Mason C F, Macdonald S M
Department of Biology, University of Essex, Colchester, United Kingdom.
Sci Total Environ. 1993 Sep 30;138(1-3):127-45. doi: 10.1016/0048-9697(93)90410-8.
A study of otter (Lutra lutra) populations and levels of organochlorine (OC) pesticide residues and PCBs in otter droppings (spraints) was made on eight stretches of river in three catchments in Wales and West Midland England. Population and contaminant levels were compared against target values. The otter populations (as measured by an index) remained stable on one stretch over 11 years, while they increased rapidly to equilibrium on four other stretches. The three lower stretches of rivers showed more erratic trends and on only one stretch did the index exceed, occasionally, the target value. Marking intensity at spraint sites was also lower at the three lowland sites. Concentrations of dieldrin, DDE and PCBs were significantly greater in spraint samples from the three lowland stretches. Over 50% of samples from the three lowland stretches had OC concentrations above the maximum allowable concentration, whereas most samples from the upland stretches had concentrations below the 'no effects level'. It is suggested that the colonization, by otters, of their former lowland range is inhibited by OC contamination of their food chain but, if contaminant levels can be reduced, spread will occur rapidly.
对威尔士和英格兰西米德兰兹郡三个集水区的八条河流段的水獭（水獭属水獭）种群以及水獭粪便（粪便）中的有机氯（OC）农药残留和多氯联苯水平进行了研究。将种群和污染物水平与目标值进行了比较。水獭种群（通过指数衡量）在一段河流上11年间保持稳定，而在其他四段河流上则迅速增长至平衡状态。下游的三段河流呈现出更不稳定的趋势，只有一段河流的指数偶尔超过目标值。在三个低地地点，粪便点的标记强度也较低。来自下游三段河流的粪便样本中，狄氏剂、滴滴伊和多氯联苯的浓度显著更高。来自下游三段河流的样本中，超过50%的有机氯浓度高于最大允许浓度，而来自上游河段的大多数样本浓度低于“无影响水平”。有人认为，水獭对其以前的低地范围的重新定居受到其食物链中有机氯污染的抑制，但如果污染物水平能够降低，其扩散将迅速发生。
