Pesticide residues in water from TPC sugarcane plantations and environs, Kilimanjaro region, Tanzania

We report herein, the analysis of water samples collected from TPC Sugarcane Plantation and its environs in Kilimanjaro region, which is the earliest intensive user of pesticides in Tanzania. A total of 50 water samples collected from 18 sampling sites between 2000 and 2001 were analyzed for pesticide residues. The organochlorines aldrin, dieldrin, heptachlor epoxide, HCHs, endosulfans and DDTs were detected with mean concentrations ranging from 1.1 to 636.7 ng/l. DDT and its metabolites were the most dominant in the detected residues whereas the endosulfans were the least dominant The residues\' concentrations were higher in the sugarcane fields than in the environs, although the fresh use of banned pesticides was evident in samples collected from the plantation's environs. In most of the sites, samples had higher concentrations and frequencies during the dry season than the rainy season. It is worth noting that the water from the rivers in the immediate environs of the plantation, which are also used for domestic purposes, had residue levels below the WHO recommended maximum residue levels for drinking water with the exception of River Kikavu. Tanzania Journal of Science Vol. 31 (1) 2005: pp. 13-2

Levels of pesticide residues and metabolites in soil at Vikuge farm, Kibaha district, Tanzania – A classic case of soil contamination by obsolete pesticides

The paper reports on the state of soil contamination by obsolete pesticides at Vikuge State Farm, Coast Region, Tanzania, where, in 1986, a 170 m3 “donation” of partially expired pesticides were stored in an open shed that eventually collapsed. Analyses of soil samples collected in 2000 from the old storage site at the farm for 80 different pesticide residues and metabolites have revealed alarmingly high concentrations of pesticide residues to qualify Vikuge as one of the most contaminated sites in the world. Most of the residues found in the soil at high concentrations were organochlorines, their concentrations being up to 282,000 mg/kg dry weight for total DDT (28.2% by mass). Commercial formulations contain only between 5 and 10 % DDT. The concentrations of HCH were up to 63,360 mg/kg (6.4 % by dry mass). A herbicide, pendimethalin [N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine], was also found at concentrations up to 40,900 mg/kg dry weight (4% by mass). As expected, higher concentrations of the residues were found in the surface soil samples and the concentrations of the residues were decreased with increasing depth and distance from the point source. Immediate decontamination of this site is highly recommended. Tanzania Journal of Science Vol. 30 (2) 2004: pp. 77-8

Contamination of water and sediments by obsolete pesticides at Vikuge farm, Kibaha distric, Tanzania

Sediments and water from Vikuge State Farm, Coast Region, Tanzania, where, in 1986, a “donation” of 170 m3 of partially expired pesticides were stored in an open shed- which eventually collapsed, were analysed for 80 different pesticide residues and metabolites. DDT and HCH, two of the most persistent organochlorines pesticides, were the most dominant pesticides found in both matrices. In sediments the levels were up to 99,620 mg/kg dry weight of &#931DDT and up to 7,400 mg/kg dry weight of &#931HCH. The mean total HCH concentrations were 0.95 &#956g/l in tap water, 0.28 &#956g/l in surface water and 3.09 &#956g/l in ground water. Of the four common HCH isomers,&#945-HCH and &#946-HCH had the highest on average concentrations in the water. Mean total DDT concentrations were 1.76 &#956g/l in tap water, 0.18 &#956g/l in surface water and 9 &#956g/l in ground water. The only other pesticides detected were in sediments and water are azinphos-methyl, an organphosphorous insecticide and thiabendazol, a systemic fungicide, respectively. During the rainy season, the well-water, which is used for domestic purposes by the villagers, has levels of pesticides higher than those allowed by WHO for drinking water. It is thus recommended that immediate decontamination measures be undertaken. In the meantime, villagers should sediment the well-water and should not use not use it at all during the rainy seasons.. Tanzania Journal of Science Vol. 30 (2) 2004: pp. 21-3

Acaricide Residues in Laying Hens Naturally Infested by Red Mite Dermanyssus gallinae

In the poultry industry, control of the red mite D. gallinae primarily relies worldwide on acaricides registered for use in agriculture or for livestock, and those most widely used are carbamates, followed by amidines, pyrethroids and organophosphates. Due to the repeated use of acaricides - sometimes in high concentrations - to control infestation, red mites may become resistant, and acaricides may accumulate in chicken organs and tissues, and also in eggs. To highlight some situations of misuse/abuse of chemicals and of risk to human health, we investigated laying hens, destined to the slaughterhouse, for the presence of acaricide residues in their organs and tissues. We used 45 hens from which we collected a total of 225 samples from the following tissues and organs: skin, fat, liver, muscle, hearth, and kidney. In these samples we analyzed the residual contents of carbaryl and permethrin by LC-MS/MS