Salinity profile in coastal non-agricultural land in Gaza.

The objectives of this study were to characterize the electric conductivity (EC), total dissolved salts (TDS), highly soluble salts (HSS), less soluble salts (LSS), cations (Na+, K+, Ca++ and Mg++) and anions (Cl-, NO-3, SO--4, PO---4) profiles in non-agricultural coastal land in Gaza Strip and to evaluate the effect of trees in salinity. Six locations were selected randomly in coastal zone in Gaza Strip and used for soil profile digging. Soil samples were collected from different layers between 0 and 150 cm depth, air dried and kept in plastic bags at lab temperature. Ten grams of soil were mixed with 25 mL distilled water and kept under shaking for 24 h, then EC, pH and TDS were determined. Then additional 25 ml distilled water was added to each bottle and kept for additional 24 h of shaking. EC and TDS were determined again. Then the soil filtrates were collected by centrifugation and used to determine cations and anions. Results showed that concentrations of TDS, HSS and LSS were higher at the top soil layer than at deeper soil layers. Concentrations of cations and anions have similar trends to TDS, HSS and LSS. Behavior of cations and anions in the soil profiles under trees were different from those in open field. Comparing between the data of soil profiles under trees (site 2 and 5) and those in the open field (sites 1, 3, 4 and 6) showed slight effects on availability of cations and anions. Strong correlations were found between cations and anions in soil profiles under trees, and week correlations were found in soil profile in open field. In conclusion the coastal soil profiles are characterized with elevated levels of TDS, HSS and LSS in the top soil layers. Accumulations of salts were more pronounced in top soil layers. These properties suggest high potential damage to the ecosystem.

Childhood lead poisoning in Gaza Strip, the Palestinian Authority.

PURPOSE: To assess lead poisoning among a pediatric population in Gaza Strip, the Palestinian Authority. METHODS: A total of 1705 questionnaires and blood samples were collected from children aged 2-6 years, by the finger stick capillary procedure, for the assessment of blood lead level (BLL), using the LeadCare kits. The samples were collected from children living close to lead processing units (hotspots) and far 100-500 m away (general population). Management of elevated BLL was achieved by gavage of chelating agent d-penicillamine at a dose of 30 mg kg-1 body weight/day for two weeks for children having BLL above 20 µg/dl. Data were statistically analyzed using SPSS computer program version 22. RESULTS: Distribution of children in Gaza Strip by sampling process illustrated those 326 children (19.1%) living in lead processing units (hot spots) and 1379 children (80.9%) from location far away 100-500 m from host spot (general population). The mean BLL was 10.4 µg/dl. A total of 440 children (25.8%) were found to be having BLL ≥ 10 µg/dl while 1265 children (74.2%) have BLL < 10 µg/dl. BLL < 10 µg/dl was taken as a cut point due to CDC standards. The prevalence of BLL in hotspot areas in children who were exposed to lead and have BLL ≥ 10 µg/dl was 95.7% while in general population it was 9.3%. The difference between the study population was statistically significant (p < 0.01). Statistical significant differences between the study populations were found among several independent variables of risk factors such as household location and exposure sources, and occupational exposure. Gavage of d-penicillamine significantly reduced BLL to the acceptable level (BLL < 10 µg/dl). CONCLUSIONS: Childhood lead poisoning accounts for a substantial burden in Gaza Strip. Hotspots of lead-related industries are the high risk areas that contributing to high BLLs in children. d-Penicillamine was effective in the treatment of lead poisoning among children. Health education and treatment campaigns should be designed to minimize or prevent childhood lead poisoning in Gaza Strip.

The fate of pathogens in treated wastewater-soil-crops continuum and the effect of physical barriers.

Secondary treated wastewater (TWW) could provide a cheap and sustainable alternative to potable water (PW) irrigation and ensure food security, especially in arid and semi-arid regions. However, TWW may pose a health risk by introducing pathogens to the irrigated soil and crop, and especially to irrigated vegetables that are eaten raw. To avoid contamination, national and international authorities have mandated the use of physical barriers, such as drip irrigation and plastic mulch, to separate the irrigation water and the crops. Although the barriers are mandated, it is not clear whether they prevent contamination of crops. To evaluate the role of barriers on crop safety, cucumbers and melons were cultivated in a field irrigated with TWW or PW with the application of barriers including surface and subsurface drip irrigation and plastic mulch. Over 500 samples of water, soil and the model crops (surface and tissue) were collected during two growing seasons and used to monitor fecal indicator bacteria and pathogens using culture dependent and independent methods. The results showed that there were no statistically significant differences in both the fecal indicator and the pathogen abundance between treatments in either the soil or the crops, regardless of the water quality or barrier applied, even though TWW supported higher diversity and abundance of indicators and pathogens than PW. Moreover, the microbial communities detected in the irrigated soils and crops could not be linked to the irrigation water. The obtained results suggest that irrigation with TWW does not result in fecal pathogen contamination of the irrigated soil or crops.

