Change in fluoride content of Maltese tapwaters : implications for oral health

Dietary intake of fluoride is believed to be largely derived from drinking water. In Malta, tap water presently contains less fluoride than is found in naturally occurring ground water obtained from aquifers. Over 55% of water production comes from reverse osmosis and such water is practically fluoride-free. Before the introduction of reverse osmosis water into the water budget, fluoride levels measured from 10 different tap waters averaged 0.51 ppm F-. Now, fluoride content measured from 19 tap water sources averaged 0.21 ppm F- and more than a third of these sources are practically fluoride-free. The incidence of dental caries in Malta has so far been low according to the international standards. We suggest that the lowering of the fluoride level in the water supplies may favour an escalation in the incidence of tooth decay in the future.peer-reviewe

Environmental forensic evidence from perchlorate in dust fall

Summer in Malta is accompanied by fireworks as part of the numerous (about 85) religious festivals (festa) that occur throughout the period. We attempted to establish whether firework activity is truly following official trade statistics, which imply a decreasing trend, or otherwise. Firework manufacture critically depends on the availability of oxidising agents, two of which (KNO3, KClO3) being controlled by permits but not potassium perchlorate (KClO4) which is freely available. Recent changes in legislation have slightly decreased the quantity of KClO3 and increased that of KNO3 and according to official trade statistics, consumption of KClO4 has decreased from 17 t/a in 2010 to ≈ 2.5 t/a during 2011--2014. However, from levels of perchlorate in dust fall and rate of total deposition we calculated the quantity of KClO4 used during 2012 and obtained ≥ 90 t/a, 36 times the official figure. This situation is serious since the danger of accidental explosion during manufacture escalates as production intensifies. Also, contamination of the environment by firework-waste appears destined to remain high with possible consequent effects on human health.peer-reviewe

The challenges for the university and its surroundings, and the role of Xjenza

This article refers to the teaching and practice of science in Malta and to the birth of the journal Xjenzapeer-reviewe

Effect of fireworks on ambient air quality in Malta

The authors gratefully acknowledge a research grant awarded in support of this work by the Maltese Catholic Church’s Archdiocesan Environment Commission.Religious festivals (festas) in the densely populated Maltese archipelago (Central Mediterranean) are ubiquitous during summer when 86 of them are celebrated between June and October, each involving the burning of fireworks both in ground and aerial displays over a period of 3 days or longer per festival. We assessed the effect of fireworks on the air quality by comparing PM10 and its content of Al, Ba, Cu, Sr and Sb which materials are used in pyrotechnic compositions. PM10 was collected mainly from two sites, one in Malta (an urban background site) and the other in Gozo (a rural site) during July-August 2005 when 59 feasts were celebrated and September-October 2005 when only 11 feasts occurred. For both Malta and Gozo, PM10 and metal concentration levels measured as weekly means were significantly higher during July-August compared to September-October and there exist strong correlations between PM10 and total metal content. Additionally, for Malta dust, Al, Ba, Cu and Sr correlated strongly with each other and also with total concentration of all five metals. The same parameters measured in April 2006 in Malta were at levels similar to those found in the previous October. Ba and Sb in dust from the urban background site in Malta during July-August were at comparable or higher concentration than recently reported values in PM10 from a heavily-trafficked London road and this suggests that these metals are locally not dominated by sources from roadside materials such as break liner wear but more likely by particulate waste from fireworks. Our findings point to the fact that festa firework displays contribute significantly and for a prolonged period every year to airborne dust in Malta where PM10 is an intractable air quality concern. The presence in this dust of elevated levels of Ba and especially Sb, a possible carcinogen, is of concern to health.peer-reviewe

Fine dust emissions from softstone quarrying in Malta

The Lower Globigerina Limestone (softstone) provides stone blocks for the construction industry in Malta: primitive techniques are used to extract and convert limestone into such blocks. An analysis is presented of the work methods and practices employed by the industry, along with estimates of fine respirable dust (PM10) emission from such techniques, to show that the rate of PM10 emission is 0.38 kg of limestone dust per building stone produced; taking into account mitigation of dust release during the wet months, it is estimated that the 67 active open pit quarries which lie in close proximity (0.2 to 2 km) to urban centres generate, annually, about 1200 t of PM10 dust. Considering that dust emission occurs mainly during the dry summer months, the average PM10 emission rate from quarries during this period is 11 500 mg m-2 day-1 which is well above international guideline values (100 – 350 mg m-2 day-1). The main emission sources accounting for 97% of fine dust are the cutting tools (76%) used to extract the mineral from the quarry bed and the dressing tools (21%) that convert the blocks into ‘fair-faced’ stones suitable for use in construction. The reason why emission factors are so large is due to the fact that all dust generated is allowed to escape unchecked to atmosphere. It is concluded that in view of the magnitude of the emissions and the vicinity of sources to residential areas, the quarrying industry may be a significant factor contributing to the lowering of air quality on the islands with possible impacts on the health of the general population and, in a more serious manner, that of the quarrying community. Artificial water wetting of the quarry bed prior to extraction may provide an effective and relatively cheap mitigation measure during the dry weather when the problem of dust emission is at its worst.peer-reviewe

