Environmental Forensics


2000 word report based on the Case Study

You are required to produce a portfolio describing the investigation of a case study provided. There are various sources for this case study problem and you must design experimental and sampling procedures that will correctly identify the source of the disaster, and provide a long term sampling programme to prevent further occurrences.

Issues that should be determined in the portfolio

• Evaluate possible source for the fish-kill event

• Evaluate what effects these may have on water quality and aquatic life

• Discuss suitable analysis techniques after considering possible site and sample collection problems

• Discuss sample methodologies for chosen analysis techniques, these sampling methods should consider aspects such as river flow, aquatic life and dissolved oxygen

• Establish recommendation to prevent future occurrences of this environmental disaster and how these may be implemented.

• Summarise findings and consider future work

Introduction: –

In the field of environmental science an analyst will often be required to observe an environmental problem without immediately knowing the underlying cause. Such problems could include chronic issues such as species decline (i.e. UK bees) or global issues surrounding climate change such as melting ice floes. Acute problems such as viral infections in cattle (foot and mouth disease) or mass human poisonings are also issues that the environmental scientist must consider. Environmental scientists will often be called up to determine what has likely happened, how to remediate the problem and finally to prevent future occurrences. This type of analytical backtracking is typically called environmental forensics and is the subject of this case study.

Background: –

Yesterday afternoon a massive fish kill occurred on the Styx River approximately five miles outside the village of Styxton (Pop. 500). As an investigator for the environment agency you have been asked to establish the cause event and make recommendations to prevent further disasters. Local residents reported this disaster to the environment agency, stating that they saw hundreds of rainbow trout (Salmo gairdneri) floating on their sides, many of them gasping. Reports of the river condition at the time were sketchy although there were a number of reports stating that the river appeared darker than normal; with a few reports of dirty coloured foam on the surface. Local industry has stated that they are not aware of any issues with either plant or procedures that may have brought about this disaster.

This section of the river is not included in the environmental agency’s monthly testing cycle. Therefore little is known of its condition with regards to water quality and aquatic population and diversity, beyond the basic annual checks performed on the three industry sites listed. The only in-depth study performed was twenty years ago by the fisheries agency who on finding the river in good health instigated the introduction of the rainbow trout to increase river diversity.

The met office has confirmed that the average daytime temperature that week was 28?C ±2 (82.4?F), and that rainfall for that week was 0mm in this area. Although the river temperature and dissolved oxygen are unknown, it can be surmised that the river temperature was fairly high.

The three industries listed on the following page and shown in Figure 1 are approximately ½ to 1 mile up-river from the site of the fish kill event, each providing a different service/product.

1) Riverside Brewery: A small brewery owned by Mr Ivor Stagger, produces a selection of fine real ales for the UK market, including ‘Trout Ahoy’, ‘Styxton Pride’ and the gold medal winning ‘Poisoned Chalice’. The brewery is permitted to discharge 500 litres of washing waste each day directly into the river. This waste should comprise of small amounts of surfactant, yeast and beer in a diluted aqueous phase.

2) Styxton Sewage Plant: This small plant handles the sewage for the small village of Stxyton (pop. 500) and two industrial units, the Riverside Brewery and AB Chemicals. The sewage plant is old and in need of modernisation. It uses primary and secondary treatments and uses chlorine as a disinfectant. The treated effluent is released into the river. Miss Anita Bath, chief engineer for the plant, informed investigators that although she is unaware of a raw sewage leakage the age of the plant and the fact that some sewage is delivered by truck means she can’t entirely discount this possibility.

3) ABChemicals: This small chemical company is a recent addition to Styxton since its relocation from the local town of Acheronton. The managing director of the plant, Dr Arsenius Beaker; informed investigators that the company specialises in the manufacture and distribution of methyl mercury. Dr Beaker assured the investigators that he is unaware of any methyl mercury leak from the manufacturing plant.

Figure 1: Representation of the fish kill site and surrounding area.

It is most probably chlorine from the Styxton Sewage Plant that is causing the issue

Questions to help you in your research:

• What is the industrial process that is used to make real ale?

• What is the industrial process used to treat sewage?

• What is the industrial process of manufacturing methyl mercury?

• What are the possible contaminants, and what effects will these have on water quality and aquatic life?

• Having established possible contaminants, what are you trying to prove, will current levels of contaminant in the river be useful?

• What samples do you want to take? (i.e. water, soil, biologics), consider cost and time implications and sample preparation requirements

• Provisionally. what analysis techniques best serve your requirements (both field and lab systems). Consider their suitability, detection limits, repeatability and ease of use, as well as cost and time implications.

• How will you perform your sample collection, and what may effect this (consider time, individual or composite samples, replicates and location)?

• How will you collect you samples (or data if field portable systems are used), consider cost and time implications.

• Will these affect your planned analysis technique, if yes, what adjustments will have to be made to allow this system to work?

• What sample/analysis methods will you use?

• What measures would you recommend to your supervisor with regards to both advice to providing future testing methodologies, consider time and cost issues?

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