Investigation of golf course chemical and herbicide contamination

. In golf course management, fertilizers and herbicides are often used to maintain the healthy growth of green and fairway grass. Using these chemicals often comes with the drawback that they tend to leech into local water bodies, from where they are dispersed outside of the golf course, harming organisms. In this study twelve water samples were collected from two golf courses in Shanghai and tested them from several indicators such as total, chemical oxygen demand, and common herbicides. The experiment found that the total nitrogen in each of the twelve samples exceeds the level rated for drinking and industrial use. Levels of chemicals other than nitrogen, however, resembles those rated for drinking water reserves, while herbicide levels are borderline undetectable. Results from this study provide insight regarding the identification of pollutant based on the abnormality of some indicators, helping golf course management in achieving eco-friendliness.


Introduction
Golf is a popular participatory sport in which the player's objective is to strike a golf ball from designated starting areas (teebox) to a hole cup placed distantly away in as few strokes as possible [1].
This modern form of golf took shape in 1774, when the first dedicated golf club was established in St. Andrews, Scotland, hosting annual competitions. In the 19th century, Britain's colonial expansion resulted in the first major explosion of golf's popularity, as golf courses started to appear in Canada, United States, and Australia [1]. China, however, was not introduced to golf until the late twentieth century, when the construction of Zhongshan Hot Spring Country Club finished [2]. Golf recognition in China grew significantly in the past decades, marked by the establishment of China Golf Association (CGA), multiple international golf tournaments host in China, and further construction of public golf courses [3]. It is projected that this positive trend in public golf consumption would continue for the next few decades.
Golf courses' construction depends largely on the topography of the environment around which they are built [4]. Factors such as elevation, slopes, water bodies, irrigation, and vegetation are considered preconstruction such that each specific golf course caters toward these aspects [5]. Maintenance of golf courses, though, may result in detrimental consequences to the environment. Excessive fertilizer use can lead to adverse contamination and nutrient pollution such as eutrophication. Besides, turf's massive water consumption undermines agricultural water use [6].
In order to keep the fairways and greens of a golf course desirable to players, high concentrations of herbicide are typically used to eliminate weed. In fact, concentrations applied to golf courses exceed those of farmland, making golf courses one of the land uses with the highest intensity of herbicide application [7]. This intense application can pose serious threats to wildlife should herbicide leach into runoff. Golf courses typically use 312 gallons of water per day for maintenance, so considerable amounts of herbicide can be picked up by this water and enter larger bodies of water [8].
In China, golf course construction is often coupled with building of residential areas alongside and within golf courses. Most of these housings serve as resort hotels, while others serve a more permanent housing purpose in the form of rent houses and sold houses. Golf courses with the ladder form of housing typically have other public facilities nearby or within. Such is the case with the golf course Shanghai Links, which contains bungalow housing for students who attend Shanghai American School, situated inside of the golf course. Moreover, these golf housing amenities often come at a premium, as they typically cater towards those who play golf frequently and thus are willing to pay more for proximity to the golf course in which the housing is situated in [9]. The on-site residential housing contributes a non-negligible amount of environmental impact, potentially rivaling that of golf courses themselves. Since the impact of golf courses and the associated residential housing on environment is integrated in nature, this study considers their impact as a whole.

Site information and sample collection
Shown in Figure 1 and 2, twelve water samples from two different golf courses in Shanghai (six from Lanhai International and six from Sheshan) were collected using disposable plastic water bottles and test tubes. Each of these two golf courses is connected to branches of the river that both flow into and out of the golf courses, so samples of both upstream and downstream waters were taken(shown in Figure 3 and 4).

