Pesticide residues in fish from the Densu River Basin in Ghana

Abstract

The Densu River is a typical river flowing through agricultural areas in Southern Ghana. Six fish species from different locations in the river were sampled and analyzed for residues of pesticides and metabolites using GC with ECD/FID. The results of the study indicate that all the detected residues and metabolites in fish samples from the Densu River Basin were organochlorines (OCs). Among the pesticides residues analyzed, DDE, α-endosulfan, γ-HCH, δ-HCH, heptachlor and endosulfan sulphate, were predominant in all the samples. About 50% of the samples recorded positive detection of DDE while α-endosulfan was detected in 60% of the samples. γ-HCH, δ-HCH were detected in 75% and 65% of the samples respectively with heptachlor occurring in 80% of the samples. In almost all the fish species analyzed, DDE was the predominant compound having a mean value of 7.99 µgKg -1 . Higher concentrations of pesticide residues were detected in fish samples from the Densu River at Nsawam than the other locations. The total concentration of residues in the fish samples ranged between 0.49 µgKg -1 and 8.90 µgKg -1 with the highest level detected in Hepsetue odoe (HO-N). The sequence of pesticide residues detected in fish samples were HO-N > HN-N > CO-N > CG-N > TZ-N > CN-W > TZ-W > CG-W. The high ratio of DDE/DDT in fish samples (0.1 -6.9 with a mean of 2.51) indicated probably old input of DDT and significant degradation. The γ -HCH isomer (lindane) was the dominant HCH in fish samples suggesting a preferential usage of lindane (purified γ-HCH) in these areas. The δ-HCH/γ-HCH ratios in most fish samples were low indicating the present input of the pesticide lindane from non-point sources.

Drawdown Farming and Pesticide Residue Levels of the Afram River in Ghana

“…This is true both for local studies by [9][10][11][12][13] as well as for studies from other regions carried out by [14][15][16][17]. However, OCP residues from Densu River [18] in Ghana were about 3 folds higher than the flood concentration from the current studies. Similarly, [19] and [20] recorded astronomical levels of pesticide residues in water samples from Lake Naivasha in Kenya and Benue River in Nigeria respectively (Table 5).…”

Levels and distribution of pesticide residues in soil and sediments in Eastern Lake Tanganyika environs

“…The ratios of (p,p'-DDE + p,p'-DDD)/p,p'-DDT can be used to establish whether the contamination is due to recent input/application or historical/past use, because the levels of the parent compound (p,p'-DDT) in the environment decrease with time relative to its metabolites, p,p'-DDE and p,p'-DDD. A high ratio (> 1) indicates past use or old source of DDT which has been largely converted to DDE and DDD, while a low ratio (< 1) indicates recent use or exposure to the parent DDT or insignificant degradation (Jaga and Dharmani, 2003;Qiu et al, 2004;Fianko et al, 2013). The (p,p'-DDE + p,p'-DDD)/p,p'-DDT ratios were low (< 1) in most of the soil samples and in almost all sediments (Table 1 and Table 3) indicating recent use of DDT in nearby areas or old input of DDT without significant degradation.…”

“…For example, Fianko et al (2013) found high ratios of DDE/DDT in fish samples (with a mean of 2.51) indicating old input of DDT and significant degradation. Similarly, the study by Sosan et al (2015) found higher concentrations of p,p'-DDD and p,p'-DDE than the concentrations of p,p'-DDT in foodstuffs from markets in Ile-Ife, Nigeria indicating that the DDT had substantially metabolized into DDD and DDE.…”

Aldicarbe et crimidine dans les eaux et les sédiments aux alentours de la décharge municipale d’Akouédo (Abidjan, Côte d’Ivoire): niveaux et fréquences de contamination

“…Il est bien connu que les résidus de pesticides et métabolites peuvent être transportés des sources de contaminations vers les eaux souterraines et de surface à travers le ruissèlement des eaux, l'érosion des sols et causer des risques écologiques (Schulz, 2004 ;Shark et al, 2004 ;Hela et al, 2005 ;Boutron et al, 2011;Ouattara et al, 2012 ;Kalogridi et al, 2014 ). Cependant, les seules données disponibles sur la contamination des estuaires par les pesticides en Afrique se sont focalisées sur les organochlorés (Henry et Kishimba, 2003;EYA et al, 2006aEYA et al, , 2006bEssumang et al, 2009 ;Koffi et al, 2009 ;Fianko et al, 2013;Okoya et al, 2013 ;Kouakou et al, 2015) et les organophosphorés (Paré et al, 2013), bien que les autres familles de pesticides puissent causer des dangers pour la santé de l'homme et de l'environnement (Charlier et Plomteux, 2001 ;Blacker et al, 2010;Ardjouma et al, 2011 ).…”