Recommended Maximum Limits Research Articles

Indoor Air Quality of Residential Building Before and After Renovation

Abstract This study investigates the impact of energy renovation on the indoor air quality of an apartment building during the heating season. The study was performed in one residential building before and after its renovation. An evaluation of the indoor air quality was performed using objective measurements and a subjective survey. The concentration of CO2 was measured in the bedrooms, and a sampling of the total volatile compounds (TVOC) was performed in the living rooms of the selected apartments. Higher concentrations of CO2 and TVOC were observed in the residential building after its renovation. The concentrations of CO2, and TVOC in some of the cases exceeded the recommended maximum limits, especially after implementing energy-saving measures on the building. The average air exchange rate was visibly higher before the renovation of the building. The current study indicates that large-scale renovations may reduce the quality of an indoor environment in many apartments, especially in the winter season.

Heavy metal accumulation and health risk assessment in wastewater-irrigated urban vegetable farming sites of Addis Ababa, Ethiopia

BackgroundWastewater irrigation for vegetable production is a highly prevalent practice in Addis Ababa and a number of articles have been published on wastewater-irrigated soils and vegetables contaminated with heavy metals. However, to the best of our knowledge, an insight into assessment of human health risks associated with the consumption of vegetable crops grown on wastewater-irrigated soils is non-existent in the city. Long-term effect of wastewater irrigation on the build-up of heavy metals in soils and selected vegetable crops in Addis Ababa urban vegetable farming sites (10) was evaluated. By calculating estimated daily intakes (EDIs) and target hazard quotients (THQs) of metals, health risk associated with the consumption of the analyzed vegetables was also evaluated.ResultsThe heavy metal concentrations in irrigation water and soils did not exceed the recommended maximum limits (RMLs). Moreover, Cd, Co, Cr, Cu, Ni and Zn concentrations in all analyzed vegetables were lower than the RML standards. In contrast, Pb concentrations were 1.4–3.9 times higher. Results of two way ANOVA test showed that variation in metals concentrations were significant (p < 0.001) across farming site, vegetable type and site x vegetable interaction. The EDI and THQ values showed that there would be no potential health risk to local inhabitants due to intake of individual metal if one or more of the analyzed vegetables are consumed. Furthermore, total target hazard quotients (TTHQs) for the combined metals due to all analyzed vegetables were lower than 1, suggesting no potential health risk even to highly exposed local inhabitants.ConclusionsThere is a great respite that toxic metals like Pb and Cd have not posed potential health risk even after long term (more than 50 years) use of this water for irrigation. However, intermittent monitoring of the metals from irrigation water, in soil and crops may be required to follow/prevent their build-up in the food chain.

Physico-chemical characterization of groundwater of Kaltungo, Gombe state, Nigeria and treatment for flouride removal

Physico-chemical characteristics of Kaltungo groundwater were determined for a period of 12 months. The physical characteristics include odour, colour, taste, temperature, turbidity and TDS; while conductivity, pH, chloride, iron, copper, lead, zinc, fluoride, cadmium, nitrates, TH, total alkalinity (TA) and fluoride were the chemical characteristics. Nine water samples, three from three hand dug wells and six from six boreholes were taken monthly for the period. This study was undertaken because the people of Kaltungo town depend on groundwater from hand dug wells and boreholes for their water needs and children who grow up in the town during the ages of teething end up having mottled teeth. The results showed that the physical parameters were below their maximum limits, except temperature that had a mean of 29.7°C, which was still within ambient temperature. Most of the chemical parameters were below the recommended maximum limits except Iron and fluoride which had mean monthly values of 0.9mg/l and 1.66mg/l as against 0.3mg/l and 1.5mg/l respectively. Treatments for flouride removal carried out with alum, bone charcoal and Moringa olifera seeds showed that fluoride concentrations in water was reduced when treated with dosages ≥ 10g/l of raw water by between 15% and 43% reduction. Kaltungo groundwater should be treated for fluoride removal before consumption to avert teeth mottling. http://dx.doi.org/10.4314/njt.v36i2.43

