Since chemical are widely used in modern society, scientists pay more attention to the side effect of these in the environment, which can exert profound and deleterious effects on wildlife and human health is linked to the health of the environment. The last two decades, in particular, scientific concern, public debate, and media focus on the potential dangerous effects in humans and wildlife that may result from exposure to the endocrine disruptor chemicals.
What regulates growth and development and controls important functions in humans and animals, includes hormones and hormone receptors distributed throughout the body are called the endocrine system. However, an endocrine-disrupting substance is a compound, either natural or synthetic, which through environmental or inappropriate developmental exposures alters the hormonal systems that enable the organism to communicate with and respond to its environment. To be specific, in Europe, symptoms of endocrine disruption in wildlife are not only be detected in areas with abnormally high levels of pollution, but have been found in river, estuaries and open sea as well.
This report is about the decision taken in EU that the ban of EDCs in the aquatic ecosystem. Our objectives of this report is to awake to the EDCs around us more strictly. From the actions which have been taken by Europeans, potential risks of the EDCs, such as organotin compounds, have been pay attention for the aquatic environment and whole ecosystem.
2. Endocrine Disruptor Chemicals
In order to figure out how much does EDCs hazard organism, the concept of EDCs should be introduced first. EDCs (Endocrine Disruptor Chemicals) encompass a variety of chemical classes, including natural and synthetic hormones, plant constituents, pesticides, compounds used in the plastics industries and other industrial by-products and pollutants. They are often pervasive and widely dispersed in the environment. Some are persistent which can be transported long distances across national boundaries and have been found in virtually all regions of the world. Others are degraded in the environment or human body or may be present for only short periods but even worse, at critical periods of development (WHO, 2002).
2.1.1 Effects on Endocrine Disruptors
As the introduction above, the sources of EDCs are variable and vary widely dispersed around the world. There are several historical examples of toxic exposures or contamination that show a direct causal relationship between a chemical and endocrine or reproductive disfunction in humans and wildlife. What was clearly related to disturbances in the hormonal system of these organisms by exogenous chemical compounds is the imposex in mollusks and feminization in fish. Contamination of industrial chemicals from a wide range of areas may leach into soil and groundwater. As the result, these complex mixtures enter the food chain and accumulate in animals higher up the food chain such as humans and other predatory animals through bioaccumulation process, thus, for developing a reproductive or endocrine abnormality. Consequently, it is suspected to change the functions of endocrine system causing adverse health effects in organisms or from its offspring to populations.
Moreover, identify appropriate policy action on the basis of the precautionary principle in order to respond quickly and effectively to the problem, thereby alleviating public concern. Exposure issues and methodologies for EDCs are generally similar to those of other chemicals. This section (Table 1) briefly summarizes the following general exposure issues: sources of exposure, fate and transport in the environment, exposure pathways in various media, bioavailability, bioaccumulation and pharmacokinetics, and internal dose.
Table 1. Illustrative Examples
For the invertebrates, a major problem is the insufficient knowledge regarding the hormone systems of these animal taxa for setting suitable endpoints to assess endocrine disruption. The complexity of reproductive systems of invertebrates has resulted in the evolution of endocrine control systems significantly different from those of the vertebrates (DeFur et al., 1999; Pinder et al., 1999; LaFont, 2000). Therefore, whether vertebrate endocrine disrupters especially related to estrogens and estrogen mimics also present a risk to invertebrates or not is still not clear.
In humans, endocrine disrupters have been suggested that they gave apparently changes in human health patterns over recent decades. These included declining sperm in some geographical regions, increased incidences in numbers of male children born with genital malformations and certain types of cancer which were known to be sensitive to hormones and more controversially included impairment in neural development and sexual behavior too.
In Wildlife, most of these exposure data came from selected species at the top of the food chain in a contaminated habitat. However, exposure data for non-persistent EDCs, for other wildlife species, at low environmental levels are generally lacking. We still can see also the diversity of the aquatic wilds create numerous challenges in determining the potential risks of EDCs to the health of these animals.
