A COMPANY headed by SAR executive councillor Leung Chun-ying is one of 30 firms invited to contend for a consultancy study to look at the environmental impact of extra cross-border links. C Y Leung & Company joins Brooke Hillier Parker as the only two property consultants asked by the Planning Department to lodge pre-qualification applications. Twelve of the firms are consulting engineers including Atkins China, Binnie Consultants, Hyder Consulting, Maunsell Consultants Asia, Mouchel Asia and Scott Wilson Kirkpatrick (Hong Kong). The remaining companies are architects such as Denton Corker Marshall Hong Kong and RMJM, environmental firms including ERM Hong Kong and Earthasia and town planning and management consultants. The study will look at environmental, ecological, land acquisition and engineering issues surrounding construction of additional transport links with Guangdong. The Government is particularly concerned about the effect development of the Lingdingyang bridge and Shenzhen Western Corridor will have on air quality in Tuen Mun and Yuen Long, which has deteriorated as a result of expansion. There are fears major health hazards could develop if cross-border traffic is channelled through the northwest New Territories. Cross-border traffic at Lok Ma Chau increased 100 per cent during 1994-96. The Planning Department is also aware that construction of the Shenzhen corridor bridge could cause adverse ecological damage in Deep Bay, part of which is protected wildlife reserve. 'Ecological modelling facilitated with a year-round survey will need to be undertaken to ensure the effects of bridge crossings on the Mai Po Marshes and inner Deep Bay Ramsar [wetland deemed to be of international importance] site are minimised,' the Planning Department said. 'If the bridge option has the potential to cause unacceptable ecological impact, other crossing options should be tested,' it said. The only practical alternative is a tunnel. Firms have to submit applications by July 25.