Occurrence of Pesticides in Groundwater and Topsoil of the Gaza Strip

Abstract

Agricultural activities in the Gaza Strip have been associated with excessive and uncontrolled use of dozens of pesticides. Accordingly, groundwater and soil are potentially contaminated causing severe threat to the crowded population. The present study describes a 3-year program to monitor types and levels of contamination by 52 pesticides in 94 groundwater wells in Gaza. Two analytical techniques (GC/MS and HPLC/MS) were applied to achieve this objective.Water from 63 wells showed no detectable levels of pesticides or levels that were much lower than the allowable limit (0.5 μg/L) of the German and the European Commission (EC) standards for groundwater. Municipal groundwater wells located in residential areas showed better quality than private wells in agricultural regions. Atrazine, atrazine-desisopropyl, propazine, simazine were detected in 18, 15, 8 and 5 wells with average concentrations of 3.5, 1.2, 1.5 and 2.3 μg/L, respectively. A linear correlation was found between the chloride concentrations in groundwater and atrazine for the same private wells.Generally speaking, shallow aquifers in sandy substances in areas of low annual precipitation in the southern areas of Gaza showed detectable concentrations of pesticides. Pesticides were more abundant in clay soils of the northern area. A linear regression analysis showed a correlation coefficient of r = 0.87 between the strawberry greenhouses and the occurrence of propazine, sebutylazine, terbutylazine, 4,4 -DDT, 4,4 -DDE, and 4,4 -DDD in soil. The averages of propazine, sebutylazine and terbutylazine were 19, 13 and 39 μg/kg, respectively. Two soil samples from greenhouses showed maximum contents of 4,4 -DDE and 4,4 -DDT up to 1150 and 823 μg/kg, respectively.Groundwater needs to be assessed for pesticide contamination on a routine basis to protect the health of Gaza's residents. Where levels of pesticides are found to exceed levels that protect health, alternative water resources need to be found for drinking and possibly other household uses.

Groundwater pesticides residue in the southwest of Iran-Shushtar plain

“…Human activities and natural factors that affect groundwater quality were studied around the world by many researchers (Jiang et al 2009;Lorite-Herrera et al 2007;Jalali et al 2008;Kim et al 2003;Shomar et al 2005).…”

Different Approaches on the Investigation of Ground Water

“…HPLC has been used for the determination of pesticides coupled to several detectors, among them the DAD [40,41] and MS [42][43][44], which help in the identification and quantification of the compounds [45]. Studies of the application of screening models for the assessment of the potential for contamination of groundwater have been increasingly used because of the easiness in obtaining the parameters and the low cost.…”

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

“…Por isso, em alguns casos, o ajuste do pH da amostra é necessário para estabilizar os agrotóxicos e aumentar sua retenção na fase sólida. 27,33,42,43 A velocidade de aplicação da amostra é importante e pode ser ajustada, controlando-se o vácuo ou a pressão aplicada no processo. Para pequenos volumes de amostra, esta etapa pode ser realizada somente com o auxílio da gravidade.…”

“…Esses solventes são denominados "solventes de lavagem" (wash solvent) e são utilizados solventes que não possuam força suficiente para remover do sorvente o analito de interesse. Diversos solventes de lavagem podem ser usados, mas quando se trata da extração de agrotóxicos em amostras aquosas, usa-se principalmente água ultrapura 42,44,45 ou uma mistura de uma pequena porcentagem de metanol com água ultrapura. 26 Uma vez que os agrotóxicos são retidos nos cartuchos são, então, eluídos com um pequeno volume de solvente adequado para a análise.…”