Friday, 21 December 2012

Ecoratorio’s article on Human-Animal Conflicts in ‘The Ship’ , a 100th anniversary publication of St. Anne’s College, University Of Oxford, UK.


We came to know that Sarah Stephen’s article exploring  Human-Animal Conflicts was published in the 100th anniversary edition of ‘The Ship', a publication of St. Anne’s College, University of Oxford, UK, where she had been a student. You can read it here






Wednesday, 19 December 2012

Why where you work could influence risk of breast cancer



Workplace plays a pivotal role in influencing cancer risk

WHO statistics show that 19% of all cancers are attributable to the environment including work settings, and result in 1.3 million deaths annually worldwide. In reality, the actual figure could be much higher than this, as an individual’s genetics, physiology, exposure to environmental cancer causing agents (carcinogens) and life style invariably crisscross and therefore it is seldom possible to study environmental exposure and cancer in isolation. One thing is clear, that cumulative exposure to certain environmental agents, could either initiate cancer, or be involved in its progression. Breast cancer is the most common cancer among women in many industrialised nations. Roughly 48,000 women in the UK and 226, 870 women in the US get breast cancer each year.  Hormones, notably estrogen, play an important role in breast cancer progression.  Several studies have shown that environmental agents exist, that interfere with hormones by mimicking them or by disrupting them called endocrine disruptors.  Those that mimic the effects of estrogens are called xenoestrogens. Well known synthetic  xenoestrogens  include Polychlorinated biphenyls (PCBs), BPA (Bisphenol A)and phthalates, which are widely used industrial compounds.


Whilst several laboratory studies implicate a link between environmental exposure and breast cancer, large scale population studies have been inconclusive. This is understandable as the laboratory systems are simplistic and can study factors in question in isolation. In the 1990s, NIEHS and the NCI conducted a large study on the environmental causes of breast cancer, to investigate the increased breast cancer rate in Long Island, New York . In the study, scientists focused their investigation on three widespread pollutants - organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons (PAHs), to which many of the Long Island residents had been exposed. Whilst a small increase in breast cancer risk was due to PAH exposure the researchers were unable to identify any environmental factor that could be responsible for the high incidence of breast cancer area.

Approximately the same time as the Long Island studies, across the border, in Essex and Kent counties of Southern Ontario, Canada, the local cancer hospital staff raised alarm about industrial workers developing breast cancer. This area then became the subject for studies which showed a link between cancer and industrial/agricultural work settings, but the questions explored in the study were not complete. A subsequent study in this region ( recently published) which has a stable population and diverse modern agriculture and industry was used for more thorough investigations and provided interesting observations. Cases were recruited over a six year period from mid 2002 through to  mid 2008 and  the occupations of 1006 women who had breast cancer and 1146 randomly selected women from the community without this disease were analysed . The results showed that women working in environments with risk of high exposure to carcinogens and endocrine disruptors had a high risk of developing breast cancer. Notable sectors with high risk were the agricultural sectors (where pesticides are used), automotive plastics manufacturing sector, food canning industry, metalworking industry and bars/gambling industry (second hand smoke exposure risk). The researchers also found that premenopausal breast risk was highest in those women working in the plastics industry and food canning industry.

The study provides resounding evidence for linking occupational exposure of endocrine disruptors/ carcinogens and breast cancer risk warranting further studies. With people generally spending an average of 8 hours at work, working environments are major influences of cancer risk. Employees  are often not made aware of  their risks of harmful exposures at work and  how they could reduce exposures. Evidently, most of the exposure risks for occupational cancers are preventable.  A clean working environment should be the basic right of a worker. A resolution by the World Health Assembly in 2005 on cancer prevention and control urged countries to develop programmes aimed at reducing cancer incidence and mortality. This resolution advocated for special attention to cancers prevention by avoiding exposure to chemicals at the workplace and in the environment.  Though, it remains to be seen what cancer prevention programmes have been developed or implemented in the workplace, to what extent,  and how it compares between different countries.


References:
Brophy, J., Keith, M., Watterson, A., Park, R., Gilbertson, M., Maticka-Tyndale, E., Beck, M., Abu-Zahra, H., Schneider, K., Reinhartz, A., DeMatteo, R., & Luginaah, I. (2012). Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case--control study Environmental Health, 11 (1) DOI: 10.1186/1476-069X-11-87

DeMatteo, R., Keith, M., Brophy, J., Wordsworth, A., Watterson, A., Beck, M., Ford, A., Gilbertson, M., Pharityal, J., Rootham, M., & Scott, D. (2012). Chemical Exposures of Women Workers in the Plastics Industry with Particular Reference to Breast Cancer and Reproductive Hazards NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy, 1 (-1), 427-448 DOI: 10.2190/NS.22.4.d

http://www.ncbi.nlm.nih.gov/pubmed/23207955


Thursday, 13 December 2012

A common fungicide used on leafy vegetables could make people fat



Obesity is on the rise globally. World Health Organization forecasts 2.3 billion overweight adults in the world by 2015 and greater than 700 million of them to be obese. In the UK, as in most industrialised nations, obesity is increasing. Figures show that 62.8% of UK adults (aged 16 or over) were overweight or obese as are 30.3% of children (aged 2-15). A recent report released by the NHS (National Child Measurement Programme) indicates that in the UK 1 in 3 of primary school children in the last year are overweight/obese.

The health implications of obesity are enormous. Studies suggest that obesity could have a causal effect or increases the risk of  several diseases, notably type 2 diabetes, heart disease,  liver disease, and selected cancers. Three major factors that influence obesity are diet, environmental factors and physical activity.

Several studies have shown that maternal diet and exposure to environmental agents has a crucial effect not only on the health of the woman, but also on foetal and child health. Our earlier post looked at how exposure of pregnant mothers to pesticides can leadto obesity in children and put them at risk for heart disease. We also discussed one study where maternal exposure of phthalates make their way to the offspring and can have detrimental effects.