Evaluation of pooled screening for anti-HCV in two blood services set-ups.

OBJECTIVE: Screening blood donations for anti-HCV is only partially performed in many developing countries due to the relatively high costs of testing. The screening expenditures can be reduced by testing donations in pools. This study evaluates the accuracy and feasibility of pooled screening procedure for anti-HCV in blood banks in Israel and the Palestinian Authority. METHODS: The sensitivity and specificity of tests performed on pool sizes of 6-24 samples were compared to singleton immunoassay testing. All negative samples and those positive for anti-HCV were obtained from the routine work of Magen David Adom Blood Services in Israel and Shifa Hospital blood bank in Palestinian Authority. The experiments were run in parallel with different technologies. RESULTS: The sensitivity of pooled-testing for anti-HCV by Magen David Adom was 94-97% for verified samples. In the Shifa Hospital, the sensitivity was estimated as 96-97% for non-verified samples. Cost-analysis showed benefits up to $2 per donation screened for anti-HCV in Shifa Hospital. CONCLUSIONS: We recommend using manually created pools of up to 6 samples when testing for anti-HCV, but at the cost of 3% loss in sensitivity. Pooling can be considered, in countries which do not perform routine screening, due to their limited economic resources.

Accuracy and cost-benefit of pooled versus singleton screening blood donations for anti-HIV: impact on different blood bank set-ups.

This study evaluates the accuracy and cost-benefit of implementing a pooled screening procedure in blood banks in general and especially in developing countries. The sensitivity of pooled testing was found to be relatively high, with the lowest levels estimated at about 98% for pools consisting of three, six, and 12 samples. Screening in pools of up to 12 samples is expected to be economically beneficial in countries with HIV prevalence rates of 8-10%, which cannot afford the cost of care for an HIV-infected patient.

Accuracy of hepatitis C virus core antigen testing in pools among seroconverters.

BACKGROUND: Screening blood units for hepatitis C virus (HCV) with nucleic acid testing (NAT) reduces the risk associated with the long "window period" (8-9 weeks) after HCV infection. The feasibility of adding the HCV core antigen assay in pools to the existing anti-HCV individual screening was examined as an alternative of NAT, for early detection of HCV. STUDY DESIGN AND METHODS: Eighteen HCV seroconversion panels were tested for HCV antibodies, HCV antigen, and HCV RNA. Each sample was tested for HCV antigen individually and in pools of 3, 6, and 12. Statistical analyses included estimation of time until detection of the first positive HCV antigen bleed in each pool size, with a locally weighted regression (LOWESS) model. Sensitivity was calculated compared to NAT. RESULTS: Detection of HCV antigen in individual samples and in pools of 3 and 6 significantly preceded the detection of antibodies by 63, 53, and 46 days, respectively. Although the sensitivity of the HCV antigen test decreased with the increase in pool size, the estimated overall sensitivity of the "two-stage" antigen and antibody screening (where NAT of individual samples was the gold standard) was not significantly different between individual and the different pool sizes. CONCLUSION: Screening for HCV antigen in pools of 6 can be considered an efficient and easier-to-implement alternative to the costly NAT for identifying blood donors in the seroconversion period. It may offer a cost-effective approach in resource utilization in poor countries, that, after the implementation of HCV antibody testing, want to further improve blood safety.

Enzyme-linked immunosorbent assay (ELISA) and sol-gel-based immunoaffinity purification (IAP) of the pyrethroid bioallethrin in food and environmental samples.

Enzyme-linked immunosorbent assay (ELISA) and sol-gel-based immunoaffinity purification (IAP) methods for the pyrethroid bioallethrin were developed and applied for monitoring bioallethrin in spiked food, soil, and dust samples. Attempts to determine bioallethrin content in fruit and vegetable extracts revealed high variability between sample preparations and marked interferences with the assay. Sol-gel IAP followed by solid-phase sample concentration was effective in removing the interfering components and resulted in high recovery of bioallethrin from spiked crude acetonic extracts of fruits and vegetables, even in the presence of high extract concentrations (28%). Solid-phase treatment alone failed to remove the interfering components from the spiked sample. Gas chromatography-mass spectrometry analysis of the IAP samples revealed bioallethrin as a doublet unsolved peak because of the cis and trans isomer present in the standard with confirmation of its mass. Unlike fruit and vegetable extracts, soil and dust samples did not interfere with the ELISA, and the bioallethrin content in those samples could be determined with high precision without the need of any further purification.

