No description available.

Thesis (M.P.H.)--University of Michigan, 1946.

Thesis (M.P.H.)--University of Michigan, 1946.

This work was undertaken in order to determine the extent and nature of PAH pollution In a freshwater riverine environment. An extensive survey of sediment, water and aquatic organisms was carried out to investigate sources of PAH, physicochemical relationships occurring in the water and sediment, the extent of bioaccumulation and the potential for bioconcentration through the food chain. Laboratory studies were designed to investigate the likely mode and extent of uptake of PAH by Noemacheilus barbatulus (L.), Glossiphonia complanata (L.) and Lymnaea peregra (MUller), the ability of these species to metabolise PAH compounds and the extent of depuration. All sediment PAH profiles were similar and indicative of an anthropogenic pyrolytic origin. Urban/road runoff was considered to be a major influence on sediment PAH concentrations. point sources consisted of industrial waste sewage and runoff containing used engine oil. , All sites were affected by diffuse PAH pollution. At certain sites and at times of heavy rainfall this is overlain by a greater input of PAH to the sediment from point sources. Positive linear relationships have been demonstrated between total and individual PAH content and organiC matter content in sediments throughout a range of particle sizes. A similar PAH profile was found in each sediment size fraction, thus organisms selectively removing certain sized particles are not being exposed to differing ratios of PAH compounds. The river system seems to be in a state of nearequilibrium with regard to the partitioning of PAH between bedload sediment, suspended sediment, water and interstitial water. Adsorption and desorption processes occur in two phases, the first being almost instantaneous and the second being a slower approach to equilibrium. There is no- evidence of PAH's being bioconcentrated through the food chain. Uptake by tubificid worms occurs by the ingestion of contaminated sediment. Uptake by Cottus goblo (L.), N. barbatulus, L. peregru, G. complanata and Erpobdella octoculata (t.) occurs mainly through water and was shown to be rapid. N. barbatulus, L. peregra and G. complanat~ have the capacity to metabolise PAH compounds to harmful derivatives and it is likely that C. gobio and E. octoculata also have this capability. Depuration of BaP and metabolite compounds was relatively slow. Prolonged exposure to low levels of BaP in the environment may lead to a buildup of DaP and metabolite compounds in these organisms.

No description available.

No description available.

No description available.

No description available.

No description available.

A wide range of synthetic chemicals and their metabolites present in the environment can antagonise the receptor activity of androgen hormones present in wildlife and humans. With increasing global production of new synthetic chemicals, little is known about their environmental fate, health consequences and end-points. This study was conducted to identify and characterise chemicals with anti-androgenic activity present in wastewater influent and effluent. This study was undertaken by applying a combination of biological and analytical chemistry techniques involving Solid Phase Extraction (SPE), High Performance Liquid Chromatography (HPLC) and an in vitro steroid receptor assay for profiling and characterising extracts of grab influent and effluent wastewater samples using a toxicity identification and evaluation (TIE) procedure. Initial work revealed variable recoveries of anti-androgenic activity from SPE of wastewaters. Therefore SPE methodology to screen wastewater samples was developed using a mixture of selected compounds which possess a range of polarities (log Kow). Their recoveries from SPE were measured by HPLC protocol and ranged from 95- 100%. The mean±SD and % RSD values of the analysed wastewater replicates were 3.20±0.03 mgFeq/L and 0.78% for influent and 0.22±0.01 mgFeq/L and 3.80% for effluent samples. The recoveries of wastewater extracts after fractionation were between 78.6% and 99.6%. Fractions containing anti-androgenic activity were analysed by Gas Chromatography Mass Spectrometry (GC-MS). A number of household chemicals were detected in both influent and effluent wastewater fractions that contained antiandrogenic activity. These included the anti-bacterial agents- triclosan, chlorophene, dichlorophene, chloroxylenol, the musk fragrance galaxolide, the flame retardantstris( 1-chloro-2-propyl)phosphate (TCPP) and tris(2-butoxyethyl)phosphate (TBEP), polymer plasticizer n-butylbenzenesulfonamide (NBBSA) and bisphenol A (BPA) which is a chemical associated with the polycarbonate usage. The anti-androgenic potency of pure contaminants compared with that of flutamide ranged from 0.04 (TCPP) to 13.40 (chlorophene). Anti-androgenic activity of 1.69 and 2.00% was recovered from the fractions of the effluent and influent samples respectively indicating that AA of about 98% are yet to be recovered. This work reveals for the first time that over 12 contaminants contribute to the total anti-androgenic activity present in wastewater effluent and that a number of compounds commonly used in household products (such as chlorophene, triclosan and NBBSA) are predominant anti-androgens in wastewater effluents.