Chemicals that increase either the number of fat cells in an organism or the amount of fat stored in those cells and promote weight gain are called obesogens. Notable culprits are environmental agents such as bisphenol A, phthalates, organophosphate pesticides etc. Some scientists hypothesise that the obesity epidemic that is seen could have links to the increased exposure  to pesticides.

Triflumizole (TFZ) is an imidazole fungicide that is used during the cultivation of  many green leafy vegetables.Whilst TFZ is not classified as toxic, its effect on development is unknown. A recent study by researchers in California shows that this fungicide promotes adipogenesis (the process by which precursors of fat cells become fat cells) in laboratory experiments with human and mouse cells in culture and also in animal models. They found that stem cells that have the potential to develop into bone, cartilage, or fat cells,  upon treatment with the fungicide, ended up as fat cells. The researchers also observed that levels of genes related to obesity increased with treatment of both human and mouse cells. Exposure with the fungicide also resulted in fat accumulation. More interestingly, exposure of pregnant mice with the fungicide at very low doses (roughly 400 fold below the levels that show no observed adverse effect ) increased mass of fat depot (where fat tissue is stored) but were not shown to increase body weights. The study further showed that blocking PPAR gamma (Peroxisome Proliferator Activated Receptor gamma)  pathway using a specific antagonistic drug, stopped the differentiation into fat cells  suggesting that that  TFZ acts through this receptor. PPAR is found in the nucleus of the cell ( hence called nuclear receptor)and functions as a transcription factor (that which switches on  genes and controls the levels). Interestingly other nuclear receptors include the receptors for estrogen, thyroid hormone, retinoic acid, Vitamin D etc. These receptors have also been shown to interact with each other. It appears that TFZ could also be grouped under ‘endocrine disruptor’  (hormone disruptor). 


Very little information exists about the exposure and the levels of TFZ in humans. The scientists suggest that further studies that monitor the levels of TFZ and its metabolites in humans must be carried out to decipher the role of the chemical’s potential influence on obesity. However one fact is clear that TFZ is now in the list of potential new obesogens. Eating green leafy vegetables is good for health, but this maxim only holds true when it is  pesticide/fungicide free.

PS- TFZ is also licensed for used on a variety of fruits and vegetables in the US (Personal communication with Dr. Blumberg, one of the authors of this study). 



Reference:
Li, X., Pham, H., Janesick, A., & Blumberg, B. (2012). Triflumizole is an Obesogen in Mice that Acts through Peroxisome Proliferator Activated Receptor Gamma (PPARγ) Environmental Health Perspectives DOI: 10.1289/ehp.1205383 

Monday, 10 December 2012

When two worlds collide : Tales from two continents



Western Ghats-  A hotspot of biodiversity



With advances in health care, eradication and effective control of fatal diseases, the world population is on the rise. One collateral effect is the enormous consequence of such an increase on natural resources including land. Humans with their might are encroaching into the forests- the natural habitat of wild animals. Consequently, whilst human inhabited lands increase, the forests decrease proportionally. As has been highlighted repeatedly, the areas in the world that are maximally impacted are the tropics, which are the areas of highest human population density. Here, forest areas are cleared, making way for habitable land (legal and illegal), agricultural land (be it subsistence farming, large scale crop cultivation, or as land for livestock grazing),  stone quarrying, or the wood from the forest is used for fuel and furniture. The consequences of all these actions are colossal, and have led to brutally endangering the existence of flora and fauna. One group of animals that are gravely affected are the larger mammals, whose territory encompasses larger areas. The Royal Bengal Tiger, a subspecies of Tiger, is in the IUCN’s list of endangered species with only about 2500 animals alive today. A census report released in, 2011 by the National Tiger Conservation Authority, estimates the current tiger number in India at 1,706.

Kerala, one of the most densely populated states in India and at 859 persons per sq km, is thrice as settled as the rest of India. Once blessed with luxuriant forests; nearly three quarters of the geographical area of Kerala was under dense forest cover at the middle of nineteenth century, human activities have restricted the forest cover to 20 to 24 % area, based on the source for the facts. The Western Ghats comprise a range of mountains along the western side of India extending to Kerala and is abundantly diverse and is the habitat of at least 325 endangered flora and fauna species. When the Western Ghats was designated as a UNESCO World Heritage Site, as one of the eight hotspots of biological diversity in the world, the Kerala minister of forests highlighted the enormous challenge of protecting this fragile yet diverse landscape citing the pressures of development and population growth.



The forests in Kerala in the Western Ghats are of different types, depending on the area, elevation, proximity and other environmental factors, consisting of tropical rain forests, tropical moist deciduous forests, tropical dry deciduous forests, montane sub tropical forests, sholas, reed brakes, grass lands,  pockets of temperate forests and barren hillocks. The diverse forests promote diversity of animals and are home to endemic species. Estimates suggest that 17% of the world’s tigers live in the Western Ghats. There are 17 wildlife sanctuaries and 5 national parks, and 1 community reserve – areas that are legally protected, in Kerala. However human- animal conflicts occur as have been previously discussed in our blog (http://ecoratorio.blogspot.co.uk/2011/07/fine-line.html)  in areas where the activities of the parties overlap, and that is not that difficult in Kerala with such high population density.  Occasionally cases are reported in the press, where a tiger, leopard, bear or elephant strays into the human communities. Whilst sometimes, the animals are coaxed into retreating from the human settlements, often their foray has disastrous consequences. The Western Ghats run throughWayanad which has a wildlife sanctuary that is shared by the neighbouring states and has a high tiger and elephant density. Earlier this year, a tiger strayed into coffee plantation in Wayanad district in Kerala. The tiger that had strayed into the plantation was reported to have preyed on domestic animals, was successfully trapped by officials and then released back into the wild ; an example of a situation which had gone according to plan. But such stories are exceptions as exemplified by the recent tragic incident. Recently, a tiger strayed into avillage area, again in Wayanad, reportedly preying on domestic animals. The wildlife authorities, attempted to tranquilize the animal. The first ‘tranquilizing’ did not affect the animal and the animal escaped. Meanwhile an ‘uncontrollable crowd’ had surrounded the forest officials on the witch hunt. After some time, the authorities and the mob found the agitated animal. The officials tried to tranquilize it again.  The animal was understandably violently aggressive, and was this time was repeatedly shot at and killed by the forest officials. It was a 10 year old male tiger. 

