Vector borne diseases (mosquito management)
Mosquito populations and the types of mosquito-borne diseases vary across WA. Existing habitats such as wetlands can support extensive mosquito populations and can cause serious nuisances to humans who may reside within these areas, as well as increase the chance of people contracting debilitating or potentially life threatening mosquito-borne diseases.
New industrial estates may be proposed in areas that are not suitable for humans to live. Re-contouring the land and installing infrastructure can create new habitats for mosquitoes to breed.
To minimise the risk of mosquito-borne disease and breeding sites, a proponent needs to provide written evidence of the following:
- existing breeding locations within close proximity to the proposed development, and the extent of known mosquito-borne disease risk and nuisance levels from biting insects.
- commitment to develop and implement a mosquito management plan that provides strategies for managing mosquito breeding sites during construction and ongoing operational phases of the development and for minimising the exposure of future occupants to adult mosquitoes.
- commitment to locate, design and maintain any proposed man-made water bodies (e.g. constructed wetlands, vegetated swales and other stormwater infiltration infrastructure) in accordance with the Chironomid midge and mosquito risk assessment guide for constructed water bodies (Midge Research Group, 2007).
Nuisance insects (including stable fly)
Consideration needs to be given to other nuisance insects such as stable fly that may cause health concerns to future workers and occupants.
Stable fly can be a significant public health concern and is generally a problem surrounding rural activities such as agriculture, irrigated horticulture, animal industries, dairies and piggeries.
Consequently, incoming industrial occupants may be exposed to nuisance fly breeding and infestation that can be associated with surrounding activities.
Stable flies are an aggressive, biting, blood sucking fly that attacks livestock, domestic pets and humans in search of a blood meal. The primary host animals are cattle and horses which are normally ‘accessible’ to stable flies in a rural environment. The repeated biting attacks can cause considerable suffering and distress to animals and in some cases, cause death. Whilst this is not strictly a public health issue it can be a significant nuisance to residents and cause suffering and annoyance to livestock and domestic pets.
Stable fly breeding has been known to be a problem in the Shires of Harvey, Gingin, Murray, Serpentine/Jarrahdale, and in areas that have mixed agriculture and horticultural activities.
One of the main sources of breeding has been the use of poultry manure for vegetable production on the Swan Coastal Plain. It is also known that stable flies also breed prolifically in rotting vegetable material, other manures, animal bedding and feed (if left exposed to the elements).
To minimise health risks associated with nuisance insects it is recommended that the proponent undertakes land-use surveys within a 5-10 kilometre radius of the proposed estate to ascertain activities that may pose a risk from nuisance fly breeding, particularly if there are known stable fly problems in the area.
If any such activities are identified then effective management plans should be developed in consultation with the landowners on which the activities occur.
Pest management
All developments are likely to attract pests such as mosquitoes, cockroaches, rats and feral animals, which need to be controlled to prevent health concerns for the surrounding community.
Written evidence should be provided on the intention to develop and implement a pest management plan that appropriately controls pests and minimises any use of pesticides in the control of insect pests, weeds and feral animals where appropriate.
Pesticide use
There are general requirements for pests (weeds, weed pathogens, vermin, vectors, feral animals etc.) control on industrial estates and open areas in residential estates. Appropriate training and licenses are required in accordance with the Health (Pesticides) Regulations 2011 to apply pesticides (insecticides and herbicides)
Written evidence should be provided on the intention to control pests by employing the use of contractors who are appropriately trained and hold a current Pest Management Technician Licence and be employed by a Registered Pest Management Business.
If a proponent wishes their own employees to apply pesticide(s) as part of their Pest Management Program, then the employees should be provided with sufficient knowledge, skills, training and the personal protective equipment to safely apply the pesticide(s). The pesticides available to non- licensed individuals may differ in formulation and strength which should be considered when developing a pest management plan.
Contaminated sites
Industrial estates may be proposed on land that is potentially contaminated from previous or existing land uses. Contamination may be of ground and surface waters and soil, and result from the release of hazardous substances associated with industrial and commercial activities, poor asbestos removal practices or dumping, or the distribution of acid sulphate soils.
If a site is suspected of or known to be contaminated it will need to be reported to the Department of Water and Environmental Regulation in accordance with the Contaminated Sites Act 2003.
The Department of Water and Environmental Regulation will assess and classify the site if necessary, which may trigger a formal process of site investigation and/or clean-up. The aim of this work is to ensure that any contamination does not present an unacceptable risk to the environment or to people.
Acid sulfate soils
Acid sulfate soils (ASS) are naturally occurring soils and sediments containing iron sulfides, most commonly pyrite.
When ASS is exposed to air the iron sulfides in the soil react with oxygen and water to produce a variety of iron compounds and sulfuric acid. Initially a chemical reaction, the process is accelerated by soil bacteria. The resulting acid can release other substances, including heavy metals, from the soil into the surrounding environment.
The production of hydrogen sulphide gas from ASS is also a concern for public health.
Further queries on contaminated sites and ASS should be directed to the Department of Water and Environmental Regulation Contaminated Sites Branch, who will request Department of Health advice on human health issues and public risk related to contaminated sites and ASS as required.