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

英国许多河流中流动的大量水来自污水处理厂(WWTW)的污水，这可能会影响当地的野生动物。我们已经证明，生活在许多英国河流中的鱼类，最明显的是蟑螂，这是鲤鱼家族中常见的成员，暴露在污水处理厂污水中含有的化学物质中，扰乱了人体的性激素系统，从而破坏了鱼类的繁殖。已确定的对这些影响负责的化学物质是雌激素(女性性激素)，包括天然雌激素激素、妇女作为避孕药一部分服用的药用雌激素，以及一些结构与天然雌激素结构相似的工业化学品。野生雌鱼的存在令人担忧，因为我们已经证明，它们的繁殖能力下降，这可能会对种群造成不利影响，并对生态系统产生更广泛的影响。人类生殖健康疾病的发生在性质上与野生鱼类的影响非常相似，其中一些影响与接触雌激素有关。对英国河流中的污水处理厂污水的进一步关注，长期暴露在鱼类中发现了额外的不良健康影响，包括破坏免疫系统和遗传损害。该项目试图以蟑螂为前哨物种，调查暴露在雌性污水处理厂污水中对生活在UK Rivers的鱼类种群的可持续性可能产生的后果。尽管蟑螂在许多受污染的水系统中很常见，但这有时会给人对人口健康的误导性印象。可以说，计算种群中繁殖的个体数量比计算鱼类总数更好，因为繁殖鱼类数量较少的鱼类种群的遗传变异和近亲繁殖较低，甚至可能面临灭绝的风险。考虑到我们迄今进行的实验结果，我们认为，与来自清洁地点的蟑螂相比，来自污染更严重地点的蟑螂种群繁殖个体数量更少，近亲交配更多，因为更高比例的鱼将无法繁殖。为了研究这一点，我们将首先评估蟑螂在群体中繁殖的能力，这些群体包括终生暴露于含有雌激素的污水处理厂污水的鱼类和终生保持在清洁水中的鱼类。我们将使用基因技术(DNA微卫星)来确定所产生的后代的父母，进而确定竞争群体中个别鱼类的繁殖成功，并试图将这种成功与它们的性生理联系起来。然后，我们将进行实验，研究在一代和两代期间暴露在含有雌激素的污水中对睾丸和卵巢的发育以及随后的第二代繁殖成功的影响。在该项目的最后部分，我们将使用DNA微卫星从污染程度不同的河流地点收集种群的DNA微卫星，以调查英国河流野生蟑螂种群的潜在遗传健康状况。最终，我们的结果将使我们能够评估终身暴露于雌激素性污水处理厂污水对个人和种群的影响，大大提高对英国河流蟑螂种群可持续性可能受到影响的认识。这项工作的目的是大大改进对暴露在复杂的化学排放物混合物中对自然环境中鱼类种群的健康影响的评估，以更好地保护我们的水产资源和生物多样性。这项工作将对排放监管具有重要意义，因此受到政府监管机构、环境保护团体、工业界和广大公众的广泛关注。

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.