Swedish National Environment Contaminant Monitoring of Cod (1984-)

The Contaminant Programme in marine biota constitutes an integrated part of the national monitoring activities in the marine environment as well as the international programmes within ICES, OSPARCOM and HELCOM. The programme is financed by the Swedish Environmental Protection Agency. The Baltic cod is living below the halocline feeding on bottom organisms. It becomes sexually mature between 2-6 years in Swedish waters. The spawning takes place during the period May - August (occasionally spawning specimens could be found in Mars or September). The cod requires a salinity of at least 11 PSU and an oxygen content of at least 2 ml/l (Nissling, 1995) for the spawning to be successful. The population shows great fluctuations and has decreased dramatically during the period 1984-1993. Cod fishing for human consumption is economically important. Cod is among the 'first choice species' recommended within the JAMP (Joint Assessment and Monitoring Programme) and BMP (Baltic Monitoring Programme). Cod liver tissue is used for all determinants except mercury for which muscle tissue is used. The cod liver is fat and organic contaminants are often found in relatively high concentrations. For that reason, it is also a very appropriate matrix for screening for 'new' contaminants. Cod is collected in the autumn from two sites: south east of Gotland and from Fladen at the Swedish west coast. Cod liver tissue samples are analysed for lead, cadmium, copper and zinc as well as for organochlorines. 1995 analyses of chromium and nickel were added. Cod muscle tissue is analysed for mercury. The cod specimens are age determined by otoliths. Specimens of both sexes, between 3-4 years from Gotland and between 2-4 years from Fladen, are analysed.

海洋生物体中的污染物项目构成了国家海洋环境监测活动以及 ICES、OSPARCOM 和 HELCOM 国际项目中的一个综合组成部分。该项目由瑞典环境保护局资助。波罗的海鳕鱼生活在盐跃层之下，以底栖生物为食。在瑞典水域，它于 2-6 年间达到性成熟。繁殖发生在 5-8 月期间（偶尔也可能会在 3 月或 9 月发现繁殖的样本）。鳕鱼为了成功繁殖，需要至少 11 PSU 的盐度和至少 2 毫升/升的氧气含量（Nissling，1995）。该种群表现出极大的波动，并在 1984-1993 年期间急剧减少。鳕鱼捕捞用于人类消费在经济上具有重要意义。鳕鱼是 JAMP（联合评估和监测计划）和BMP（波罗的海监测计划）中推荐的“首选物种”之一。鳕鱼的肝脏组织用于除汞以外的所有测定，而肌肉组织则用于汞的测定。由于鳕鱼肝脏富含脂肪，且有机污染物往往在相对较高的浓度下存在，因此它也非常适合作为筛选“新”污染物的合适基质。鳕鱼在秋季从两个地点采集：哥特兰岛东南部和瑞典西海岸的 Fladen。对鳕鱼肝脏组织样本进行分析，检测铅、镉、铜和锌，以及有机氯。1995 年增加了铬和镍的分析。对鳕鱼肌肉组织进行分析，检测汞。鳕鱼的年龄通过耳石进行鉴定。来自哥特兰岛的 3-4 年和来自 Fladen 的 2-4 年的雌雄鳕鱼样本均进行分析。