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= Stream Sediment Sampling = Stream sediments refer to the minerals that are eroded, carried, and deposited by moving bodies of water such as streams, rivers, and creeks. By studying eroded minerals in water bodies, it is possible to infer the geologic composition of upstream landscapes. This is a cost-effective research method that identifies targets for further exploration, as well as the monitoring of environmental quality. It is one of the most valuable and effective geochemical prospecting techniques, and can provide information for element transportation through hydrological mediums.

The Process
Geologists will commonly utilize shovels and metal sieves to collect the catchment basin sediment material, through a processes called panning. The top 10-20cm is often placed back into the stream, as it is frequently contaminated with naturally occurring iron and manganese. The process continues by continuing to remove the largest particles, eventually leaving fine sediments that can be bagged for transportation to a lab for further research. Stream sediment techniques are often conducted partnered with soil testing, in order to generate the most accurate results possible. It is also important to consider the physical composition of what element is being searched for. Generally coarser minerals are searched for when looking for gold, tungsten, and titanium, where as copper, lead, and zinc are typically finer particles, smaller than 0.06mm.

The selection of the sampling medium, the location of said sample, and the frequency are all important factors to consider when conducting stream sediment sampling. Some of the most common techniques are stream sediments, pan concentrates, different layers of organic sediment, and occasionally materials from flood plains and moss mat sediments.

The benefits of sampling from moss mats stem from wide availability, easy collection, and abundant fine-grained sediment. Sediments are deposited into moss mats only during high water events, when sediment-rich water flows over the moss. As the water retreats, the sediment is left behind and the moss grows around, entrapping potentially valuable minerals.

There are also environmental and seasonal factors to consider, as sampling can be greatly impacted by local events. Stream sampling works best under certain conditions, something that improves the precision and applicability of the data gathered. To expand, the accumulation of heavy minerals within the gaps of riverbed bars results in the greatest concentration of heavy metal elements (HMEs) immediately following the peak levels of a flood. This is evident in British Columbia, commonly as a result of snowmelt and increased precipitation. As seasons progress with frequent deposition and erosion, these streams can see a significant reduction in gold concentration on the bars surface. This is not restricted to British Columbia, as in tropic regions the impact of high stream discharge on HME concentrations (Fe, Mn, V, and Ti) surged after a cyclone passed through the area.

Early Beginnings
Mining for gold has been around since the Roman empire, where Romans found gold filled in the Transylvanian Alps. This early exploration, which included sluicing and hydraulic mining, paved the way for technological advancements and efficiency improvements around the globe.

Gold Rush
The gold rush era of the 1800s was a time of great excitement and the large scale movement of people towards areas of gold deposits, which created great economic opportunity, while also affecting environmental, social, and cultural landscapes. During this time, sluicing or panning was the most common prospecting technique, allowing for miners to evaluate whether the land they were standing on was worth extracting. Originally, gold mining was a labour intensive process, relying on tools like hammers, picks, and pans for sifting through river sands. Mechanical mining was quickly developed, one of the earliest methods being a arraste. This device was horse driven, using a large stone to pulverize gold-bearing rock, where eventually the ground quartz would release gold.

As demand for gold increased, mining technologies were becoming increasingly sought after. Some of the most popular methods were placer mining, hydraulic mining, pocket mining or drift mining, dredging, hard rock or quartz mining, and open air mining.

Current Sampling Applications
Like any prospecting practice, there are environmental concerns to consider, as fine sediment remains a significant concern for water pollution, affecting aquatic ecosystems in various ways. Soil erosion occurs naturally, but industrial activities such as agriculture, forestry, mining, and urban development can accelerate the process. Agriculture has been identified as one of the key contributors to soil erosion. Average rate of erosion in ploughed fields are one to two times higher than that of areas with native vegetation. This issue will only persist as the global population rises and more land is needed for growing, worsening environmental degradation and water quality. In saying this, it provides unique opportunity to use stream samples as not only a tool for mining opportunity, but also as an asset for monitoring water quality.

Due to humans extreme reliance upon water for agricultural and industrial activities, population centres are often along river basins. This leaves the water vulnerable for harmful pollutants to be spread without commercial accountability. A contemporary method of dealing with this issue is monitoring programs that pinpoint specific pollutants causing water degradation. This also allows for quotas and threshold levels to be established, allowing for policymakers to be better informed when addressing industrial culprits.

Legal & Ethical Considerations
Understanding legal frameworks and ethical guidelines is crucial for conducting stream sediment sampling in a sustainable manner. This section will offer fundamental legal and regulatory principles that address environmental justice concerns.

Similar to soil sampling, stream sediments serve as an inexpensive and effective method for mineral exploration. After rights have been awarded, prospectors will take targeted samples from a variety of locations using varying techniques. If initial findings are promising, soil sampling may be conducted as well in order to confirm mineral content. If development and resource extraction is feasible, mining could commence providing licenses and permissions from stakeholders and governments are in order.

Exploring the ethical considerations is important when conducting responsible geological fieldwork and sampling, as there is an extensive network of stakeholders and shareholders. The International Association for Promoting Geoethics highlights these complexities, describing in detail the following categories:


 * Engaging stakeholders and showing respect
 * Detailed planning and adhering to regulations
 * Transparency and data sharing
 * Establishing ethical guidelines and promoting education
 * Incorporating geoheritage
 * Formal training and resource development
 * Offering advice and guidance
 * Formal ethical commitments
 * Ethical publication practices
 * Archiving and long-term care
 * Indigenous lands and cultural significance
 * Equitable collaboration
 * Sharing knowledge and teaching ethical techniques
 * Inclusive decision-making

Effective Sampling and Equipment
The following section will outline some of the recommended equipment for successful sediment collection, as well as steps to take to ensure samples are able to be studied with accuracy.

There are there key sampling technologies most frequently used for stream sediment collection, all with their own benefits in different applications. First being suspended-coring samplers, which can be box cores, dredges, or gravity cores, which is ideal in deep, slow-moving water. The second type is a hand-coring sampler, which is most suited for sampling sediments in slow-moving water. The third type is a scoop or a teflon spoon capable of capturing surface sediment that is trapped among rocks and debris in shallow, easily traversable streams.

The following website from the United States Geological Survey provides a detailed outline on the entire process, which can be found here.