40 years after exposure, Pesticide linked to higher breast cancer risk

DDT and Breast Cancer: Prospective Study of Induction Time and Susceptibility Windows

According to a recent study, DDT exposure before puberty may have increased the breast cancer risk for women in their 50s. Study is the latest to suggest early-life exposures, even prior to birth, may hold the key to understanding who gets diseases, Environmental Health News reports.

2019 Study Abstract

In a previous Child Health and Development Studies report, p, p’-DDT was associated with a fivefold increased risk of premenopausal (before age 50 years) breast cancer for women first exposed before puberty. Here we extend our observation to breast cancer diagnosed during early postmenopause (ages 50–54 years) to determine whether age at diagnosis modifies the interaction of DDT with age at exposure.

We conducted a second prospective, nested case-control study in the Child Health and Development Studies (153 incident breast cancer cases diagnosed at ages 50–54 years and 432 controls matched to cases on birth year). These were analyzed separately and pooled with our previous study (129 breast cancer cases diagnosed at ages 31–49 years and 129 controls matched on birth year). Blood samples were obtained during pregnancy (median age, 26 years), 1–3 days after delivery from 1959 to 1967 in Oakland, California. Serum was assayed for p, p’-DDT, o, p’-DDT, and p, p’-DDE. Odds ratios (ORs) below are given for doubling of serum p, p’-DDT. All statistical tests were two-sided.

For early postmenopausal breast cancer, p, p’-DDT was associated with risk for all women (ORDDT 50–54 = 1.99, 95% CI = 1.48 to 2.67). This association was accounted for by women first exposed to DDT after infancy (ORDDT 50–54 for first exposure after infancy = 2.83, 95% CI = 1.96 to 4.10 vs ORDDT 50–54 for first exposure during infancy = 0.56, 95% CI = 0.26 to 1.19; Pinteraction DDT x age at first exposure = .01). In contrast, for premenopausal breast cancer, p, p’-DDT was associated with risk among women first exposed during infancy through puberty, but not after (ORDDT<50 for first exposure during infancy = 3.70, 95% CI = 1.22 to 11.26, Pinteraction DDT x age at first exposure x age at diagnosis = .03).

p, p’-DDT was associated with breast cancer through age 54 years. Risk depended on timing of first exposure and diagnosis age, suggesting susceptibility windows and an induction period beginning in early life. DDT appears to be an endocrine disruptor with responsive breast targets from in utero to menopause.

Can exposure to insecticide during pregnancy link to autism in children ?

Association of Maternal Insecticide Levels With Autism in Offspring From a National Birth Cohort

New research published in the American Journal of Psychiatry says that exposure to the notorious pesticide dichlorodiphenyltrichloroethane (DDT) during pregnancy could raise the risk of a child developing autism, ScienceAlert reports.

2018 Abstract

Autism is a complex neurodevelopmental disorder with a largely unknown etiology. To date, few studies have investigated prenatal exposure to toxins and risk of autism by using maternal biomarkers of exposure. Persistent organic pollutants are lipophilic halogenated organic compounds and include the insecticide dichlorodiphenyltrichloroethane (DDT), as well as its metabolite p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE), and polychlorinated biphenyls (PCBs). The objective of this study was to test whether elevated maternal levels of persistent organic pollutants are associated with autism among offspring.

The investigation was derived from the Finnish Prenatal Study of Autism, a national birth cohort study based on a nested case-control design. Cases of autism among children born between 1987 and 2005 were ascertained by national registry linkages. In cases of childhood autism and matched control subjects (778 matched case-control pairs), maternal serum specimens from early pregnancy were assayed for levels of p,p′-DDE and total levels of PCBs.

The odds of autism among offspring were significantly increased with maternal p,p′-DDE levels that were in the highest 75th percentile, with adjustment for maternal age, parity, and history of psychiatric disorders (odds ratio=1.32, 95% CI=1.02, 1.71). The odds of autism with intellectual disability were increased by greater than twofold with maternal p,p′-DDE levels above this threshold (odds ratio=2.21, 95% CI=1.32, 3.69). There was no association between total levels of maternal PCBs and autism.

These findings provide the first biomarker-based evidence that maternal exposure to insecticides is associated with autism among offspring. Although further research is necessary to replicate this finding, this study has implications for the prevention of autism and may provide a better understanding of its pathogenesis.

