Levels and Trophic Transfer of Selected Pesticides in the Lake Ziway Ecosystem

The levels of 30 selected pesticides and trophic biomagnification of DDT were investigated in biota samples of the Lake Ziway in the Rift valley region, Ethiopia. Carbon source and trophic position were calculated by using ¹³C and ¹⁵N stable isotopes, individually, and trophic magnification factors (TMFs) were inferred. Only DDT and its metabolites were quantified in all samples analyzed. The most prominent metabolite was p,p?-DDE with mean concentration ranging from the 0.82–33.69 ng g^?1 lipid weight. Moreover, the ratio of DDT/DDD?+?DDE in all the biota samples was less than 1 signifying historical DDT application. Regression of log [ΣDDT] vs TL (trophic level) among all biota species showed a significant correlation, indicating that DDTs are biomagnifying along with the food web of Lake Ziway with an estimated TMF of 2.75. The concentrations of DDTs and other organochlorine pesticides found in biota from Lake Ziway were, in general, lower than studies found in previous studies carried out in the same lake.

     

Prevalence of dental caries and associated factors among 12 years old students in Eritrea

Background

Dental caries is one of the most prevalent diseases of childhood in developing countries. However, there is a paucity of epidemiological data on the prevalence and associated factors of dental caries in Eritrea. The objective of this study was to assess the prevalence and associated factors of dental caries among 12 years old school children in Eritrea.

Methods

A school based cross sectional study was conducted among 225 twelve years old students in two selected schools. One school from randomly selected urban and rural subzones of the country were selected. WHO adopted questionnaire and a standard checklist were used to collect relevant data. To assess dental caries, two examiners were calibrated by a certified dentist and inter observer agreement was calculated using the Cohen’s Kappa statistic (0.82). All data analysis was done using SPSS version 20.

Results

The prevalence of dental caries was 78%, without significant difference between males (78%) and females (79%).The mean DMFT value was 2.50 (±2.21). The decayed component contributed 98.3% of the score as it had 2.44 (±1.2) share to the mean DMFT value. The first molar was the most affected tooth with a DMFT value of 1.55 (±1.36). The mean significant caries index score (SiC) was 4.97 (±1.9) which is higher than the upper limit of SiC value of 3 set by the WHO as a global average. More than half of the respondents had never visited a dentist and out of the students who had utilized a dental health facility, 82% of visits were due to dental pain while visits for regular checkups were cited by only 6.6% of the respondents.

Conclusion

Dental caries was found to be a common public health problem among 12 years old Eritrean students. The prevalence of dental caries, mean DMFT and SiC scores were higher than the average score of other developing countries. Gaps in dental health service utilization, dental health practices and suboptimal water fluoride levels contribute to poor dental health among school children in Eritrea.