Heavy metal content of two major commercial fish species of Cross River Estuary, Mbo Local Government Area, Akwa Ibom State, Nigeria

Heavy metal pollution of aquatic environments is increasing all over the world in recent years. Under certain environmental conditions, fish may concentrate large amounts of some heavy metals from the water in their tissues. This study assessed the concentration of lead, copper, cadmium, chromium and zinc in two commercially important fish species, Pseudotolithus senegalenses and Ethmalosa fimbriata from Cross River estuary of Akwa Ibom State, Nigeria. The concentrations of these metals were analyzed using atomic absorption spectrophotometer (UNICAM) by direct aspiration of samples into air acetylene flame. Pseudotholithus senegalenses had 0.023±0.02, 2.15±0.50, 0.08±0.04, 0.06±0.07 and 5.59±0.94 mg kg -1 as the mean concentration of lead, copper, cadmium, chromium and zinc respectively, while Ethmalosa fimbriata had 0.05±0.01, 1.23±0.29, 0.04±0.01, 0.60±0.24 and 4.35±0.80 mg kg -1 as the mean concentration of these metals. The overall mean concentration of each heavy metal varied significantly (p<0.05) depending on the species of fish and according to month of sampling. This study reveals that the levels of these metals were below the recommended maximum limit for human consumption. However, effort should be made to avoid future contamination of the water body and subsequently the fish living in it since their synergistic effect can still pose a very serious health problem. Keywords: Bioaccumulation, lead, perturbation, pollution, zinc

Assessment of gamma radiation exposure of beach sands in highly touristic areas associated with plutonic rocks of the Atticocycladic zone (Greece)

This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along beaches close to the plutonic rocks of the Atticocycladic zone that ranged from 15 to 628, 12-2292, 16-10,143, 14-9953 and 191-1192 Bq/kg respectively. A sample from island of Mykonos contained the highest 232Th content measured in sediments of Greece. The heavy magnetic fraction and the heavy non-magnetic fraction as well as the total heavy fraction, were correlated with the concentrations of the measured radionuclides in the bulk samples. The heavy fractions seem to control the activity concentrations of 238U and 232Th of all the samples, showing some local differences in the main 238U and 232Th mineral carrier. Similar correlations have been found between 238U, 232Th content and rare earth elements concentrations. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which at least in most cases are their most probable parental rocks, so as to provide data upon their enrichment or depletion. Since the Greek beaches are among the most popular worldwide the annual effective dose equivalent received due to sand exposure has been estimated and found to vary between 0.002 and 0.379 mSv y−1 for tourists and from 0.018 to 3.164 mSv y−1 for local people working on the beach. The values corresponding to ordinary sand samples are orders of magnitude lower than the limit of 1 mSv y−1, only in the case of heavy minerals-rich sands the dose could reach or exceed the recommended maximum limit.

Macro and trace elements in edible mushrooms, Shiitake, Shimeji and Cardoncello from Petrópolis, Rio de Janeiro, Brazil

The concentrations of twenty-five elements (Al, As, Ba, Bi, Ca, Cd, Cr, Cu, Fe, Ga, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Rb , Sb, Se, Sn, Sr, V and Zn) were determined in three edible mushrooms, Shiitake (Lentinula edodes), Black Shimeji (Pleurotus ostreatusi) and Cardoncello (Pleurotus eryngyii) from Petrópolis, Rio de Janeiro, Brazil. Samples were collected along the year 2010 and their preparations were made after drying, milling, an acid pre-digestion and a decomposition procedure in a muffle furnace. The analytical techniques employed for the elements determination were Mass Spectrometry with Inductively Coupled Plasma and Flame Atomic Absorption Spectrometry. Two certified reference materials, Apple Leaves and Mussel Tissue, were used for the evaluation of the analytical procedure and recovery values around 98% were obtained. The results showed that the analyzed mushrooms have high levels of Cu, Fe, K, Mg, Mn and Zn containing more than 30% the recommended daily intake for these nutrients according to Brazilian legislation. These mushrooms presented a very low ratio Na/K. Regarding the levels of some contaminants, the mushrooms had concentrations of Cd, Pb and As below the recommended maximum limits allowed by Brazilian legislation.

