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This work presents the concentrations of five pesticide residues, lindane, chlorpyrifos, endosulfan, p, p'-DDE and p, p'-DDD in soil samples collected from tomato fields in Ngarenanyuki, Tanzania. Endosulfan sulphate was detected in 100 % of the sample analysed with mean concentration of 0.2407 mg/kg dw. Chlorpyrifos was detected in 87 % of the samples with mean concentration of 0.1253 mg/kg dw. p, p'-DDE and p, p'-DDD were detected in 46 and 40 % of the samples analysed with mean concentrations of 0.1482 and 0.154 mg/kg dw, respectively. Lindane was the least detected pesticide. It was detected in 5 (33 %) of soil samples analysed with mean concentration of 0.2126 mg/kg dw. Low concentrations detected indicate the past usage of the pesticides. @ JASEM

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Saltwater intrusion problems are widespread where there are over pumping of groundwater from coastal aquifers. Water samples were collected from production boreholes in Zanzibar municipality and analyzed for salinity indication parameters comprising of chloride, electrical conductivity, total dissolved salts and percentage salinity levels. Historical water quality data of boreholes were also collected and used to establish trends. The water quality results indicated that the groundwater from the boreholes is progressively becoming more saline against the pumping age. The increase in salinity indicates progressive saltwater ingress in the aquifers. These trends show that saltwater intrusion is still limited around the shoreline areas especially Beit-el-Ras and Mbweni. The aquifer under the historic Stone Town area is also showing high potential for saltwater intrusion for which increased pumping of groundwater may render it saline. To curb this problem, controlled groundwater pumping and establishment of a long-term monitoring programme have been recommended.