Source Of Dioxin Contamination Research Articles

The source of dioxin contamination of free-range eggs investigated through a geostatistical approach.

The source of dioxin contamination of free-range eggs investigated through a geostatistical approach.

Soil as a source of dioxin contamination in eggs from free-range hens on a Polish farm

The transfer of dioxins from contaminated soil into the food chain has recently become an up-and-coming topic in the environmental policy and health-related consumer protection. Within the framework of the 2011 National Food Survey that monitored the levels of PCDD/Fs and PCBs in foods of animal origin, the sum of the WHO-PCDD/F/PCB-TEQ concentrations exceeding two-fold the European Union's maximum level was detected in eggs from a free-range farm (12.55±2.37pg WHOPCDD/F/PCB-TEQ/g fat). Investigations have revealed that the source of egg contamination was the backyard soil on which the hens were foraging. A follow-up study of laying hens from this farm has demonstrated the transfer of dioxins into all tested tissues (breast and leg muscles, abdominal fat), liver and ovarian follicles. The bioaccumulation of dioxins was found to be congener and tissue-dependent. The highest concentration was found in the liver, followed by the ovarian follicles, and the adipose tissue. The PCDD/F levels in the liver often were approximately two times higher from those in other materials from the same hen. The potential dioxin intakes with eggs were expressed as the percent of the Tolerable Weekly Intake (TWI), and the Provisional Tolerable Monthly Intake (PTMI). The weekly intake of dioxins would be 3.5pg WHO-TEQ/kg b.w. (24.9% TWI) for an adult and 20.3pg WHO-TEQ/kg b.w. (145.2% TWI) for a 3-year old child. Considering a monthly consumption of such contaminated eggs, intake of dioxins would be slightly lower, but still over 100% of the PTMI for a child. The obtained results complement the knowledge on possible dioxin sources in food and are important for risk management authorities.

An episode of dioxin contamination in feedingstuff: the choline chloride case

In 2000, as part of a survey programme, the German authorities detected high levels of dioxins in a choline chloride (CC) premix used as animal food component. The contaminated additive consisted of different products of mineral and vegetable origin acting as a carrier. The CC was manufactured in Belgium. The final product was produced in and distributed from a plant in Spain. The German authorities informed all European Community members of the incident. The Spanish Ministry of Agriculture, Fisheries and Food and the Regional Authorities immediately conducted a survey in collaboration with the Spanish Council for Scientific Research (CSIC) to determine and isolate the source of the contamination. Analysis of a large number of samples of pure CC, pine sawdust, almond shell and other substances currently used in the preparation of the premix confirmed the presence of a significant amount of polychlorinated dibenzo- p-dioxins/polychlorinated dibenzofurans in mixtures in which pine sawdust was present. An analysis of the congener profiles revealed similarities with those found in technical pentachlorophenol (PCP) formulations. The conclusion was that PCP-contaminated sawdust as carrier for CC was source of dioxin contamination in feedingstuff.

Aspects of the Life History of the Stippled Darter Etheostoma punctulatum

Aspects of the life history of the stippled darter Etheostoma punctulatum were studied in the Spring River in SW Missouri. Females attained a maximum standard length of 85 mm and males 83 mm. Both sexes lived slightly more than 4 years. Sparvning began in early February and continued through late May. Males were mature at 1 year of age while only those yearling females at least 49 mm long produced mature ova. Females contained an average of 447 ova2-0.55 mm in diam in two distinct size modes and a group of smaller developing ova. The presence of these distinct size groups of ova throughout the spawning period indicates that two or more clutches of eggs were produced by each mature female. The fertilized eggs were 1.6 mm in diam and hatched in 11 days at 16 C. The diet was made up primarily of crustaceans and aquatic insect larvae. INTRODUCTION The stippled darter Etheostoma punctulatum is a robust darter and the largest in the subgenus Ozarka, reaching 88 mm SL (Kuehne and Barbour, 1983). This darter is distributed throughout the Ozarks where it is most often found in small creeks and spring branches having clear water with permanent flow and silt-free bottoms. Pflieger (1975) indicates it may be found in quiet pools and backwaters where it hides around large rocks or in beds of organic debris. Although not uncommon within its known range of distribution, there are very few populations large enough to permit taking the numbers necessary for life history analysis. Fishes restricted to small headwater streams are frequently subjected to wide fluctuations in environmental conditions. This study was begun with samples being taken in two streams but was terminated in Weaubleau Creek in Hickory Co., Missouri, when dry weather reduced the stream to a few isolated pools and destroyed the darter population. The danger faced by darter populations in headwater locations is also increased by human activity. The second stream location is immediately downstream from a troutrearing facility through which nearly all water in the stream passes. Cleaning of the trout pools in February 1983 produced silt which covered the gravel bottom of the sampling area to a depth of 0.5 m in many places. This site is also 2-km upstream from a well-publicized source of dioxin contamination in the watershed and fishes in the area are known to be concentrating this substance. Activities affecting this stream section may eliminate the desirable habitat which sustains populations of Etheostoma cragini, E. microperca and E. punctulatum among others. Important contributions on life history and ecology of other members of the subgenus Ozarka have been made, but a basic study of the stippled darter has been lacking. Life history features of the threatened paleback darter Etheostoma pallididorsum were determined from preserved museum specimens by Hambrick and Robison (1979). Taber et al. (1986) discussed several aspects of the life history of E. cragini; Boschung (1979) commented on the life history and distribution of E. boschungi, and Etnier (1970) made significant contributions to the known distribution of E. trisella. More recently Ryon (1986) studied the life history and ecology of E. trisella. Information gained by studying the stippled darter is important to the information base which could be used in conservation of this and other less abundant species of its subgenus.