A study of environmental impact on the heavy metal content in the meconium of newborns of the Split-Dalmatian County : doctoral thesis

Grad Split i područje Splitsko-dalmatinske županije je do 1990. godine bilo najveće industrijsko središte na istočnoj obali Jadrana. Aktivna industrijska postrojenja kao npr. željezara, čeličana, brodogradilišta, proizvodnja poli(vinil-klorida), tvornice cementa, tvornica ferolegura, bila su, a neka od njih su i danas, najvažniji antropološki izvori onečišćenja okoliša teškim metalima. Iako je nekoliko značajnih industrijskih onečišćivača na ovom području ugasilo proizvodnju (proizvodnja vinil-klorida u Kaštel Sućurcu, ferolegura u Dugom Ratu, tri tvornice cementa) značajne količine otpada su ispuštene u okoliš. Približno 200 t elementarne žive iz pogona kloralkalne elektrolize iz proizvodnje vinil-klorida ispušteno je izravno u more Kaštelanskog zaljeva, a oko 1,3 milijuna tona troske iz proizvodnje ferokroma deponirano je uz morsku obalu i odbačeno u more na području Dugog Rata. Kruženjem metala kroz biogeokemijski ciklus, ljudi i ostali živi organizmi izloženi su njihovom štetnom djelovanju. Osnovni cilj ovog istraživanja je utvrditi utjecaj onečišćenja okoliša iz industrijskih pogona i drugih izvora na bioakumulaciju metala u tijelu čovjeka. U radu je ispitana bioakumulacija olova, kadmija, žive, kroma i nikla u 182 uzorka mekonija novorođenčadi čije majke žive na području Splitsko-dalmatinske županije. Geografsko područje istraživanja je podijeljeno na nekoliko lokacija, zaleđe županije, otoke bez industrijske proizvodnje i Splitsku aglomeraciju koja je urbani, prometni i industrijski centar županije. Koncentracija pojedinog metala je praćena u ovisnosti o sociodemografskim obilježjima i životnim navikama majke. Teški metali su identificirani u 85% uzoraka što potvrđuje njihovu rasprostranjenost u okolišu, odnosno bioakumulaciju u organizmu različitim putevima kao npr. inhalacijom i prehranom. Najviše koncentracije su utvrđene za olovo 2423,64 ng/g, zatim za nikal 2233,90 ng/g, krom 1180,05 ng/g, živu 394,69 ng/g, a najniže za kadmij 26,58 ng/g. Analizom dobivenih rezultata je utvrđeno da bioakumulaciji olova snažno doprinose izvori onečišćenja iz industrijske zone grada i okolice Splita, sa značajno višim koncentracijama u prometnim zonama, dok je dominantna varijabla u bioakumulaciji žive konzumacija morske ribe. Za kadmij i krom nema značajnih razlika između rezultata dobivenih s ruralnih i urbanih lokacija što ukazuje na njihovu ujednačenu rasprostranjenost u okolišu. Konzumacija povrća za kadmij i konzumacija ribe za krom su najvažniji putevi njihova unosa u organizam. Više koncentracije kroma javljaju se u uzorcima s područja u blizini napuštenog postrojenja za proizvodnju ferokroma. Prisutnost nikla se povezuje s prehrambenim navikama i lokalnim izvorima onečišćenja, obzirom na visoke koncentracije utvrđene u uzorcima koji potječu iz ruralnih kopnenih krajeva. Rezultati dobiveni deskriptivnom statističkom obradom potvrđeni su primjenom umjetnih neuronskih mreža što se pokazalo kao dobar način procjene utjecaja tj. važnosti pojedinih varijabli na bioakumulaciju pojedinih metala. Provedeno istraživanje je jedinstveno u Republici Hrvatskoj obzirom na vrstu uzorka pribavljenog neinvazivnom metodom i činjenicu da je bioakumulacija teških metala u mekoniju pokazatelj dugotrajne izloženosti. Rezultati ove studije mogu poslužiti kao osnova za uspostavu biomonitoringa, kao i modela procjene rizika od izloženosti teškim metalima u okolišu.Until 1990, the city of Split and the area of the Split-Dalmatian county was the largest industrial centre on the east coast of the Adriatic sea. Active industrial plants such as ironworks, steelworks, shipyards, the production of poly(vinyl chloride), cement industry, ferroalloy plant, were, and some still are, the most significant anthropological sources of environmental contamination with heavy metals. Although several major industrial polluters in this area have shut down their production (the production of vinyl-chloride in Kaštel Sućurac, the ferroalloy plant in Dugi Rat, three cement factories), significant amounts of waste have been discharged into the environment. Approximately 200 tons of elemental mercury from the chlor-alkali electrolysis section of the production of vinyl-chloride were discharged directly into the sea of the Kaštela bay, and about 1.3 million tons of slag from the production of ferrochrome were deposited along the coast and dumped into the sea in the area of Dugi Rat. Metals are cycling through the biogeochemical cycle, so people and other living organisms are exposed to their harmful effects. The main objective of this study has been to determine the effect of environmental pollution from industrial plants and other sources on the bioaccumulation of metals in the human body. The bioaccumulation of lead, cadmium, mercury, chromium and nickel has been studied in 182 samples of meconium of new-borns whose mothers live in the Split-Dalmatian County. The geographical scope of research has been divided into several locations: county inland, islands without industrial production and the Split agglomeration which is the urban, transport and industrial centre of the County. The concentration of individual metals has been monitored as a function of sociodemographic characteristics and mothers' lifestyles. Heavy metals have been identified in 85% of samples, which confirms their distribution in the environment, i.e. bioaccumulation in organisms through different pathways, e.g. inhalation and eating. Highest concentrations have been found for lead (up to 2423,64 ng/g), then nickel (up to 2233,90 ng/g), chromium (up to 1180,05 ng/g), mercury (up to 394,69 ng/g), and lowest ones for cadmium (up to 26,58 ng/g). The analysis of results obtained shows that strong contributors to lead bioaccumulation are sources of pollution from the industrial zone and the surroundings of Split, with significantly higher concentrations in traffic zones, while the dominant variable in mercury bioaccumulation is the consumption of seawater fish. No significant differences between results obtained for rural and urban locations have been found for cadmium and chromium, indicating their uniform distribution in the environment. The most important pathway for cadmium input into the organism is the consumption of vegetables and for chromium the consumption of fish. Increased chromium concentrations occur in the vicinity of the abandoned ferrochrome production plant. The presence of nickel is associated with eating habits and local sources of pollution, due to its high concentrations found in samples originating from rural inland areas. The results obtained by means of descriptive statistical analysis have been confirmed by the application of artificial neural networks, which has proven to be a good method of assessing the impact i.e. importance of certain variables on the bioaccumulation of certain metals. This study is unique in Croatia with regard to the type of sample obtained by a non- invasive method and the fact that the bioaccumulation of heavy metals in meconium is the indicator of long-term exposure. The results of this study can serve as a basis for the establishment of biomonitoring as a model of assessment of the risk of exposure to heavy metals in the environment. environmental pollution, anthropogenic emissions, Pb, Cd, Hg, Cr, Ni, bioaccumulation, meconium, biomonitoring, cement industry, ferrochromium, chloralkali electrolysis, iron production