Herbicides are being used widely in agriculture and aquaculture for controlling noxious weeds. Paraquat and 2, 4-Dichlorophenoxyacetic acid(2,4-D) have been the most widely used herbicide during the past three decades. Toxicological properties of Paraquat are attributed to its abilityto produce reactive oxygen species such as superoxide anion that may directly or indirectly cause cell death. 2,4-Dichlorophenoxyacetic acid(2,4-D) is a broad-leaf, systemic, phenoxy herbicide used as the active ingredient in several commercially available aquatic herbicide products.Bioassay technique has been the cornerstone of programs on environmental health and chemical safety. The application of environmentaltoxicology studies on non-mammalian vertebrates is rapidly expanding. So the present study investigated the acute toxicity of Paraquat and2,4- Dichlorophenoxy acetic acid (2,4-D) as aquatic ecosystems pollutants on Artemia franciscana. Artemia is one of the most suitable testorganisms available for ecotoxicity testing and research and most commonly used live food in aquaculture. Acute toxicity (48 h LC50) of twoherbicides (Paraquat, 2, 4-dichlorophenoxy acetic acid) was determined. A. franciscana exposed to Serial concentrations of both mentionedherbicides. Mortalities at 12, 24, 36 and 48 hours after exposure were recorded and LC50 were calculated using Probit software. The resultsobtained indicate that the acute toxicity of these herbicides is significantly different in adult A. franciscana. The lethal concentration of Paraquatand 2,4-D were calculated 2.701, 14.475 mg/L in A. fransiscana respectively. So The LC50 of two examined herbicides was significantly differentand the mortality rate was increased by increasing exposure time. Finally, these data support the hypothesis the possible risks associatedwith the presence of herbicides particularly Paraquat residues in the aquatic animals and their environment.

Herbicides are being used widely in agriculture and aquaculture for controlling noxious weeds. Paraquat and 2, 4-Dichlorophenoxyacetic acid(2,4-D) have been the most widely used herbicide during the past three decades. Toxicological properties of Paraquat are attributed to its abilityto produce reactive oxygen species such as superoxide anion that may directly or indirectly cause cell death. 2,4-Dichlorophenoxyacetic acid(2,4-D) is a broad-leaf, systemic, phenoxy herbicide used as the active ingredient in several commercially available aquatic herbicide products.Bioassay technique has been the cornerstone of programs on environmental health and chemical safety. The application of environmentaltoxicology studies on non-mammalian vertebrates is rapidly expanding. So the present study investigated the acute toxicity of Paraquat and2,4- Dichlorophenoxy acetic acid (2,4-D) as aquatic ecosystems pollutants on Artemia franciscana. Artemia is one of the most suitable testorganisms available for ecotoxicity testing and research and most commonly used live food in aquaculture. Acute toxicity (48 h LC50) of twoherbicides (Paraquat, 2, 4-dichlorophenoxy acetic acid) was determined. A. franciscana exposed to Serial concentrations of both mentionedherbicides. Mortalities at 12, 24, 36 and 48 hours after exposure were recorded and LC50 were calculated using Probit software. The resultsobtained indicate that the acute toxicity of these herbicides is significantly different in adult A. franciscana. The lethal concentration of Paraquatand 2,4-D were calculated 2.701, 14.475 mg/L in A. fransiscana respectively. So The LC50 of two examined herbicides was significantly differentand the mortality rate was increased by increasing exposure time. Finally, these data support the hypothesis the possible risks associatedwith the presence of herbicides particularly Paraquat residues in the aquatic animals and their environment.

The study determined the types of pesticide/herbicide pollutants in water, sediment and fish from the Kafue River. A preliminary investigation of the oxidative stress from these pesticides/herbicides was also assessed by measurement of catalase activity. Water, sediment and fish samples were collected upstream, midstream and downstream the Kafue river in Chingola, Kitwe, Kafue National Park and Kafue Town. Water, sediment and fish muscle were sampled and analysed for pesticides using Gas chromatography. For catalase activity fish liver samples only were examined. The pesticides/herbicides detected in all samples collectively included: Heptachlor, pp'-DDE, Cypermethrin, Chlordane, Toxaphene, Terbufos, Kelthane, Endosulfan, Dieldrin, pp'-DDD, pp'-DDT, Atrazine, Disulfoton, d-trans-Allethrin and Endrin. On the other hand, catalase activity was detected in all fish liver samples from all sites. Its levels increased significantly from Chingola upstream to sites down-stream with highest being in Kafue town. This study therefore, demonstrates that there is widespread contamination of the Kafue River with pesticides/herbicides. It also demonstrates that organochlorides are found throughout the river especially in fish samples. The spectrum of pesticides/herbicides was much wider in fish probably due to bioaccumulation. It was also observed that fish are subjected to oxidative stress as determined by catalase levels. The stress is more pronounced downstream where the catalase levels were significantly higher than Chingola. The observation that more pesticide varieties are also found downstream may suggest a likely causative effect of the pesticides on oxidative stress although this needs further investigation. This study further tentatively highlights the potential dangers of these agro-related substances to dependants of the Kafue River water body and the need to carry out risk assessments and thereafter institute corrective measures to help reduce contamination and adverse effects.