A Tiger at the London Zoo. Are tigers only going to be safe in captivity? (Photo : Sarah Stephen)


Environmentalists and environmental enthusiasts are bitter and distressed at the outcome. One environmentalist  who has worked extensively on biodiversity  in the Western Ghats condemned what had happened as ‘barbaric and insane’. He commented, ‘The hunting of this tiger was carried out by creating panic and insecurity among the public, that this tiger which had killed so many livestock, will eventually become a man eater.’ Several questions remain as to why the authorities resorted to the cold blooded killing of the tiger in broad daylight. It has been alleged that when the tiger embarked on the cattle hunt; the people were infuriated, blocking roads, setting ablaze the forest office, and demanding that the tiger be shot dead and that the authorities appeased the people by killing the animal. The environmentalist added, ‘The mass search of the forest areas with gunmen and a huge uncontrollable crowd following them was not the way to tranquilize an animal.’  Some sections of the media say that the story is much more complicated than what it appears to be and that illegal land mafia gangs are behind this. Allegations are rife that these unscrupulous cliques, who wanted the forests to be cleared for land, incited scare among the people in the pretext of the tiger menace, and that the animal paid a heavy price.

A task force will now conduct an independent enquiry.

Despite such incidents, some hope remains, a wildlife survey of 2011 indicates that in the state, the elephant population is growing.
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Closer to home, a few weeks ago, one peaceful Sunday afternoon was interrupted by the sound of a gunshot. As the hunting season has started in the county, it is not uncommon to see people dressed in hunting attire, en route hunts and distant sounds of shots being fired are not uncommon. But this time, the deafening noise was closer to our house. It transpired that someone had shot two squirrels. For some time, it had been a common sight seeing squirrels scurrying up and down with nuts and burying them in the gardens. They had provided unlimited entertainment to the enclave where we live. Brown squirrels are classified as vermin and can be legally shot. However, I will never comprehend the mentality of macabre recreational shooting.
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PS: If you witnessed the tiger incident or have comments on the issue, please use the comments field to voice your opinions. 

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References:
http://whc.unesco.org/en/list/1342
http://www.iucn.org/?6481/IUCN-Council-statement-on-the-tiger.
http://timesofindia.indiatimes.com/city/kozhikode/NTCA-to-conduct-independent-probe-into-Wayanad-tiger-killing/articleshow/17484167.cms
http://www.thehindu.com/news/states/kerala/straying-tiger-meets-with-a-bloody-end/article4159420.ece
http://www.thehindu.com/news/states/kerala/tiger-killed-in-wayanad-was-not-a-maneater-maneka/article4160564.ece
 http://www.manoramaonline.com/cgi-bin/MMOnline.dll/portal/ep/malayalamContentView.do?contentId=12949143&programId=1073753760&tabId=11&contentType=EDITORIAL&BV_ID=@@@
http://www.thehindu.com/news/states/kerala/article3240036.ece
http://keralaforest.gov.in/index.php?option=com_content&view=article
http://www.thehindu.com/todays-paper/tp-national/forest-officials-blame-land-mafia-for-protests/article4118109.ece.

Wednesday, 26 September 2012

You've drunk from this can before


 Aluminium recycling has many advantages for the environment, in reducing the need for mining (see http://ecoratorio.blogspot.com.br/2011/06/dams-on-xingu.html) and waste disposal. Aluminium is found in all sorts of things, but because of their rapid turnover and ease of handling, recycling normally means drinks cans. Of course, for it to be meaningful recycling has to be done on a large scale. A very large scale.

In 2009, according to the Associação Brasileira do Alumínio, Brazil recycled 98,800 tonnes of cans for their aluminium content, that's about 14 billion units. Much of this recycling is done at the Novelis plant in Pindamonhangaba (owned by the Indian Adytia Birla company), conveniently located on the main road between the two largest cities in Latin America, Sao Paulo and Rio.

What's driving all this is simple economics. Brazil produces aluminium ore (bauxite), in fact Brazilian production is 3rd in the world (28,000 tons in 2009) behind Australia and China. But actually getting the aluminium out of the ore is a complicated and energy intensive process, whilst recycling of aluminium cans involves, more or less, just melting them. Well, there is of course more to it than that, but still the process uses about 5% of the energy needed to produce "fresh" aluminium, with equivalent savings in production costs.

You still need a raw material. Brazil has the highest can recovery rate in the world at 85%, ahead of even Japan at 82.5%. This in turn is helped by low labour costs. Many of these cans are separated by hand, either at waste disposal sites or directly from bins, and men pulling carts of crushed cans are not uncommon. The Inter Press news agency quoted a can collector in Rio in 2010 who collected 15 kilograms of aluminium cans a day, selling them to the collection center for about 30 reals (17 dollars at the time). This isn´t much, but supports many thousands of people around the country. Even then, supply cannot meet demand. Every day trucks arrive at Pindamonhangaba loaded with crushed cans from all over South America, and the world. Over 42,000 tonnes were imported last year, from countries as far afield as Albania and Saudi Arabia.

So, for recycling to really work it has to make, not lose, money, which pays for the infrastructure. The difference in cost between recycled and ore-derived aluminium ensures that, in this case, can collection is well worth the effort.