Benzene and toluene in urban air in Malta

This is the first published report on the presence of benzene and toluene in street air in Malta. The data refers to one hour average concentrations obtained from active samplers positioned at 1.5 m height in urban, suburban and rural sites and in a road tunnel. Two sampling time periods were chosen, one just before and the other after the morning rush hour traffic. Both benzene, a known carcinogen, and toluene are found to be present in higher concentrations in street air from urban sites than from suburban sites and are not detectable in rural areas unless these sites are visited by motor traffic as on weekends. ln general, concentrations of these hydrocarbons increase after the passage of morning traffic. Benzene concentrations ranged from 7 to 84 pg m·3 and toluene from 26 to 306 pg m-3. lt is suggested that the air quality in Malta with respect to the presence of benzene and toluene is probably poor for sites where automotive traffic is prevalent but is generally good for rural areas. Air quality can be improved with the phaseout of leaded petrol which will allow the introduction of catalytic converters in petrol-powered vehicles.peer-reviewe

Atmospheric sulphur dioxide pollution in Malta : a preliminary study

The results of a preliminary survey of the air quality in Malta during May-December 1990 with respect to sulphur dioxide are presented. One-hour-average S02 concentrations as high as 320 ug m-3 have been measured from areas proximate to the Marsa power station. The concentration of S02 in ambient air was found to be strongly dependent on atmospheric conditions and especially on wind direction. At Paola, measured concentrations varied from below the detection limit of 25 ug m-3 to about 160 ug m-3. These preliminary results suggest that specific areas in Malta which are close to the Marsa power station may have an air pollution problem which is significantly more pronounced than that in other areas. The results also indicate the need for a thorough air monitoring programme which would allow the pollution problem to be assessed more accurately and to be followed continually.peer-reviewe

Fl-Antiporta tal-Millennju

The Table of Contents and Introductory section of book is attached.M'hemmx għalfejn globu tal-ħġieġ biex jgħinek tbassar li fost il-problemi li se jkollna niffaċċjaw fil-bidu tas-Seklu l-ġdid se jkun hemm dawk li jikkonċernaw l-użu tar-riżorsi, inkluż ir-riżors ambjentali. Mhux talli hekk, imma wkoll, dawn l-istess problemi se jkunu ta' natura globali u mhux biss tagħna f Malta. Aktar minn hekk, huwa faċli tipprevedi li l-mod ta' kif dawn il-problemi se jiġu ttrattati minn popli ikbar minna se jkollu impatt tremend fuq il-kwalita ta' ħajja tagħna wkoll. Mhux l-iskop ta' din id-diskussjoni li nitkellmu mill-perspettiva globali iżda ejjew naraw biss x'jistgħujkunu wħud minn dawk il-problemi li se noħolqu aħna stess u x'jista' jsir biex forsi dawn il-problemi jkunu evitati, imqar parzjalment.peer-reviewe

Geochemistry of the soll facies of the Lower Globigerina Limestone formation, Malta

Rock from the "soll" seams of the Lower Globigerina Limestone Formation is distinguishable from 'franka" because of its characteristic honeycomb weathering. However, when freshly quarried, "soll" limestone, aninferior building material, is not so readily recognizable. This study was aimed at characterizing "soll" on the basis of its inorganic geochemistry. It is shown that "soll" has a significantly higher silicon content than normal "franka". The silica content of "soll', which is a measure of its clay content, is typically less than 5%. Therefore, the traditional belief that "soll" is a limestone which is rich in clay is untenable. The silicon content may be useful in differentiating "soll" limestone from 'franka ". Besides that in silicon, other elemental anomalies are found associated with the "soll" facies of the Lower Globigerina and also with "soll ahdar ", a stratigraphically related grey-green variety.peer-reviewe

Limestone surfaces in built-up environment as indicators of atmospheric pollution

The concentration of sulphate on limestone surfaces of the external walls of churches in Malta is shown to be related to their position and distance from a power station, the main local point source of sulphur dioxide pollution. Limestone powder collected from these surfaces was examined for the presence of particles which, under low-power optical microscopy, appear as shiny black amorphous bodies which were interpreted as soot particles; the abundance of these bodies was expressed as a 'black particle count' (BPC). The degree of sulphation and BPC were shown to be correlated with each other and both appeared to be strongly dependent on the prevailing wind. The BPC contour map indicated an important contribution to the parameter from vehicular traffic. It is suggested that the degree of sulphation and BPC of limestone surfaces from the built environment should function as environmental indicators of the relative air quality with respect to S02 and soot pollution. This data is possibly more accurately representative of the relative long-term air-quality status of different areas of habitation than that deduced from single or episodic measurements of atmospheric pollutant levels.peer-reviewe