Accumulation of ammonia and other potentially noxious gases on live export shipments from Australia to the Middle East

Noxious gases on ships are irritant pollutants that have potential impacts on the comfort and health of both livestock and humans. Identification of environmental influences on the pollutants will assist live exporters to control them. Ammonia, hydrogen sulphide and carbon dioxide, as well as wet and dry bulb temperature, dew point, air speed and depth of faeces that the sheep stood in, were measured on two ship voyages in which sheep were transported from Australia to the Middle East. Daily measurements were made at 20 measurement locations over 12 days. At four sites, the mean ammonia concentration for the voyage was above the recommended maximum limit for the live export industry (25 ppm). The mean ammonia concentrations at the remaining 16 sites were below 18 ppm and considered safe. High ammonia concentrations were localised and occurred particularly on closed decks, as well as at the front of the vessel and near the engine block on open decks. Ammonia concentration on the open decks was correlated with cumulative wind during the voyage, air speed, dew point, wet bulb temperature and faecal pad depth, and on the closed decks with dew point, and wet and dry bulb temperature. Hydrogen sulphide (<1.8 ppm) and carbon dioxide (<1900 ppm) concentrations were low and did not pose a risk to animal or human welfare or health. The results suggest that high ammonia concentrations occur in those parts of the ship where there is insufficient ventilation and/or high temperatures and humidity.

Measurement of natural radionuclides and dose assessment of granites from Ondo State, Nigeria

The activity concentrations of 226 Ra, 232 Th and 40 K in fifty granite samples collected from five different quarry industries in Ondo State, Nigeria, were determined using gamma-ray spectrometry. The mean activity concentrations for each industry ranged from 16.7(6.4) to 85.4(23.0), 62.4(10.1) to 113.6(7.6), and 1315(136) to 1551(84) Bq.kg-1 for 226 Ra, 232 Th and 40 K, respectively. The values in parenthesis are the standard deviations. When compared with results from some parts of the world, the 226 Ra and 232 Th contents were lower, whereas the 40 K content was similar. Using different approaches to estimate the potential radiological hazard of the samples, the results obtained were below the recommended maximum limits. This shows that the radiological hazards associated with the use of the granites examined in this study as building material are within the acceptable limit.

First impressions: an information leaflet for patients attending a musculoskeletal outpatient department

Objective The purpose of this work was to design and evaluate an information leaflet for new patients attending a physiotherapy outpatient department. This formed part of a wider agenda of improving the patients’ experience and increasing adherence to the Chartered Society of Physiotherapy's core standards. Design A needs analysis was undertaken with existing patients to determine the content of the new leaflet. This was then tested for readability, reviewed by physiotherapy staff and evaluated by patients via a questionnaire. Setting The musculoskeletal outpatient physiotherapy department at Southampton General Hospital. Participants Patients referred to the outpatient physiotherapy service, plus all clinical and support staff employed in the musculoskeletal outpatient team. Main outcome measures Numerical Rating Scale and Gunning's Fog Index. Results Thirty-seven of 50 patients completed the needs analysis (74%), generating 42 ideas for the leaflet content. The definitive leaflet addressed one core standard and 16 specific criteria, and had a readability of grade 8.3, which is below the recommended maximum limit of grade 9 for health education leaflets. Using an 11-point Numerical Rating Scale, where 0 = of no benefit and 10 = extremely helpful, the mean rating for the leaflet from 29 of 100 patients was 8.6. Conclusions This work has produced a patient information leaflet for physiotherapy outpatients, a copy of which is freely available (electronically) from the author. The leaflet forms part of an ongoing commitment to improving the patients’ experience.

