Human health concerns

Effects on wildlife are important in their own right, but are also of significance to human health concerns because of the information that may be conveyed regarding possible parallel changes in humans. The adverse effects that have been identified and the compounds that have been implicated, with at least some degree of certainty, are summarized below. 

YELLAYI S, NAAZ A, SZEWCZYKOWSKI M A, SATO T, WOODS J A, CHANG J, SEGRE M, ALLRED C D, HELFERicH w G, COOKE p s (2002) The ph)Toestrogen genistein induces thymic and immune changes a human health concern Proc Natl Acad Sci USA. 99 7616-21. 

When pushed to the limit by overriding human health concerns, residue chemists have achieved detection limits of Ippt (Ingkg ) or even into the low ppqr (1 pg kg ) range. An example at the 1 ppt level is provided by methods for 2,3,7,8-tetrachlorodibenzodioxin (TCDD) in milk and TCDD in adipose tissue. Eor relatively clean matrices such as water and air, preconcentration on solid-phase adsorbents followed by GC or gas chromatography/mass spectrometry (GC/MS) can provide detection limits of 1 ng m and less for air (examples in Majewski and Capel ) and 1 ngL and less for water (examples in Larson et A summary of units of weight and concentration used to express residue data is given in Table 1. 

One of the main human health concerns about organophosphate esters is the potential for neurotoxicity reactions, in particular a condition known as organophosphate-induced delayed neurotoxicity (OPIDN). Tri-ort/20-cresyl phosphate (TOCP) has been identified as one of the more potent OPIDN neurotoxins in humans, and was formerly a constituent in some organophosphate ester hydraulic fluid products (Marino 1992 Marino and Placek 1994). Production processes now routinely remove virtually all the TOCP. For instance, tricresyl phosphate (TCP) products now typically are manufactured to contain over 98% meta and para isomers and virtually no TOCP (Marino and Placek 1994). Products containing these compounds associated with OPIDN have now entirely disappeared from commercial use, and the vast majority of the industrial organophosphate esters are based on triaryl phosphates with no halogenated components (Marino 1992). At waste disposal sites, however, site contaminants from older product formulations containing the ortho form may be encountered. 

Commentary This problem demonstrates that potential health issues receive high priority. While many possible sources of the fish kill were identified, they were likely approached simultaneously and the most obvious sources were eliminated from consideration first. While there may be some ethical concerns with the use of live fish as a pollution detector, it is important to solve this problem in the most efficient manner possible, at least until it is determined whether this is a human health concern. 

As a result of human health concerns, production of mirex ceased in 1976, at which time industrial releases of this chemical to surface waters were also curtailed. However, releases from waste disposal sites continue to add mirex to the environment. Virtually all industrial releases of mirex were to surface waters, principally Lake Ontario via contamination of the Niagara and Oswego Rivers. About 75% of the mirex produced was used as a fire retardant additive, while 25% was used as a pesticide. As a pesticide, mirex was widely dispersed throughout the southern United States where it was used in the fire ant eradication program for over 10 years. 

Production of chlordecone ceased in 1975 as a result of human health concerns at that time industrial releases of this chemical to surface waters via a municipal sewage system were curtailed. However, releases from waste disposal sites may continue to add chlordecone to the environment. Major releases of chlordecone occurred to the air, surface waters, and soil surrounding a major manufacturing site in Hopewell, Virginia. Releases from this plant ultimately contaminated the water, sediment, and biota of the James River, a tributary to the Chesapeake Bay. 

S. Yellayi, A. Naaz, M.A. Szewczykowski, T. Sato, J.A. Wood, J.S. Chang, M. Segre, C.D. Alfred, W.G. Helferich and P.S. Coke, The phytoestrogen genistein induces thymic and immun changes a human health concern Proc. Nat. Acad. Sci. 99 (2002) 7616-7621. 

