Kinetics of Polychlorinated Biphenyls (Aroclor 1254) in Lactating Bovines and Their Distribution in Dairy Products

Abstract

Lactating cows were given orally, single or multiple graded doses of polychlorinated biphenyls (PCB) as Aroclor 1254 and the tissue distribution and excretion were measured. Persistence of PCB in milk was determined at all dose levels of PCB administered. A distinct predilection of PCB for tissues with high lipid content was noted. Similarly, PCB appeared in higher concentration in dairy products with high fat content.

Model of the Fate of Hydrophobic Contaminants in Cows

“…This conclusion is supported by the literature. In several studies, the concentrations of various PCDD/F and PCB have been found to be at least an order of magnitude higher in fat than in other tissues (11)(12)(13).…”

“…It is therefore reasonable to assume that the hydrophobic compounds in the blood are in equilibrium with those in the milk glands. In those feeding studies with hydrophobic compounds where the blood and milk concentrations were both measured, the time courses were very similar (11,13), and where the concentrations were determined on a fat basis, they were virtually the same in blood and milk (25).…”

Transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) from oral exposure into cow’s milk – Part I: state of knowledge and uncertainties

“…gelatine capsule) into the rumen. The time of exposure in feeding studies varied from 1 d (62,75,79,80,87,88,95,97,98,102,103,120,(124)(125)(126) to several weeks (<28 d) (60,77,78,98,113) (Table 2). In some feeding studies, the animals were exposed to PCDD/Fs and PCBs during their dry period (61,88,91,93,94,100,114,115,119) .…”

“…limit of quantification). Dairy cattle Dairy (70)(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82) Holstein cows Dairy (41,83,84) Holstein Friesian Dairy (85) English Holstein Friesian Dairy (86) Italian Holstein Friesian Dairy (87)(88)(89)(90)(91)(92)(93)(94) German Holstein Dairy (95)(96)(97)(98) Jersey Dairy (99,100) Angler Dairy German Red Pied German Black Pied (61,(101)(102)(103)(104)(105) Fries Holland Dairy (106,107) Guernsey Dairy (108) Brown Swiss Dairy (109)(110)(111)(112)(113)(114) Simmental Dual purpose (43,115) Simmental cr...…”

“…Most studies expressed the amount of PCDD/F and PCB on (91) the basis of milk fat corresponding to regulatory maximum residue levels or daily excretion via milk. However, in some studies the amount was expressed on a whole milk basis (77,95,98,115,142,151) , not necessarily providing information about the respective milk fat content.…”