In order for Yokohama Rubber to confirm the effect onbiodiversity through our business activities, we havestarted preliminary exploration in the surrounding areasof our offices. Here, we would like to introduce the casestudy of the area surrounding our Mie Plant, in Japan, conducted from April to June in 2011.
Yokohama Rubber's Various Efforts Addressing the Preservation of Biodiversity
Our business activities will surely have various impacts on the biodiversity in our local communities, including utilization of biological resources primarily for natural rubber, metal and mineral resources, and so on, also, water withdrawal and discharge, etc., at our production sites. Based on this recognition, in the light of long-term global perspectives and in order to preserve biodiversity within the range of our company's impacts, we set out Yokohama Rubber's Guidelines on Biodiversity in the fiscal year of 2010. From the same year, we started our preliminary exploration in the areas surrounding our offices for 15 production sites in Japan and another 15 overseas. After confirming the natural abundance surrounding each office, we can select an office located to a great abundance of nature. After the round of selection process, we will study the impact on biodiversity in the surrounding area, make our objectives clear, identify what kind of preservation activities are feasible, and go about further studies of the actual sites to set out our exact schemes.
Relationship between our Mie Plant and Biodiversity
Midstream of Hinokijiri River
What we have discovered through our preliminary exploration in June 2010 was that so many of our plants turned out to be the beneficiaries of an ever so rich ecosystem called Water from the Valley. Especially, since our Mie plant is located adjacent to Miyagawa Valley, which has one of the clearest streams in entire Japan, we came to know that our Mie plant had a lot to do with the biodiversity there, which is generating water circulation of Miyagawa Valley (blessings from the ecosystem). This is the reason we have decided to start from our Mie Plant with our environmental studies.
The Miyagawa River cascading around the Mie Plant is the biggest river in Mie Prefecture. It runs through Odaigahara to Ise Bay; the entire length is approximately 90 km and its basin area is about 920 km². Our Mie Plant is withdrawing groundwater from Miyagawa Valley and discharging it into Hinokijiri River, which is the subsidiary stream of Seta River.
The sewage system for the residential areas near Hinokijiri River is notcompletely established yet; we have noticed that there were some outlet conduits of organic sewage directly discharged into the river. This is the reason why in the daytime of sunny days we saw a number of oil films floating on the surface of the river, which makes the water looked cloudy and white.
Henceforth our Mie Plant has established oil filtering equipment in theirindustrial sewage treatment facility. After making sure there is no oil through the oil filtering sensor; about 350 tons of water per hour per day is discharged into the upstream of Hinokijiri River with water quality as 1.1mg/ℓ on the average for BOD. In the event such water discharge were to stop, the density of organic sewage from households would rise and deprive the upstream of Hinokijiri River of oxygen; this explains how our Mie Plant's water discharge is contributing to the preservation of quality water.
Japanese Killifish habitant in Hinokijiri River (midstream of Hinokijiri River)
Now, by understanding the relationship between water discharge and Hinokijiri River, plus inhabitation of biota and rare species in Miyagawa River as the riverhead area, we have proceeded with Biota Studies in Miyagawa River in order to explore any future possibilities for the activities to safely preserve Miyagawa Valley and some other activities to preserve rare species under the cooperation of local environmental NPOs as well as the Agencies for Education and Research.
The Result of Biota Studies in Miyagawa River
Our Exploration on Aquatic Organisms in Miyagawa River Area
During our studies conducted in June 2011, due to Typhoon No. 2 approaching at the end of May, massive floods occurred and raised its river water level. Even though we were unable to dig up inside the river stream, we were able to understand the overall condition of biota therein instead.
In Hinokijiri River, we were able to observe the habitat of young killifish and mullet, plus Southern Atyidae in the upstream and midstream. We have measured EC (Electrical Conductivity) and COD (Chemical Oxygen Demand); and both upstream and midstream read 91 μS/cm (micro siemens per centimeter: a unit to express electrical conductivity). As for COD, it read 2.9 mg/ℓ for upstream, 2.4 mg/ℓ for downstream; whereas BOD showed 1.6 mg/ℓ for upstream and 1.1 mg/ℓ for downstream. Generally for the river, less than 2 mg/ℓ as BOD is equivalent to the water quality standard as Fishery Class 1, where the fish like trout, etc. can inhabit it. Also, EC under 100 μS/cm is considered as low contamination rate. For the studies in June, due to potential dilution of contaminated water comes from the raised water level owing to typhoons and heavy rain, we are planning to conduct the same nature of studies in August one more time.