3. Scientific Findings
3.1.1 TBT (tributyltins) case
Take only one of the EDCs, TBT, for example. In fact, TBT belongs to the group of trisubstituted organotins. Moreover, TBT degrades less rapidly in the sediment than has been anticipated. It is broken down in water in a matter of days or a few weeks but its half life in sediment may be a matter of months or even years. Furthermore, TBT is extremely toxic to aquatic organisms in general and to molluscs in particular, even in low environmental concentration, for which the NOELs are below 1μg-1 (imposex, calcification anomalies).
The enhancement of TBT concentrations in the surface microlayer may present a hazard to littoral organisms, neustonic species (including benthic invertebrate and fish larvae), and surface-feeding seabirds and wildfowl. Accumulation and low biodegradation of TBT in sediment may pose a hazard to aquatic organisms when these polluted sediments are disturbed by natural processes or dredging activities. There are a number of reports on the occurrence of TBT residues in marine organisms. Levels of total butyltin residues of 5-230 ppb in muscle of fish; 300 ppb in liver and kidney of marine birds; and 13-395 ppb in muscle of marine mammals have been reported. In marine mammals, much higher total butyltin residues were reported for blubber (48-744 ppb), kidney (25-3210 ppb), and liver (40-11340 ppb).
In Biotic breakdown of tributyltin is a progressive oxidative debutylization founded on the splitting of the carbon-tin. TBT is only slightly soluble in seawater: 1-10 mgl-1 for TBTO. TBTO is moderately to highly acutely toxic to laboratory mammals. Short-term study is focusing on effects on the immune system (Table 3).Long-term study finds the relationship in carcinogenicity (Table 4).
In the only study involving repeated inhalation exposure that reported effects in the respiratory tract, rats (10 males and 10 females per dose) were exposed in"nose-only" chambers for 4 h to TBTO doses of 0, 0.03 (vapor), 0.16 (vapor), or 2.8 (aerosol) mg/m3, 5 days/week, for a total of 21-24 treatments. At the highest dose, severe toxic effects were produced. Mortality was 5/10 in males and 6/10 in females. In addition, inflammatory reactions (not further specified) in the total respiratory tract and histological changes (not further specified) in the lymphatic organs were observed. No local or systemic changes were observed at the lower doses (WHO, 1999).
Table 3. Summary of Toxic Studies on TBT
Table 4. Neoplastic lesions in rats
Since we have known TBT is highly toxic to various aquatic organisms, it is still released into the marine environment through TBT-based antifouling paints used on ships. Tin, the basic substance used in TBT, is very effective for persisting longer time than the normal additive in paints, but is more poisonous. Measurements taken prior to restrictions on TBT use in antifouling paints had shown levels generally ranging between 50 and 500 ngl-1 in European marinas. By the late 1980s, high TBT concentrations were still recorded in European harbor waters (10-1500 ngl-1) and coastal waters (<2-50 ngl-1). The highest values (above 1μgl-1) were found in the Mediterranean Sea (tideless sea), in major harbor areas and, on a single occasion, in the vicinity of a discharge outlet for TBT-treated cooling water (Lintelmann J. etc, 2003)
Today, maximum concentrations in marina waters rarely exceed 100 ngl-1 along the English Channel and Atlantic coasts (average 42 and 22 ngl-1 respectively) and 200 ngl-1 along the Mediterranean coast (average 42 ngl-1). In 1992, it is reported that maximum concentrations of 17 ngl-1 in the estuaries and above 100 ngl-1 in the harbors and shipyards along the English and Welsh coasts. Since the great stability of the TBT adsorbed onto sediments, contamination is sometimes found to reach very high levels, reflecting the long-term storage capacity of this compartment. In harbor areas, average concentrations generally range between 1 and 2 mgkg-1 dry weight (Alzieu C., 1998).