Inter Press news agency.
http://www.ipsnews.net/2010/08/brazil-world-leader-in-recycling-aluminium-cans/


Globo News Brasil
http://g1.globo.com/jornal-nacional/noticia/2012/09/empresas-brasileiras-ganham-dinheiro-reciclando-aluminio.html

Saturday, 22 September 2012

The future of the Dead Sea

You could say that Ein Gedi is literally after miles of endless highway, past scattered kibbutzim. This windy beach on the western coast of the Dead Sea was teeming with hordes of tourists plastering themselves with mud and floating on the water to the backdrop of Cutting Crew’s “(I just) died in your arms tonight” and lots of human poo on the beach and on the sea itself (which dissuaded us from getting more adventurous). Although  it was late autumn, it was warm (around 24-25 deg C); the sun shone in all his glory, but (incongruously) we noticed the lack of searing heat (explained by being located in the lowest altitude in the world at around 415 m below sea level- due to the high barometric pressure, UV radiation is low).

A misnomer, Dead Sea is a saline lake, extending for approx. 60 kms, located in the Jordan Rift Valley and sandwiched between Lake Tiberias in the North and the formidable Red Sea in the south and surrounded by hostile hills and mountains. The adjective 'dead' illustrates that the lake is practically devoid of life due to its extreme saline content (nearly 9 times more saline than the oceans). There were some exceptions (the Dunaliella algae which nourished halobacteria) when the salinity dropped due to flooding. The surrounding barren terrain has wildlife (hares, ibex, jackals, etc). The water is supposedly curative and therapeutic and there is a booming mineral/salts/mud industry (I too have a hand cream of Dead Sea salts- and I must admit that it does its job).

The Dead Sea is historically significant. The Bible refers to it as the Sea of Salt (Genesis 14:3) or the Eastern Sea. More significantly, the destroyed towns of Sodom & Gomorrah ("the cities of the plain") are said to be under the lake (others maintain that the towns were in Mt Sodom); indeed, overlooking the lake is a rock formation considered to be Lot's wife who was transformed into a pillar of salt when she disobeyed the angels' instructions and turned back to look at the cities being destroyed by God. David hid from Saul in the wilderness surrounding the lake and several centuries later, people used to hide in the caves by the hills bordering the lake.

The major sources of the lake are the Jordan River itself and the Dead Sea wadis. However, the river water is now predominantly diverted for human purposes by three countries (Israel, Jordan, and Syria). Since the lake is in the rain shadow area, rainfall is negligible (2-4 inches per annum). Compounding this is the high evaporation rate due to high temperatures and low humidity. All of this has contributed to a rather grave situation- the shrinking of the lake (more popularly known as the Death of the Dead Sea). Some sources state that the lake has lost a third of its surface area, with the water level falling by more than 80 ft in the past 8-9 decades (and a fall of around 2-3 ft each year). Indeed, as seen in the satellite map, the southern half of the Dead Sea is separated from the northern half, connected by a canal, which prevents the southern part from drying up completely.

On the flip side, many industries depend on the lake for their profits (and even existence). Many are the hotels and resorts by the Dead Sea with customers keen on either floating in water (due to the high salt concentration) or taking advantage of the supposedly therapeutic nature of the mud and water. And there is also a lucrative trade on Dead Sea minerals and chemicals (who are also identified as one of the banes of the lake since they evaporate the waters to obtain the products).

Some preventive measures have been proposed:
1. Siphoning water via a canal (specifically, from the Gulf of Eilat): The intention is to desaline the waters from the Red Sea and diverting the desalinated water towards Jordan and discharging the brine in the Dead Sea. Proponents justify this by pointing out how the waters in the lake would be replenished and surrounding countries address water and electricity problems. However, this does not consider the impacts (and consequences) on the lake's limnology, geochemistry, and ecology (Gavrieli et al, 2005). For instance, there would be increased evaporation due to the relative dilution- which could also result in blooming; another consequence is the change in composition and the accumulation of sea salts- one outcome of this would be a reduction in the therapeutic qualities.
2. A sustainable method of harvesting the Dead Sea minerals (instead of evaporation)
3. Efficient harvesting of the even-if-minimal rainwater. This would decrease the dependency on Jordan River.
4.  Increasing the flow of water from Jordan River which might be achieved by reducing farming in the region

Any thoughts on what else could be done?
 Radwan A. Al-Weshah (2000). The water balance of the Dead Sea: an integrated approach Hydrological Processes, 14 (1), 145-154 DOI: 10.1002/(SICI)1099-1085(200001)14:1
Gertman, I., Hecht, A (2002). The Dead Sea hydrography from 1992 to 2000. Journal of Marine Systems, 35, 3–4, 169–181.
Gavrieli, I, Bein, A., Oren, A. (2005). The Expected Impact of the Peace Conduit Project (The Red Sea – Dead Sea Pipeline) on the Dead Sea. Mitigation and Adaptation Strategies for Global Change, 10, 1, 3-22,

References:

Image source: Google maps

Friday, 21 September 2012

Country tales: A game of tennis, a newt and a country estate

Living in the English countryside has several disadvantages such as no Starbucks in the vicinity, few buses to the nearest town (which is not really a town, but, shhhh, don’t tell the locals!), no cinema, no book store, no supermarket, etc.  But there are also advantages: miles and miles of beautiful countryside, clear air, less populated, less polluted, and being in close communion with nature, which includes having pheasants stray into your garden, having wild ducklings visit your garden, a glass snake slowly sneaking through the conservatory door, swarms of insects invading your  kitchen when combined harvesters plough through the fields. The countryside can also be brutal- you realise that the innocent and cuddly lambs grazing on the fields are destined for the slaughterhouse and then would be neatly packaged for the shelves in Sainsbury’s or Tescos. You see dead pheasants, foxes, rabbits, pigeons, doves, cats, and badgers on the road – unsuspecting causalities that have strayed into the country roads that have 60 mph speed limit.

