Population-level Consequences Of Exposure Of Fish To Oestrogenic Wastewater Treatment Works Effluents

在英国的许多河流中，大量的水来自废水处理厂（WWTW）的废水，这可能会影响当地的野生动物。我们已经证明，生活在英国许多河流中的鱼类，特别是鲤鱼家族的常见成员蟑螂的繁殖，已经被暴露于WWTW污水中所含的化学物质所破坏，这些化学物质会破坏人体的性激素系统。确定造成这些影响的化学物质是雌激素（女性性激素），包括天然雌激素、妇女作为避孕药的一部分服用的药物雌激素，以及一些结构与天然雌激素相似的工业化学品。野生鱼类雌性化的存在令人担忧，因为我们已经表明它们的繁殖能力降低，这可能会对种群产生不利影响，并更广泛地影响生态系统。人类生殖健康出现的疾病在性质上与在野生鱼类中看到的影响非常相似，其中一些影响与接触雌激素有关。增加了对英国河流中WWTW废水的进一步关注，长期暴露于鱼类已发现额外的不良健康影响，包括破坏免疫系统和遗传损伤。该项目旨在调查暴露于雌激素污水处理厂废水的可能后果，为生活在英国河流的鱼类种群的可持续性，使用蟑螂作为哨兵物种。虽然蟑螂在许多受污染的水系统中很常见，但这有时会对人口的健康产生误导性的印象。可以说，统计种群中繁殖个体的数量比统计鱼的总数更好，因为繁殖鱼数量少的鱼类种群遗传变异和近亲繁殖都很低，甚至可能面临灭绝的风险。鉴于我们迄今为止进行的实验结果，我们认为，来自污染较严重的地点的蟑螂种群的繁殖个体数量较少，并且比来自清洁地点的蟑螂种群的近交系更多，因为更高比例的鱼类将无法繁殖。为了调查这一点，我们将首先对蟑螂在群体中繁殖的能力进行评估，这些群体包括在其整个生命中一直暴露于雌激素WWTW污水的鱼类和在其整个生命中一直保持在清洁水中的鱼类。我们将使用遗传技术（DNA微卫星）来识别所产生后代的父母，从而确定竞争群体中个体鱼的繁殖成功率，并试图将这种成功与它们的性生理学联系起来。然后，我们将进行实验，以调查如何暴露于雌激素的污水处理厂污水超过一个和两个世代的影响睾丸和卵巢的发展和随后的繁殖成功的第二代。在这个项目的最后一部分，我们将调查潜在的遗传健康的野生蟑螂种群在英国河流使用DNA微卫星的人口从河流网站收集不同程度的污染与雌激素污水处理厂污水。最终，我们的研究结果将使我们能够评估终身暴露于雌激素污水处理厂污水对个人和人群的影响，推进显着的知识如何在英国河流蟑螂种群的可持续性可能会受到影响。这项工作的目的是大大改善评估暴露于复杂的化学排放物混合物对自然环境中鱼类种群的健康影响，以更好地保护我们的水生资源和生物多样性。这项工作对于排放监管非常重要，因此引起了政府监管机构、环境保护组织、工业界和广大公众的广泛兴趣。

A very significant amount of the water flowing in many UK rivers originates from the effluent of wastewater treatment works (WWTW) and this can affect the native wildlife. We have shown that reproduction in fish living in many UK Rivers, most notably in the roach, a common member of the carp family of fish, has been damaged by exposure to chemicals contained in the WWTW effluents that disrupt the body's sex hormone systems. The chemicals identified responsible for these effects were oestrogens (female sex hormone) and included natural oestrogen hormones, pharmaceutical oestrogens taken by women as part of the contraceptive pill, and some industrial chemicals similar in their structure to natural oestrogens. The presence of feminised fish in the wild is of concern because we have shown that they have a reduced capacity to breed and this may potentially lead to adverse effects for the population and impact the ecosystem more widely. Disorders in human reproductive health occur that are very similar in nature to effects seen in wild fish and some of these effects have been associated with exposure to oestrogens. Adding further concern about WWTW effluents in UK Rivers, long term exposures of fish have found additional adverse health effects including disruption to the immune system and genetic damage. This project seeks to investigate the likely consequences of exposure to oestrogenic WWTW effluents for the sustainability of fish populations living in UK Rivers, using the roach as sentinel species. Although the roach is common in many polluted water systems, this can sometimes give misleading impressions of the health of the population. Arguably, it is better to count the number of breeding individuals in a population rather than the total number of fish because fish populations with low numbers of breeding fish have low genetic variation and inbreeding and may even be at risk of extinction. Given the results of our experiments performed to date, we think that populations of roach from more polluted sites will have smaller numbers of breeding individuals and will be more inbred than those from clean sites, because a higher proportion of fish will be unable to breed. To investigate this we will first make assessments on the ability of roach to breed in in groups that include fish that have been exposed throughout their whole lives to an oestrogenic WWTW effluent and fish that have been maintained throughout their lives in clean water. We will use a genetic technique (DNA microsatellites) to identify the parents of the offspring produced and in turn determine the reproductive success of individual fish in the competing groups and try to relate this success to their sexual physiology. We will then conduct experiments to investigate how exposure to the oestrogenic WWTW effluent over one and two generations impacts the development of the testes and ovaries and consequent breeding success in the second generation. In the final part of this project we will investigate the underlying genetic health of wild roach populations in UK Rivers using DNA microsatellites for populations collected from rivers sites with different levels of pollution with oestrogenic WWTW effluent. Ultimately, our results will enable us to assess the implications of life long exposure to oestrogenic WWTW effluents on both individuals and populations, advancing significantly knowledge on how the sustainability of roach populations in UK Rivers may be impacted. This work is intended to greatly improve the assessment of the health impacts of exposure to complex mixtures of chemical discharges on fish populations in the natural environment for the better protection of our aquatic resources and biodiversity. The work will have importance in the regulation of discharges and thus is of very wide interest to the government regulatory bodies, environment protection groups, industry and the wider public.