Apart from affecting marine organisms like bacteria, tubeworms, shellfish and algae which cling to the hull of a ship, TBT also affects non-target marine organisms such as oysters and mussels, causing them an abnormal shell development, imposex and leading to poor weight gain. Nowadays, TBT is further found to bioaccumulate in fish, dolphins, whales, and other sea mammals, and it negatively affects a range of invertebrates, even causing death.
3.1.2 A case of the Baltic Sea
Take the case in Baltic Sea instance, it says that potential endocrine-mediated adverse effects have been observed in a number of species in the Baltic Sea. Examples include an increased prevalence of female salmon producing offspring with a low survival rate; lowered reproductive capacity and eggshell thinning in white-tailed sea eagles, razor bill, and guillemot, and immune and reproductive impairment in marine mammals.
Take DDT and PCBs as an example of EDCs. The concentrations of DDT and PCBs were highest in white-tailed sea eagle eggs sampled during the 1960s and 1970s, and although these levels decreased during the 1980s and 1990s, concentrations remain high compared with species lower in the food web. the food web. Figure 1 summarizes data on total PCB and DDT concentrations for species at several trophic levels for the periods 1969-1972 and 1988-1998.
Figure 1. Representative concentrations of total DDT and PCB
According to the results of the phenomenon of these organisms, we have reasons to believe that there is some relationship between these two appearances.
Therefore, endocrine disruptors have clearly been shown to cause abnormalities and impaired reproductive performance in some species, and to be associated with changes in immunity, behavior and skeletal deformities (WHO, 2002).
4. Decisions now active in Europe:
So far, one examples of EDCs, especially TBT, were introduced as a very effective antifouling paints in ships, however producing TBT using on small vessels on ships was banned in the mid 1980s due to cause unwanted effects on marine organisms such as oysters and gastropods.
According to the regulation (EC) No 782/2003, which have been published, of the European Parliament and of the council on the prohibition of organotin compounds on ship, we take more attention on the purpose of this Regulation to reduce or eliminate adverse effects on the marine environment and human health caused by organotin compounds, which act as active biocides in anti-fouling systems used on ships flying the flag of, or operating under the authority of, a Member State, and on ships, regardless of the flag they fly, sailing to or from ports of the Member States. In the action part, we will focus on the one of the EDCs-TBT, which seems more possible to pollute the European aquatic ecosystem.
Actions:
What's more, over 70 scientists and policy-makers from the EU, USA and Japan as well as from organizations such as OECD, WHO, ESF and CEFIC and non-governmental organizations, concluded that due to some cases exist in the EU marine where adverse endocrine effects, or reproductive toxicity, in birds and mammals coincide with high levels of substances, shown to have endocrine-disrupting properties in some test systems.
Therefore, in the EU, an increasing number of parliamentary questions have been addressed to the Commission since 1997 concerning the use and regulation of a range of suspected endocrine disrupting substances. In 1997, the European Parliament decided to draw up an 'own-initiative' Report on the topic, which was debated and voted on in the Plenary Session in October 1998. Also, The Court of Justice, in its Judgement of 5 May 1998, C180/96, Point 99, has said that "where there is uncertainty as to the existence or extent of risks to human health, the Commission may take protective measures without having to wait until the reality and seriousness of those risks become apparent".
Somehow, the AFS convention set restrictions on the marketing and use of certain dangerous compounds like organotins urging to prohibit sale and marketing on the application of organotin compounds. The EU legislation should not duplicate the decision of the AFS conference, but contrast to it, this regulation should not affect on the marketing and use of certain dangerous substances. Instead of, they considered the situation of third countries and shipping industry.
At the end, the entry into force of this regulation should be such as to allow the effective prohibition of organotin compounds on ships as soon as possible. This is the contents added in the EU regulation 782/2003 as follows.
This Regulation shall apply to:
(a) Ships flying the flag of a Member State,
(b) Ships operating under the authority of a Member State, and
(c) Ships that enter a port or offshore terminal of a Member State.
Prohibition of the application of organotin compounds which act as biocides
Organotin compounds which act as biocides in anti-fouling systems shall not be applied or reapplied on ships. However, during the interim period this provision shall only apply to ships referred to in points (a) or (b) the former.