For studies on the mainstream of Miyagawa River, we have conducted the exploration of plants, birds, and benthic fauna, in midstream, downstream, river outlet, and bay areas. Midstream area is surrounded by series of River beach, straits, and brink; forest is still remaining nicely beside the river bank terrace on. You may wish to refer to the table compiled of the plants, birds, benthic fauna confirmed through our studies in June; we came to know that each location is still blessed with richly diversified species inhabiting it.
Our Exploration on Aquatic Organisms in Miyagawa River Area
| Clusters | Plants | Birds | Benthic fauna | |
|---|---|---|---|---|
| Midstream area | Reed Vine cluster and River Tansy cluster | Reed Vine, River tansy, Polyantha, Butterweed, Mematsuyoi Weed, Deutzia, and so on | Grey Heron, Common Sandpiper, Black Kite, Japanese Wagtail, Oriental Greenfinch, and Carrion Crow | Long-Barbed River Caddice-Worm, Young White Valley River Dayfly, Young Dabido Sanae, Young White-Tailed Sanae, Young Psephenidae, and Southern Atyidae
|
| Downstream area | Reed Vine cluster, Ogi cluster, and Futoi cluster | Reed Vine, Ogi, Futoi, Water Pepper, and so on | Grey Heron, Little Egret, Grey-headed Lapwing, Common Cormorant, Little Ringed plover, House Swallow, and Siberian Meadow Bunting | Ooaoito, Young Dragonfly, and Young Noshime Dragonfly |
| River outlet (mud flat) |
Yoshi cluster and Fukudo cluster
|
Yoshi, Yoshi Vine, Fukudo, Sea Bells, Beach Peas, Beach Radish, Beach Saji, Onishiba with Long Coat, and so on | Large Egret, Grey Heron, Common Cormorant, Spotbilled Duck, and Great Read Warbler | Ashihara Crab and Black Benkei Crab
|
| Bay area (sand beach) |
Sea Bells cluster, Kobo Wheat cluster, Cogon cluster | Sea Bells, Kobo Wheat, Cogon, Komatsu Yoigusa, and so on | Black Kite, Fan-tailed Warbler, Skylark, and Siberian Meadow Bunting |
Also, we have conducted hearings from the residents of local communities in Hinokijiri River area. We had distributed questionnaire forms to ten individuals residing in the area of Hinokijiri River as to the impression of Hinokijiri River, the situation in the past, and any requests in the future, followed by our visits to hear from them in person.
The result showed that the majority of them had responded they think the current Hinokijiri River is dirty. As for Hinokijiri River until 35 years ago, it used to be rich in flora and fauna such as the golden-ringed dragonfly, black-spotted pond frogs, and Japanese firefly; but it started to be contaminated since about 25 years ago. As for the requests for Hinokijiri River, respondents expressed such comments as "I wish all the sludge in it will be removed", "I wish the river will be restored to transparency again", "I wish the river will become a place for our children to play", "I wish the
river can be a place for our physical and mental healing", and so on.
The Roadmap for our Future Exploration
In the fiscal year of 2011, we are planning to conduct our exploration mainly in Miyagawa River and Hinokijiri River both in summer and autumn.
As for Hinokijiri River, we shall explore the possibilities for the preservation of water quality and aquatic organisms by understanding the water quality of drainage destination and the condition of biota. As for Miyagawa River, we will continue to study on the biota in midstream, downstream, river outlet, and bay areas to consider our approach methods and so on as to how to preserve biota therefrom.
We are planning to conduct such exploration in two of our overseas offices in the fiscal year of 2012. It is our sincere desire to proceed proactively with such exploration work in order to build a trusted identity as a contributing member of the global community.