Toxic Time Bombs

Decades of evidence point to the untoward health effects of endocrine disruptor exposures, yet little is being done to regulate the chemicals


… “Although the U.S. has been slow to control endocrine disruptors, pressure is mounting for legislators to make significant regulatory changes in Europe, although the European Commission has also dragged its feet. In December 2015, the European Union’s Court of Justice decreed that the Commission had breached EU law by failing to adopt scientific criteria for identifying and regulating endocrine disruptors. The European Parliament met in February 2017 to consider a proposal defining those criteria, but member states decided to postpone a decision. France did not wait for the E.U. to take effective action. As of January 2015, new French legislation outlawed any contact between the known endocrine disruptor bisphenol A (BPA) and beverages or food.

The challenge to developing appropriate regulations for endocrine disruptors is that evidence from epidemiology for health effects is indirect and difficult to collect. Cancers abound in modern industrialized societies. Environmental factors are surely involved, yet hard to pinpoint. It took three decades to establish that DDT (dichloro-diphenyl-trichloroethane) and DES (diethylstilbestrol) impair health. Both are now strictly controlled, but their effects persist across generations.” …

  • Read Opinion: Toxic Time Bombs, by Robert Martin for The Scientist, September 25, 2017.
  • Featured image Portrait of Sir Edward Charles Dodds credit wikimedia.
More DES DiEthylStilbestrol Resources

Banned pesticides continue to affect toxicity in streams

Sources, occurrence and predicted aquatic impact of legacy and contemporary pesticides in streams

Many toxic pesticides have been banned by the EU, however some can remain in the environment for many decades. Aquatic invertebrates are particularly vulnerable to pesticides, which can alter their feeding behaviour, growth and mobility. New research has found that persistent pesticides can increase toxicity in streams by up to 10 000 times compared to the residues of currently used pesticides. The researchers recommend these be taken into account when calculating overall toxicity.

Study Highlights

  • Findings comprised a range of contemporary and banned legacy pesticides in streams.
  • Groundwater is a significant pathway for some herbicides entering streams.
  • Legacy pesticides increased predicted aquatic toxicity by four orders of magnitude.
  • Sediment-bound insecticides were identified as the primary source for ecotoxicity.
  • Stream monitoring programs should include legacy pesticides to assess impacts.


Banned pesticides continue to affect toxicity in streams, Science for Environment Policy, 12 January 2017.

Sources, occurrence and predicted aquatic impact of legacy and contemporary pesticides in streams, science direct, February 2015.

We couple current findings of pesticides in surface and groundwater to the history of pesticide usage, focusing on the potential contribution of legacy pesticides to the predicted ecotoxicological impact on benthic macroinvertebrates in headwater streams. Results suggest that groundwater, in addition to precipitation and surface runoff, is an important source of pesticides (particularly legacy herbicides) entering surface water. In addition to current-use active ingredients, legacy pesticides, metabolites and impurities are important for explaining the estimated total toxicity attributable to pesticides. Sediment-bound insecticides were identified as the primary source for predicted ecotoxicity. Our results support recent studies indicating that highly sorbing chemicals contribute and even drive impacts on aquatic ecosystems. They further indicate that groundwater contaminated by legacy and contemporary pesticides may impact adjoining streams. Stream observations of soluble and sediment-bound pesticides are valuable for understanding the long-term fate of pesticides in aquifers, and should be included in stream monitoring programs.

Herbicide found in German estuaries, transported to the Baltic Sea

Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study

Glyphosate is a widely used herbicide, able to kill a broad range of plants (‘weeds’) that compete with crops. This study used a validated method to assess its presence in 10 German estuaries that lead to the Baltic Sea. All but one was contaminated with glyphosate, and all were contaminated with its metabolite AMPA. The researchers recommend risk assessments for these chemicals in the Baltic Sea and other marine environments.


  • An LC–HESI-MS/MS method for glyphosate and AMPA analysis in estuarine water
  • Contamination of the Baltic estuaries with glyphosate and AMPA
    Glyphosate and AMPA concentrations exceed the European guideline of 100 ng/L.
  • The first study on transport glyphosate and AMPA from land to sea
  • Glyphosate concentrations may cause a toxic effect in some Baltic rivers and estuaries.


