Evaluation of heavy metals composition of drinking water distributed to Addis Ababa City, Addis Ababa, Ethiopia.

Background Compromised drinking water quality due to accumulation of heavy metals is becoming a serious concern for many countries, including Ethiopia. Chronic exposure to heavy metals is associated with many human diseases. This study aimed at determining the levels of heavy metals in drinking water supplied to Addis Ababa city. There has been no such study done on drinking water supplied to the city Methodology: A community based cross-sectional study design was employed from April 2018 to December 2018. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to measure the concentration of heavy metals in drinking water samples. Result The highest concentration of lead was recorded in water samples taken from Gefersa, Asko and Kolfie areas. Results of this study also showed that there was a statistically significant difference in the mean levels of lead in water samples taken from different treatment plants and their respective catchments (p-value < 0.01). Conclusion The mean lead level in water samples were higher than the maximum admissible limit set by the WHO in 2011. The mean level of cadmium concentration was higher than the maximum admissible limit of cadmium set by WHO in 2011 in water samples of the Gefersa surface water & catchment area. However, all values of heavy metals were lower than their respective maximum contaminant level set by USEPA in 2010.

Detecting and modeling critical dependence structures between random inputs of computer models

Uncertain information on input parameters of computer models is usually modeled by considering these parameters as random, and described by marginal distributions and a dependence structure of these variables. In numerous real-world applications, while information is mainly provided by marginal distributions, typically from samples, little is really known on the dependence structure itself. Faced with this problem of incomplete or missing information, risk studies that make use of these computer models are often conducted by considering independence of input variables, at the risk of including irrelevant situations. This approach is especially used when reliability functions are considered as black-box models. Such analyses remain weakened in absence of in-depth model exploration, at the possible price of a strong risk misestimation. Considering the frequent case where the reliability output is a quantile, this article provides a methodology to improve risk assessment, by exploring a set of pessimistic dependencies using a copula-based strategy. In dimension greater than two, a greedy algorithm is provided to build input regular vine copulas reaching a minimum quantile to which a reliability admissible limit value can be compared, by selecting pairwise components of sensitive influence on the result. The strategy is tested over toy models and a real industrial case-study. The results highlight that current approaches can provide non-conservative results.

Fluoride Contamination Studies in Belchampa Pratappur Villages of Garhwa District Jharkhand

Belchampa-Pratappur villages about 8 Kms towards East from district head-quarter Garhwa has been undertaken to study the groundwater quality, especially fluoride contamination. These places are situated on the border of the Garhwa and Palamu district. Bishrampur is the prominent place lying to about 11 km east of area under consideration. The area is underlain mostly by granite and gneisses. Fluoride containing minerals as indeed Fluorite, apatite, different amphiboles and micas occur in association with these rocks. 18 Groundwater samples during Pre-and Post-monsoon have been collected from tube wells and analyzed for major cation ( Ca+2,Mg+2,Na+,K+) and anion(HCO3-, Cl-,SO42-,F-) in addition to fluoride. Fluoride concentration as high as 5 mg/l has been found in many samplesof groundwater in the area, which is above the admissible limit of 1.5 mg/l (WHO). The inhabitants of these two villages belong to very poor economic background and of diverse communities. Many people of these villages are fluoride affected. Dental and Skeletal fluorosis is common in the area, which is very alarming. The total dissolved solid (T.D.S.) is also found to be much higher, at many places. It ranges from 586 mg/l to 408 mg/l in pre-monsoon and 736 mg/l to 194 mg/l in post monsoon season respectively. Consequently the electrical conductivity is also much higher at several places which ranges from 915 micro mhos/cm to 637 micro mhos/cm at 250C in pre-monsoon and 1150 micro mhos/cm to 303 micro mhos/cm in post-monsoon season respectively.

Removal of Fluoride from Groundwater by Batch Electrocoagulation Process Using Al Plate Electrodes

Dental fluorosis cases are observed due to the high consumption of high fluoride drinking water in some parts of Anatolia. Fluorosis is resulted from high concentrations of fluoride in groundwater and observed in some regions of Turkey having volcanic rocks and geothermal fields. Results of fluoride analyses showed that the concentrations in groundwater samples were above the admissible limit values for potable water (&amp;gt;1.5 mg/L). Objectives of this work are; to study the high fluoride in groundwater of Sarım-Karataş region, its health effects and to examine its removal efficiency from groundwater by electrocoagulation (EC). EC process including the electrodes, reactor and the power source successfully removed the fluoride from groundwater sample. F removal rate was found as ~96% at the end of 3 hour.

Experimental Results Regarding the Groundwater Quality in Bacau City, Romania

The state of groundwater in terms of quality and quantity are a fundamental importance in urban areas. This paper aims to identify qualitative status of groundwater in Bacau city. To determine groundwater quality in Bacau city were taken samples from ten sources. Physico-chemical parameters chosen for making determinations are represented by ammonium, magnesium, manganese, nitrite and total nitrogen. After performing of measurements, it was observe that the admissible limit values of water quality parameters were exceeded in all ten sampling points. It has been established so that any source of groundwater in Bacau is not recommend for human consumption. In this regard, it is recommended to order measures by the competent authorities for the safety and health of the population.

