Monthly Archives: April 2012

What on earth are we doing?

While it is to late to save the baiji, there is still time for the Maui dolphin, cousin of the pictured Hectors dolphin. Photo Source: Wikimedia Commons.

Before I started writing this blog, I asked myself:  Should I do this? Am I just becoming a fear mongering sensationalist? But eventually I decided that these stories are important and need to be told. Today I will present to you two tragic case studies, which hopefully will show to you the relevance of global water concerns, and the outcomes that come with apathy towards our environment.

Death of the River Goddess

In 2007, Turvey et al. published a paper in the journal Biology letters, entitled “First Human caused extinction of a cetacean species?”  They had just returned from an intensive six week survey of the Yangtze River, China, looking for Lipotes vexillifer, known as the Yangtze River Dolphin or baiji.

The baiji was said to be the reincarnation of a beautiful princess, thrown into the Yangtze after she refused to marry a man she did not love. The earliest surviving description of the baiji was in the Erya, a Chinese dictionary dating from approximately 3 BC, with the population estimated at 5000.

During the six week study, covering 1669 km, Turvey et al. did not once see a baiji. As a result of this, the baiji was declared functionally extinct. Functional extinction means the population is no longer viable, and can no longer sustain itself.

The article states that the last authenticated sightings of the baiji were a stranded female found in 2001, and a live animal photographed in 2002. Subsequent to the publication of this article, in August 2007, A Chinese businessman photographed one further baiji in the Yangtze River.

Chinas huge population has put pressure on the Yangtze River basin, increasing pollution, but the primary cause is harmful fishing practices by local fisherman, with baijis being killed by hooks, nets and electro fishing.

The extinction is the end of the line for the family Lipotidea, which are thought to have diverged from other river dolphins 20-25 million years ago.

For more information on the baiji, and its journey to extinction, I would highly recommend Samuel Turvey’s book, Witness to Extinction, How We Failed to Save the Yangtze River Dolphin.

Carcinogenic water

This case study is based on an article published in Environmental Health, “Cancer in Wildlife, a Case Study: Beluga from the St. Lawrence Estuary, Québec, Canada” by Martineau et al. (2002).

This article describes  how researchers studying the Beluga whale population in the Saint Lawrence Estuary (a population of approximately 650 whales), discovered extreme cancer rates, especially in the intestinal tract. These cancers can be attributed to water contaminants, likely from aluminium smelters in the region.

The authors examined 129 whale carcasses found stranded in the Saint Laurence estuary between the years 1983-1999, and found that 27% of the dead animals had cancer. This rate of 163/100 000 is on par with human cancer rates. Intestinal cancer in the whales was estimated at 63/100 000, which is higher than rates observed in humans and other mammals worldwide.

Furthermore, only 33 cases of cancer have been reported globally in cetaceans (whales dolphins and porpoises), both in the wild and captivity outside the studied Saint Laurence Beluga population. And only one of these was in a beluga whale. This information strongly indicates that there is something unfortunately unique about the Saint Laurence Beluga whale population.

The Saint Lawrence belugas were found to have high concentrations of heavy metals, polycyclic aromatic hydrocarbons (PAHS), PCBS  and DDT in their metabolic systems. These are all extremely toxic compounds, and are released into the environment as by products from industry.

The authors suggest that the high cancer rates can be attributed to the PAH’s found in the water in the Saint Laurence Estuary. These PAH’s contaminate invertebrates living in the sediment, which the belugas then feed on.

The presence of the contaminants has been attributed to the aluminium smelters in the region. Workers in these plants also display a high prevalence of cancers, as do residents who do not work in the plants. It is suggested that this is due to the high levels of PAH’s in drinking water, sourced from local rivers and lakes.


If hearing about the baiji made you sad, why not try to stop it happening here? The Maui dolphin population, found only in New Zealand is estimated at 55 individuals. To find out more, and what you can do to help, visit the Department of Conservation (DOC) fact page on Maui dolphins. If dolphins aren’t your thing, what about the damaging effect of mice on seabirds? For more information on what is being done to stop this, see Sub Antarctic Science.

I found both the story of the baiji, and of the belugas incredibly upsetting. The lesson I will take from this is that while we may not be able to influence the outcome of things happening half a world away, we can certainly take a strong stance in our own back yard.