A couple of  Saturdays ago, being one of the rare sunny days in the part of Britain where we live, we decided to play tennis in our village tennis court. Now the net is secured in a huge wooden box with a padlock. As we were unfurling the net, we noticed an 8 cm long brightly coloured reptile-like thing. The reason, I say ‘thing’ is because it was immobile and it looked so unreal that at first glance we mistook it for a prank by one of the children. Surely a rubber toy, we thought. A close inspection proved to tell a different story. It was a newt, an amphibian, barely alive, but surely not dead. Somehow the poor creature had made its way to the padlocked net box, which had a crack at the top, and had got entangled inside the net once it was there.

Newt in the plastic bag

We gently transferred the newt to small plastic bag we luckily had with us and sprinkled some water from our water bottle. Within minutes the amphibian became alert. Now the question remained as to where to leave it. A quick pow-wow led us to two options: i. we could just release it on the grass or ii. take it to one of the ponds about 4 km away in one of the country estates where we had seen newts before. We opted for the latter. A quick drive and brisk walk later we came to our destination by which time, the newt was very alert. 

We found the ditch which had a supply of clean water and could also see several newt larvae. As we gently lowered the newt into the surrounding grass, it quickly darted off into the water , swimming off elegantly into the undergrowth. It had finally come home and we left, content, back to our tennis court.





The  permanently waterlogged ditch where the newt was released

The parish Councillor was alerted to the fact. Good thing in the villages is that the Councillors do listen. They take public service far more seriously in small villages. But that is a topic for another day.....

PS- If anyone can identify the species, please comment in the post

Photos: Courtesy Tim Whallett

Sunday, 26 August 2012

Dengue fever - the Brazilian experience


Now and again through the evening calm comes the sound of a powerful petrol motor, and soon afterwards the streets are filled with a thick, grey, pungent cloud. This is insecticide, and they are fumigating against Aedes mosquitoes, principally Aedes aegypti but also increasingly Aedes albopictus. Aedes are one of the banes of mankind, in many ways, but the worry here is Dengue fever.

Dengue, or "breakbone" fever causes fever (clearly), muscle pains and, in a small % of cases, internal hemorrhaging and death. Brazil has by far the highest numbers of Dengue cases in the world, 936,000 confirmed cases in 2010 out of 1,785,059 worldwide (52%) and 592 deaths out of 2,398. This year Rio de Janeiro alone had 31,176 registered cases up to April 7th, and 6 deaths.

There is as yet no vaccine against Dengue, although progress is being made. Just this year the results came in of a four year Brazilian study in which 180 volunteers were vaccinated, and 95% produced sufficient antibodies for immunity. This study has been increased to 800 people, and eventually there will be a full scale clinical trial of 20,000 people throughout Latin America.


You can´t catch Dengue by shaking hands, or sneezing or eating the wrong food, it has to be transmitted blood to blood, which in practice means the bite of a female mosquito. Dengue prevention measures mean mosquito prevention measures. Public health varies from city to city, but as an example, this is the situation in Vitoria (Pop. 330,500) in the state of Espirito Santo.

i) Mosquitoes can breed in any little pot of dirty water. Shops and businesses are regularly monitored to ensure there are no possible breeding sites, especially trucking and type recycling companies as tyres are notorious breeding grounds for Aedes aegypti. Failure of an inspection can result in a R$2000 fine and persistent offenders can be closed down. Vitoria has 250 inspectors for Dengue and other diseases. This is backed up by a regular television campaign aimed at households.

ii) Mosquito numbers are monitored using 35 traps around the city which both collect adults and have a space for eggs to be laid.

iii) The above mentioned insecticide "foggers" operate 120 hours per month. Additionally 22,800 manholes and culverts are treated with larvicide each week.

iv) Staff education courses and workshops.


This sounds impressive, but there are problems. The most important is probably the issue of breeding sites. Urban areas are dotted with building sites and waste ground and Aedes aegypti only needs a rain filled puddle. It doesn´t even have to be clean puddle, they can tolerate oily, polluted or even slightly brackish water. A survey of workers at a rubbish tip in Rio found 23% had had Dengue. And in Brazilian temperatures mosquitoes develop very quickly, the time from egg to adult is only 10 days at 30 C. Cases of Dengue peak from December to May, the months of hottest temperatures.

The situation in the countryside is different, as Aedes aegypti tends to be a city mosquito, and larvae are snapped up by fish in lakes and ponds. But there are still plenty of holes and puddles, and the bromeliads common to the Mata Atlantica region provide perfect, safe, breeding sites. Also, various native mammals seem to be host to the Dengue virus, though not as many as in other continents as Dengue is not native to South America. Nonetheless, scientists in neighbouring French Guyana have found the virus in rodents, opossums and bats, which suggests that it is adapting. It has also been found in the forest mosquito, Haemagogus leucocelaenus. In other words, you could completely sterilise a city of mosquitoes, and the Dengue virus would still survive in the countryside, ready to return.

The only long term hope is a vaccine.

Wednesday, 27 June 2012

Phthalate exposure alters heart muscle cell behaviour and could lead to heart disease


Phthalates, as plasticisers, are ubiquitous in the environment, found in everyday objects such as cosmetics, packaging, pharmaceutical pills, children’s toys, shampoos, detergents etc. In fact, phthalates are so pervasive that measurable levels of many metabolites are found in the urine of the general American population.

Phthalates are easily leached into the environment due to its structure; the process  is hastened as plastics age and breakdown. Exposure of humans occurs largely through diet and through contact with phthalate containing materials.

Phthalate exposures in laboratory animals have been show to affect the reproductive system leading to disruptions of hormones and could be endocrine disruptors. Phthalates have also been linked to behavioral disorders in children.  Previously in our blog, we discussed how phthalate exposure in expectant mothers could lead to aggression, conduct problems, attention problems, and depression in children. Now a new study by scientists from George Washington University, USA, explored the effect of a phthalate Diethylhexyl phthalate (DEHP)  on cardiomyocytes (cells that comprise the heart muscles). DEHP is found in a range of products such as  building materials, medical devices, paints and adhesives and also found in food products due to leaching during food production and storage. The researchers found that  Di(2-ethylhexyl)phthalate (DEHP ) can cause changes in metabolic processes in the cardiomyocytes by increasing the genes that are involved in the transport of fatty acids, oxygen consumption etc.