Herbicide found in German estuaries, transported to the Baltic Sea, Science for Environment Policy, 25 November 2016.

Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study, science direct, November 2015.

Muta @ the Baltic Sea by Satorare.

Water samples from ten German Baltic estuaries were collected in 2012 in order to study the presence of the herbicide glyphosate, its primary metabolite AMPA and their potential transport to the marine environment. For the analyses an LC–MS/MS based analytical method after derivatization with FMOC-Cl was optimized and validated for marine water samples. All investigated estuarine stations were contaminated with AMPA and nine of them also with glyphosate. Concentration ranges observed were 28 to 1690 ng/L and 45 to 4156 ng/L for glyphosate and AMPA, respectively with strong spatial and temporal fluctuations. Both contaminants were found at inbound sampling sites in the stream Muehlenfliess and concentrations decreased along the salinity gradient to the estuaries of the Baltic Sea. The data obtained in this study clearly depict the transport of glyphosate and AMPA to the Baltic Sea. Hence, detailed fate and risk assessment for both contaminants in marine environments are required.

The persistence of DDT and POPs chemicals contamination and the extinction risk for our wildlife

Extinction Risk for Many Species of Plants and Animals are Higher Than Suspected

A new study indicates that the number of plant and animal species at risk of extinction may be considerably higher than previously thought. A team of researchers, however, believe they’ve come up with a formula that will help paint a more accurate picture.

2017 Study Highlights

  • Range maps used by IUCN for threat assessment are inaccurate and mostly overestimated.
  • Citizen science, georeferenced ecological data, and distribution modeling allow accurate range estimates.
  • We found the ranges of 17 of 18 Western Ghats endemic bird species overestimated.
  • We also found 10 of those species requiring an uplisting of their IUCN threat status.
  • Methods used here to refine range estimates have conservation implications for taxa worldwide.


The validity of the threat status assigned to a species by the International Union for Conservation of Nature’s (IUCN) Red List relies heavily on the accuracy of the geographic range size estimate for that species. Range maps used to assess threat status often contain large areas of unsuitable habitat, thereby overestimating range and underestimating threat. In this study, we assessed 18 endemic birds of the Western Ghats to test the accuracy of the geographic range sizes used by the IUCN for their threat assessment.

Using independently reviewed data from the world’s largest citizen science database (eBird) within a species distribution modeling framework, our results show that:

  • geographic ranges have been vastly overestimated by IUCN for 17 of the 18 endemic bird species;
  • range maps used by IUCN contain large areas of unsuitable habitat,
  • and ranges estimated in this study suggest provisional uplisting of IUCN threat status for at least 10 of the 18 species based on area metrics used by the IUCN for threat assessment.

Since global range size is an important parameter for assigning IUCN threat status, citizen science datasets, high resolution and freely available geo-referenced ecological data, and the latest species distribution modeling techniques should be used to estimate and track changes in range extent whenever possible. The methods used here to significantly revise range estimates have important conservation management implications not only for endemic birds in the Western Ghats, but for vertebrate and invertebrate taxa worldwide.

Sources and Press Releases
  • IUCN greatly underestimates threat levels of endemic birds in the Western Ghats, science direct, doi.org/10.1016/j.biocon.2017.03.019, 26 April 2017.
  • Extinction risk for many species vastly underestimated, study suggests, phys.org, April 25, 2017.
  • Extinction Risk For Many Species Of Plants & Animals Are Higher Than Suspected, science times, Apr 30, 2017.
  • Image Credit: V. Ramesh et al. / Biological Conservation – The new models identified 10 species in need of potential uplisting on IUCN’s Red List. The white portion of pie chart shows percent suitable habitat within IUCN range, the blue portion shows percent of the range where unsuitable or no habitats are predicted.

Late lessons from early warnings : science, precaution, innovation

An investment in knowledge pays the best interest ~ Benjamin Franklin ~


There is something profoundly wrong with the way we are living today. There are corrosive pathologies of inequality all around us — be they access to a safe environment, healthcare, education or clean water. These are reinforced by short-term political actions and a socially divisive language based on the adulation of wealth. A progressive response will require not only greater knowledge about the state of the planet and its resources, but also an awareness that many aspects will remain unknown. We will need a more ethical form of public decision-making based on a language in which our moral instincts and concerns can be better expressed. These are the overall aims of Volume 2 of Late lessons from early warnings.

