Studies were conducted to ascertain in vitro effects and effects of percutaneous application (in vivo) of dichlorvos (2,2-dichlorovinyl dimethyl phosphate; DDVP) on cholinesterase activities in bovine erythrocytes and plasma. Treatment in vitro of erythrocytes and plasma with DDVP resulted in concentration- and time-dependent inhibition of erythrocyte acetylcholinesterase (AChE) and plasma cholinesterase (ChE) activities. Mean (+/- SD) DDVP concentrations required to cause 50% enzyme inhibition were 15.7 +/- 3.3 muM and 43.1 +/- 5.7 muM for AChE and ChE, respectively; however, these values required to achieve this inhibition were markedly decreased with increasing incubation time. The inhibited AChE activity failed to be reactivated after incubation of erythrocytes with 2-pyridine aldoxime methiodide (2-PAM); however, limited reactivation of inhibited AChE and ChE activities was observed with excess concentration of 2-PAM. Percutaneous application of a DDVP-containing livestock spray on cattle also caused a marked decrease in the in vivo activities of AChE and ChE; however, the inhibited enzyme activities were reactivated rapidly after incubation with 2-PAM.

Residual materials such as veterinary drugs, environmental contaminants, and pesticides are affecting food safety. High resolution techniques and quality controls are needed to analyze these materials from part per million to part per trillion quantities in food. In order to achieve quality results, standardized methods and techniques are required. Our laboratories were prepared to obtain a certificate of accreditation for ISO/IEC 17025 in the analytical criteria of animal drugs, dioxins, pesticides, and heavy metals. ISO together with IEC has built a strategic partnership with the World Trade Organization with the common goal of promoting a free and fair global trading system.

Pesticides are extensively used for the control of crop pests in agriculture and forestry. Organophosphate (OP) and carbamate pesticides are especially effective for the control of a variety of harmful insects. However, these cholinesterase inhibitors are also dangerous to non-target organisms (wildlife and other animals) because of their high acute toxicity. Most poisonings by pesticides occur as a result of misuse or accidental exposure, but intentional killing of unwanted animals also occurs. At the request of a local autonomous entity, we investigated wild bird poisonings by pesticides from 2003 to 2007. The 207 suspicious samples of pesticide poisoning based on the necropsy were analyzed by GC/NPD, GC/FPD, or GC/MSD. We looked for trends in the identification of pesticides in wild birds thought to have died from poisoning. Pesticides were determined in 59% of the total samples analyzed. Phosphamidon and monochrotophos were the most common pesticides identified, which amounted to 77% of the subtotal. Other OP and carbamate pesticides were also found in various concentrations from dead wild birds. The determined rates of pesticides were as high as 86% and 76% in 2003 and 2006, respectively, during an outbreak of avian influenza in Korea.

Pesticides are useful to eliminate harmful insects and grow crops however, misuse and abuse of pesticides may cause a death of wild birds, livestock, and companion animals. We analyzed residual pesticides in the ingesta and tissues from the dead wild birds, livestock, and companion animals which were suspected pesticide poisoning based on the diagnosis of the Animal Disease Diagnostic Center of National Veterinary Research and Quarantine Service (NVRQS). The samples were primarily brought to NVRQS from local communities and veterinary diagnostic laboratories. The 231 suspicious samples of pesticide poisoning based on the necropsy were analyzed by GC/NPD, GC/FPD, GC/ECD, or GC/MSD in 2008 and 2009. Pesticides were identified from the 55 samples of total 143 samples analyzed in 2008 and from the 34 samples of total 88 samples analyzed in 2009. The pesticide identification rates in 2008 were higher than the rates in 2009. It may have relevance to the increased samples with the outbreak of avian influenza in 2008 in Korea. The concentrations of pesticides found in the dead animals varied and exceeded the respective LD∧50 of pesticides in many cases. Monochrotophos, phosphamidon, and methomyl were the most common pesticides found and those pesticides are high rank sales in Korea. The cause of pesticide poisoning in animal is assuming a misuse and an abuse of commonly used pesticides in Korea.

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.