 So what are the implications of this finding?  Dependence of the cardiomyocytes to fatty acids for energy production could lead to an abundance of lipid intermediates and reactive oxygen species. Phthalate induced change in the heart muscle cells could lead the heart  to be sensitive to injury caused by reduced oxygen and also cause dysfunction of ventricles which could lead to a range of heart diseases resulting in heart failure. 



References:


Posnack NG, Swift LM, Kay MW, Lee NH, & Sarvazyan N (2012). Phthalate Exposure Changes the Metabolic Profile of Cardiac Muscle Cells. Environmental health perspectives PMID: 22672789


Thursday, 21 June 2012

Computer, computer, on a desk, Who is the greenest of fonts all?

We are humans, with our own unique quirks. This quirkiness also exhibits itself in our typeset of preference. For instance, Garamond is my favourite since it is neat and very comfortable to read (and, indeed, I have experimented with all fonts on Word, including MT Extra and the various Wingdings)- admittedly, the Oxonian in me often shifts towards Perpetua. But a curiosity to know more about the fonts made me stumble against something else- green fonts!


So, these are those which use less ink and paper when printing, conditional on the font size used. There are quite a many contenders for the title of greenest font. Those suggested so far are Century Gothic (font size: 10) which is supposedly better than Ecofont (font size: 10) but loses out on the paper front since the font itself is wide. This is followed by Times New Roman (font size: 11), Calibri (11), Verdana (10), Arial (11), Sans serif (11), Trebuchet (11), Tahoma (11), and Franklin Gothic Medium (11). However, Matt Robinson and Tom Wrigglesworth identified Garamond as fitting the bill.

I conducted a little experiment using normal fonts (i.e unitalicised or not bold or too narrow/wide), all size 11, from MS Office 2007 - the purpose, after all, is to write/print something readable! I have deliberately included the ruler from MS Word so that you can judge its dimensions. I apologise for the rudimentary photo- this was made using Windows Paint since I no longer have access to Adobe Photoshop.

I await your thoughts!

Wednesday, 13 June 2012

Diesel engine exhausts does indeed cause cancer in humans



In an earlier post, Sarah Stephen (April 2012, http://ecoratorio.blogspot.co.uk/2012/04/minefield-of-diesel-emissions.html ) wrote about diesel fuel emissions, its health effects, and the impending International Agency for Research on Cancer (IARC) meeting scheduled for June 2012 at which the labelling of diesel engine exhausts would be evaluated.

IARC is an intergovernmental agency which is part of the World Health Organisation with the role of conducting and coordinating research into the causes and prevention of cancer. The organisation places emphasis on understanding the role of environmental and lifestyle risk factors and studying their interplay with genetic factors in population-based studies and relevant experimental models. A major thrust of the organisation is the IARC Monographs Programme where international experts evaluate the evidence of the carcinogenicity (cancer causing property) of environmental factors.

IARC classifies environmental factors in 5 groups:
• Group 1 - Carcinogenic to humans
• Group 2A - Probably carcinogenic to humans
• Group 2B - Possibly carcinogenic to humans
• Group 3 - Not classifiable as to its carcinogenicity to humans
• Group 4 - Probably not carcinogenic to humans

Over 900 environmental agents have been evaluated by IARC since 1971 of which more than 100 have been identified as carcinogenic to humans (Group 1), and more than 300 as probably carcinogenic, or possibly carcinogenic to humans (Groups 2A, 2B).

As early as 1988, the experts at IARC classified diesel exhaust as ‘probably carcinogenic’
(carcinogenic- that which can cause cancer) to humans. Now, nearly 25 years later, after the emergence of a compelling study that occupational exhaust of miners predisposed them to lung cancer (Silverman et al 2012), the experts reconvened and reviewed all available data on diesel exhaust and cancer. They concluded that there was sufficient evidence that diesel engine exhaust can cause lung cancer. Their review also showed that there was limited evidence showing a link between diesel exhausts and bladder cancers. The experts retained gasoline exhaust in the 'possibly carcinogenic to humans' category which has remained unchanged from the previous evaluation. With the ubiquitous presence of diesel fuel exhaust in the environment contributed by vehicles and power generators and other occupational exposure, the implications of the findings is colossal. The reclassification puts diesel exhausts in the same category as asbestos and tobacco smoke well known lung carcinogens (cancer causing agents). Lung cancer is the most common cancer in the world and the most common cause of death from cancer, with 1.38 million deaths, with the majority of the cases now occuring in the developing countries (55%) which, apart from tobacco consumption, could be attributed to rapid industrialisation and low regulatory standards for vehicular emissions.
 
In the press release Dr Christopher Portier, Chairman of the IARC working group, said “The scientific evidence was compelling and the Working Group’s conclusion was unanimous: diesel engine exhaust causes lung cancer in humans. Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide.”

One question that emerges is why did it take so long for such a reclassification?  But more importantly, what are we going to do about it now?