No milk can be considered hormone free as natural hormones are always present. The question that has been under heated debate since approximately 1995 is whether the bovine somatotropin hormone (BST) injected into cows to increase milk production results in harmful levels of hormone in milk. The use of BST, which is based upon an economic return rather than any health benefit to the animal, raises two important questions what are the health risks to the human consumer, primarily children and what are the effects on the animals It is fairly well accepted that the use of BST increases the incidence of mastitis and therefore the potential for increased residues of antibiotic and antimicrobials in milk. Because of this Canada, Australia, Japan, the U.K., and other European Union countries decided that the health impact on animals was unacceptable and that BST was not to be used in their jurisdictions. Their decisions were not based upon any human health concerns, but strictly on concerns for animal health. 

Herbicides are designed to kill plants, not animals, and in general have lower mammalian toxicity than insecticides. Most herbicides interfere with plant hormones or enzymes that do not have any direct counterpart in animals. The most serious human health concerns have been related to contaminants of the primary chemical herbicide. There is an enormous amount of animal and some human toxicity data on 2,4-D and 2,4,5-T, but it now appears that much of this toxicity is caused by the contaminant TCDD. Military personnel exposed to Agent Orange, often contaminated with TCDD, reported birth defects, cancers, liver disease, and other illness. These concerns led to improvement in the manufacturing process to reduce TCDD contamination and ultimately to a reduction in use of 2,4-D herbicides. There is also concern that some herbicides may affect wildlife. For example, atrazine, a persistent herbicide, may adversely affect frogs. Persistence of herbicides may also... 

Ball, J. C and T. J. Wallington, Formation of Trifluoroacetic Acid from the Atmospheric Degradation of Flydrofluorocarbon 134a A Human Health Concern Air Waste, 43, 1260-1262 (1993). Barone, S. B A. A. Turnipseed, and A. R. Ravishankara, Kinetics of the Reactions of the CFsO Radical with Alkanes, J. Phys. Chem., 98, 4602-4608 (1994). 

Toxicological issues fall into two quite distinct areas first, human health concerns resulting from consumption of arsenic compounds in seafood, and second, ecological concerns arising from the effects of these compounds on marine organisms. 

The increasing use of the precautionary principle is stifling development in Europe and to a lesser, but increasing, extent in America and around the world.29 In rich countries, the precautionary principle costs money, and because of its inflexible application, it is unlikely to provide benefits. In poorer countries, it is likely to be harmful, sometimes causing catastrophic effects on human health. Concerns about chlorination and the push for a DDT ban are the most obvious examples of this phenomenon. 

Annex I contains the list of pharmacologically active substances in respect of which MRLs have been established. Entry into Annex I depends on full packages of toxicological and residue data, the analysis of which suggests no major human health concerns. 

Several compounds may be used as flame-retardants for PS foams but generally halogen flame-retardants are the most used even if, due to environmental and human health concerns, a continuous search for halogen-free FR is going on. A very recent detailed review on FR for PS foams is reported by Levchik and Weil,79 other useful data may be found in patent literature. 

Kortenkamp A, Faust M, Scholze M, Backhaus T. 2007. Low-level exposure to multiple chemicals reason for human health concerns Environ Health Perspect 115(Suppl 1) 106-114. 

A quick scan of newspapers, television, science magazines, or the internet on any given day has a fairly high likelihood of encountering a story (usually accompanied by a creative headline such as those above) regarding human health concerns linked to dusts, soils, or other earth materials. Many such concerns have been recognized and studied for decades, but new concerns arise regularly. 

A primary human health concern associated with mine wastes, tailings, and smelting byproducts produced during the extraction of metals from metallic mineral deposits has been the incidental ingestion exposure, and resulting heavy metal uptake, especially for small children who play on waste piles, tailings, slag heaps, or... 

Tingle CC, Rother JA, Dewhurst CE, Lauer S, and King WJ (2003) Fipronil Environmental fate, ecotoxicology, and human health concerns. Reviews of Environmental Contamination and Toxicology 176 1-66. 

Because the lack of evidence of health effects cannot conclusively show that GMOs are not a human health concern, current global efforts are focused on the development of protocols to proactively and sys-temically detect and assess potential adverse effects. 

BDE-47 is one of the main PBDE congers found in both environmental samples and human tissue, and is undergoing considerable research. It is biologically persistent, and has a high bioaccumulation potential. It is under investigation as an endocrine disruptor and studies for human health concerns are on going. 

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