Moganti Shanti, Richardson Bruce J, McClellan Katherine, Martin Michael, Lam Paul K S, Zheng Gene J
Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong.
Mar Pollut Bull. 2008;57(6-12):672-80. doi: 10.1016/j.marpolbul.2008.02.035. Epub 2008 Apr 29.
In order to test its ability as a bioaccumulator, the deposit feeding clam Asaphis deflorata, collected from a clean coastal area in Hong Kong (Ding Chau, Ma On Shan), was exposed to field-collected sediments representing a gradient of contamination. Sediments were collected from four sites, namely Shek O in the southeast of Hong Kong Island, Ap Lei Chau in Aberdeen district, Tai Kok Tsui in the Mong Kok waterfront, and To Kwa Wan near Kowloon City pier. Shek O was the cleanest and To Kwa Wan was the most polluted site. Replicate 30L fiberglass tanks containing equal numbers of organisms were maintained for 28 days, with equal quantities of sediment and filtered seawater. Prior to this the animals were depurated for 10 days in clean sediment. During the 28-day holding period, sampling of both sediment and clams was performed on days 0, 10 and 28, along with condition index measurements. Concentrations of organochlorine pesticides and PCBs in sediments showed that Shek O was the cleanest of the sites, followed by Ap Lei Chau, Tai Kok Tsui and To Kwa Wan. There were marked differences among the sites, especially in PAH concentrations, with To Kwa Wan showing extremely high sediment concentrations. Following exposure, the biota concentrations of various organochlorine pesticides and PCBs suggested that there was sediment concentration-dependent accumulation by A. deflorata on day 10 of the experiment. However, there was no significant increase on day 28 for any of the compounds tested. Contaminant concentrations in clams feeding on Shek O sediments were minimal and almost the same on all sampling days, indicating the presence of only baseline contaminant concentrations. The condition indices (CI) of the clams on various sampling days showed that the animals were relatively more stable in sediment from Shek O. There were some deaths in all the test tanks (including those containing Shek O sediments). In addition, clams appeared to bury faster in the cleaner Shek O sediment and remained buried, unlike those in the sediment from the other locations, where some remained predominantly on the surface. Nevertheless, despite not completely burying, the clams in other test sediments still exhibited sediment concentration-dependent tissue accumulation. The results of the investigation indicate the possibility of developing a standard test protocol for bioaccumulation by sediment dwelling invertebrates, for practical use in Hong Kong, using A. deflorata.
为了测试沉积食性蛤蜊Asaphis deflorata作为生物累积者的能力，从香港一个清洁的沿海区域（汀洲、马鞍山）采集的该蛤蜊，被暴露于代表污染梯度的现场采集沉积物中。沉积物从四个地点采集，即香港岛东南部的石澳、香港仔区的鸭脷洲、旺角海滨的尖沙咀以及九龙城码头附近的土瓜湾。石澳是最清洁的地点，土瓜湾是污染最严重的地点。将装有等量生物的30升重复玻璃纤维水箱维持28天，加入等量的沉积物和过滤后的海水。在此之前，动物在清洁沉积物中净化10天。在28天的饲养期内，在第0天、第10天和第28天对沉积物和蛤蜊进行采样，并测量状况指数。沉积物中有机氯农药和多氯联苯的浓度表明，石澳是最清洁的地点，其次是鸭脷洲、尖沙咀和土瓜湾。各地点之间存在显著差异，尤其是在多环芳烃浓度方面，土瓜湾的沉积物浓度极高。暴露后，各种有机氯农药和多氯联苯的生物群浓度表明，在实验的第10天，A. deflorata存在沉积物浓度依赖性积累。然而，在第28天，所测试的任何化合物都没有显著增加。以石澳沉积物为食的蛤蜊中的污染物浓度极低，并且在所有采样日几乎相同，表明仅存在基线污染物浓度。不同采样日蛤蜊的状况指数（CI）表明，动物在石澳的沉积物中相对更稳定。所有测试水箱（包括装有石澳沉积物的水箱）中都有一些死亡情况。此外，蛤蜊似乎在较清洁的石澳沉积物中埋得更快，并一直埋在其中，这与其他地点沉积物中的蛤蜊不同，其他地点的一些蛤蜊主要仍留在表面。然而，尽管没有完全掩埋，其他测试沉积物中的蛤蜊仍表现出沉积物浓度依赖性的组织积累。调查结果表明，有可能制定一种用于沉积物栖息无脊椎动物生物累积的标准测试方案，在香港实际使用，以A. deflorata作为测试对象。