Photos: Ruth Stephen 

References:
Silverman DT, Samanic CM, Lubin JH, Blair AE, Stewart PA, Vermeulen R, Coble JB, Rothman N, Schleiff PL, Travis WD, Ziegler RG, Wacholder S, & Attfield MD (2012). The diesel exhaust in miners study: a nested case-control study of lung cancer and diesel exhaust. Journal of the National Cancer Institute, 104 (11), 855-68 PMID: 22393209
Attfield MD, Schleiff PL, Lubin JH, Blair A, Stewart PA, Vermeulen R, Coble JB, & Silverman DT (2012). The diesel exhaust in miners study: a cohort mortality study with emphasis on lung cancer. Journal of the National Cancer Institute, 104 (11), 869-83 PMID: 22393207

Monday, 11 June 2012

Exposure of mothers to pesticides could lead to obesity in children


Environmental agents be it dietary factors, chemicals- drugs, pesticides etc. affect the genetic make-up of individuals. Conversely, changes in the genetic make-up influence variation in individual response to similar environmental agent exposure making some individuals at increased risk for developing certain diseases. Interactions between genes and environmental agents are responsible for most diseases (http://www.niehs.nih.gov/health/topics/science/gene-env/index.cfm). It is also known that exposure of expectant mothers to environmental factors affects the development of diseases in the children. A previous post explored this aspect. http://ecoratorio.blogspot.co.uk/2010/04/paper-of-week-effects-of-prenatal.html

A recent paper (Andersen et al , 2012)  ties all these facts and shows that prenatal exposure to pesticides could affect risk of cardiovascular disease development later in life. Results from a Danish study, which is a part of an on-going prospective study of the effects of pesticide exposure in early pregnancy on the growth and development in the children, offers important insight. From 1996 to 2000 pregnant women working in greenhouses, were recruited consecutively in this study and were categorized as high, medium, or not exposed to pesticides. The children underwent a physical examination at age 6 to11 years that measured blood pressure, body weight, BMI etc. The presence of a gene PON1 and the different types of this gene in the children was also studied.This gene codes for the enzyme HDL-associated  paraoxonase 1 (PON1) has anti-oxidative functions that may protect against atherosclerosis. Additionally it hydrolyses many substrates including organophosphate pesticides. Changes in PON1 ( a common polymorphism- PON1 Q192R) affects both properties. Children with PON1 192R-allele of women exposed to pesticides had higher body fat content, BMI-scores, blood pressure and increased abdominal girth than unexposed children. For children with the PON1 192QQ genotype, exposure of pesticide exposure prenatally had no effect.

This study highlights the complications in gene-environment interactions and  how maternal pesticide exposure can put children with a certain genetic make up  at risk for developing cardiovascular diseases.


Image: Timothy Whallett 
References: Andersen HR, Wohlfahrt-Veje C, Dalgård C, Christiansen L, Main KM, Nellemann C, Murata K, Jensen TK, Skakkebæk NE, & Grandjean P (2012). Paraoxonase 1 polymorphism and prenatal pesticide exposure associated with adverse cardiovascular risk profiles at school age. PloS one, 7 (5) PMID: 22615820

Sunday, 3 June 2012

Little monkeys need lots of space


This charming little creature is a White headed marmoset or "Sagui" (Callithrix geoffroyi). Tolerant of humans, they are often seen by tourists and will readily take pieces of fruit in their little hands. Classified as Least Concern (LC) on the IUCN Red List and in appendix II of CITES, surely conservation is no problem? Well, more or less.

Historically many were taken from the wild as pets, their very tolerance of man acting against them. This is tightly controlled these days, but their numbers are still decreasing. In the 21st century loss of habitat is the major problem, or more specifically, fragmentation of habitat. You might think that 20 forests of 1 km sq.would hold the same number of monkeys as 1 of 20 km sq. Indeed, given that predators tend to require much larger ranges and so are less likely to occur in small pockets, you might assume there would be more monkeys. You would be wrong (Chiarello & de Melo, 2001). There are various reasons.

a) Long term of course, small populations lack enough genetic diversity to stay healthy, but there are more immediate reasons.

b) Small forest fragments tend to favour trees and shrubs which are forest edge species, with proportionally less canopy or forest interior species (Cardoso da Silva and Tabarelli, 2000). Unfortunately, these are the very ones that produce the most fruit. Thus small monkeys, which tend to need a lot of fruit, suffer accordingly. In the same way, large fruit eating birds like macaws and toucans tend to be absent from isolated forests less than 250 hectares (Willis 1979).

Our little saguis are quite adaptable, and eat a lot of tree gum and insects (and anything really), so suffer less than fruit eating specialists, but it still cuts down their options. And they have another problem.


c). Small fragments may have fewer large fragments, but they still have plenty of cats, either native or feral from surrounding farm and residential land. Saguis and other small monkeys are especially susceptible to cats. They do their best, mobbing them and screeching, but that's not always enough. As an aside, it has been shown that being part of a "mob" actually reduces rather than increases monkey stress - it is tempting to extrapolate that to humans!

Driving through a landscape of fields and copses may appear more "natural" than a prairie of wheat or sugar cane, and it is, but maybe not that much more.

References
Cardoso da Silva JM, & Tabarelli M (2000). Tree species impoverishment and the future flora of the Atlantic forest of northeast Brazil. Nature, 404 (6773), 72-4 PMID: 10716443
Chiarello, A.G., de Melo, F.R. (2001). Primate population densities and sizes in Atlantic forest remnants of northern Espirito Santo, Brazil. International Journal of Primatology, 22, 379-396.

Willis, E.O. (1979). The composition of avian communities in remanescent woodlots in southern Brazil. Papéis Avulsos de Zoologia, São Paulo, 33, 1-25. 

Tuesday, 29 May 2012

Four continents and a fish

As a child in the seventies, I remember clutching my grandfather’s arm and marvelling at Tilapia being reared in a shallow pond in his land in a South Indian village. Many years later, one summer in the late nineties, in an oriental store in Ohio, USA, I was introduced to a packet of frozen fish which turned out to be Tilapia. Needless to say, I enjoyed it much and felt that it was one of the most delicious fishes I had ever eaten.