Prohibition of the bearing of organotin compounds which act as biocides
1. Ships entitled to fly the flag of a Member State, and whose anti-fouling system has been applied, changed or replaced after that date, shall not bear organotin compounds which act as biocides in anti-fouling systems on their hulls or external parts and surfaces, unless they bear a coating that forms a barrier to such compounds to prevent them leaching from the underlying non-compliant anti-fouling system.
2. The ships referred to above shall not bear a coating that forms a barrier to such compounds leaching from the underlying non-compliant antifouling system.
5. Stakeholders
Take one of the EDCs, TBT, as the example, Stakeholder - state, industries (shipping, paint manufacturer, fishing and aquaculture) and others (non-government organization, environmental organization, international transport worker's federation et al.) who don't want to ban of organotin compounds, of course there are some conflicts between them. The shipping industry which is a major stakeholder gave a big opposition against the decision because as above we said TBT is highly effective antifouling paints so they never gave up. Also, manufacture and sales of TBT-based paint are not prohibited so far, but some have urged for voluntary initiatives from the paint manufacturing industry to stop the manufacture and sale of organotin-based paints then, paint manufacturers would not welcome of the ban of manufacture and sale of TBT-based paints. Furthermore, International Transport Worker's Federation for development in the transport industry of the world is in conflict with the government.
On the other hand, Fishing and aquaculture industry is expected to benefit from the EU regulations, and their feedback may be crucial in monitoring the effective implementation. Besides, some Environmental organization like NGOs, play an important role in the manifestation of the decision. Biological invasions in the marine environment represent a serious ecological and economic menace leading to biodiversity loss, ecosystem imbalance, and fishery and tourism impairment.
6. Discussion
To sum up, with the development of the new technology and method, we will find out more and more evidences of harm of EDCs to organism. In the scientific finds part, one of the EDCs, TBT, has been introduced hazard to wildlife and mankind, even in the low concentration. Moreover, the case of Baltic Sea also proved that EDCs are so harmful for the animals. Furthermore, there are a lot of rHYPERLINK "http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJ7-4TTNCJ9-1&_user=10&_coverDate=02/15/2009&_rdoc=1&_fmt=full&_orig=gateway&_origin=gateway&_cdi=6871&_sort=d&_docanchor=&view=c&_searchStrId=1664153522&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=774895560ca9852d275c4aa8e831b141&searchtype=a#sec3"elated international conventions, such as OSPAR,CEMP assessment and North-East Atlantic and International Action for protection to eliminate pollution by hazardous substances from land-based sources. As like those regulations, this decision had considerable influences on other international and national decisions. It is a signatory to many international conventions for the protection of marine environment but not all of the country. In many developing countries, the risks related to EDCs antifouling are not commonly known or generally recognized as a problem because there is no or little monitoring program of EDCs in sea and it might be difficult. Moreover, so far, although many EDCs are listed out, still many potential EDCs are unknown. Also, those mechanisms are unknown, yet. However, this kind of international regulation drives a more general awareness of the issue.
In other words, the EU regulation has played an important role in promoting a global ban on, for example, organotin antifouling paint which directly affects the entire EU fleet and all ships with EU ports as destinations. It harmonizes the antifouling requirements within the member states to a standard equivalent to the AFS Convention, making it easy for these states to ratify the Convention and further prevent distorted competition that favors the least environmentally responsible ship owners. The EU ban of TBT antifouling shows the potential of the EU to have effect on at least its member countries to the whole world.
Therefore, we think EDCs, include TBT, should be banned in European aquatic ecosystems. Moreover, with an integrated point of view, the whole ecosystem from a precautionary approach of the possibility that small effect extends to strong long term effects, though there are rare information about low concentration of EDCs will have potential risk the wildlife and mankind. As The Court of Justice has said "where there is uncertainty as to the existence or extent of risks to human health, the Commission may take protective measures without having to wait until the reality and seriousness of those risks become apparent".