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The State of the Environment

Riparian strips such as these act as biofilters, removing pollutants from water flowing into waterways. Source: Wikimedia Commons.

I couldn’t bring myself to give this blog a fancy title. “The State of the Environment” really says it all. These large and comprehensive reports released by the Ministry for the Environment (MfE) about environmental health in New Zealand, come out every 5 years. With the last one released in December 2007, we can expect a new one at the end of this year.

 Measuring water quality

 To begin with, water quality is measured using key indicators such as:

  • Concentrations of nutrients
  • Concentrations of bacteria
  • Visual clarity
  • Water temperature
  • Dissolved oxygen
  • Richness of invertebrate species in rivers

 Today I’m going to focus on nutrient concentrations.

Nutrient concentrations are arguably one of the most significant indicators of ecosystem health, which impact upon many of the other indicators, such as dissolved oxygen concentration.

 Nutrients are beneficial for many aquatic plants, however an over abundance of nitrogen and phosphorus especially, may lead to algal blooms and weed growth. Nitrogen and phosphorus enter water ways mainly as a result of fertilization and stock effluent in agricultural catchments.

 So what did the 2007 SotE report say about freshwater nutrient concentrations?

 Findings for rivers and lakes:

  • From 1989- 2003 there was an increase of total nitrogen (TN) and dissolved reactive phosphorus (DRP) from 0.5%-1%. This indicates a long term trend of nutrient enrichment.
  • There has been a decrease in total phosphorus (an indicator of poor fertilizing practice), and ammoniacal nitrogen (primarily from sheep and cow effluent). This is likely a result of applying effluent to land, rather than discharging it into waterways.
  • Urban streams have the highest levels of nutrient enrichment, followed by agricultural catchments. Median nutrient concentrations for both are higher than the AZNECC upper guidelines for river health.
  • This is significant as agricultural and urban land use combined comprise 44% of total catchment land use in New Zealand.
  • 75/134 monitored lakes have high- very high nutrient levels. 13% of these are hypertrophic (which means that nutrient levels are extreme, and water quality is very poor). This mainly occurs in shallow lakes, such as Lake Ellismere near Christchurch.
  • On a brighter note, our most enriched rivers are still lower than the average level of enrichment of rivers in Europe, USA and Asia.

Monitoring was also carried out to determine groundwater quality. One third of monitored groundwater sites have elevated levels of nitrate, a form of nitrogen which can cause “blue baby syndrome”. This is likely due to leaching through the soils of fertilizer and stock effluent. 5% of sites exceeded the safe level for New Zealand drinking water (11.3 mg per L), especially in the Waikato and Manawatu regions.

 How is this explained?

 Urban steams were generally found to have the lowest water quality. The main causes of this are bacteria and nutrients leaking from damages sewage pipes, and runoff to streams from contaminated surfaces such as roads. Roads can be covered in particulate pollutants from exhaust emissions, brake linings and tire wear.

Agriculture showed high levels of nutrient concentrations, with TN and DRP showing an increasing trend. Because of a shift from low intensity agriculture (such as sheep farming) to high intensive agriculture (such as dairy farming) in recent years, increased amounts of nutrients and sediment are entering our water ways.

Point sources of pollution (such as water flow from an effluent pipe) have been legislated against under the Resource Management Act 1991, so the current problem is non-point sources, such as overland runoff, and stock in waterways.

 What is being done about this?

 There are several initiatives underway discussed in the SotE report to improve fresh water quality. These include:

  • Support from the Taranaki Regional Council for riparian planting on stream banks in Taranaki. Riparian plants filter water flowing into the waterway, and lower nutrient and sediment levels.
  • The Dairying and Clean Streams Accord: This is an agreement signed by Fonterra, local councils and the Ministries for the Environment and for Agriculture and Forestry. It sets targets to exclude stock from waterways, and decrease effluent discharge, amongst others.
  • And, the development of a Cultural Health Index for Streams and Waterways (CHI) by Ngāi Tahu, which facilitates water quality monitoring by local iwi.

 To conclude, It must be remembered that these statistics and information come from a report released five years ago. It is my hope that the initiatives in place will help to halt the increasing nutrient trends, and if possible begin to lower nutrient concentration in our freshwater.

It is with baited breath that I await the next State of the Environment Report, which will enable us to evaluate the effectiveness of New Zealands strategies to protect this vital resource.

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