Volume 1 of Late lessons from early warnings was published at a time when the world was experiencing an economic slowdown, China had joined the World Trade Organization and western Europe was still a 15-member Union. Global grain production had declined for the third time in four years due mainly to droughts in North America and Australia, and the world saw major recalls of contaminated meat, foot and mouth disease and bovine spongiform encephalopathy (mad cow disease). Global temperatures continued to climb and many bird populations were in decline, but the United States of America had rejected the Kyoto Protocol. We were seeing ourselves through the lens of the first human genome sequence, yet we were trying to manage chemicals known to be harmful to humans and ecosystems, through international conventions and treaties such as the Basel Convention to deal with toxic waste dumping in the developing world; the OSPAR/HELCOM Conventions to reduce the discharges, emissions and the loss of hazardous substances into the sea and the Montreal Protocol, to phase out ozone-depleting substances. The destruction of the World Trade Center had just happened.

The 2013 Late lessons from early warnings report is the second of its type produced by the European Environment Agency (EEA) in collaboration with a broad range of external authors and peer reviewers.

Since then, we have witnessed a period of extraordinary hubris. Most visibly, the financial profligacy of the first decade of the century led inexorably to the crises of 2007–2009 whereby the major components of the international financial system were weakened to the extreme by indebtedness, mispriced products, lax monetary policies and mis-engineered protection against risks and uncertainty. The world experienced more not less volatility. Political systems became silted up by vested interests and a determination by citizens to protect assets accumulated in easier times, and beneath it all lay a deeper environmental crisis epitomised by climate change and biodiversity loss.

There was also a collapse of trust, not only in financial institutions but in big companies, as they abandoned staff, pensions and health care schemes. Recent evidence from social psychology has shown that despite rising levels of education and innovation in products and services, people trust only those they know and not strangers. As Stephen Green said in Good value: reflections on money, morality, and an uncertain world in 2009:

‘There has been a massive breakdown of trust: trust in the financial system, trust in bankers, trust in business and business leaders, trust in politicians, trust in the media, trust in the whole process of globalisation — all have been severely damaged, in rich countries and poor countries alike’.

The scientific elites have also been slowly losing public support. This is in part because of the growing number of instances of misplaced certainty about the absence of harm, which has delayed preventive actions to reduce risks to human health, despite evidence to the contrary.

Suddenly, our problems have grown into what Charles W. Churchman in 1967 termed wicked problems — difficult or impossible to solve because of incomplete, contradictory and changing requirements, difficult to recognize, resistant to resolution because of the complexity of their interdependencies and needing to be tackled not by one but via many forms of social power. Solving them requires a new combination of hierarchical power, solidarity and individualism.

What could this mean, for example, for the 100 thousand chemicals currently in commercial use?

To begin with we have more conventions and treaties in place than a decade ago: the 2004 Rotterdam Convention on the Prior Informed Consent (PIC) Procedure covering international trade of 24 pesticides, four severely hazardous pesticide formulations and 11 industrial chemicals; the 2004 Stockholm Convention on Persistent Organic Pollutants to protect human health and the environment from substances which are highly toxic, persistent, bio-accumulative and move long distances in the environment, such as DDT, PCBs, various industrial chemicals, and a set of unintentional chemical by-products such as dioxin. But these conventions only address the top-down hierarchical approach to power.

At the same time Europe has put in place legislation to achieve a global regulatory influence including the EU Cosmetic Directive banning the use of chemicals known or strongly suspected of being carcinogens, reproductive toxins, or mutagens causing cancer, mutation or birth defects; the EU Restriction of Hazardous Substances Directive, which restricts the use of hazardous materials in the manufacture of various types of electronic and electrical equipment including lead, mercury, cadmium, hexavalent chromium, the flame retardents polybrominated biphenyls and polybrominated diphenyl ethers, and which encourages the substitution to safe/or safer alternatives in the electric and electronic equipment industry; the closely linked 2006 EU Waste Electrical and Electronic Equipment Directive for collection, recycling and recovery of electrical goods; the 2006 Strategic Approach to International Chemicals Management (SAICM); and the 2007 EU Registration, Evaluation and Authorisation of Chemicals, widely known as REACH, to assign greater responsibility to industry to manage the risks from chemicals and to provide safety information on substances. The effects of these regulatory tools are described in different chapters, but once again point to the main economic actors rather than communities or individuals.