CEMENT STABILIZATION TREATMENT OF LEAD AND NAPHTHALENE CONTAMINATED LATERITIC SOILS

This article presents an investigation on the influence of Ordinary Portland Cement (OPC) as a binder in the stabilization treatment of lateritic soil contaminated with lead or naphthalene. To evaluate the performance of the binder, the contaminated soils were tested for mechanical strength and environmental performance before and after the stabiliza­tion treatment. Results showed that the strength as inferred from the unconfined compressive strength (UCS) and cohesion values increased with the addition of the binder. Cement stabilization of the lead contaminated samples also prompted a reduction in the release of lead below the admissible limit during the leaching test. Cement stabilization of the naphthalene contaminated samples, on the other hand, could not contain the release of naphthalene below the regulatory level during the leaching test. The batch equilibrium adsorption test (BEAT) showed that cement stabilization increased the adsorption capacity of the soil for the contaminants.

Heavy metals contamination of the soil – water – vegetables chain in the Ilfov region

Dietary exposure to several heavy metals such as Cd, Cr, Pb, As represents a risk to human health through the consumption of vegetables. Due to the possible risks for the human body, contamination of soils as well as drinking and irrigation water has been the subject of many researches. In this study, the analysis of heavy metals content from soil, water and vegetable samples from households in Ilfov County it was carried out. As a result, no contamination of soil and water with heavy metals was observed. Cadmium content is above the maximum allowable limit for all analyzed vegetables, excepting cabbage and green onion. Two lettuce samples have an alarmingly high content of lead, the values being even 10 times higher than the maximum admissible limit of 0.3 mg/kg. The high values obtained for chromium content in lettuce and radish samples raise serious questions about possible contamination. Arsenic content values ranged between 0.87 and 7.69 mg/kg, which also represents high values. Based on the transfer factor (TF) calculated the strongest accumulation of the metals was in lettuce.

A STUDY ON THE WORK TIME STRUCTURE WHEN SOWING WITH VARIOUS AGGREGATES

One of the factors that influence the working time structure in sowing crops with different aggregates is the utilization of working time. The study dealt with two seed drills for precise and two seed drills for fused sowing. The shift time utilization coefficient in the types of seed drills was determined, which is within the admissible limit: the SZU-3,6 τ=0.86; for the Horsch Pronto 6 DC τ=0.88 for Gaspardo SP-8 τ=0.92 and for the Kurt PM-8 seed driller τ=0.85. It has been established that the field length, its shape and the method of loading the seed drills have an impact on the working time structure when sowing crops with different aggregates. It has been established that in order to exploit the technical capabilities of the sowing aggregate and to achieve higher productivity and good economic performance of the sowing technological operation, the field length of the cultivated area under 600 m is economically inexpedient.

STUDY CONCERNING THE MONITORING OF PARTICULATE MATTER PM2,5 AND PM10 IN THE LIBRARY OF “VASILE ALECSANDRI” UNIVERSITY OF BACAU

<p>Air pollution is a problem both for outdoor as well for indoor environment (working environment). The work environment is represented by ambient where the worker operates and includes the physical environment and on other part the social environment. This paper presents the results of measurements for particulate matter (PM_2,5and PM₁₀) in a closed environment, respectively the library of “Vasile Alecsandri” University of Bacau. The measurement for particulate matter PM_2,5and PM₁₀ in the library was performed in seven halls: two deposits for old books, two deposits for new books, newspaper deposit, reading room and computer room. After accomplishing the measurements, were established the points where the admissible limit values have been exceeded for particulate matter PM_2,5and PM₁₀, according to law. Thus, it is observed that the permissible values were not exceeded for either PM_2,5and PM₁₀ particulate matter in any sampling points.</p>

Analysis of Mineral and Heavy Metal Content of Some Commercial Fruit Juices by Inductively Coupled Plasma Mass Spectrometry

The presence of potentially toxic elements and compounds in foodstuffs is of intense public interest and thus requires rapid and accurate methods to determine the levels of these contaminants. Inductively coupled plasma mass spectrometry is a powerful tool for the determination of metals and nonmetals in fruit juices. In this study, 21 commercial fruit juices (apple, peach, apricot, orange, kiwi, pear, pineapple, and multifruit) present on Romanian market were investigated from the heavy metals and mineral content point of view by ICP-MS. Our obtained results were compared with those reported in literature and also with the maximum admissible limit in drinking water by USEPA and WHO. For Mn the obtained values exceeded the limits imposed by these international organizations. Co, Cu, Zn, As, and Cd concentrations were below the acceptable limit for drinking water for all samples while the concentrations of Ni and Pb exceeded the limits imposed by USEPA and WHO for some fruit juices. The results obtained in this study are comparable to those found in the literature.