Excess dietary iodine intake in long-term African refugees

To assess the iodine status of long-term refugees dependent on international food aid and humanitarian assistance. A series of cross-sectional two-stage cluster or systematic random sample surveys which assessed urinary iodine excretion and the prevalence of visible goitre. Salt samples were also collected and tested for iodine content by titration. Six refugee camps in East, North and Southern Africa. Male and female adolescents aged 10-19 years. The median urinary iodine concentration (UIC) ranged from 254 to 1200 microg l(-1) and in five of the camps exceeded the recommended maximum limit of 300 microg l(-1), indicating excessive iodine intake. Visible goitre was assessed in four surveys where it ranged from 0.0 to 7.1%. The camp with the highest UIC also had the highest prevalence of visible goitre. The iodine concentrations in 11 salt samples from three camps were measured by titration and six of these exceeded the production-level concentration of 20 to 40 ppm recommended by the World Health Organization (WHO), but were all less than 100 ppm. Excessive consumption of iodine is occurring in most of the surveyed populations. Urgent revision of the level of salt iodisation is required to meet current WHO recommendations. However, the full cause of excessive iodine excretion remains unknown and further investigation is required urgently to identify the cause, assess any health impact and identify remedial action.

Greenhouse studies on the phyto-extraction capacity of Cynodon nlemfuensis for lead and cadmium under irrigation with treated wastewater

For over 30 years, discharge of sewage effluent and sludge on pasturelands has been used in Zimbabwe as a cheap method for secondary treatment of wastewater without any monitoring of accumulation of heavy metals in soils and grasses, let alone in animals grazing on the pastures. Cynodon nlemfuensis (star grass) has been the main grass planted on the wastewater irrigated pasturelands. This study was conducted to assess the capacity of star grass to accumulate lead (Pb) and cadmium (Cd) and develop models incorporating grass yield, metal uptake and soil bio-available (EDTA extractable) metal content, that could be used to determine critical grass and soil concentrations at which grass productivity declines. Star grass was planted in 30 fertilized pots containing sandy soil within a greenhouse. The pots consisted of nine treatments of varying levels of added inorganic Pb and Cd subjected to treated wastewater application and one control that had no added metals and received water application only. The elements were applied to the soils once just after planting the grass. Chemical analyses showed that star grass had a relatively high phyto-extraction capacity of Pb and Cd, comparable to that of hyper-accumulating grasses such as Lolium perenne (rye grass). It accumulated Pb and Cd to levels far beyond the recommended maximum limits for pasture grass. Analysis of variance on log-normal transformed data showed that bio-available soil metal concentrations correlated strongly with grass metal content and grass metal content correlated strongly with the yield. There was however a weak correlation between the yield and bio-available soil levels. The yield versus grass metal content models that were developed for the first crop and re-growth predicted similar critical metal concentrations and yields. Using the critical grass metal concentrations in the soil bio-available metal concentration versus grass metal concentration models allowed for the prediction of the corresponding critical soil concentrations.

Measurement of force applied during mammography.

The discomfort that patients experience during mammography is probably related to a variety of factors, one of which might be the amount of compression used. The authors measured the amount of force applied to the breasts during mammography and the resulting breast thickness in 560 women and correlated these measurements with the patient's subjective impression of the examination. The amount of force applied ranged from 49 to 186.2 N (median, 122.5 N). Breast thickness ranged from 10 to 88 mm (median, 46.5 mm). Forty-seven women (8%) rated the examination as painful (ie, mammography was either "very uncomfortable" or "intolerable"). Logistic regression analysis revealed a highly significant relationship between probability of a painful response and ratio of force to thickness (P = .007). Current guidelines suggest that maximum available force be at least 160 N but not more than 200 N. However, because increasing force is associated with increasing likelihood of pain, technologists should be aware that these recommended maximum limits are not intended to be used routinely for all women. In this study, high-quality mammograms were obtained in a majority of women with forces less than the maximum available level.

Radiation exposure to medical personnel during iodine-125 seed implantation of the prostate.

Radiation exposure to operating room personnel was measured by thermoluminescent dosimeters and an ionization chamber during a simulated iodine-125 seed implantation of the prostate gland. The exposure rates at points around the implanted phantom were measured and compared with the calculated values. The data suggested that even with a schedule of 25 prostate implants per year, exposure levels would not exceed 5% of the recommended maximum limits for occupationally exposed personnel.