One thing that has become clearer over the past decade is that certain chemical substances are highly stable in nature and can have long-lasting and wide ranging effects before being broken down into a harmless form. The risk of a stable compound is that it can be bio-accumulated in fatty tissues at concentrations many times higher than in the surrounding environment. Predators, such as polar bears, fish and seals, are known to bio-magnify certain chemicals in even higher concentrations with devastating consequences for both humans and ecosystems. So exposure to toxic chemicals and certain foodstuffs are at risk of causing harm, especially to vulnerable groups such as foetuses in the womb or during childhood when the endocrine system is being actively built. Even with small dose exposures, the consequences can in some instances be devastating with problems ranging from cancer, serious impacts on human development, chronic diseases and learning disabilities. Here the power to act could be more properly set by well-informed individuals and communities.

The relationship between knowledge and power lies at the heart of Volume 2. In many chapters, the implicit links between the sources of scientific knowledge about pollutants, changes in the environment and new technologies, and strong vested interests, both economic and paradigmatic, are exposed. A number of authors also explore in greater depth, the short-sightedness of regulatory science and its role in the identification, evaluation and governance of natural resources, physical and chemical hazards. By creating a better understanding of these normally invisible aspects, it is hoped that this volume will enable communities and people to become more effective stakeholders and participants in the governance of innovation and economic activities in relation to the associated risks to humans and the planet.

Much of what we are able to learn from the histories of past environmental and public health mistakes is also directly applicable to the better regulation and governance of global institutions and financial and economic risks. Robin G. Collingwood argued in his Autobiography (1939), that:

‘History can offer something altogether different from [scientific] rules, namely insight. The true function of insight is to inform people about the present…we study history in order to see more clearly into the situation in which we are called upon to act… the plane on which, ultimately, all problems arise is the plane of ‘real’ life: that to which they are referred for their solution is history.’

In this volume, we go further. Whilst still drawing lessons from such widely accepted tragedies as leaded petrol, mercury poisoning in Japan’s Minamata Bay and older pesticides which sterilised many men who used it, we have ventured into the uncertainties of potential yet contested harm, from genetically modified products; nanotechnologies; chemicals such as Bisphenol A; new pesticides and mobile phones. There is also an examination of the 80 or so potential ‘false positives’ where there had been indications of harm but where it was subsequently claimed that there were in fact no risks to prevent: these cases too can provide information that can help to improve future decision-making about innovation and emerging technologies.

A major part of effective decision-making lies in the way issues are framed. In the case of climate change, the first order question is whether it is worth worrying about at all. US Vice President Al Gore chose to make the question a matter of choice between believers and sceptics. However, problems arose when the public was asked to make a scientific decision when too few people had the qualifications to make any kind of reasoned judgement. They were in fact asked to make a false choice. Instead the question should have been framed around which areas should people and governments make decisions and which should be delegated to experts.

In the end there are few certain and enduring truths in the ecological and biological sciences, nor in the economics, psychologies, sociologies and politics that we use to govern them. One, however, comes from the work of Elinor Ostrom, a late and widely missed colleague, who showed from her work on managing fisheries and ecosystems that complex problems can be solved if communication is transparent and open, visions are shared, trust is high and communities are activated to work from the bottom-up as well as from the top down.

As we navigate the Anthropocene, the epoch named in recognition of our impact on the planet, we will need to encourage more people to become involved in solving the wicked problems of our times. Whether through gathering local information or becoming more aware of the many uncertainties and unpredictabilities in our surroundings, the power structures of knowledge will need to change. And if we are to respond more responsibly to the early warning signals of change, we will need to re-design our style of governance to one which reflects a future defined by the local and specific rather than only the global and the average. We hope that Volume 2 of Late lessons from early warnings with its many lessons and insights can help us all meet such a challenge.