Fast forward to 2010… in a lakeside restaurant by the Sea of Galilee, in Israel, we were served St. Peter’s fish which was delectable. St. Peter’s fish is so named after the account in the gospel of St. Matthew where Jesus asks His disciple Peter to catch a fish, open the mouth of the fish, and find the coin that is to be paid as taxes. It turns out that St. Peter’s fish was indeed Tilapia. The species of the fish in Israel carries its small young in its mouth until large enough to survive on their own. The fish also seems to have a penchant for shining objects and is known to pick up small pebbles and bottle caps from the lake floor. In the idyllic restaurant by the Sea of Galilee, our tour guide repeatedly threw pieces of bread into the water and we could see Tilapia shoaling in and catching the food, vying with hoards of kittens and cats perched on the rocks that had learnt to traverse the shallow waters. Later I learnt that St.Peter’s fish has been used in small-scale low-technology commercial or subsistence fishing practices in that area for thousands of years.

I had forgotten all about Tilapia until recently I read the correspondence in Nature by Vitule et al arguing against the proposed law that, if implemented, would lead to the culture of invasive non-native species of Tilapia and other fishes in cages in dammed areas in Brazil.

The name ‘Tilapia’ is used loosely to describe over hundred species of cichlid fish from the tilapine cichlid tribe. Cichlids are most diverse in Africa and South America. The native cichlids in Asia are restricted to very few species in Israel, Iran, India, Syria and Sri Lanka. Other cichlids include fishes commonly grown in aquariums like the angel fish and discus. Tilapia seems to be highly resilient in the nature of its habitats-living in ponds, streams, lakes and rivers. Due to their ease of farming, size, protein content and taste they are among the top ten fish used in farming. Tilapia meat which is a good protein source, low in saturated fat, and calories does not accumulate mercury. Tilapia can effectively controls algae which they feed upon and replaces the need for the use of chemical algaecides. In Africa, they control pests such as mosquitos. Whilst native species are rich in nutrients, farmed species have low levels of omega 3 fatty acids due to their diet. Additionally, farmed fish are fed with hormones such as testosterone which may have endocrine disrupting effects in the food chains.

Whilst tilapia require warm waters to survive and cannot live in natural temperate habitats (indicating that farming of tilapia in controlled conditions may not disrupt the native species if accident release does take place), such a situation could be catastrophic in the long run in the tropical areas by leading to the disruption of native fish species. In Lake Victoria, introduction of the Nile Tilapia led to the disappearance of two native species. The alien species has a higher growth and fecundity rate compared to the native species. Rightly, Tilapia is listed in IUCN’s compendium of invasive alien species.

Farming of native species of Tilapia is beneficial as long as it is subsistence and sustainable farming. However, current aquaculture practices of non-native fishes often involves aggressive farming methods. Further culture of non-native species in cages in natural water bodies might pose significant risk to containment which could be compounded in sub-tropical and tropical environments where escape would lead to colonisation and disruption of the already fragile ecosystems. J.R.S. Vitule, the lead author of the correspondence in Nature from Laboratório de Ecologia e Conservação, Paraná, Brazil, whose research focuses on the conservation of the endemic freshwater fishes of the Atlantic rain forest and the management of non-native fish species that threaten their survival, says ‘Fish escapes are inevitable, and cage aquaculture may create a constant flow of propagules into the wild, establishment, spread and invasions’ (Personal correspondence with Dr. Vitule). Other issues relate to the release of nutrients such as fish feed that can lead to water pollution and also potential endocrine disruption (Ortiz -Rodas et al, 2008), a topic requiring further investigation. The debate continues……



References:




Image source: Sarah Stephen (image shows a typical St. Peter’s fish lunch in the Sea of Galilee)

Monday, 28 May 2012

Aquaculture of non-native fish species

What are your views on the aquaculture of non-native fish species?  Please find a survey on the side bar of this blog where you can make your voice heard.

Friday, 25 May 2012

When introductions go bad

My first sighting of the red squirrel was in Camperdown Park in Dundee in 2003. I remember that scene vividly. I had since tried desperately to see this elusive animal again but to no avail, save a brief sighting, again in Camperdown Park, in Autumn 2010. This is because although red squirrel, which is native to UK and  is  protected in Europe, is outnumbered by its foreign relative, the grey squirrel that was introduced to the UK from America. Grey squirrel has several competitive advantages including its resistance to squirrel parapox virus which is fatal to the red (grey squirrels are vectors), increased fecundity, and greater ability to digest a wider variety of food. In fact, the future of the red squirrel in the British Isles is rather precarious. The Forestry Commission estimates that there there are only 140,000 red squirrels compared to over 2.5 million greys.

Recently during a holiday near Lake Geneva, Switzerland, I encountered 2 red squirrels and 1 black squirrel  (resembled the red squirrel with respect to the ear tufts, but with a black/grey rather than red coat). You can see a video here in Youtube:  http://www.youtube.com/watch?v=g4SqcK9CME8

There is a lot of debate on how the introduction of alien species can affect the native species and tilt ecosystems, but studies indicate that certain ecosytems could be more vulnerable that others. As early as 1958, Charles Elton claimed that ecosystems with higher species diversity were less subject to invasive species as there are  fewer available niches. A recent paper by Eisenhauer et al shows that species diversity could stabilise communities during invasions. It appears as if biodiversity of ecosystems provides increased resilience against onslaughts including that by foreign invaders. Caution should be exercised when foreign species are introduced. In light of these observations, a  proposed law in Brazil is of importance. A recent correspondence in Nature by Vitule et al (May 2012) warns of the repecussions of a new law that, if approved, would allow farming of foreign fish species in cages. The fishes that are being considered for introduction are tilapia and carp. The authors warn that the indigenious aquatic ecosystem would be disrupted if these  introduced species were to escape and would jeopardise the aquatic biodiversity which is already fragile due to  human activities such as pollution and construction.

References:
Vitule JR (2012). Ecology: Preserve Brazil's aquatic biodiversity. Nature, 485 (7398) PMID: 22596145
Eisenhauer N, Scheu S, & Jousset A (2012). Bacterial diversity stabilizes community productivity. PloS one, 7 (3) PMID: 22470577
http://www.europeansquirrelinitiative.org/the_threat.html


Red Squirrel image source: Sarah Stephen

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