Childhood lead exposure in the palestinian authority, Israel, and Jordan: results from the Middle Eastern regional cooperation project, 1996-2000.

In the Middle East, the major sources of lead exposure have been leaded gasoline, lead-contaminated flour from traditional stone mills, focal exposures from small battery plants and smelters, and kohl (blue color) in cosmetics. In 1998-2000, we measured blood lead (PbB) levels in children 2-6 years of age in Israel, Jordan, and the Palestinian Authority (n = 1478), using a fingerstick method. Mean (peak; percentage > 10 microg/dL) PbB levels in Israel (n = 317) , the West Bank (n = 344), Jordan (n = 382) , and Gaza (n = 435) were 3.2 microg/dL (18.2 ; 2.2%) , 4.2 microg/dL (25.7; 5.2%), 3.2 microg/dL (39.3; < 1%) , and 8.6 microg/dL (> 80.0; 17.2%), respectively. High levels in Gaza were all among children living near a battery factory. The findings, taken together with data on time trends in lead emissions and in PbB in children in previous years, indicate the benefits from phasing out of leaded gasoline but state the case for further reductions and investigation of hot spots. The project demonstrated the benefits of regional cooperation in planning and carrying out a jointly designed project.

Adsorption of phenanthrene on organoclays from distilled and saline water.

Isotherms of phenanthrene adsorption on different organoclay complexes were obtained using the HPLC technique to understand the adsorption behavior and to characterize the effect of sodium chloride (NaCl) on the adsorption. The adsorbed amounts of phenanthrene on montmorillonite exchanged by organic cations such as tetraheptylammonium, benzyltrimethylammonium, hexadecyltrimethylammonium, or tetraphenylphosphonium were several times higher than those obtained using montmorillonite clay without surface modification. At the same equilibrium concentration, the adsorbed amount of phenanthrene is higher on clay modified with benzyltrimethylammonium than on clay modified with hexadecyltrimethylammonium or other cations. Adsorption of phenanthrene on clay modified with benzyltrimethylammonium increased dramatically as the concentration of NaCl increased up to 150 g/l in the aqueous solution. The shape of the curves obtained can be classified as S-type. The adsorption data obtained from salinity experiments support a mathematical model that links the Langmuir constant with the salinity constant. This model may be useful to predict the equilibrium concentration of a contaminant in saline solution. FTIR studies showed strong interactions between the aromatic rings of phenanthrene and the preadsorbed benzyltrimethylammonium on clay surfaces.

Association between chronic exposure to pesticides and recorded cases of human malignancy in Gaza Governorates (1990-1999).

Epidemiological association between chronic exposure to pesticides and recorded cases of human malignancy in Gaza Governorates during the years 1990-1999 was studied. The pesticide usage in Gaza Governorates was recorded in detail. It ranged from 216.9 to 393.3 t from 1990 to 1999, respectively. Banned and extremely hazardous pesticides are identified according to their carcinogenicity, genotoxicity and cytotoxicity. Hospital cases of cancers in men and women were recorded. Each tumor type was grouped according to sex and age group from 0 to > 65 years. Total cases recorded in males were 2277, with average annual incidence and age-adjusted rate/100,000 was 53.2 and 96.8 respectively, whereas the total for females was 2458 cases, average annual incidence and age-adjusted rate/100,000 was 59.7 and 105.3, respectively, over the same 10 years. Lung cancer, lymphomas, leukemia, cancers of the urinary bladder, prostate, brain, colon, stomach and liver were the most abundant among males, while breast cancer, leukemia, lymphomas, cancers of the brain, uterus, lung, thyroid gland and liver were the most abundant in females. Statistical analysis using correlation coefficients and P values showed highly significant positive correlations between the type of pesticide and cancer incidence for male, female and both sexes. Correlation coefficients and P values, respectively, for both sexes were: 0.992 and 0.000 for insecticides; 0.952 and 0.000 for fungicides; 0.812 and 0.004 for herbicides; 0.925 and 0.000 for nematicides; 0.992 and 0.000 for others; and 0.994 and 0.000 for all types of pesticides. In the densely populated agricultural areas, it is not possible to separate or differentiate between occupational and general public exposure. Consequently, the introduction of and heavy use and misuse of pesticides and other toxic substances in the Gaza environment is suspected to correlate with the growing incidence of cancer. Precise determination of the effects of chronic exposure is, therefore, urgently needed. Future legislation to stop and regulate the use of extremely hazardous compounds will be essential. Continuous records for chronic diseases and cancers are also required for future follow-ups and periodical risk-assessment evaluations. Hence, further epidemiological studies are needed with detailed exposure assessment for individual pesticides, taking measures to reduce risk into consideration.