  1. Introduction
  2. The precautionary principle and false alarms — lessons learned
  3. Lead in petrol ‘makes the mind give way’
  4. Too much to swallow: PCE contamination of mains water
  5. Minamata disease: a challenge for democracy and justice
  6. Beryllium’s ‘public relations problem’
  7. Tobacco industry manipulation of research
  8. Vinyl chloride: a saga of secrecy
  9. The pesticide DBCP and male infertility
  10. Bisphenol A: contested science, divergent safety evaluations
  11. DDT: fifty years since Silent Spring
  12. Booster biocide antifoulants: is history repeating itself?
  13. Ethinyl oestradiol in the aquatic environment
  14. Climate change: science and the precautionary principle
  15. Floods: lessons about early warning systems
  16. Seed‑dressing systemic insecticides and honeybees
  17. Ecosystems and managing the dynamics of change
  18. Late lessons from Chernobyl, early warnings from Fukushima
  19. Hungry for innovation: from GM crops to agroecology
  20. Invasive alien species: a growing but neglected threat?
  21. Mobile phones and brain tumour risk: early warnings, early actions?.
  22. Nanotechnology — early lessons from early warnings
  23. Understanding and accounting for the costs of inaction
  24. Protecting early warners and late victims
  25. Why did business not react with precaution to early warnings?
  26. Science for precautionary decision‑making
  27. More or less precaution?
  28. In conclusion.
More Information
Endocrine Disruptors

Legacy pesticides, and the compounds produced as they break down, remain a hazard to aquatic environments

Banned pesticides continue to affect toxicity in streams

The green revolution in the 1940s produced many effective and apparently safe pesticides, including synthetic insecticides such as DDT. Many of these chemicals were later discovered to have toxic effects, such as carcinogenicity, and subsequently banned from use. Another important issue is persistence; their long lifetimes mean some of these so-called ‘legacy’ pesticides can persist in the environment several decades after their use is prohibited.

Researchers examined the presence of both contemporary and legacy pesticides in 14 streams in Denmark, and used their results to predict the overall toxicity of the streams. They looked at both the influence of surface run-off and groundwater on concentrations in streams by taking samples in the streams shortly after periods of high precipitation, when surface runoff is high, and during a period of low precipitation, when groundwater was expected to be the largest source of inflow to the streams. Twelve of the streams were located in catchments where agriculture represents 80% or more of land use.

Banned pesticides continue to affect toxicity in streams, Science for Environment Policy, 12 January 2017.

Sources, occurrence and predicted aquatic impact of legacy and contemporary pesticides in streams, science direct, February 2015.

Water samples were collected from 2010 to 2012 mostly during May and June, the main periods when pesticides are applied to crops. The researchers used two methods to sample sediment: direct sampling of bed sediment using a core sampler, to give a snapshot for a specific moment in time; and time-integrated sampling for particulates (suspended sediment flowing in the stream), to which pesticides washed from agricultural fields can bind. They say this helped them to capture the pesticides which are expected to attach preferentially to (fine) particle surfaces.

The total toxicity was assumed to be the sum of the individual toxicities of all pesticides detected, neglecting any enhanced or reduced toxicity which may occur when different pesticides interact. The toxicity measure used was the LC50 — the concentration of the chemicals leading to 50% mortality for the test animals during an observation period of 48 hours — for the benchmark organism Daphnia magna. The study only provides an estimation of toxicity, by measuring the concentration of substances of known toxicity (the researchers did not assess the direct effect of the pesticides on aquatic organisms).

A total of 32 pesticides were detected. Two of the four most commonly detected were dinitro-ortho-cresol and trichloroacetic acid, both last sold in Denmark in the 1980s. The researchers believe these pesticides were generated in and transported from the atmosphere, rather than being present in surface runoff or groundwater. Three commonly detected pesticides in groundwater were mecoprop, dichlorprop, and dichlobenil. All of these chemicals were banned in Denmark in the late 1990s.

The estimated aquatic ecotoxicity increased by up to 10 000 times when legacy pesticides were included. Insecticides bound to sediments were found to be the largest source for the predicted ecotoxicity.

In this study, eight of the nine pesticides included on the Water Framework Directive’s1 list of 33 Priority Substances2 at the time of the study — shown to be of major concern for European Waters — were detected. For two of these, diuron and isoproturon, some detected concentrations were above or close to the EU aquatic Predicted No Effect Concentrations (PNECs)3 — below which no adverse ecosystem effects can be measured. Meanwhile the fungicide hexachlorobenzene — never authorised for use in Denmark — and the insecticide lindane were detected in the sediment at concentrations well above the sediment PNEC values used in the context of the selection of the 33 priority substances listed in Directive 2008/105/EC4 .

