract cleanup already reported, the elusion was continued with another 50 ml of 50 + 49.65 + 0.35 DCM/hexane/acetonitrile mixture and the eluate collected in another 100 ml round bottom flask.…”

“…The extracted samples were subjected to Gas Chromatography (GC) (Hewlett Packard GC 5890 series 11 with electron capture detector) for identification/quantification. Further details, optimization of the instrument, oven temperature programme, flow rate, calibrations, and confirmation (using Shimadzu GCMS QP2010), have been reported elsewhere [ 7 ].…”

Polychlorinated Biphenyls in Brackish Water Fish in the River Niger, Nigeria

“…High levels of PCBs in the water of the River Niger have recently been reported, along with other persistent organic pollutants (POPs) such as organochlorine pesticides. 8 , 9 There is a need to determine if PCBs are bioaccumulated in the fish species of the River Niger. This study, therefore, aims to determine PCB levels in the brackish water fish of the River Niger.…”

Persistence and Bioaccumulation of Persistent Organic Pollutants (POPs) in the Soil and Aquatic Ecosystems: Syrian Frontiers in Ecology and Environment

“…1,2,3,4-tetrachlorobenzene 0.10 0.03 0.01 (Koelmans & Luklema, 1992) Hexachlorobenzene 0.01 0.006 ˂0.01 (Jiang et al, 2015) Ɣ-HCH 0.03 0.03 0.01 (Gupta et al, 2000) PCB 0.08 0.04 (Aluani et al, 2016) Bis-(2-chloroisopropyl)teeth 3.00 2.00 0.30 (Manwaring et al, 1977) Aniline 2.30 1.40 (Pierpoint et al, 2003) 4-chloroaniline 0.10 0.03-0.10 ˂0.01 (Vangnai et al, 2007) 3,4-dichloroaniline 0.70 0.03-0.20 ˂0.01 (Roehrs et al, 2012) Nitrobenzene 0.50 ˂0.01 ˂0.01 (Yan et al, 2015) p-nitrotoluene 0.50 ˂0.01 ˂0.01 (Ju et al, 2011) p-nitroaniline 0.50 ˂0.01 ˂0.01 (Zhu et al, 2005) p-chloronitrobenzene 0.30 ˂0.01 ˂0.01 (Mohadesi et al, 2017) Trifluoromethylaniline 0.10 0.08 ˂0.01 (Unyimadu et al, 2017) Generally, dune filtration results in a better removal of organic compounds. This is most dramatically found for the trihalomethanes (THMs, CHX) which show a high persistence during bank filtration, but already have been efficiently removed from the water phase by dune infiltration during the last five decades.…”