ISSS608 2017-18 T3 Assign Kaushik Jaganathan - Insights and Conclusion

ISSS608 2017-18 Mini Challenge 2 - Kaushik Jaganathan

Introduction

Methodology & Design

Insights & Conclusion

Assignment Dropbox

Question 1
Characterize the past and most recent situation with respect to chemical contamination in the Boonsong Lekagul waterways. Do you see any trends of possible interest in this investigation?

The data for chemicals across locations is present from 1998-2016. For this analysis, I am considering only chemicals which have more than 200 records over all locations during this time. The threshold is set at 200 since there are totally 18*12=216 months in this period and at least one reading a month is required. So, the following chemicals haven’t been considered for this analysis for having too few records.

1,2,3-Trichlorobenzene
1,2,4-Trichlorobenzene
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Berilium
Boron
Carbonates
Cesium
Barium
Aluminium
Chrysene
Dissolved organic carbon
Fluoranthene
Fluorene
Hexachlorobenzene
Indeno(1,2,3-c,d)pyrene
Inorganic nitrogen
Isodrin
Methoxychlor
Naphthalene
Organic nitrogen
PAHs
PCB 101
PCB 118
PCB 138
PCB 153
PCB 180
PCB 28
PCB 52
Pentachlorobenzene
Phenanthrene
Pyrene
Selenium
Trifluralin

From plotting the chemical value against date, it is found out that 3 locations have values from 2009.
1. Achara
2. Decha
3. Tansanee

Let's compare the value of chemicals at the preserve taking 5 year intervals from 2001 to 2016. The chemicals taken into consideration have all been measured in mg/L

From the above visualisation, the chemical value trends across locations over the last 15 years is observed. Bicarbonates had higher average value in all locations in the early years and continued to reduce with time. On the other hand, total dissolved salt has constantly increased over time.

August 2003 - Iron spikes

From 1998-2016, across all locations, Iron has been following a normal trend except for in 2003 when a huge spike was observed across all locations

Let’s drill down to 2003 to find out more.

The average value for Iron in August 2003 is extremely high across all locations. This indicates that the entire waterway system of the Reserve was affected. According to WHO, in well-water, iron concentrations below 0.3 mg/litre are characterized as unnoticeable, whereas levels of 0.3–3 mg/litre are found acceptable. But the concentrations found during this period are almost 3000-6000 times more than the threshold.

Methylosmoline rise at Kohsoom and Somchair

The above graph is a representation of monthly max for methylosmoline across locations over the last few years. It is seen that the chemical has seen a sharp upward trend in Kohsoom and Somchair over the last 3 years. It is interesting to note that a peak value of 145 was observed in Kohsoom in August 2016. Kohsoom is one of the sampling sites close to the claimed waste dumping site.

Chlorodinine drops across the preserve

Chlorodinine has seen a sharp decline when monthly max is plotted against time in all locations at the turn of 2016.

High coliform content in Kohsoom

An upward trend in the coliform content is observed at Kohsoom and also a steep spike in Achara. Presence of coliform in water above permissible levels is dangerous.

Kannika-Sakda Mystery

The above plot presents an interesting case of comparison between Chlorodinine and Methylosmoline at Kannika and Sakda. it is observed that the chemicals have similar values and have exact same trends at both locations. So, there is a possibility that the manufacturing plant might have been located between these 2 sites emitting both these chemicals into the water.

Question 2
What anomalies do you find in the waterway samples dataset? How do these affect your analysis of potential problems to the environment? Is the Hydrology Department collecting sufficient data to understand the comprehensive situation across the Preserve? What changes would you propose to make in the sampling approach to best understand the situation?

Same day sampling

Boonsri, Chai, Kannika and Sakda have a flat line at 0 because in each month, there was atleast one instance of a chemical being sampled multiple times on the same day. This approach might not be very efficient as the chemical measures in the water might not change rapidly within a few hours.

Average difference in days in sampling - month-wise

It is seen that average difference in days for January and February is higher than the rest of the months. The average is mostly over 60 for some of the locations. It might be due to the fact that water gets frozen during the winter months and sampling might not happen in these locations. Also, the locations in which the average is on the lower side across all months is due to the same day sampling which brings the average difference in days to 0.

Boonsri and Chai over the years

Overall, considering all the chemicals, it is seen that Boonsri and Chai have had the maximum samples collected during 2005-2007. Also, Achara, Decha and Tansanee have samples only from 2009. Even though this image doesn’t give a very clear picture of what chemicals were sampled, it is at least noted that sampling was done regularly in Boonsri and Chai from 2005 to 2007. The samples have reduced recently when compared to that period in the image.

Water temperature - Chai - 2016

A very unusual and high number of sampling events for Water temperature is observed in Chai. Let’s have a look at the day wise breakdown of this sampling. The day-wise breakdown doesn’t indicate any specific pattern in sampling except that almost all of the multiple one-day sampling events were either on Friday or Saturday. It remains a mystery why the authorities were more active going into the weekend.

At some places, data is collected more than once a day and at some places the difference in days between sampling is high as 3000. So, there is no consistent gap between sampling days and analysis made with the data collected on these days might not give accurate results. So, the sampling strategy should be consistent and chemicals should be sampled on a regular basis. If a spike is observed in any chemical, sampling should be done more often following the spike to ensure the environment is not affected by the chemical.

Question 3
After reviewing the data, do any of your findings cause particular concern for the Pipit or other wildlife? Would you suggest any changes in the sampling strategy to better understand the waterways situation in the Preserve?

Dissolved oxygen is key to survival of aquatic life. Let’s have a look into DO patterns in the Reserve. The below image indicates that a level of atleast 5mg/L is required for most of the fish to survive.

I have constructed a threshold at 5mg/L. DO levels above 5 are colored green and red when value falls below 5 and threatens aquatic life.

I have divided the locations into 4 streams and analysed the DO levels for all locations in a stream over time. In the above image, for locations in the stream 1 (Boonsri,Chai,Busarakhan,Kannika,Kohsoom), the DO levels at Busarakhan have been below threshold recently placing the aquatic species in danger. Kohsoom initially had low DO levels but in the recent years the levels are normal.

Let’s have a look at stream 2 (Somchair,Achara,Sakda)

Achara and sakda don’t have any anomalies while Somchair has had drop in DO levels in the recent years.

Looking at stream 3(Tansanee) & 4(Decha) indicate no alarming trends in DO.

Also, An interesting relationship is observed between Water temperature and DO levels.

In the below visualisation, a dual axis chart is created for Average monthly Dissolved Oxygen level and Water temperature over the last 5 years. It is clearly seen that an inverse relationship exists between the 2 parameters.

For example, this relationship is studied for all locations in the stream 1 and it is seen that the trend is similar across all regions. Greater the area between the two lines, greater the effect on aquatic life as pointed out by the black arrow at Busarakhan.

The DO level trends and the spikes in methylosmoline near Kohsoom do possess a threat to aquatic and wild life. A more regular and consistent sampling strategy needs to be adopted to ensure that the spikes aren't left unattended and don't affect the wildlife around the preserve.

Conclusion

After looking at the trends and anomalies for chemical measures and sampling frequencies across the Boonsong Lekagul Waterways, it is observed that there is no consistent pattern in the sampling over the years. Some of the chemicals have been sampled multiple times on the same day while some at a few locations have been sampled even after 10 years.Also, a new dumping site/factory may be present between Sakda and Kannika according to the findings. A consistent and routine sampling protocol needs to be establised to make sure the contamination levels are always under the control. This ensures the aquatic and wildlife at the preserve aren't affected.