Since the study looked at only selected areas of Denmark, it is possible that similar results would not be found elsewhere. However, the researchers note that most of the maximum concentrations measured are similar to the reported median values of concentrations for European streams.

The study indicates that, alongside contemporary pesticides, legacy pesticides, and the compounds produced as they break down, remain a hazard to aquatic environments. The researchers recommend that monitoring programmes which estimate the ecotoxicity of streams be adjusted to reflect this. Furthermore, they advise that a greater research emphasis be put on the analysis of groundwater, often presumed to contain low levels of pollution. They also highlight that pesticides bound in particular to suspended sediments were a major source of predicted toxicity and need to be further studied.

Glyphosate and its Metabolite AMPA Transport from Land to Sea

Herbicide found in German estuaries, transported to the Baltic Sea

Marine pollution is a problem worldwide, but it is particularly acute in semi-closed seas. Areas surrounded by land are more at risk of pollution than open marine areas, due to increased human input, such as chemicals from industry and agriculture, e.g. pesticides and fertilisers.

The Baltic Sea, a semi-closed sea in northern Europe, is one of the most polluted seas in the world. Due to significant agricultural inputs leading to eutrophication, oxygen levels in the sea have declined, creating large ‘dead zones’ and challenging the survival of marine biota.

This study focused on pollution of the Baltic Sea from Germany. The Baltic Sea is bordered by four German states. The German Baltic drainage basin (which receives inflow from three rivers) is characterised by lots of human activity. Germany has the highest agricultural activity of all Baltic countries and has in the past contributed to the Sea becoming polluted with hazardous compounds, such as pesticides. Although a number of these compounds have since been banned, many continue to persist in the environment, including the insecticide DDT, which has a known negative effect on biodiversity.

Herbicide found in German estuaries, transported to the Baltic Sea, Science for Environment Policy, 25 November 2016.

Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study, science direct, November 2015.

Muta @ the Baltic Sea by Satorare.

In this study, researchers focused on the levels of a chemical in current use in the EU: the herbicide glyphosate, which may have toxic effects on marine microorganisms.

Germany is Europe’s second largest pesticide consumer. In 2012, over 45 000 tonnes of pesticides were used, 44% of which were herbicides (mostly glyphosate). Glyphosate has been identified in fresh surface- and ground-water bodies in Germany, at concentrations above the European threshold for drinking water (100 nanograms per litre — ng/l); however, its presence in the marine environment is difficult to monitor. Using a suitably sensitive method, this study quantified glyphosate (and its major breakdown product AMPA) in German Baltic Sea estuaries.

Water samples were collected from 10 estuaries between May and September 2012, then analysed for the presence of glyphosate and AMPA. All estuaries were contaminated with AMPA, and nine were also contaminated with glyphosate. Glyphosate was found in concentrations ranging from 28 to 1 690 ng/l, while AMPA was found at higher concentrations (between 45 and 4 156 ng/l), which the authors attribute to AMPA’s higher mobility and stability. However, it is important to note that AMPA is also formed during the breakdown of other chemicals, such as laundry agents and detergents and, therefore, its presence in the samples cannot be attributed to use of glyphosate alone.

The authors looked more closely at the seventh sampling station — Mühlenfliess — which was the most heavily contaminated. Water samples from inbound sampling stations along the stream were analysed. Concentrations of glyphosate were 2 768 ng/l and of AMPA 5 190 ng/l but these decreased (as the water became saltier) towards the estuaries of the Baltic, which suggests its transport into the Sea, the authors say.

Concentrations measured in water samples were also (generally) higher following rainfall than during dry weather, which suggests rainfall may help to transport the compounds.

The data obtained strongly suggest transport of both compounds in rivers, from their site of application into the Baltic Sea. The long-term effects of these contaminants at the concentrations measured here are unknown. The researchers, therefore, recommend assessments of the environmental fate of, and risk posed by, these two contaminants in marine environments.

This study also describes a straightforward analytical method to measure glyphosate and AMPA in marine environments above a concentration of 27 ng/L, which may facilitate monitoring programmes in the future.