Presence of three pesticides in rural drinking water sources in Kenya

A cross-sectional study on the use of three pesticides and their presence in drinking water sources was conducted in Githunguri/Kiaria community between January 1994-March 1995. The main objective of the study was to determine the extent to which some of the pesticides used by the Githunguri/Kiaria agricultural community were polluting their drinking water sources. Due to monetary and physical limitations, only DDT, its isomers and metabolites, carbofuran and carbaryl pesticides were identified and used as surrogates of pollution for the other pesticides.^ The study area was divided into high and low lying geographic surface areas. Thirty-four and 38 water sampling sites were randomly selected respectively. During wet and dry seasons, a total of 144 water samples were collected and analyzed at the Kenya Bureau of Standards Laboratory in Nairobi. Gas chromatography was used to analyze samples for possible presence of DDT, its isomers and metabolites, while high pressure liquid chromatography was used to analyze samples for carbofuran and carbaryl pesticides.^ Six sites testing positively for DDT, its isomers and metabolites represented 19.4% of the total sampled sites, with a mean concentration of 0.00310 ppb in the dry season and 0.0130 ppb in the wet season. All the six sites testing positively for the same pesticide exceeded the European maximum contaminant limit (MCL) in the wet season, and only one site exceeded the European MCL in the dry season.^ Those sites testing positively for carbofuran and carbaryl represented 5.6% of the total sampled sites. The mean concentration for the carbofuran at the sites was 2.500 ppb and 1.590 ppb in the dry and wet seasons respectively. Similarly, the mean concentration for carbaryl at the sites was 0.281 ppb in the dry season and 0.326 ppb in the wet season.^ One site testing positively for carbofuran exceeded the European MCL and WHO set limit in the wet season, while one site testing positively for the same pesticide exceeded the USA, Canada, European and WHO MCLs in the dry season. Similarly, one site which tested positively for carbaryl pesticide exceeded the European MCL in both seasons.^ Out of the 2,587 community members in the study area, 333 (13%) were exposed through their drinking water sources to the three pesticides investigated by this study. As a public health measure, integrated pest management approaches (IPM), protection of the wells and education of the community is necessary to minimize the pollution of the environment and safeguard the drinking water sources from pollution by the pesticides. ^

The use of unmanned aerial vehicles and wireless sensor networks for spraying pesticides

The application of pesticides and fertilizers in agricultural areas is of crucial importance for crop yields. The use of aircrafts is becoming increasingly common in carrying out this task mainly because of their speed and effectiveness in the spraying operation. However, some factors may reduce the yield, or even cause damage (e.g., crop areas not covered in the spraying process, overlapping spraying of crop areas, applying pesticides on the outer edge of the crop). Weather conditions, such as the intensity and direction of the wind while spraying, add further complexity to the problem of maintaining control. In this paper, we describe an architecture to address the problem of self-adjustment of the UAV routes when spraying chemicals in a crop field. We propose and evaluate an algorithm to adjust the UAV route to changes in wind intensity and direction. The algorithm to adapt the path runs in the UAV and its input is the feedback obtained from the wireless sensor network (WSN) deployed in the crop field. Moreover, we evaluate the impact of the number of communication messages between the UAV and the WSN. The results show that the use of the feedback information from the sensors to make adjustments to the routes could significantly reduce the waste of pesticides and fertilizers.

A survey of warning colours of pesticides

Pesticides are used to protect plants all over the world. Their increasing specificity has been due to utilization of differences in biochemical processes, and has been accompanied by lower human toxicity. Nevertheless cases of poisoning are still observed. While certain toxic substances are provided with characteristic dyes or pigments to facilitate easy identification, no overview of pesticide colors exists. The lack of available product information prompted us to explore the colors and dyes of pesticides registered in Germany, most of which are commercially available worldwide. A compilation of the colors and odors of 207 pesticide products is presented. While some of the substances can be identified by their physical characteristics, in other cases, the range of possibilities can be narrowed by their nature and color.

SAMPLING METHODOLOGY FOR AIRBORNE SEMIVOLATILE ORGANIC POLLUTANTS USING POLYURETHANE FOAMS (COLLECTION, PESTICIDES, VOLATILE)

Indoor and ambient air organic pollutants have been gaining attention because they have been measured at levels with possible health effects. Studies have shown that most airborne polychlorinated biphenyls (PCBs), pesticides and many polycyclic aromatic hydrocarbons (PAHs) are present in the free vapor state. The purpose of this research was to extend recent investigative work with polyurethane foam (PUF) as a collection medium for semivolatile compounds. Open-porous flexible PUFs with different chemical makeup and physical properties were evaluated as to their collection affinities/efficiencies for various classes of compounds and the degree of sample recovery. Filtered air samples were pulled through plugs of PUF spiked with various semivolatiles under different simulated environmental conditions (temperature and humidity), and sampling parameters (flow rate and sample volume) in order to measure their effects on sample breakthrough volume (V(,B)). PUF was also evaluated in the passive mode using organo-phosphorus pesticides. Another major goal was to improve the overall analytical methodology; PUF is inexpensive, easy to handle in the field and has excellent airflow characteristics (low pressure drop). It was confirmed that the PUF collection apparatus behaves as if it were a gas-solid chromatographic system, in that, (V(,B)) was related to temperature and sample volume. Breakthrough volumes were essentially the same using both polyether and polyester type PUF. Also, little change was observed in the V(,B)s after coating PUF with common chromatographic liquid phases. Open cell (reticulated) foams gave better recoveries than closed cell foams. There was a slight increase in (V(,B)) with an increase in the number of cells/pores per inch. The high-density polyester PUF was found to be an excellent passive and active collection adsorbent. Good recoveries could be obtained using just solvent elution. A gas chromatograph equipped with a photoionization detector gave excellent sensitivities and selectivities for the various classes of compounds investigated. ^

Analysis of symptoms of rural workers exposed to pesticides

This cross-sectional study was conducted in southern Minas Gerais, in two counties: São Gonçalo do Sapucaí and Silvianópolis. Presented as objective to verify the important variables associated with the occurrence of symptoms of subacute intoxication related to pesticides exposure. A questionnaire was dedicated to a sample of 412 workers. An analysis of non-conditional logistic regression was applied gradually. The likelihood ratio method was used to define the significant variables in the final model. Of the analysed population, 59.2% reported symptoms typical of subacute intoxication. Of the respondents, 91.5% reported knowing the deleterious effects associated with exposure to pesticides. The adjusted model was found with the significant variables: being male that presented Prevalence Odds Ratio (POR) adjusted . PORof 0.54 (95% CI 0.36 to 0.81), already hospitalized for poisoning with pesticides, POR of 3.26 (95% CI 1.08 to 9.82), living in the rural area of residence., POR of 2.17 (95% CI 1.20 to 3.93) and type of employment relationship or temporary employment, POR of 2.32 (95% CI 1.08 to 4.95).