Chemical analysis
We used a spectrophotometer to analyze water samples. First, 1.5 mL of distilled water is added into a small vial that is opaque in one horizontal direction and translucent in another horizontal direction after rinsing it with distilled water. This vial is inserted into the spectrophotometer, and the measured transmittance is manually set to 100%. 1.5 mL of sample water is pipetted into the same vial after rinsing the pipette and the vial using the corresponding sample water. The vial is then inserted into the spectrophotometer, and the device returns the measured transmittance pertaining to a specific input wavelength. Nitrate concentration is measured by monitoring the transmittance of water samples at 220nm ultraviolet light, the signature frequency of nitrate ions. The transmittance for each water sample is recorded as a percentage from 0 to 100%. A higher measured transmittance corresponds to a lower nitrate level, and vice versa.
Standard samples of known concentrations were also measured. 6.3g/L nitric acid stock solution was diluted to concentrations that are 1/1000, 1/750, 1/500, 1/250 in relation to the stock solution. The transmittance of these solutions is measured to produce a calibration curve, with which the exact concentrations of water samples can be deduced.
Moreover, a portion of each sample was packaged into a labeled test tube and submitted to Shanghai Jiao Tong University laboratory for mass spectrometer scan under Chinese national standard GB 23200-8.2016 to identify Herbicide remanent and measure concentrations of heavy metal ion. Total nitrogen, phosphorus, ammonia-nitrogen, and nitrite-nitrogen were also analyzed.

Data analysis and error propagation
A directly linear equation relating absorbance and total nitrogen concentration was generated using Microsoft excel using standard samples. Absorbance of each sample can be calculated with = log( 1 ) , where A represents absorbance and T represents transmittance. The slope's value and uncertainty can be deduced. The uncertainty of the spectrophotometer used has an uncertainty of 0.001.   All twelve samples were sent to (Shanghai Jiaotong University) laboratory for testing. Table 2 and  table 3 summarize the results of the test. None of the twelve samples from either Lanhai or Sheshan displayed any detectable amounts of chromium, copper, or mercury. With exception of Lanhai sample 3 and Sheshan sample 1, none of the samples yielded detectable amounts of any of the nine herbicides listed above.     Table 4 listed above summaries the result of lab analysis. Total nitrogen, phosphorus, and ammonianitrogen all displayed a generally increasing trend from Lanhai sample one to sample six(shown in Figure 6). This is similar to the results in 3.1 regarding nitrate-nitrogen, where samples displayed a generally upwards trend from one to six as well. As for Sheshan, both total nitrogen and total phosphorus do not display any significant trend just like nitrate-nitrogen. Ammonia-nitrogen does however decrease from sample one to sample six(shown in Figure 7). None of the twelve samples show any detectible amounts of nitrite-nitrogen.   Table 5 and Figure 8 lists the chemical oxygen demand (COD) of the twelve samples. Each sample was tested three times, so the result of each trial-as well as the mean of them-are reported above. The six samples from Lanhai displayed a generally increasing trend in COD, having a range 6.1 mg/L. Samples one to four are almost equal in COD, having a mean of approximately 13 mg/L. This increases to 15.7 at sample five and 18.9 at sample six. The COD of the six samples from Sheshan were all higher than the samples from Lanhai, with the exception of Sheshan sample four being 0.7 mg/L lower than Lanhai sample six. The Sheshan samples exhibits a range of 1.9 mg/L-significantly lower than those of Lanhai. It also has an increasing trend, but not as significant as Lanhai's trend, though.

Conclusion
Analysis from both Shanghai Jiaotong university lab and spectrophotometer classifies Sample one of Lanhai as class IV and the rest eleven samples as class V, pertaining to national standard GB 3838-2002. Class V indicates that water bodies flowing through Lanhai and Sheshan are "suitable as agricultural or regular touristy site water," as opposed to water that are adequate for drinking, endangered aquatic species habitat, fishing, or swimming [10]. The main factor for these water samples to be categorized as such is the overabundance of total nitrogen, suggesting that fertilizer may have been used in golf course maintenance. Aside from total nitrogen, levels of other chemicals and chemical oxygen demand are similar to those of class II or class III waters. Most importantly, lab analysis returned undetectable levels heavy metal and little to no amounts of herbicides for all samples. This means that the only source of pollution in both Lanhai and Sheshan is likely from fertilizer runoff. Data from this study contribute to the understanding of golf course pollution.
Identifying what kinds of pollution are present in golf courses is key to understanding what steps are best suited to reduce it. With the pollutant identified, management of golf course will become easier in order to eliminate it and promote environmental stewardship.